在最近一個(gè)項(xiàng)目中碰到這樣一個(gè)場(chǎng)景,在被push進(jìn)來的一個(gè)頁面設(shè)置導(dǎo)航欄透明,且要求控制對(duì)tableview組的頭視圖進(jìn)行懸停顯示,nav隨著tableview偏移量改變透明度,當(dāng)然這樣的需求確實(shí)不是什么難事,但是如果當(dāng)前頁面繼續(xù)push一個(gè)不需要此類效果的頁面,當(dāng)在返回當(dāng)前頁面的時(shí)候就會(huì)出現(xiàn)一個(gè)坑,nav的展示很突兀,下面是直接上解決方法...ps:假設(shè)A頁面為需要設(shè)置透明,B頁面被Apush且不需要設(shè)置透明
A.m
首先在需要設(shè)置導(dǎo)航欄透明的頁面的viewDidload中寫上
self.title = @"Title";
[self.navigationController.navigationBar setBackgroundImage:[UIImage new] forBarMetrics:UIBarMetricsDefault];
self.navigationController.navigationBar.shadowImage = [UIImage new];
self.barImageView = self.navigationController.navigationBar.subviews.firstObject;
self.barImageView.alpha = 0;
//設(shè)置狀態(tài)欄
[[UIApplication sharedApplication] setStatusBarStyle:UIStatusBarStyleLightContent];
//設(shè)置標(biāo)題顏色
self.navigationController.navigationBar.titleTextAttributes = @{NSForegroundColorAttributeName : [UIColor clearColor]};
在scrollViewDidScroll代理方法中
-(void)scrollViewDidScroll:(UIScrollView *)scrollView {
CGFloat offset = scrollView.contentOffset.y;
//根據(jù)自己需要設(shè)置(136)的大小
CGFloat alpha = offset / 136;
_barImageView.alpha = alpha;
//記錄下當(dāng)前的透明度,在返回當(dāng)前頁面時(shí)需要
_alpha = alpha;
[[NSUserDefaults standardUserDefaults] setObject:[NSNumber numberWithFloat:alpha] forKey:@"_alpha"];
//設(shè)置標(biāo)題的透明度
self.navigationController.navigationBar.titleTextAttributes = @{NSForegroundColorAttributeName : [UIColor colorWithWhite:0 alpha:alpha]};
}
當(dāng)前頁的viewWillAppear, viewDidAppear, viewWillDisappear
-(void)viewWillAppear:(BOOL)animated
{
[super viewWillAppear:animated];
self.table.delegate = self;
BOOL isGesturePop = [[[NSUserDefaults standardUserDefaults] objectForKey:@"isGesturePop"] boolValue];
self.navigationController.navigationBar.titleTextAttributes = @{NSForegroundColorAttributeName : [UIColor colorWithWhite:0 alpha:_alpha]};
if (!isGesturePop) {
[UIView animateWithDuration:0.25 animations:^{
_barImageView.alpha = _alpha;
self.navigationController.navigationBar.titleTextAttributes = @{NSForegroundColorAttributeName : [UIColor colorWithWhite:0 alpha:_alpha]};
}];
}
}
-(void)viewDidAppear:(BOOL)animated {
//BOOL isGesturePop = [[[NSUserDefaults standardUserDefaults] objectForKey:@"isGesturePop"] boolValue];
// if (!isGesturePop) {
// _barImageView.alpha = _alpha;
// self.navigationController.navigationBar.titleTextAttributes = @{NSForegroundColorAttributeName : [UIColor colorWithWhite:0 alpha:_alpha]};
//}
[super viewDidAppear:animated];
}
-(void)viewWillDisappear:(BOOL)animated
{
[super viewWillDisappear:animated];
self.table.delegate = nil;
self.navigationController.navigationBar.titleTextAttributes = @{NSForegroundColorAttributeName : [UIColor blackColor]};
_barImageView.alpha = 1;
[[NSUserDefaults standardUserDefaults] setObject:[NSNumber numberWithBool:NO] forKey:@"isGesturePop"];
}
那么在我們需要push的下一個(gè)頁面需要什么操作呢,我們需要在這個(gè)頁面顯示正常的nav并且禁掉系統(tǒng)的手勢(shì)pop,自己寫一個(gè)pop手勢(shì),以方便我們拿到pop滑動(dòng)時(shí)的偏移量,在做的時(shí)候使用了兩個(gè)類,在最后會(huì)有源碼貼出
B.m 須遵守UIGestureRecognizerDelegate,并導(dǎo)入NavigationInteractiveTransition.h
全局變量
@property (nonatomic, strong) NavigationInteractiveTransition *navT;
viewDidLoad
self.navigationController.interactivePopGestureRecognizer.enabled = NO;
UIGestureRecognizer *gesture = self.navigationController.interactivePopGestureRecognizer;
gesture.enabled = NO;
UIView *gestureView = gesture.view;
UIPanGestureRecognizer *popRecognizer = [[UIPanGestureRecognizer alloc] init];
popRecognizer.delegate = self;
popRecognizer.maximumNumberOfTouches = 1;
[gestureView addGestureRecognizer:popRecognizer];
_navT = [[NavigationInteractiveTransition alloc] initWithViewController:self.navigationController];
[popRecognizer addTarget:_navT action:@selector(handleControllerPop:)];
UIGestureRecognizerDelegate 代理方法gestureRecognizerShouldBegin
- (BOOL)gestureRecognizerShouldBegin:(UIGestureRecognizer *)gestureRecognizer {
//記錄當(dāng)前是是否是通過手勢(shì)滑動(dòng)回去
[[NSUserDefaults standardUserDefaults] setObject:[NSNumber numberWithBool:YES] forKey:@"isGesturePop"];
/**
* 這里有兩個(gè)條件不允許手勢(shì)執(zhí)行，1、當(dāng)前控制器為根控制器；2、如果這個(gè)push、pop動(dòng)畫正在執(zhí)行（私有屬性）
*/
return self.navigationController.viewControllers.count != 1 && ![[self.navigationController valueForKey:@"_isTransitioning"] boolValue];
}
需要依賴的兩個(gè)類源碼
NavigationInteractiveTransition.h
#import <UIKit/UIKit.h>
@class UIViewController, UIPercentDrivenInteractiveTransition;
@interface NavigationInteractiveTransition : NSObject <UINavigationControllerDelegate>
- (instancetype)initWithViewController:(UIViewController *)vc;
- (void)handleControllerPop:(UIPanGestureRecognizer *)recognizer;
- (UIPercentDrivenInteractiveTransition *)interactivePopTransition;
@end
NavigationInteractiveTransition.m
#import "NavigationInteractiveTransition.h"
#import "PopAnimation.h"
@interface NavigationInteractiveTransition ()
@property (nonatomic, weak) UINavigationController *vc;
@property (nonatomic, strong) UIPercentDrivenInteractiveTransition *interactivePopTransition;
@property(nonatomic, strong) UIImageView *barImageView;
@end
@implementation NavigationInteractiveTransition
- (instancetype)initWithViewController:(UIViewController *)vc
{
self = [super init];
if (self) {
self.vc = (UINavigationController *)vc;
self.vc.delegate = self;
}
return self;
}
/**
* 我們把用戶的每次Pan手勢(shì)操作作為一次pop動(dòng)畫的執(zhí)行
*/
- (void)handleControllerPop:(UIPanGestureRecognizer *)recognizer {
/**
* interactivePopTransition就是我們說的方法2返回的對(duì)象，我們需要更新它的進(jìn)度來控制Pop動(dòng)畫的流程，我們用手指在視圖中的位置與視圖寬度比例作為它的進(jìn)度。
*/
CGFloat progress = [recognizer translationInView:recognizer.view].x / recognizer.view.bounds.size.width;
[self.vc.navigationBar setBackgroundImage:[UIImage new] forBarMetrics:UIBarMetricsDefault];
self.vc.navigationBar.shadowImage = [UIImage new];
self.barImageView = self.vc.navigationBar.subviews.firstObject;
CGFloat alpha = [[[NSUserDefaults standardUserDefaults] objectForKey:@"_alpha"] floatValue];
self.barImageView.alpha = 1 - progress > alpha ? alpha : 1 - progress;
// NSLog(@"===progress==%.2f",progress);
/**
* 穩(wěn)定進(jìn)度區(qū)間，讓它在0.0（未完成）～1.0（已完成）之間
*/
progress = MIN(1.0, MAX(0.0, progress));
if (recognizer.state == UIGestureRecognizerStateBegan) {
/**
* 手勢(shì)開始，新建一個(gè)監(jiān)控對(duì)象
*/
self.interactivePopTransition = [[UIPercentDrivenInteractiveTransition alloc] init];
/**
* 告訴控制器開始執(zhí)行pop的動(dòng)畫
*/
[self.vc popViewControllerAnimated:YES];
}
else if (recognizer.state == UIGestureRecognizerStateChanged) {
/**
* 更新手勢(shì)的完成進(jìn)度
*/
[self.interactivePopTransition updateInteractiveTransition:progress];
}
else if (recognizer.state == UIGestureRecognizerStateEnded || recognizer.state == UIGestureRecognizerStateCancelled) {
/**
* 手勢(shì)結(jié)束時(shí)如果進(jìn)度大于一半，那么就完成pop操作，否則重新來過。
*/
if (progress > 0.5) {
[self.interactivePopTransition finishInteractiveTransition];
self.barImageView.alpha = 0;;
}
else {
[self.interactivePopTransition cancelInteractiveTransition];
}
self.interactivePopTransition = nil;
}
}
- (id<UIViewControllerAnimatedTransitioning>)navigationController:(UINavigationController *)navigationController
animationControllerForOperation:(UINavigationControllerOperation)operation
fromViewController:(UIViewController *)fromVC
toViewController:(UIViewController *)toVC {
/**
* 方法1中判斷如果當(dāng)前執(zhí)行的是Pop操作，就返回我們自定義的Pop動(dòng)畫對(duì)象。
*/
if (operation == UINavigationControllerOperationPop)
return [[PopAnimation alloc] init];
return nil;
}
- (id<UIViewControllerInteractiveTransitioning>)navigationController:(UINavigationController *)navigationController
interactionControllerForAnimationController:(id<UIViewControllerAnimatedTransitioning>)animationController {
/**
* 方法2會(huì)傳給你當(dāng)前的動(dòng)畫對(duì)象animationController，判斷如果是我們自定義的Pop動(dòng)畫對(duì)象，那么就返回interactivePopTransition來監(jiān)控動(dòng)畫完成度。
*/
if ([animationController isKindOfClass:[PopAnimation class]])
return self.interactivePopTransition;
return nil;
}
@end
PopAnimation.h
#import <Foundation/Foundation.h>
#import <UIKit/UIKit.h>
@interface PopAnimation : NSObject <UIViewControllerAnimatedTransitioning>
@end
PopAnimation.m
#import "PopAnimation.h"
@interface PopAnimation ()
@property (nonatomic, strong) id <UIViewControllerContextTransitioning> transitionContext;
@end
@implementation PopAnimation
- (NSTimeInterval)transitionDuration:(id <UIViewControllerContextTransitioning>)transitionContext {
//這個(gè)方法返回動(dòng)畫執(zhí)行的時(shí)間
return 0.25;
}
/**
* transitionContext你可以看作是一個(gè)工具，用來獲取一系列動(dòng)畫執(zhí)行相關(guān)的對(duì)象，并且通知系統(tǒng)動(dòng)畫是否完成等功能。
*/
- (void)animateTransition:(id <UIViewControllerContextTransitioning>)transitionContext {
/**
* 獲取動(dòng)畫來自的那個(gè)控制器
*/
UIViewController *fromViewController = [transitionContext viewControllerForKey:UITransitionContextFromViewControllerKey];
/**
* 獲取轉(zhuǎn)場(chǎng)到的那個(gè)控制器
*/
UIViewController *toViewController = [transitionContext viewControllerForKey:UITransitionContextToViewControllerKey];
/**
* 轉(zhuǎn)場(chǎng)動(dòng)畫是兩個(gè)控制器視圖時(shí)間的動(dòng)畫，需要一個(gè)containerView來作為一個(gè)“舞臺(tái)”，讓動(dòng)畫執(zhí)行。
*/
UIView *containerView = [transitionContext containerView];
[containerView insertSubview:toViewController.view belowSubview:fromViewController.view];
NSTimeInterval duration = [self transitionDuration:transitionContext];
/**
* 執(zhí)行動(dòng)畫，我們讓fromVC的視圖移動(dòng)到屏幕最右側(cè)
*/
[UIView animateWithDuration:duration animations:^{
fromViewController.view.transform = CGAffineTransformMakeTranslation([UIScreen mainScreen].bounds.size.width, 0);
}completion:^(BOOL finished) {
/**
* 當(dāng)你的動(dòng)畫執(zhí)行完成，這個(gè)方法必須要調(diào)用，否則系統(tǒng)會(huì)認(rèn)為你的其余任何操作都在動(dòng)畫執(zhí)行過程中。
*/
[transitionContext completeTransition:!transitionContext.transitionWasCancelled];
}];
}
- (void)animationDidStop:(CATransition *)anim finished:(BOOL)flag {
[_transitionContext completeTransition:!_transitionContext.transitionWasCancelled];
}
@end
ps:如果是自定義view設(shè)置nav或者是直接隱藏nav可以參考我的另一篇簡(jiǎn)書http://www.lxweimin.com/p/b46166b05f02
備注:還有些許不足請(qǐng)各位見諒指正
