#import"ViewController.h"

@interfaceViewController()

@property(nonatomic,strong)CALayer*imageLayer;

@property(nonatomic,strong)dispatch_source_ttimer;

@property(nonatomic,strong)UIImageView*backImage;

@end

@implementationViewController

- (void)viewDidLoad {

[superviewDidLoad];

UIImageView*backImage = [[UIImageViewalloc]initWithFrame:CGRectMake(100,100,200,300)];

_backImage= backImage;

[self.viewaddSubview:backImage];

UIImage*image1 = [UIImageimageNamed:@"1"];

//創(chuàng)建出圖片layer埠戳；

self.imageLayer= [CALayerlayer];

self.imageLayer.frame=CGRectMake(100,100,200,300);

[self.view.layeraddSublayer:self.imageLayer];

self.imageLayer.contents= (__bridgeid)(image1.CGImage);

[selfperformSelector:@selector(changeImages)withObject:nilafterDelay:1.0f];

}

-(void)changeImages {

__blockNSString*str =@"2";

self.backImage.image= [UIImageimageNamed:str];

//定時器開始執(zhí)行的延時時間

NSTimeIntervaldelayTime =0.0f;

//定時器間隔時間

NSTimeIntervaltimeInterval =2.0f;

//創(chuàng)建子線程隊列

dispatch_queue_tqueue =dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT,0);

//使用之前創(chuàng)建的隊列來創(chuàng)建計時器

_timer=dispatch_source_create(DISPATCH_SOURCE_TYPE_TIMER,0,0, queue);

//設置延時執(zhí)行時間妒牙，delayTime為要延時的秒數(shù)

dispatch_time_tstartDelayTime =dispatch_time(DISPATCH_TIME_NOW, (int64_t)(delayTime *NSEC_PER_SEC));

//設置計時器

dispatch_source_set_timer(_timer, startDelayTime, timeInterval *NSEC_PER_SEC,0.1*NSEC_PER_SEC);

dispatch_source_set_event_handler(_timer, ^{

//執(zhí)行事件

if( [strisEqualToString:@"1"]) {

str =@"2";

}else{

str =@"1";

}

dispatch_async(dispatch_get_main_queue(), ^{

//圖片動畫；

CABasicAnimation*contentsAnimation = [CABasicAnimationanimationWithKeyPath:@"contents"];

contentsAnimation.fromValue=self.imageLayer.contents;

contentsAnimation.toValue= (__bridgeid)(self.backImage.image.CGImage);

contentsAnimation.duration=1;

//設定layer動畫結束之后的值倡勇，（必須設定，否則會恢復到動畫之前的狀態(tài)）

self.imageLayer.contents= (__bridgeid)(self.backImage.image.CGImage);

//提交動畫著角；

[self.imageLayeraddAnimation:contentsAnimationforKey:nil];

[self.backImagesetImage:[UIImageimageNamed:str]];

}) ;

});

//啟動計時器

dispatch_resume(_timer);

}