#import "ViewController.h"
@interface ViewController ()
@property (strong, nonatomic) CAGradientLayer *gradientLayer;
@property (strong, nonatomic) NSTimer *timer;
@end
@implementation ViewController
- (void)viewDidLoad {
[super viewDidLoad];
//初始化imageView
UIImageView *imageView = [[UIImageView alloc] initWithImage:[UIImage imageNamed:@"image"]];
imageView.frame = CGRectMake(0, 0, self.view.bounds.size.width, 200);
imageView.center = self.view.center;
[self.view addSubview:imageView];
//初始化漸變層
self.gradientLayer = [CAGradientLayer layer];
self.gradientLayer.frame = imageView.bounds;
[imageView.layer addSublayer:self.gradientLayer];
//設置漸變顏色方向
self.gradientLayer.startPoint = CGPointMake(0, 0);
self.gradientLayer.endPoint = CGPointMake(0, 1);
//設定顏色組
self.gradientLayer.colors = @[(__bridge id)[UIColor clearColor].CGColor,
(__bridge id)[UIColor purpleColor].CGColor];
//設定顏色分割點
self.gradientLayer.locations = @[@(0.5f) ,@(1.0f)];
//定時器
//? ? self.timer = [NSTimer scheduledTimerWithTimeInterval:2.0f
//? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? target:self
//? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? selector:@selector(TimerEvent)
//? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? userInfo:nil
//? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? repeats:YES];
}
- (void)TimerEvent
{
//定時改變顏色
self.gradientLayer.colors = @[(__bridge id)[UIColor clearColor].CGColor,
(__bridge id)[UIColor colorWithRed:arc4random() % 255 / 255.0
green:arc4random() % 255 / 255.0
blue:arc4random() % 255 / 255.0
alpha:1.0].CGColor];
//定時改變分割點
self.gradientLayer.locations = @[@(arc4random() % 10 / 10.0f), @(1.0f)];
}
@end
