IOS常用代碼總結(二)

轉自：http://www.lxweimin.com/p/10b2323f502e

1、禁止手機睡眠

[UIApplication sharedApplication].idleTimerDisabled = YES;

2、隱藏某行cell

(CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath

{

// 如果是你需要隱藏的那一行，返回高度為0
if(indexPath.row == YouWantToHideRow)

    return 0;

return 44;
}

// 然后再你需要隱藏cell的時候調用

[self.tableView beginUpdates];

[self.tableView endUpdates];

3、禁用button高亮

button.adjustsImageWhenHighlighted = NO;

或者在創建的時候

UIButton *button = [UIButton buttonWithType:UIButtonTypeCustom];

4、tableview遇到這種報錯failed to obtain a cell from its dataSource

是因為你的cell被調用的早了。先循環使用了cell，后又創建cell。順序錯了

可能原因：1、xib的cell沒有注冊 2、內存中已經有這個cell的緩存了(也就是說通過你的cellId找到的cell并不是你想要的類型)，這時候需要改下cell的標識

5、cocoa pods報這個錯誤：unable to access 'https://github.com/facebook/pop.git/': Operation timed out after 0 milliseconds with 0 out of 0 bytes received

解決辦法：原因可能是網絡問題，網絡請求超時了，只需要重試就行了

6、cocoa pods 出現ERROR: While executing gem ... (Errno::EPERM)

解決辦法：

https://segmentfault.com/q/1010000002926243

7、動畫切換window的根控制器

// options是動畫選項

[UIView transitionWithView:[UIApplication sharedApplication].keyWindow duration:0.5f options:UIViewAnimationOptionTransitionCrossDissolve animations:^{
    BOOL oldState = [UIView areAnimationsEnabled];

    [UIView setAnimationsEnabled:NO];

    [UIApplication sharedApplication].keyWindow.rootViewController = [RootViewController new];

    [UIView setAnimationsEnabled:oldState];

} completion:^(BOOL finished) {
}];

8、去除數組中重復的對象

NSArray *newArr = [oldArr valueForKeyPath:@“@distinctUnionOfObjects.self"];

9、編譯的時候遇到no such file or directory: ／users／apple／XXX

是因為編譯的時候，在此路徑下找不到這個文件，解決這個問題，首先是是要檢查缺少的文件是不是在工程中，如果不在工程中，需要從本地拖進去，如果發現已經存在工程中了，或者拖進去還是報錯，這時候需要去build phases中搜索這個文件，這時候很可能會搜出現兩個相同的文件，這時候，有一個路徑是正確的，刪除另外一個即可。如果刪除了還是不行，需要把兩個都刪掉，然后重新往工程里拖進這個文件即可

[圖片上傳失敗...(image-d3f000-1528096993264)]

10、iOS8系統中，tableView最好實現下-tableView: heightForRowAtIndexPath:這個代理方法，要不然在iOS8中可能就會出現顯示不全或者無法響應事件的問題

11、iOS8中實現側滑功能的時候這個方法必須實現，要不然在iOS8中無法側滑

// 必須寫的方法，和editActionsForRowAtIndexPath配對使用，里面什么不寫也行

(void)tableView:(UITableView *)tableView commitEditingStyle:(UITableViewCellEditingStyle)editingStyle forRowAtIndexPath:(NSIndexPath *)indexPath {

}

12、三個通知

NSSystemTimeZoneDidChangeNotification監聽修改時間界面的兩個按鈕狀態變化

UIApplicationSignificantTimeChangeNotification 監聽用戶改變時間（只要點擊自動設置按鈕就會調用） NSSystemClockDidChangeNotification 監聽用戶修改時間（時間不同才會調用）

13、SDWebImage本地緩存有時候會害人。如果之前緩存過一張圖片，即使下次服務器換了這張圖片，但是圖片url沒換，用sdwebimage下載下來的還是以前那張,所以遇到這種問題，不要先去懟服務器，清空下緩存再試就好了。

14、上線前注意：

1）、刪掉代碼中所有的測試代碼

2）、如果后臺有審核模式，提醒后臺開啟此模式

3）、主流程再跑一跑

4）、全局搜索waring，檢查所有標記waring的地方

15、跳進app權限設置

// 跳進app設置

        if (UIApplicationOpenSettingsURLString != NULL) {

            UIApplication *application = [UIApplication sharedApplication];

            NSURL *URL = [NSURL URLWithString:UIApplicationOpenSettingsURLString];

            if ([application respondsToSelector:@selector(openURL:options:completionHandler:)]) {

                [application openURL:URL options:@{}

                   completionHandler:nil];

            } else {

                [application openURL:URL];

            }

}

16、給一個view截圖

UIGraphicsBeginImageContextWithOptions(view.bounds.size, YES, 0.0);
[view.layer renderInContext:UIGraphicsGetCurrentContext()];

UIImage *img = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();

17、開發中如果要動態修改tableView的tableHeaderView或者tableFooterView的高度，需要給tableView重新設置，而不是直接更改高度。正確的做法是重新設置一下tableView.tableFooterView = 更改過高度的view。為什么？其實在iOS8以上直接改高度是沒有問題的，在iOS8中出現了contentSize不準確的問題，這是解決辦法。

18、注意對象為nil的時候，調用此對象分類的方法不會執行

19、collectionView的內容小于其寬高的時候是不能滾動的，設置可以滾動：

collectionView.alwaysBounceHorizontal = YES;

collectionView.alwaysBounceVertical = YES;

20、設置navigationBar上的title顏色和大小

[self.navigationController.navigationBar setTitleTextAttributes:@{NSForegroundColorAttributeName : [UIColor youColor], NSFontAttributeName : [UIFont systemFontOfSize:15]}]

21、顏色轉圖片

+ (UIImage )cl_imageWithColor:(UIColor )color {

CGRect rect = CGRectMake(0.0f, 0.0f, 1.0f, 1.0f);

UIGraphicsBeginImageContext(rect.size);

CGContextRef context = UIGraphicsGetCurrentContext();

CGContextSetFillColorWithColor(context, [color CGColor]);

CGContextFillRect(context, rect);

UIImage *image = UIGraphicsGetImageFromCurrentImageContext();

UIGraphicsEndImageContext();

return image;

}

22、view設置圓角

define ViewBorderRadius(View, Radius, Width, Color)\

[View.layer setCornerRadius:(Radius)];\

[View.layer setMasksToBounds:YES];\

[View.layer setBorderWidth:(Width)];\

[View.layer setBorderColor:[Color CGColor]] // view圓角

23、強／弱引用

define WeakSelf(type) __weak typeof(type) weak##type = type; // weak

define StrongSelf(type) __strong typeof(type) type = weak##type; // strong

24、由角度轉換弧度

define DegreesToRadian(x) (M_PI * (x) / 180.0)

25、由弧度轉換角度

define RadianToDegrees(radian) (radian*180.0)/(M_PI)

26、獲取圖片資源

define GetImage(imageName) [UIImage imageNamed:[NSString stringWithFormat:@"%@",imageName]]

27、獲取temp

define PathTemp NSTemporaryDirectory()

28、獲取沙盒 Document

define PathDocument [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) firstObject]

29、獲取沙盒 Cache

define PathCache [NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, YES) firstObject]

30、GCD代碼只執行一次

define kDISPATCH_ONCE_BLOCK(onceBlock) static dispatch_once_t onceToken; dispatch_once(&onceToken, onceBlock);

31、自定義NSLog

ifdef DEBUG

define NSLog(fmt, ...) NSLog((@"%s [Line %d] " fmt), PRETTY_FUNCTION, LINE, ##VA_ARGS)

else

define NSLog(...)

endif

32、Font

define FontL(s) [UIFont systemFontOfSize:s weight:UIFontWeightLight]

define FontR(s) [UIFont systemFontOfSize:s weight:UIFontWeightRegular]

define FontB(s) [UIFont systemFontOfSize:s weight:UIFontWeightBold]

define FontT(s) [UIFont systemFontOfSize:s weight:UIFontWeightThin]

define Font(s) FontL(s)

33、FORMAT

define FORMAT(f, ...) [NSString stringWithFormat:f, ## VA_ARGS]

34、在主線程上運行

define kDISPATCH_MAIN_THREAD(mainQueueBlock) dispatch_async(dispatch_get_main_queue(), mainQueueBlock);

35、開啟異步線程

define kDISPATCH_GLOBAL_QUEUE_DEFAULT(globalQueueBlock) dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), globalQueueBlocl);

36、通知

define NOTIF_ADD(n, f) [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(f) name:n object:nil]

define NOTIF_POST(n, o) [[NSNotificationCenter defaultCenter] postNotificationName:n object:o]

define NOTIF_REMV() [[NSNotificationCenter defaultCenter] removeObserver:self]

37、隨機顏色

(UIColor *)RandomColor {

NSInteger aRedValue = arc4random() % 255;

NSInteger aGreenValue = arc4random() % 255;

NSInteger aBlueValue = arc4random() % 255;

UIColor *randColor = [UIColor colorWithRed:aRedValue / 255.0f green:aGreenValue / 255.0f blue:aBlueValue / 255.0f alpha:1.0f];

return randColor;

}

38、獲取window

+(UIWindow*)getWindow {

UIWindow* win = nil; //[UIApplication sharedApplication].keyWindow;

for (id item in [UIApplication sharedApplication].windows) {

    if ([item class] == [UIWindow class]) {

        if (!((UIWindow*)item).hidden) {

            win = item;

            break;

        }

    }

}

return win;

}

39、修改textField的placeholder的字體顏色、大小

[textField setValue:[UIColor redColor] forKeyPath:@"_placeholderLabel.textColor"];

[textField setValue:[UIFont boldSystemFontOfSize:16] forKeyPath:@"_placeholderLabel.font"];

40、統一收起鍵盤

[[[UIApplication sharedApplication] keyWindow] endEditing:YES];

41、控制屏幕旋轉，在控制器中寫

/** 是否支持自動轉屏 */

(BOOL)shouldAutorotate {

return YES;

}

/** 支持哪些屏幕方向 */

(UIInterfaceOrientationMask)supportedInterfaceOrientations {

return UIInterfaceOrientationMaskLandscapeLeft | UIInterfaceOrientationMaskLandscapeRight;

}

/** 默認的屏幕方向（當前ViewController必須是通過模態出來的UIViewController（模態帶導航的無效）方式展現出來的，才會調用這個方法） */

(UIInterfaceOrientation)preferredInterfaceOrientationForPresentation {

return UIInterfaceOrientationLandscapeLeft | UIInterfaceOrientationLandscapeRight;

}

42、獲取app緩存大小

(CGFloat)getCachSize {

NSUInteger imageCacheSize = [[SDImageCache sharedImageCache] getSize];

//獲取自定義緩存大小

//用枚舉器遍歷一個文件夾的內容

//1.獲取文件夾枚舉器

NSString *myCachePath = [NSHomeDirectory() stringByAppendingPathComponent:@"Library/Caches"];

NSDirectoryEnumerator *enumerator = [[NSFileManager defaultManager] enumeratorAtPath:myCachePath];

__block NSUInteger count = 0;

//2.遍歷

for (NSString *fileName in enumerator) {
  NSString *path = [myCachePath stringByAppendingPathComponent:fileName];

  NSDictionary *fileDict = [[NSFileManager defaultManager] attributesOfItemAtPath:path error:nil];

  count += fileDict.fileSize;//自定義所有緩存大小
}

// 得到是字節轉化為M

CGFloat totalSize = ((CGFloat)imageCacheSize+count)/1024/1024;

return totalSize;
}

43、清理app緩存

(void)handleClearView {

//刪除兩部分

//1.刪除 sd 圖片緩存

//先清除內存中的圖片緩存

[[SDImageCache sharedImageCache] clearMemory];

//清除磁盤的緩存

[[SDImageCache sharedImageCache] clearDisk];

//2.刪除自己緩存

NSString *myCachePath = [NSHomeDirectory() stringByAppendingPathComponent:@"Library/Caches"];

[[NSFileManager defaultManager] removeItemAtPath:myCachePath error:nil];

}

44、模型轉字典

static NSSet *classes;

(NSMutableDictionary *)getParameterDictionary {

NSMutableDictionary *dict = [NSMutableDictionary dictionary];

Class c = self.class;

while (c) {

  unsigned count;

  objc_property_t *properties = class_copyPropertyList([c class], &count);

  for (int i = 0; i < count; i++) {

      NSString *key = [NSString stringWithUTF8String:property_getName(properties[i])];

      dict[key] = [self valueForKey:key];

  }

  free(properties);

  // 獲得父類

  c = class_getSuperclass(c);

  if ([self isClassFromFoundation:c]) break;

}

return dict;

}

(BOOL)isClassFromFoundation:(Class)c

{

if (c == [NSObject class] || c == [NSManagedObject class]) return YES;

__block BOOL result = NO;

[[self foundationClasses] enumerateObjectsUsingBlock:^(Class foundationClass, BOOL *stop) {

    if ([c isSubclassOfClass:foundationClass]) {

        result = YES;

        *stop = YES;

    }

}];

return result;

}

(NSSet *)foundationClasses

{

if (classes == nil) {

    // 集合中沒有NSObject，因為幾乎所有的類都是繼承自NSObject，具體是不是NSObject需要特殊判斷

    classes = [NSSet setWithObjects:

                          [NSURL class],

                          [NSDate class],

                          [NSValue class],

                          [NSData class],

                          [NSError class],

                          [NSArray class],

                          [NSDictionary class],

                          [NSString class],

                          [NSAttributedString class], nil];

}

return classes;

}

45、交換兩個方法實現

Class aClass = [self class];

    SEL originalSelector = @selector(viewWillAppear:);

    SEL swizzledSelector = @selector(xxx_viewWillAppear:);

    Method originalMethod = class_getInstanceMethod(aClass, originalSelector);

    Method swizzledMethod = class_getInstanceMethod(aClass, swizzledSelector);

    BOOL didAddMethod =

        class_addMethod(aClass,

            originalSelector,

            method_getImplementation(swizzledMethod),

            method_getTypeEncoding(swizzledMethod));

    if (didAddMethod) {

        class_replaceMethod(aClass,

            swizzledSelector,

            method_getImplementation(originalMethod),

            method_getTypeEncoding(originalMethod));

    } else {

        method_exchangeImplementations(originalMethod, swizzledMethod);

}

46、打印百分號和引號

NSLog(@"%%");

NSLog(@""");

47、幾個常用權限判斷

if ([CLLocationManager authorizationStatus] ==kCLAuthorizationStatusDenied) {

    NSLog(@"沒有定位權限");

}

AVAuthorizationStatus statusVideo = [AVCaptureDevice authorizationStatusForMediaType:AVMediaTypeVideo];

if (statusVideo == AVAuthorizationStatusDenied) {

    NSLog(@"沒有攝像頭權限");

}

//是否有麥克風權限

AVAuthorizationStatus statusAudio = [AVCaptureDevice authorizationStatusForMediaType:AVMediaTypeAudio];

if (statusAudio == AVAuthorizationStatusDenied) {

    NSLog(@"沒有錄音權限");

}

[PHPhotoLibrary requestAuthorization:^(PHAuthorizationStatus status) {

    if (status == PHAuthorizationStatusDenied) {

        NSLog(@"沒有相冊權限");

    }

}];

48、獲取手機型號

(NSString *)getDeviceInfo {

struct utsname systemInfo;

uname(&systemInfo);

NSString *platform = [NSString stringWithCString:systemInfo.machine encoding:NSASCIIStringEncoding];

if ([platform isEqualToString:@"iPhone1,1"]) return @"iPhone 2G";

if ([platform isEqualToString:@"iPhone1,2"]) return @"iPhone 3G";

if ([platform isEqualToString:@"iPhone2,1"]) return @"iPhone 3GS";

if ([platform isEqualToString:@"iPhone3,1"]) return @"iPhone 4";

if ([platform isEqualToString:@"iPhone3,2"]) return @"iPhone 4";

if ([platform isEqualToString:@"iPhone3,3"]) return @"iPhone 4";

if ([platform isEqualToString:@"iPhone4,1"]) return @"iPhone 4S";

if ([platform isEqualToString:@"iPhone5,1"]) return @"iPhone 5";

if ([platform isEqualToString:@"iPhone5,2"]) return @"iPhone 5";

if ([platform isEqualToString:@"iPhone5,3"]) return @"iPhone 5c";

if ([platform isEqualToString:@"iPhone5,4"]) return @"iPhone 5c";

if ([platform isEqualToString:@"iPhone6,1"]) return @"iPhone 5s";

if ([platform isEqualToString:@"iPhone6,2"]) return @"iPhone 5s";

if ([platform isEqualToString:@"iPhone7,1"]) return @"iPhone 6 Plus";

if ([platform isEqualToString:@"iPhone7,2"]) return @"iPhone 6";

if ([platform isEqualToString:@"iPhone8,1"]) return @"iPhone 6s";

if ([platform isEqualToString:@"iPhone8,2"]) return @"iPhone 6s Plus";

// 日行兩款手機型號均為日本獨占，可能使用索尼FeliCa支付方案而不是蘋果支付

if ([platform isEqualToString:@"iPhone9,1"]) return @"國行、日版、港行iPhone 7";

if ([platform isEqualToString:@"iPhone9,2"]) return @"港行、國行iPhone 7 Plus";

if ([platform isEqualToString:@"iPhone9,3"]) return @"美版、臺版iPhone 7";

if ([platform isEqualToString:@"iPhone9,4"]) return @"美版、臺版iPhone 7 Plus";

if ([platform isEqualToString:@"iPhone8,4"]) return @"iPhone SE";

if ([platform isEqualToString:@"iPod1,1"]) return @"iPod Touch 1G";

if ([platform isEqualToString:@"iPod2,1"]) return @"iPod Touch 2G";

if ([platform isEqualToString:@"iPod3,1"]) return @"iPod Touch 3G";

if ([platform isEqualToString:@"iPod4,1"]) return @"iPod Touch 4G";

if ([platform isEqualToString:@"iPod5,1"]) return @"iPod Touch 5G";

if ([platform isEqualToString:@"iPad1,1"]) return @"iPad 1G";

if ([platform isEqualToString:@"iPad2,1"]) return @"iPad 2";

if ([platform isEqualToString:@"iPad2,2"]) return @"iPad 2";

if ([platform isEqualToString:@"iPad2,3"]) return @"iPad 2";

if ([platform isEqualToString:@"iPad2,4"]) return @"iPad 2";

if ([platform isEqualToString:@"iPad2,5"]) return @"iPad Mini 1G";

if ([platform isEqualToString:@"iPad2,6"]) return @"iPad Mini 1G";

if ([platform isEqualToString:@"iPad2,7"]) return @"iPad Mini 1G";

if ([platform isEqualToString:@"iPad3,1"]) return @"iPad 3";

if ([platform isEqualToString:@"iPad3,2"]) return @"iPad 3";

if ([platform isEqualToString:@"iPad3,3"]) return @"iPad 3";

if ([platform isEqualToString:@"iPad3,4"]) return @"iPad 4";

if ([platform isEqualToString:@"iPad3,5"]) return @"iPad 4";

if ([platform isEqualToString:@"iPad3,6"]) return @"iPad 4";

if ([platform isEqualToString:@"iPad4,1"]) return @"iPad Air";

if ([platform isEqualToString:@"iPad4,2"]) return @"iPad Air";

if ([platform isEqualToString:@"iPad4,3"]) return @"iPad Air";

if ([platform isEqualToString:@"iPad4,4"]) return @"iPad Mini 2G";

if ([platform isEqualToString:@"iPad4,5"]) return @"iPad Mini 2G";

if ([platform isEqualToString:@"iPad4,6"]) return @"iPad Mini 2G";

if ([platform isEqualToString:@"i386"]) return @"iPhone Simulator";

if ([platform isEqualToString:@"x86_64"]) return @"iPhone Simulator";

return platform;

}

49、長按復制功能

(void)viewDidLoad

{
[self.view addGestureRecognizer:[[UILongPressGestureRecognizer alloc] initWithTarget:self action:@selector(pasteBoard:)]];
}
(void)pasteBoard:(UILongPressGestureRecognizer *)longPress {

if (longPress.state == UIGestureRecognizerStateBegan) {
  UIPasteboard *pasteboard = [UIPasteboard generalPasteboard];

  pasteboard.string = @"需要復制的文本";
}
}

50、cocoapods升級

在終端執行 sudo gem install -n / usr / local / bin cocoapods --pre

51、設置啟動頁后，依然顯示之前的

刪除app，手機重啟，重新安裝

52、判斷圖片類型

//通過圖片Data數據第一個字節來獲取圖片擴展名

(NSString *)contentTypeForImageData:(NSData *)data

{

uint8_t c;

[data getBytes:&c length:1];

switch (c)

{

    case 0xFF:

        return @"jpeg";

    case 0x89:

        return @"png";

    case 0x47:

        return @"gif";

    case 0x49:

    case 0x4D:

        return @"tiff";

    case 0x52:

    if ([data length] < 12) {

        return nil;

    }

    NSString *testString = [[NSString alloc] initWithData:[data subdataWithRange:NSMakeRange(0, 12)] encoding:NSASCIIStringEncoding];

    if ([testString hasPrefix:@"RIFF"]

        && [testString hasSuffix:@"WEBP"])

    {

        return @"webp";

    }

    return nil;

}

return nil;

}

53、獲取手機和app信息

NSDictionary *infoDictionary = [[NSBundle mainBundle] infoDictionary];

CFShow(infoDictionary);

// app名稱

NSString *app_Name = [infoDictionary objectForKey:@"CFBundleDisplayName"];

// app版本

NSString *app_Version = [infoDictionary objectForKey:@"CFBundleShortVersionString"];

// app build版本

NSString *app_build = [infoDictionary objectForKey:@"CFBundleVersion"];

//手機序列號 

NSString* identifierNumber = [[UIDevice currentDevice] uniqueIdentifier]; 

NSLog(@"手機序列號: %@",identifierNumber); 

//手機別名： 用戶定義的名稱 

NSString* userPhoneName = [[UIDevice currentDevice] name]; 

NSLog(@"手機別名: %@", userPhoneName); 

//設備名稱 

NSString* deviceName = [[UIDevice currentDevice] systemName]; 

NSLog(@"設備名稱: %@",deviceName ); 

//手機系統版本 

NSString* phoneVersion = [[UIDevice currentDevice] systemVersion]; 

NSLog(@"手機系統版本: %@", phoneVersion); 

//手機型號 

NSString* phoneModel = [[UIDevice currentDevice] model]; 

NSLog(@"手機型號: %@",phoneModel ); 

//地方型號  （國際化區域名稱） 

NSString* localPhoneModel = [[UIDevice currentDevice] localizedModel]; 

NSLog(@"國際化區域名稱: %@",localPhoneModel ); 

NSDictionary *infoDictionary = [[NSBundle mainBundle] infoDictionary]; 

// 當前應用名稱 

NSString *appCurName = [infoDictionary objectForKey:@"CFBundleDisplayName"]; 

NSLog(@"當前應用名稱：%@",appCurName); 

// 當前應用軟件版本  比如：1.0.1 

NSString *appCurVersion = [infoDictionary objectForKey:@"CFBundleShortVersionString"]; 

NSLog(@"當前應用軟件版本:%@",appCurVersion); 

// 當前應用版本號碼   int類型 

NSString *appCurVersionNum = [infoDictionary objectForKey:@"CFBundleVersion"];

NSLog(@"當前應用版本號碼：%@",appCurVersionNum);

54、獲取一個類的所有屬性

id LenderClass = objc_getClass("Lender");

unsigned int outCount, I;

objc_property_t *properties = class_copyPropertyList(LenderClass, &outCount);

for (i = 0; i < outCount; i++) {
objc_property_t property = properties[I];

fprintf(stdout, "%s %s\n", property_getName(property), property_getAttributes(property));
}

55、image圓角

(UIImage *)circleImage

{

// NO代表透明

UIGraphicsBeginImageContextWithOptions(self.size, NO, 1);

// 獲得上下文

CGContextRef ctx = UIGraphicsGetCurrentContext();

// 添加一個圓

CGRect rect = CGRectMake(0, 0, self.size.width, self.size.height);

// 方形變圓形

CGContextAddEllipseInRect(ctx, rect);

// 裁剪

CGContextClip(ctx);

// 將圖片畫上去

[self drawInRect:rect];

UIImage *image = UIGraphicsGetImageFromCurrentImageContext();

UIGraphicsEndImageContext();

return image;

}

56、image拉伸

(UIImage *)resizableImage:(NSString *)imageName

{

UIImage *image = [UIImage imageNamed:imageName];

CGFloat imageW = image.size.width;

CGFloat imageH = image.size.height;

return [image resizableImageWithCapInsets:UIEdgeInsetsMake(imageH * 0.5, imageW * 0.5, imageH * 0.5, imageW * 0.5) resizingMode:UIImageResizingModeStretch];

}

57、JSON字符串轉字典

(NSDictionary *)parseJSONStringToNSDictionary:(NSString *)JSONString {

NSData *JSONData = [JSONString dataUsingEncoding:NSUTF8StringEncoding];

NSDictionary *responseJSON = [NSJSONSerialization JSONObjectWithData:JSONData options:NSJSONReadingMutableLeaves error:nil];

return responseJSON;

}

58、身份證號驗證

(BOOL)validateIdentityCard {

BOOL flag;

if (self.length <= 0) {
  flag = NO;

  return flag;
}

NSString *regex2 = @"^(\d{14}|\d{17})(\d|[xX])$";

NSPredicate *identityCardPredicate = [NSPredicate predicateWithFormat:@"SELF MATCHES %@",regex2];

return [identityCardPredicate evaluateWithObject:self];
}

59、獲取設備mac地址

(NSString *)macAddress {

int mib[6];

size_t len;

char *buf;

unsigned char *ptr;

struct if_msghdr *ifm;

struct sockaddr_dl *sdl;

mib[0] = CTL_NET;

mib[1] = AF_ROUTE;

mib[2] = 0;

mib[3] = AF_LINK;

mib[4] = NET_RT_IFLIST;

if((mib[5] = if_nametoindex("en0")) == 0) {
  printf("Error: if_nametoindex error\n");

  return NULL;
}

if(sysctl(mib, 6, NULL, &len, NULL, 0) < 0) {
  printf("Error: sysctl, take 1\n");

  return NULL;
}

if((buf = malloc(len)) == NULL) {
  printf("Could not allocate memory. Rrror!\n");

  return NULL;
}

if(sysctl(mib, 6, buf, &len, NULL, 0) < 0) {
  printf("Error: sysctl, take 2");

  return NULL;
}

ifm = (struct if_msghdr *)buf;

sdl = (struct sockaddr_dl *)(ifm + 1);

ptr = (unsigned char *)LLADDR(sdl);

NSString *outstring = [NSString stringWithFormat:@"%02X:%02X:%02X:%02X:%02X:%02X",
                     *ptr, *(ptr+1), *(ptr+2), *(ptr+3), *(ptr+4), *(ptr+5)];
free(buf);

return outstring;
}

60、導入自定義字體庫

1、找到你想用的字體的 ttf 格式，拖入工程

2、在工程的plist中增加一行數組，“Fonts provided by application”

3、為這個key添加一個item，value為你剛才導入的ttf文件名

4、直接使用即可：label.font = [UIFont fontWithName:@"你剛才導入的ttf文件名" size:20.0]；

61、拿到當前正在顯示的控制器，不管是push進去的，還是present進去的都能拿到
(UIViewController )getVisibleViewControllerFrom:(UIViewController)vc {

if ([vc isKindOfClass:[UINavigationController class]]) {
  return [self getVisibleViewControllerFrom:[((UINavigationController*) vc) visibleViewController]];
}else if ([vc isKindOfClass:[UITabBarController class]]){
  return [self getVisibleViewControllerFrom:[((UITabBarController*) vc) selectedViewController]];
} else {
  if (vc.presentedViewController) {

      return [self getVisibleViewControllerFrom:vc.presentedViewController];

  } else {

      return vc;

  }
}
}

62、runtime為一個類動態添加屬性

// 動態添加屬性的本質是: 讓對象的某個屬性與值產生關聯

objc_setAssociatedObject(self, WZBPlaceholderViewKey, placeholderView, OBJC_ASSOCIATION_RETAIN_NONATOMIC);

63、獲取runtime為一個類動態添加的屬性

objc_getAssociatedObject(self, WZBPlaceholderViewKey);

64、KVO監聽某個對象的屬性

// 添加監聽者

[self addObserver:self forKeyPath:property options:NSKeyValueObservingOptionNew context:nil];

// 當監聽的屬性值變化的時候會來到這個方法
(void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary *)change context:(void *)context {

if ([keyPath isEqualToString:@"property"]) {
 [self textViewTextChange];

 } else {
}
}

65、Reachability判斷網絡狀態

NetworkStatus status = [[Reachability reachabilityForInternetConnection] currentReachabilityStatus];
if (status == NotReachable) {

    NSLog(@"當前設備無網絡");

}

if (status == ReachableViaWiFi) {

    NSLog(@"當前wifi網絡");

}

if (status == ReachableViaWWAN) {

    NSLog(@"當前蜂窩移動網絡");
}

66、AFNetworking監聽網絡狀態

// 監聽網絡狀況

AFNetworkReachabilityManager *mgr = [AFNetworkReachabilityManager sharedManager];

[mgr setReachabilityStatusChangeBlock:^(AFNetworkReachabilityStatus status) {

    switch (status) {

        case AFNetworkReachabilityStatusUnknown:

            break;

        case AFNetworkReachabilityStatusNotReachable: {

            [SVProgressHUD showInfoWithStatus:@"當前設備無網絡"];

        }

            break;

        case AFNetworkReachabilityStatusReachableViaWiFi:

            [SVProgressHUD showInfoWithStatus:@"當前Wi-Fi網絡"];

            break;

        case AFNetworkReachabilityStatusReachableViaWWAN:

            [SVProgressHUD showInfoWithStatus:@"當前蜂窩移動網絡"];

            break;

        default:

            break;

    }

}];

[mgr startMonitoring];

67、透明顏色不影響子視圖透明度

[UIColor colorWithRed:<#(CGFloat)#> green:<#(CGFloat)#> blue:<#(CGFloat)#> alpha:<#(CGFloat)#>];

68、取圖片某一點的顏色

if (point.x < 0 || point.y < 0) return nil;

CGImageRef imageRef = self.CGImage;

NSUInteger width = CGImageGetWidth(imageRef);

NSUInteger height = CGImageGetHeight(imageRef);

if (point.x >= width || point.y >= height) return nil;

unsigned char *rawData = malloc(height * width * 4);

if (!rawData) return nil;

CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();

NSUInteger bytesPerPixel = 4;

NSUInteger bytesPerRow = bytesPerPixel * width;

NSUInteger bitsPerComponent = 8;

CGContextRef context = CGBitmapContextCreate(rawData,

                                             width,

                                             height,

                                             bitsPerComponent,

                                             bytesPerRow,

                                             colorSpace,

                                             kCGImageAlphaPremultipliedLast

                                             | kCGBitmapByteOrder32Big);

if (!context) {

    free(rawData);

    return nil;

}

CGColorSpaceRelease(colorSpace);

CGContextDrawImage(context, CGRectMake(0, 0, width, height), imageRef);

CGContextRelease(context);

int byteIndex = (bytesPerRow * point.y) + point.x * bytesPerPixel;

CGFloat red   = (rawData[byteIndex]     * 1.0) / 255.0;

CGFloat green = (rawData[byteIndex + 1] * 1.0) / 255.0;

CGFloat blue  = (rawData[byteIndex + 2] * 1.0) / 255.0;

CGFloat alpha = (rawData[byteIndex + 3] * 1.0) / 255.0;

UIColor *result = nil;

result = [UIColor colorWithRed:red green:green blue:blue alpha:alpha];

free(rawData);

return result;

69、判斷該圖片是否有透明度通道

(BOOL)hasAlphaChannel

{

CGImageAlphaInfo alpha = CGImageGetAlphaInfo(self.CGImage);

return (alpha == kCGImageAlphaFirst ||

        alpha == kCGImageAlphaLast ||

        alpha == kCGImageAlphaPremultipliedFirst ||

        alpha == kCGImageAlphaPremultipliedLast);

}

70、獲得灰度圖

(UIImage)covertToGrayImageFromImage:(UIImage)sourceImage

{

int width = sourceImage.size.width;

int height = sourceImage.size.height;

CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceGray();

CGContextRef context = CGBitmapContextCreate (nil,width,height,8,0,colorSpace,kCGImageAlphaNone);

CGColorSpaceRelease(colorSpace);

if (context == NULL) {

    return nil;

}

CGContextDrawImage(context,CGRectMake(0, 0, width, height), sourceImage.CGImage);

CGImageRef contextRef = CGBitmapContextCreateImage(context);

UIImage *grayImage = [UIImage imageWithCGImage:contextRef];

CGContextRelease(context);

CGImageRelease(contextRef);

return grayImage;

}

71、根據bundle中的文件名讀取圖片

(UIImage *)imageWithFileName:(NSString *)name {

NSString *extension = @"png";

NSArray *components = [name componentsSeparatedByString:@"."];

if ([components count] >= 2) {
  NSUInteger lastIndex = components.count - 1;

  extension = [components objectAtIndex:lastIndex];

  name = [name substringToIndex:(name.length-(extension.length+1))];
}

// 如果為Retina屏幕且存在對應圖片，則返回Retina圖片，否則查找普通圖片

if ([UIScreen mainScreen].scale == 2.0) {
  name = [name stringByAppendingString:@"@2x"];

  NSString *path = [[NSBundle mainBundle] pathForResource:name ofType:extension];

  if (path != nil) {

      return [UIImage imageWithContentsOfFile:path];

  }
}

if ([UIScreen mainScreen].scale == 3.0) {
  name = [name stringByAppendingString:@"@3x"];

  NSString *path = [[NSBundle mainBundle] pathForResource:name ofType:extension];

  if (path != nil) {

      return [UIImage imageWithContentsOfFile:path];

  }
}

NSString *path = [[NSBundle mainBundle] pathForResource:name ofType:extension];

if (path) {
  return [UIImage imageWithContentsOfFile:path];
}

return nil;
}

72、合并兩個圖片

(UIImage)mergeImage:(UIImage)firstImage withImage:(UIImage*)secondImage {

CGImageRef firstImageRef = firstImage.CGImage;

CGFloat firstWidth = CGImageGetWidth(firstImageRef);

CGFloat firstHeight = CGImageGetHeight(firstImageRef);

CGImageRef secondImageRef = secondImage.CGImage;

CGFloat secondWidth = CGImageGetWidth(secondImageRef);

CGFloat secondHeight = CGImageGetHeight(secondImageRef);

CGSize mergedSize = CGSizeMake(MAX(firstWidth, secondWidth), MAX(firstHeight, secondHeight));

UIGraphicsBeginImageContext(mergedSize);

[firstImage drawInRect:CGRectMake(0, 0, firstWidth, firstHeight)];

[secondImage drawInRect:CGRectMake(0, 0, secondWidth, secondHeight)];

UIImage *image = UIGraphicsGetImageFromCurrentImageContext();

UIGraphicsEndImageContext();

return image;

}

73、根據bundle中的圖片名創建imageview

(id)imageViewWithImageNamed:(NSString*)imageName

{
return [[UIImageView alloc] initWithImage:[UIImage imageNamed:imageName]];
}

74、為imageView添加倒影

CGRect frame = self.frame;

frame.origin.y += (frame.size.height + 1);

UIImageView *reflectionImageView = [[UIImageView alloc] initWithFrame:frame];

self.clipsToBounds = TRUE;

reflectionImageView.contentMode = self.contentMode;

[reflectionImageView setImage:self.image];

reflectionImageView.transform = CGAffineTransformMakeScale(1.0, -1.0);

CALayer *reflectionLayer = [reflectionImageView layer];

CAGradientLayer *gradientLayer = [CAGradientLayer layer];

gradientLayer.bounds = reflectionLayer.bounds;

gradientLayer.position = CGPointMake(reflectionLayer.bounds.size.width / 2, reflectionLayer.bounds.size.height * 0.5);

gradientLayer.colors = [NSArray arrayWithObjects:

                        (id)[[UIColor clearColor] CGColor],

                        (id)[[UIColor colorWithRed:1.0 green:1.0 blue:1.0 alpha:0.3] CGColor], nil];

gradientLayer.startPoint = CGPointMake(0.5,0.5);

gradientLayer.endPoint = CGPointMake(0.5,1.0);

reflectionLayer.mask = gradientLayer;

[self.superview addSubview:reflectionImageView];

75、畫水印

// 畫水印

(void) setImage:(UIImage *)image withWaterMark:(UIImage *)mark inRect:(CGRect)rect

{

if ([[[UIDevice currentDevice] systemVersion] floatValue] >= 4.0)

{

    UIGraphicsBeginImageContextWithOptions(self.frame.size, NO, 0.0);

}

//原圖

[image drawInRect:self.bounds];

//水印圖

[mark drawInRect:rect];

UIImage *newPic = UIGraphicsGetImageFromCurrentImageContext();

UIGraphicsEndImageContext();

self.image = newPic;

}

76、讓label的文字內容顯示在左上／右上／左下／右下／中心頂／中心底部

自定義UILabel

// 重寫label的textRectForBounds方法

(CGRect)textRectForBounds:(CGRect)bounds limitedToNumberOfLines:(NSInteger)numberOfLines {

CGRect rect = [super textRectForBounds:bounds limitedToNumberOfLines:numberOfLines];

switch (self.textAlignmentType) {

  case WZBTextAlignmentTypeLeftTop: {

      rect.origin = bounds.origin;

  }

      break;

  case WZBTextAlignmentTypeRightTop: {

      rect.origin = CGPointMake(CGRectGetMaxX(bounds) - rect.size.width, bounds.origin.y);

  }

      break;

  case WZBTextAlignmentTypeLeftBottom: {

      rect.origin = CGPointMake(bounds.origin.x, CGRectGetMaxY(bounds) - rect.size.height);

  }

      break;

  case WZBTextAlignmentTypeRightBottom: {

      rect.origin = CGPointMake(CGRectGetMaxX(bounds) - rect.size.width, CGRectGetMaxY(bounds) - rect.size.height);

  }

      break;

  case WZBTextAlignmentTypeTopCenter: {

      rect.origin = CGPointMake((CGRectGetWidth(bounds) - CGRectGetWidth(rect)) / 2, CGRectGetMaxY(bounds) - rect.origin.y);

  }

      break;

  case WZBTextAlignmentTypeBottomCenter: {

      rect.origin = CGPointMake((CGRectGetWidth(bounds) - CGRectGetWidth(rect)) / 2, CGRectGetMaxY(bounds) - CGRectGetMaxY(bounds) - rect.size.height);

  }

      break;

  case WZBTextAlignmentTypeLeft: {

      rect.origin = CGPointMake(0, rect.origin.y);

  }

      break;

  case WZBTextAlignmentTypeRight: {

      rect.origin = CGPointMake(rect.origin.x, 0);

  }

      break;

  case WZBTextAlignmentTypeCenter: {

      rect.origin = CGPointMake((CGRectGetWidth(bounds) - CGRectGetWidth(rect)) / 2, (CGRectGetHeight(bounds) - CGRectGetHeight(rect)) / 2);

  }

      break;

  default:

      break;

}

return rect;

}

(void)drawTextInRect:(CGRect)rect {

CGRect textRect = [self textRectForBounds:rect limitedToNumberOfLines:self.numberOfLines];

[super drawTextInRect:textRect];

}

77、scrollView上的輸入框，鍵盤擋住的問題

推薦用IQKeyboardManager這個框架！

手動解決如下

1、監聽鍵盤彈出／消失的通知

2、在通知中加入代碼：

NSDictionary* info = [aNotification userInfo];

CGRect keyPadFrame=[[UIApplication sharedApplication].keyWindow convertRect:[[info objectForKey:UIKeyboardFrameBeginUserInfoKey] CGRectValue] fromView:self.view];

CGSize kbSize =keyPadFrame.size;

CGRect activeRect=[self.view convertRect:activeField.frame fromView:activeField.superview];

CGRect aRect = self.view.bounds;

aRect.size.height -= (kbSize.height);

CGPoint origin = activeRect.origin;

origin.y -= backScrollView.contentOffset.y;

if (!CGRectContainsPoint(aRect, origin)) {
CGPoint scrollPoint = CGPointMake(0.0,CGRectGetMaxY(activeRect)-(aRect.size.height));

[backScrollView setContentOffset:scrollPoint animated:YES];
}

78、frame布局的cell動態高度

這種通常在你的模型中添加一個輔助屬性cellHeight，在模型中重寫這個屬性的get方法，根據你的布局和模型中的其他屬性值計算出總高度。最后在tableView：heightForRow方法中，根據indexPath找出對應的模型，返回這個高度即可。

79、AutoLayout布局的cell動態高度

// 1、設置tableView的屬性

self.tableView.rowHeight = UITableViewAutomaticDimension;

self.tableView.estimatedRowHeight = 44.0; // 這個屬性非0，估計cell高度

// 2、至上而下設置cell的約束，注意，上下左右最好都要頂到cell的四周

[圖片上傳失敗...(image-f26e48-1528096993264)]

80、使用performSelector:調用函數，內存泄漏問題

當我們在開發中使用[obj performSelector:NSSelectorFromString(@"aMethod")];這類方法時可能會收到一個警告"performSelector may cause a leak because its selector is unknown".

是因為編譯器不清楚這個對象能不能相應這個方法，如果不能，則是不安全的，而且編譯器也不清楚該怎么處理這個方法的返回值！

使用以下代碼調用即可：

if (! obj) { return; }

SEL selector = NSSelectorFromString(@"aMethod");

IMP imp = [obj methodForSelector:selector];

void (*func)(id, SEL) = (void *)imp;

func(obj, selector);

或者：

SEL selector = NSSelectorFromString(@"aMethod");

((void (*)(id, SEL))[obj methodForSelector:selector])(obj, selector);

81、一個字符串是否包含另一個字符串

// 方法1

if ([str1 containsString:str2]) {
    NSLog(@"str1包含str2");

} else {

    NSLog(@"str1不包含str2");

}
// 方法2

if ([str1 rangeOfString: str2].location == NSNotFound) {
    NSLog(@"str1不包含str2");

} else {

    NSLog(@"str1包含str2");
}

82、cell去除選中效果

cell.selectionStyle = UITableViewCellSelectionStyleNone;

83、cell點按效果

(void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath {

[tableView deselectRowAtIndexPath:indexPath animated:YES];

}

84、當刪除一個從xib拖出來的屬性時，一定記得把xib中對應的線也刪掉，不然會報類似[ setValue:forUndefinedKey:]: this class is not key value coding-compliant for the key的crash

[圖片上傳失敗...(image-f165d6-1528096993264)]

點擊這個叉號刪除

85、真機測試的時候報錯：Could not launch "你的 App"，process launch failed: Security

因為你的app沒有上線，iOS9開始，需要手動信任Xcode生成的描述文件，打開手機設置->通用->描述文件->點擊你的app的描述文件->點擊信任

86、真機測試的時候報錯：Could not find Developer Disk Image

這是因為你的設備系統版本大于Xcode能兼容的系統版本，比如你的設備是iOS10.3，而Xcode版本是8.2（Xcode8.2最大兼容iOS10.2），就會報這個錯誤。解決辦法就是升級Xcode！

87、UITextView沒有placeholder的問題？

網上有很多此類自定義控件，也可以參考下我寫的一個UITextView分類UITextView-WZB

88、移除字符串中的空格和換行

(NSString *)removeSpaceAndNewline:(NSString *)str {

NSString *temp = [str stringByReplacingOccurrencesOfString:@" " withString:@""];

temp = [temp stringByReplacingOccurrencesOfString:@"\r" withString:@""];

temp = [temp stringByReplacingOccurrencesOfString:@"\n" withString:@""];

return temp;

}

89、判斷字符串中是否有空格

(BOOL)isBlank:(NSString *)str {

NSRange _range = [str rangeOfString:@" "];

if (_range.location != NSNotFound) {
  //有空格

  return YES;
} else {
  //沒有空格

  return NO;
}
}

90、獲取一個視頻的第一幀圖片

NSURL *url = [NSURL URLWithString:filepath];

AVURLAsset *asset1 = [[AVURLAsset alloc] initWithURL:url options:nil];

AVAssetImageGenerator *generate1 = [[AVAssetImageGenerator alloc] initWithAsset:asset1];

generate1.appliesPreferredTrackTransform = YES;

NSError *err = NULL;

CMTime time = CMTimeMake(1, 2);

CGImageRef oneRef = [generate1 copyCGImageAtTime:time actualTime:NULL error:&err];

UIImage *one = [[UIImage alloc] initWithCGImage:oneRef];

return one;

91、獲取視頻的時長

(NSInteger)getVideoTimeByUrlString:(NSString *)urlString {

NSURL *videoUrl = [NSURL URLWithString:urlString];

AVURLAsset *avUrl = [AVURLAsset assetWithURL:videoUrl];

CMTime time = [avUrl duration];

int seconds = ceil(time.value/time.timescale);

return seconds;

}

92、字符串是否為空

(BOOL)isEqualToNil:(NSString *)str {

return str.length <= 0 || [str isEqualToString:@""] || !str;

}

93、將app上傳到App Store的時候通常會遇到這個問題

[圖片上傳失敗...(image-d31d20-1528096993264)]

try again

很多人說這事蘋果爸爸服務器問題，重復嘗試幾次，總會成功的！

但是經過嘗試發現如果使用Application Loader上傳成功率就非常高，所以還是推薦把ipa文件導出直接用Application Loader上傳。

如果Application Loader也不行，需要檢查下自己的網絡，有時候vpn也會提高速度。

94、當tableView占不滿一屏時，去除下邊多余的單元格

self.tableView.tableHeaderView = [UIView new];

self.tableView.tableFooterView = [UIView new];

95、isKindOfClass和isMemberOfClass的區別

isKindOfClass可以判斷某個對象是否屬于某個類，或者這個類的子類。

isMemberOfClass更加精準，它只能判斷這個對象類型是否為這個類(不能判斷子類)

96、__block

當一個局部變量需要在block里改變時，需要在定義時加上__block修飾，具體請看官方文檔http://developer.apple.com/library/ios/documentation/cocoa/Conceptual/Blocks/Articles/bxVariables.html#//apple_ref/doc/uid/TP40007502-CH6-SW6

97、-[ViewController aMethod:]: unrecognized selector sent to instance 0x7fe91e607fb0

這是一個經典錯誤，ViewController不能響應aMethod這個方法，錯誤原因可能viewController文件中沒有實現aMethod這個方法

98、UITableView () failed to obtain a cell from its dataSource ()

這個錯誤原因是tableView的代理方法-tableView:cellForRowAtIndexPath:需要返回一個UITableViewCell,而你返回了一個nil。另外這個地方返回值不是UITableViewCell類型也會導致崩潰

99、約束如何做UIView動畫？

1、把需要改的約束Constraint拖條線出來，成為屬性

2、在需要動畫的地方加入代碼，改變此屬性的constant屬性

3、開始做UIView動畫，動畫里邊調用layoutIfNeeded方法

@property (weak, nonatomic) IBOutlet NSLayoutConstraint *buttonTopConstraint;

self.buttonTopConstraint.constant = 100;
[UIView animateWithDuration:.5 animations:^{

    [self.view layoutIfNeeded];
}];

100、從NSURL中拿到鏈接字符串

NSString *urlString = myURL.absoluteString;

101、將tableView滾動到頂部

[tableView setContentOffset:CGPointZero animated:YES];

或者

[tableView scrollRectToVisible:CGRectMake(0, 0, 1, 1) animated:YES];

102、如果用addTarget:action:forControlEvents:方法為一個button添加了很多點擊事件，在某個時刻想一次刪除怎么辦？只需要調用下邊這句代碼

[youButton removeTarget:nil action:nil forControlEvents:UIControlEventAllEvents];

103、某個字體的高度

font.lineHeight;

104、刪除某個view所有的子視圖

[[someView subviews]

makeObjectsPerformSelector:@selector(removeFromSuperview)];

105、刪除NSUserDefaults所有記錄

//方法一

NSString *appDomain = [[NSBundle mainBundle] bundleIdentifier];

[[NSUserDefaults standardUserDefaults] removePersistentDomainForName:appDomain];

//方法二
(void)resetDefaults {

NSUserDefaults * defs = [NSUserDefaults standardUserDefaults];

NSDictionary * dict = [defs dictionaryRepresentation];

for (id key in dict) {
    [defs removeObjectForKey:key];
}
[defs synchronize];
}

// 方法三

[[NSUserDefaults standardUserDefaults] setPersistentDomain:[NSDictionary dictionary] forName:[[NSBundle mainBundle] bundleIdentifier]];

106、禁用系統滑動返回功能

(void)viewDidAppear:(BOOL)animated

{
 [super viewDidAppear:animated];
if ([self.navigationController respondsToSelector:@selector(interactivePopGestureRecognizer)]) {self.navigationController.interactivePopGestureRecognizer.delegate = self;
}
}

(void)viewWillDisappear:(BOOL)animated {

[super viewWillDisappear:animated];

if ([self.navigationController respondsToSelector:@selector(interactivePopGestureRecognizer)]) {self.navigationController.interactivePopGestureRecognizer.delegate = nil;

}

}

(BOOL)gestureRecognizerShouldBegin:(UIGestureRecognizer *)gestureRecognizer

{
 return NO;
}

107、模擬器報錯

[圖片上傳失敗...(image-f07198-1528096993264)]

模擬器報錯

解決辦法：

打開模擬器->Simulator->Reset Content and Settings...

如果不行，就重啟試試！

108、自定義cell選中背景顏色

UIView *bgColorView = [[UIView alloc] init];

bgColorView.backgroundColor = [UIColor redColor];

[cell setSelectedBackgroundView:bgColorView];

109、UILabel設置內邊距

子類化UILabel，重寫drawTextInRect方法

(void)drawTextInRect:(CGRect)rect {

// 邊距，上左下右

UIEdgeInsets insets = {0, 5, 0, 5};

[super drawTextInRect:UIEdgeInsetsInsetRect(rect, insets)];

}

110、UILabel設置文字描邊

子類化UILabel，重寫drawTextInRect方法

(void)drawTextInRect:(CGRect)rect

{

CGContextRef c = UIGraphicsGetCurrentContext();

// 設置描邊寬度

CGContextSetLineWidth(c, 1);

CGContextSetLineJoin(c, kCGLineJoinRound);

CGContextSetTextDrawingMode(c, kCGTextStroke);

// 描邊顏色

self.textColor = [UIColor redColor];

[super drawTextInRect:rect];

// 文本顏色

self.textColor = [UIColor yellowColor];

CGContextSetTextDrawingMode(c, kCGTextFill);

[super drawTextInRect:rect];

}

111、使用模擬器截圖

快捷鍵command + s

或者File->Save Screen Shot

112、scrollView滾動到最下邊

CGPoint bottomOffset = CGPointMake(0, scrollView.contentSize.height - scrollView.bounds.size.height);

[scrollView setContentOffset:bottomOffset animated:YES];

113、UIView背景顏色漸變

UIView *view = [[UIView alloc] initWithFrame:CGRectMake(0, 0, 320, 100)];
[self.view addSubview:view];

CAGradientLayer *gradient = [CAGradientLayer layer];

gradient.frame = view.bounds;

gradient.colors = [NSArray arrayWithObjects:(id)[[UIColor blackColor] CGColor], (id)[[UIColor whiteColor] CGColor], nil];
[view.layer insertSublayer:gradient atIndex:0];

114、停止UIView動畫

[yourView.layer removeAllAnimations]

115、為UIView某個角添加圓角

// 左上角和右下角添加圓角

UIBezierPath *maskPath = [UIBezierPath bezierPathWithRoundedRect:view.bounds byRoundingCorners:(UIRectCornerTopLeft | UIRectCornerBottomRight) cornerRadii:CGSizeMake(20, 20)];
CAShapeLayer *maskLayer = [CAShapeLayer layer];

maskLayer.frame = view.bounds;

maskLayer.path = maskPath.CGPath;
view.layer.mask = maskLayer;

116、刪除Xcode Derived data緩存數據

依次點擊Xcode -> Preferences -> location，然后點擊 Derived data路徑后到小箭頭，刪除這個文件夾下的數據就可以了，如圖

[圖片上傳失敗...(image-74106b-1528096993264)]

Xcode Derived data

117、將一個view放置在其兄弟視圖的最上面

[parentView bringSubviewToFront:yourView]

118、將一個view放置在其兄弟視圖的最下面

[parentView sendSubviewToBack:yourView]

119、讓手機震動一下

倒入框架

import

AudioServicesPlayAlertSound(kSystemSoundID_Vibrate);

或者

AudioServicesPlaySystemSound(kSystemSoundID_Vibrate);

120、layoutSubviews方法什么時候調用？

1、init方法不會調用

2、addSubview方法等時候會調用

3、bounds改變的時候調用

4、scrollView滾動的時候會調用scrollView的layoutSubviews方法(所以不建議在scrollView的layoutSubviews方法中做復雜邏輯)

5、旋轉設備的時候調用

6、子視圖被移除的時候調用

參考請看：http://blog.logichigh.com/2011/03/16/when-does-layoutsubviews-get-called/

121、讓UILabel在指定的地方換行

// 換行符為\n,在需要換行的地方加上這個符號即可，如

label.numberOfLines = 0;

label.text = @"此處\n換行";

122、搖一搖功能

1、打開搖一搖功能
[UIApplication sharedApplication].applicationSupportsShakeToEdit = YES;
2、讓需要搖動的控制器成為第一響應者

[self becomeFirstResponder];

3、實現以下方法

// 開始搖動

(void)motionBegan:(UIEventSubtype)motion withEvent:(UIEvent *)event

// 取消搖動

(void)motionCancelled:(UIEventSubtype)motion withEvent:(UIEvent *)event

// 搖動結束

(void)motionEnded:(UIEventSubtype)motion withEvent:(UIEvent *)event

123、獲取圖片大小

CGFloat imageWidth = image.size.width;

CGFloat imageHeight = imageWidth * image.scale;

124、獲取view的坐標在整個window上的位置

// v上的(0, 0)點在toView上的位置

CGPoint point = [v convertPoint:CGPointMake(0, 0) toView:[UIApplication sharedApplication].windows.lastObject];

或者

CGPoint point = [v.superview convertPoint:v.frame.origin toView:[UIApplication sharedApplication].windows.lastObject];

125、提交App Store審核程序限制

您的應用程序的未壓縮大小必須小于4GB。每個Mach-O可執行文件（例如app_name.app/app_name）不能超過這些限制：

對于MinimumOSVersion小于7.0的應用程序：TEXT二進制文件中所有部分的總數最多為80 MB 。

對于MinimumOSVersion7.x到8.x的應用程序：TEXT對于二進制文件中每個體系結構片段的每個片段，最大為60 MB 。

對于MinimumOSVersion9.0或更高版本的應用程序：__TEXT二進制文件中所有部分的總數最多為500 MB 。參閱：iTunes Connect開發者指南

126、修改UISegmentedControl的字體大小

[segment setTitleTextAttributes:@{NSFontAttributeName : [UIFont systemFontOfSize:15.0f]} forState:UIControlStateNormal];

127、在非ViewController的地方彈出UIAlertController對話框

// 最好抽成一個分類

UIAlertController *alertController = [UIAlertController alertControllerWithTitle:@"Title" message:@"message" preferredStyle:UIAlertControllerStyleAlert];

//...

id rootViewController = [UIApplication sharedApplication].delegate.window.rootViewController;

if([rootViewController isKindOfClass:[UINavigationController class]])

{
rootViewController = ((UINavigationController *)rootViewController).viewControllers.firstObject;
}

if([rootViewController isKindOfClass:[UITabBarController class]])

{
rootViewController = ((UITabBarController *)rootViewController).selectedViewController;
}

[rootViewController presentViewController:alertController animated:YES completion:nil];

128、獲取一個view所屬的控制器

// view分類方法
(UIViewController *)belongViewController {

for (UIView *next = [self superview]; next; next = next.superview) {
  UIResponder* nextResponder = [next nextResponder];

  if ([nextResponder isKindOfClass:[UIViewController class]]) {

      return (UIViewController *)nextResponder;

  }
}

return nil;
}

129、UIImage和base64互轉

// view分類方法

(NSString *)encodeToBase64String:(UIImage *)image {

return [UIImagePNGRepresentation(image) base64EncodedStringWithOptions:NSDataBase64Encoding64CharacterLineLength];

}

(UIImage *)decodeBase64ToImage:(NSString *)strEncodeData {

NSData *data = [[NSData alloc]initWithBase64EncodedString:strEncodeData options:NSDataBase64DecodingIgnoreUnknownCharacters];

return [UIImage imageWithData:data];

}

130、UIWebView設置背景透明

[webView setBackgroundColor:[UIColor clearColor]];

[webView setOpaque:NO];

131、判斷NSDate是不是今天

NSDateComponents *otherDay = [[NSCalendar currentCalendar] components:NSCalendarUnitEra | NSCalendarUnitYear | NSCalendarUnitMonth | NSCalendarUnitDay fromDate:aDate];

NSDateComponents *today = [[NSCalendar currentCalendar] components:NSCalendarUnitEra | NSCalendarUnitYear | NSCalendarUnitMonth | NSCalendarUnitDay fromDate:[NSDate date]];

if([today day] == [otherDay day] &&

[today month] == [otherDay month] &&

[today year] == [otherDay year] &&

[today era] == [otherDay era]) {
// 是今天
}

132、設置tableView分割線顏色

[self.tableView setSeparatorColor:[UIColor myColor]];

133、設置屏幕方向

NSNumber *orientationTarget = [NSNumber numberWithInt:UIInterfaceOrientationLandscapeLeft];

[[UIDevice currentDevice] setValue:orientationTarget forKey:@"orientation"];

[UIViewController attemptRotationToDeviceOrientation];

134、比較兩個顏色是否相等

(BOOL)isEqualToColor:(UIColor *)otherColor {

CGColorSpaceRef colorSpaceRGB = CGColorSpaceCreateDeviceRGB();

UIColor (^convertColorToRGBSpace)(UIColor) = ^(UIColor *color) {
  if (CGColorSpaceGetModel(CGColorGetColorSpace(color.CGColor)) == kCGColorSpaceModelMonochrome) {

      const CGFloat *oldComponents = CGColorGetComponents(color.CGColor);

      CGFloat components[4] = {oldComponents[0], oldComponents[0], oldComponents[0], oldComponents[1]};

      CGColorRef colorRef = CGColorCreate( colorSpaceRGB, components );

      UIColor *color = [UIColor colorWithCGColor:colorRef];

      CGColorRelease(colorRef);

      return color;           

  } else

      return color;
};

UIColor *selfColor = convertColorToRGBSpace(self);

otherColor = convertColorToRGBSpace(otherColor);

CGColorSpaceRelease(colorSpaceRGB);

return [selfColor isEqual:otherColor];
}

135、tableViewCell分割線頂到頭

(void)tableView:(UITableView *)tableView willDisplayCell:(UITableViewCell *)cell forRowAtIndexPath:(NSIndexPath *)indexPath {

[cell setSeparatorInset:UIEdgeInsetsZero];

[cell setLayoutMargins:UIEdgeInsetsZero];

cell.preservesSuperviewLayoutMargins = NO;

}

(void)viewDidLayoutSubviews {

[self.tableView setSeparatorInset:UIEdgeInsetsZero];

[self.tableView setLayoutMargins:UIEdgeInsetsZero];

}

136、不讓控制器的view隨著控制器的xib拉伸或壓縮

self.view.autoresizingMask = UIViewAutoresizingFlexibleWidth | UIViewAutoresizingFlexibleHeight;

137、cocoaPods報錯 : [!] Unable to add a source with urlhttps://github.com/CocoaPods/Specs.gitnamed master-1.

You can try adding it manually in ~/.cocoapods/repos or via pod repo add.

解決方法：這是因為電腦里安裝了另外一個Xcode導致cocoapods找不到路徑了

在終端執行 sudo xcode-select -switch /Applications/Xcode.app 即可

138、安裝cocoapods的時候出現 ERROR: While executing gem ... (Errno::EPERM)

Operation not permitted - /usr/bin/pod

解決辦法：直接在終端執行 sudo gem install -n /usr/local/bin cocoapods

139、在狀態欄增加網絡請求的菊花，類似safari加載網頁的時候狀態欄菊花

[UIApplication sharedApplication].networkActivityIndicatorVisible = YES;

140、檢查一個rect是否包含一個point

// point是否在rect內

BOOL isContains = CGRectContainsPoint(rect, point);

141、在指定的寬度下，讓UILabel自動設置最佳font

label.adjustsFontSizeToFitWidth = YES;

142、將一個image保存在相冊中

UIImageWriteToSavedPhotosAlbum(image, nil, nil, nil);

或者

import

[[PHPhotoLibrary sharedPhotoLibrary] performChanges:^{

    PHAssetChangeRequest *changeRequest = [PHAssetChangeRequest creationRequestForAssetFromImage:image];

    changeRequest.creationDate          = [NSDate date];

} completionHandler:^(BOOL success, NSError *error) {

    if (success) {

        NSLog(@"successfully saved");

    }

    else {

        NSLog(@"error saving to photos: %@", error);

    }

}];

143、修改cell.imageView的大小

UIImage *icon = [UIImage imageNamed:@""];

CGSize itemSize = CGSizeMake(30, 30);

UIGraphicsBeginImageContextWithOptions(itemSize, NO ,0.0);

CGRect imageRect = CGRectMake(0.0, 0.0, itemSize.width, itemSize.height);

[icon drawInRect:imageRect];

cell.imageView.image = UIGraphicsGetImageFromCurrentImageContext();

UIGraphicsEndImageContext();

144、為一個view添加虛線邊框

CAShapeLayer *border = [CAShapeLayer layer];

border.strokeColor = [UIColor colorWithRed:67/255.0f green:37/255.0f blue:83/255.0f alpha:1].CGColor;

border.fillColor = nil;

border.lineDashPattern = @[@4, @2];

border.path = [UIBezierPath bezierPathWithRect:view.bounds].CGPath;

border.frame = view.bounds;

[view.layer addSublayer:border];

145、UITextView中打開或禁用復制，剪切，選擇，全選等功能

// 繼承UITextView重寫這個方法

(BOOL)canPerformAction:(SEL)action withSender:(id)sender

{

// 返回NO為禁用，YES為開啟

// 粘貼

if (action == @selector(paste:)) return NO;

// 剪切

if (action == @selector(cut:)) return NO;

// 復制

if (action == @selector(copy:)) return NO;

// 選擇

if (action == @selector(select:)) return NO;

// 選中全部

if (action == @selector(selectAll:)) return NO;

// 刪除

if (action == @selector(delete:)) return NO;

// 分享

if (action == @selector(share)) return NO;

return [super canPerformAction:action withSender:sender];

}

作者：百事小武
鏈接：http://www.lxweimin.com/p/10b2323f502e
來源：簡書
著作權歸作者所有。商業轉載請聯系作者獲得授權，非商業轉載請注明出處。

?著作權歸作者所有,轉載或內容合作請聯系作者

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