CALayer

一、簡介

1.CALayer

簡單的說是層（圖層）的概念，類似與PS中的圖層。一個用來完成繪制、渲染、動畫等效果的可見的容器。

2.CALayer 與 UIView 的聯系與區別

UIView中有一個layer屬性，為根圖層。UIView之所以能顯示在屏幕上，完全是因為它內部的CALayer對象。在創建UIView對象時，UIView內部會自動創建一個層(即CALayer對象)，通過UIView的layer屬性可以訪問這個層。當UIView需要顯示到屏幕上時，會調用drawRect:方法進行繪圖，并且會將所有內容繪制在自己的層上，繪圖完畢后，系統會將層拷貝到屏幕上，于是就完成了UIView的顯示。UIView本身不具備顯示的功能，顯示的是UIView的CALayer。
UIView可以通過subviews屬性訪問所有的子視圖，同樣地，CALayer也可以通過sublayers屬性訪問所有的子層；UIView可以通過superview屬性訪問父視圖，同樣地，CALayer也可以通過superlayer屬性訪問父層。
UIView可以通過addSubview:方法添加子視圖，同樣地，CALayer可以通過addSublayer:方法添加子層。

在使用時，往往CALayer和UIView都能實現相同的顯示效果，但是UIView具有交互的能力，可以處理事件。如果顯示出來的東西需要跟用戶進行交互的話，那么就要使用用UIView。

3.常用屬性

注：

• 在CALayer中很少使用frame屬性，因為frame本身不支持隱式動畫，通常使用bounds和position代替
• anchorPoint屬性是圖層的錨點，范圍在（0_1,01）表示在x、y軸的比例，這個點決定著CALayer身上的哪個點會與position所指定的位置重合，當圖層中心點固定后，調整anchorPoint即可達到調整圖層顯示位置的作用（因為它永遠和position重合）

4.隱式動畫屬性

每一個UIView內部都默認關聯著一個CALayer，這個CALayer為Root Layer（根層）。對于所有的非Root Layer，即手動創建的CALayer對象，當對非Root Layer的部分屬性進行相應的修改時，默認會自動產生一些動畫效果，這些屬性稱為Animatable Properties(可動畫屬性)。隱式屬性動畫的本質是這些屬性的變動默認隱含了CABasicAnimation動畫實現，例如修改bounds屬性會產生縮放動畫，修改backgroundColor屬性會產生背景色的漸變動畫，修改position屬性會產生平移動畫。

可以通過動畫事務(CATransaction)關閉默認的隱式動畫效果
[CATransactionbegin];
[CATransactionsetDisableActions:YES];
self.myview.layer.position= CGPointMake(100, 100);
[CATransactioncommit];

二、簡單使用

1. 設置陰影

  imageView.layer.shadowColor = [UIColor grayColor].CGColor;  //陰影顏色
  imageView.layer.shadowOffset = CGSizeMake(10, 10); //陰影偏移量
  imageView.layer.shadowOpacity = 0.5;  //陰影透明度

2.設置圓角

 imageView.layer.masksToBounds = YES;   
 imageView.layer.cornerRadius = 10;     //當cornerRadius等于邊長的一半時，就是圓

3.設置邊框

 imageView.layer.borderWidth = 5;
 imageView.layer.borderColor = [UIColor redColor].CGColor;

4.設置旋轉

 imageView.layer.transform = CATransform3DMakeRotation(M_PI_4, 0, 0, 1);// 順時針旋轉45

5.繪制圖層

繪制圖層有兩種方法

1.通過圖層代理drawLayer: inContext:方法繪制
2.通過自定義圖層drawInContext:方法繪制
不管使用哪種方法繪制完必須調用圖層的setNeedDisplay方法.

① 使用代理方法繪制圖層
通過代理方法進行圖層繪圖只要指定圖層的代理，然后在代理對象中重寫-(void)drawLayer:(CALayer *)layer inContext:(CGContextRef)ctx方法即可。需要注意這個方法雖然是代理方法但是不用手動實現CALayerDelegate，因為CALayer定義中給NSObject做了分類擴展，所有的NSObject都包含這個方法。另外設置完代理后必須要調用圖層的setNeedDisplay方法，否則繪制的內容無法顯示。

例

- (void)viewDidLoad {
    [super viewDidLoad];

    CALayer * layer = [[CALayer alloc]init];
    layer.bounds = CGRectMake(0, 0, 100, 100);
    layer.position = CGPointMake(50, 50);
    layer.masksToBounds = YES;
    layer.cornerRadius = 50;
    layer.borderWidth = 2;
    layer.borderColor = [UIColor yellowColor].CGColor;

    layer.delegate = self; //設置代理
    [self.view.layer addSublayer:layer]; //添加圖層
    [layer setNeedsDisplay]; //重繪
}

- (void)drawLayer:(CALayer *)layer inContext:(CGContextRef)ctx{
    CGContextSaveGState(ctx);
    CGContextScaleCTM(ctx, 1, -1); //轉換坐標系
    CGContextTranslateCTM(ctx, 0, -100);
    UIImage * image = [UIImage imageNamed:@"me"];
    CGContextDrawImage(ctx, CGRectMake(0, 0, 100, 100), image.CGImage);
    CGContextRestoreGState(ctx);
}

② 使用自定義圖層繪制圖層
創建一個CALayer的子類，然后重寫drawInContext:方法，在方法中使用Quartz2D API進行繪圖；
同樣，使用時，必須要調用圖層的setNeedDisplay方法，才會觸發drawInContext:方法的調用。

Core Animation

一、簡介

1.概念

Core Animation 是作用在CALayer上的，使用Core Animation 創建動畫不僅簡單，而且還有更好的性能，因為Core Animation 是在單獨的線程中完成的，不會阻塞主線程，而且只會重繪界面上變化的部分（局部刷新）。

2.分類

基礎動畫、關鍵幀動畫都屬于屬性動畫，是通過修改屬性值產生動畫效果，只需要設置初始值和結束值，中間的過程動畫（“補間動畫”）是由系統自動計算產生。和基礎動畫不同的是關鍵幀動畫可以設置多個屬性值，每兩個屬性中間的補間動畫由系統自動完成，基礎動畫也可以看成是有兩個關鍵幀的關鍵幀動畫。

二、使用

1. CAAnimation

CAAnimation 是基類，其屬性它的子類也擁有。它不能直接使用。

代理方法 : 給NSObject添加了分類，所以任何對象，都可以成為CAAnimation的代理。

動畫開始的時候調用 - (void)animationDidStart:(CAAnimation *)anim;
動畫停止的時候調用 - (void)animationDidStop:(CAAnimation *)anim finished:(BOOL)flag;

2.CAPropertyAnimation

位移動畫通常使用屬性動畫控制 CALayer 的 position 屬性持續改變，如果要實現 CALayer 的旋轉、縮放等動畫效果，若在平面上（二維空間）上，則修改 CALayer 的 affineTransform 屬性，該屬性值為一個CGAffineTransform 對象；若在三維空間上，則修改 CALayer 的 transform 屬性，該屬性值為一個 CATransform3D 對象。

CATransform3D : 三維變換矩陣

3.CABasicAnimation 和 CAKeyframeAnimation

CAPropertyAnimation的子類，首先創建初始化一個CALayer，初始化動畫CABasicAnimation是設置 fromValue 和 toValue ，CAKeyframeAnimation是設置 values ，再設置其他動畫屬性，將動畫添加到圖層上。

CALayer 為動畫提供的方法

① 位移動畫
CABasicAnimation

CABasicAnimation * anim = [CABasicAnimation animationWithKeyPath:@"position"];
anim.fromValue = [NSValue valueWithCGPoint:self.layer.position];
CGPoint toPoint = CGPointMake(300, 300);
anim.toValue = [NSValue valueWithCGPoint:toPoint];
anim.duration = 1.0;
self.layer.position = toPoint;
anim.removedOnCompletion = YES;
[self.layer addAnimation:anim forKey:@"KCBasicAnimation_Position"];

CAKeyframeAnimation

CAKeyframeAnimation * keyframeAnimation = [CAKeyframeAnimation animationWithKeyPath:@"position"];
NSValue * value1 = [NSValue valueWithCGPoint:self.layer.position];
NSValue * value2 = [NSValue valueWithCGPoint:CGPointMake(80, 220)];
NSValue * value3 = [NSValue valueWithCGPoint:CGPointMake(45, 300)];
NSValue * value4 = [NSValue valueWithCGPoint:CGPointMake(55, 400)];
NSArray * values=@[value1,value2,value3,value4];
keyframeAnimation.values = values;
keyframeAnimation.duration = 2.0;
[self.layer addAnimation:keyframeAnimation forKey:@"KCKeyframeAnimation_Position"];    

通過描繪路徑進行關鍵幀動畫控制

CAKeyframeAnimation * keyframeAnimation=[CAKeyframeAnimation animationWithKeyPath:@"position"];
CGMutablePathRef path = CGPathCreateMutable();
CGPathMoveToPoint(path, NULL, self.layer.position.x, self.layer.position.y);
CGPathAddCurveToPoint(path, NULL, 160, 280, -30, 300, 55, 400);
keyframeAnimation.path = path;
CGPathRelease(path);
keyframeAnimation.duration = 4.0;
keyframeAnimation.removedOnCompletion = YES;
[self.layer addAnimation:keyframeAnimation forKey:@"KCKeyframeAnimation_Position"];

② 旋轉動畫
CABasicAnimation

CABasicAnimation * anim = [CABasicAnimation animationWithKeyPath:@"transform"];
CATransform3D fromValue = self.layer.transform;
anim.fromValue = [NSValue valueWithCATransform3D:fromValue];
CATransform3D toValue = CATransform3DRotate(fromValue, M_PI, 1, 0, 0);
anim.toValue = [NSValue valueWithCATransform3D:toValue];
anim.duration = 0.5;
self.layer.transform = toValue;
anim.removedOnCompletion = YES;
[self.layer addAnimation:anim forKey:@"KCBasicAnimation_Rotate"];

CAKeyframeAnimation

CAKeyframeAnimation * keyframeAnimation = [CAKeyframeAnimation animationWithKeyPath:@"transform"];
NSValue * value1 = [NSValue valueWithCATransform3D:self.layer.transform];
NSValue * value2 = [NSValue valueWithCATransform3D:CATransform3DMakeRotation(M_PI, 1, 0, 0)];
NSValue * value3 = [NSValue valueWithCATransform3D:CATransform3DMakeRotation(M_PI, 0, 1, 0)];
NSValue * value4 = [NSValue valueWithCATransform3D:CATransform3DMakeRotation(M_PI, 0, 0, 1)];
NSArray * values = @[value1,value2,value3,value4];
keyframeAnimation.values = values;
keyframeAnimation.duration = 2.0;
[self.layer addAnimation:keyframeAnimation forKey:@"KCKeyframeAnimation_Rotate"];

③ 縮放動畫
CABasicAnimation

CABasicAnimation * anim = [CABasicAnimation animationWithKeyPath:@"transform"];
CATransform3D fromValue = self.layer.transform;
anim.fromValue = [NSValue valueWithCATransform3D:fromValue];
CATransform3D toValue = CATransform3DScale(fromValue, 0.5, 0.5, 1);
anim.toValue = [NSValue valueWithCATransform3D:toValue];
anim.duration = 0.5;
self.layer.transform = toValue;
anim.removedOnCompletion = YES;
[self.layer addAnimation:anim forKey:@"KCBasicAnimation_Scale"];

CAKeyframeAnimation

CAKeyframeAnimation * keyframeAnimation = [CAKeyframeAnimation animationWithKeyPath:@"transform"];
NSValue * value1 = [NSValue valueWithCATransform3D:self.layer.transform];
NSValue * value2 = [NSValue valueWithCATransform3D:CATransform3DMakeScale(0.5, 0.5, 1)];
NSValue * value3 = [NSValue valueWithCATransform3D:CATransform3DMakeScale(1, 1, 1)];
NSArray * values = @[value1,value2,value3];
keyframeAnimation.values = values;
keyframeAnimation.duration = 2.0;
[self.layer addAnimation:keyframeAnimation forKey:@"KCKeyframeAnimation_Scale"];

④ 動畫組
CABasicAnimation

CGPoint fromPoint = self.layer.position;
CGPoint toPoint = CGPointMake(280, fromPoint.y + 300);

CABasicAnimation * moveAnim = [CABasicAnimation animationWithKeyPath:@"position"];
moveAnim.fromValue = [NSValue valueWithCGPoint:fromPoint];
moveAnim.toValue = [NSValue valueWithCGPoint:toPoint];
moveAnim.removedOnCompletion = YES;

CABasicAnimation * transformAnim = [CABasicAnimation animationWithKeyPath:@"transform"];
CATransform3D fromValue = self.layer.transform;
transformAnim.fromValue = [NSValue valueWithCATransform3D:fromValue];
CATransform3D scaleValue = CATransform3DScale(fromValue, 0.5, 0.5, 1);
CATransform3D rotateValue = CATransform3DRotate(fromValue, M_PI, 0, 0, 1);
CATransform3D toValue = CATransform3DConcat(scaleValue, rotateValue);
transformAnim.toValue = [NSValue valueWithCATransform3D:toValue];
transformAnim.cumulative = YES;
transformAnim.repeatCount = 2;
transformAnim.duration = 3;

CAAnimationGroup * animGroup = [CAAnimationGroup animation];
animGroup.animations = @[moveAnim,transformAnim];
animGroup.duration = 6;
[self.layer addAnimation:animGroup forKey:@"KCBasicAnimation_Group"];

CAKeyframeAnimation

CAKeyframeAnimation * moveAnim = [CAKeyframeAnimation animationWithKeyPath:@"position"];
NSValue * move1 = [NSValue valueWithCGPoint:self.layer.position];
NSValue * move2 = [NSValue valueWithCGPoint:CGPointMake(300, 100)];
NSValue * move3 = [NSValue valueWithCGPoint:CGPointMake(300, 300)];
NSValue * move4 = [NSValue valueWithCGPoint:CGPointMake(100, 300)];
NSValue * move5 = [NSValue valueWithCGPoint:CGPointMake(100, 100)];
NSArray * values = @[move1,move2,move3,move4,move5];
moveAnim.values = values;
moveAnim.removedOnCompletion = YES;

CAKeyframeAnimation * transformAnim = [CAKeyframeAnimation animationWithKeyPath:@"transform"];
CATransform3D rotate1 = self.layer.transform;
CATransform3D rotate2 = CATransform3DMakeRotation(M_PI, 1, 0, 0);
CATransform3D rotate3 = CATransform3DMakeRotation(M_PI, 0, 1, 0);
CATransform3D rotate4 = CATransform3DMakeRotation(M_PI, 0, 0, 1);
CATransform3D rotate5 = CATransform3DMakeRotation(M_PI, 1, 1, 1);

CATransform3D scale1 = self.layer.transform;
CATransform3D scale2 = CATransform3DMakeScale(0.5, 0.5, 1);
CATransform3D scale3 = CATransform3DMakeScale(1, 1, 1);
CATransform3D scale4 = CATransform3DMakeScale(0.5, 0.5, 1);
CATransform3D scale5 = CATransform3DMakeScale(1, 1, 1);

NSValue * transform1 = [NSValue valueWithCATransform3D:CATransform3DConcat(rotate1, scale1)];
NSValue * transform2 = [NSValue valueWithCATransform3D:CATransform3DConcat(rotate2, scale2)];
NSValue * transform3 = [NSValue valueWithCATransform3D:CATransform3DConcat(rotate3, scale3)];
NSValue * transform4 = [NSValue valueWithCATransform3D:CATransform3DConcat(rotate4, scale4)];
NSValue * transform5 = [NSValue valueWithCATransform3D:CATransform3DConcat(rotate5, scale5)];
transformAnim.values = @[transform1,transform2,transform3,transform4,transform5];
transformAnim.removedOnCompletion = YES;

CAAnimationGroup * animGroup = [CAAnimationGroup animation];
animGroup.animations = @[moveAnim,transformAnim];
animGroup.duration = 8;
self.layer.position = CGPointMake(100, 100);
[self.layer addAnimation:animGroup forKey:@"KCBasicAnimation_Group"];

④ 動畫暫停

-(void)pauseLayer{
    CFTimeInterval interval=[self.layer convertTime:CACurrentMediaTime() fromLayer:nil];
    [self.layer setTimeOffset:interval];
    self.layer.speed=0;
}

⑤ 動畫恢復

-(void)resumeLayer{
    CFTimeInterval beginTime= CACurrentMediaTime() - self.layer.timeOffset;
    self.layer.timeOffset = 0;
    self.layer.beginTime = beginTime;
    self.layer.speed=1.0;
}

4.CATransition

CATransition的type屬性用于控制動畫類型，還有私有動畫。

值| 說明 |是否支持方向設置
-----|-----
kCATransitionFade|通過漸隱效果過渡，默認屬性值|是
kCATransitionMoveIn|通過移入動畫過渡，新視圖移到舊視圖上面|是
kCATransitionPush|通過推入動畫過渡，新視圖把舊視圖推出去|是
kCATransitionReveal|通過揭開動畫過渡，將舊視圖移開,同時顯示下面的新視圖|是
@"cube"|通過立方體旋轉動畫過渡|是
@"oglFlip"|通過翻轉動畫過渡|是
@"suckEffect"|通過收縮（吸入）動畫過渡|否
@"rippleEffect"|通過水波動畫過渡|否
@"pageCurl"|通過向后翻頁動畫過渡|是
@"pageUnCurl"|通過向前翻頁動畫過渡|是
@"cameraIrisHollowOpen"|通過相機鏡頭打開效果動畫過渡|否
@"cameraIrisHollowClose"|通過相機鏡頭關閉效果動畫過渡|否

CATransition的subtype屬性用于控制動畫方向

#import "ViewController.h"
#define IMAGE_COUNT 5

typedef enum {
    GestureDirectionUp = 1,
    GestureDirectionDown,
    GestureDirectionLeft,
    GestureDirectionRight
}GestureDirection;

@interface ViewController () <UIPickerViewDelegate,UIPickerViewDataSource>

@property (nonatomic,strong) UIImageView * imageView;
@property (nonatomic,assign) int currentIndex;
@property (nonatomic,strong) CATransition * transition;
@property (nonatomic,strong) UIPickerView * pickerView;
@property (nonatomic,copy) NSArray * transitions;
@property (nonatomic,assign) BOOL isPop;

@end

@implementation ViewController

- (NSArray *)transitions{
    if (_transitions == nil) {
        _transitions = @[kCATransitionFade,kCATransitionMoveIn,kCATransitionPush,kCATransitionReveal,@"cube",@"oglFlip",@"suckEffect",@"rippleEffect",@"pageCurl",@"pageUnCurl",@"cameralIrisHollowOpen",@"cameraIrisHollowClose"];
    }
    return _transitions;
}

- (void)viewDidLoad {
    [super viewDidLoad];

    self.view.backgroundColor = [UIColor whiteColor];

    CGFloat screenWidth = [UIScreen mainScreen].bounds.size.width;
    CGFloat screenHeight = [UIScreen mainScreen].bounds.size.height;

    self.navigationItem.title = @"轉場";
    UIBarButtonItem * rightBarButtonItem = [[UIBarButtonItem alloc]initWithTitle:@"效果" style:UIBarButtonItemStyleDone target:self action:@selector(selectTransition:)];
    self.navigationItem.rightBarButtonItem = rightBarButtonItem;

    self.imageView = [[UIImageView alloc]initWithFrame:self.view.frame];
    self.imageView.backgroundColor = [UIColor whiteColor];
    self.imageView.contentMode = UIViewContentModeScaleAspectFit;
    self.imageView.image = [UIImage imageNamed:@"0.jpg"];
    [self.view addSubview:self.imageView];

    self.pickerView = [[UIPickerView alloc]initWithFrame:CGRectMake(0, screenHeight, screenWidth, 300)];
    self.pickerView.dataSource = self;
    self.pickerView.delegate = self;
    [self.view addSubview:self.pickerView];

    UISwipeGestureRecognizer * upSwipeGesture = [[UISwipeGestureRecognizer alloc]initWithTarget:self action:@selector(swipe:)];
    [upSwipeGesture setDirection:UISwipeGestureRecognizerDirectionUp];
    [self.view addGestureRecognizer:upSwipeGesture];

    UISwipeGestureRecognizer * downSwipeGesture = [[UISwipeGestureRecognizer alloc]initWithTarget:self action:@selector(swipe:)];
    [downSwipeGesture setDirection:UISwipeGestureRecognizerDirectionDown];
    [self.view addGestureRecognizer:downSwipeGesture];

    UISwipeGestureRecognizer * leftSwipeGesture = [[UISwipeGestureRecognizer alloc]initWithTarget:self action:@selector(swipe:)];
    [leftSwipeGesture setDirection:UISwipeGestureRecognizerDirectionLeft];
    [self.view addGestureRecognizer:leftSwipeGesture];

    UISwipeGestureRecognizer * rightSwipeGesture = [[UISwipeGestureRecognizer alloc]initWithTarget:self action:@selector(swipe:)];
    [rightSwipeGesture setDirection:UISwipeGestureRecognizerDirectionRight];
    [self.view addGestureRecognizer:rightSwipeGesture];

    self.transition = [[CATransition alloc]init];
    self.transition.type = kCATransitionFade;
    self.isPop = NO;
}

- (void)selectTransition:(UIBarButtonItem *)btn{
    self.isPop = !self.isPop;
    if (self.isPop) {
        CGContextRef context = UIGraphicsGetCurrentContext();
        [UIView beginAnimations:nil context:context];
        [UIView setAnimationCurve:UIViewAnimationCurveEaseInOut];
        [UIView setAnimationDuration:0.6];
        [self.view bringSubviewToFront:self.pickerView];
        CGFloat screenHeight = [UIScreen mainScreen].bounds.size.height;
        CGFloat pickerViewWidth = [UIScreen mainScreen].bounds.size.width;
        CGFloat pickerViewHeight = 300;
        self.pickerView.frame = CGRectMake(0, screenHeight - pickerViewHeight, pickerViewWidth, pickerViewHeight);
        [UIView commitAnimations];
}
else {
        CGContextRef context = UIGraphicsGetCurrentContext();
        [UIView beginAnimations:nil context:context];
        [UIView setAnimationCurve:UIViewAnimationCurveEaseInOut];
        [UIView setAnimationDuration:0.6];
        CGFloat screenHeight = [UIScreen mainScreen].bounds.size.height;
        CGFloat pickerViewWidth = [UIScreen mainScreen].bounds.size.width;
        CGFloat pickerViewHeight = 300;
        self.pickerView.frame = CGRectMake(0, screenHeight, pickerViewWidth, pickerViewHeight);
        [UIView commitAnimations];
    }
}

-(void)swipe:(UISwipeGestureRecognizer *)gesture{
    if (gesture.direction == UISwipeGestureRecognizerDirectionUp){
        [self transitionAnimation:GestureDirectionUp];
    }
    else if (gesture.direction == UISwipeGestureRecognizerDirectionDown){
        [self transitionAnimation:GestureDirectionDown];
    }
    else if (gesture.direction == UISwipeGestureRecognizerDirectionLeft){
        [self transitionAnimation:GestureDirectionLeft];
    }
    else {
        [self transitionAnimation:GestureDirectionRight];
    }
}

- (void)transitionAnimation:(GestureDirection)gestureDirection{
    switch (gestureDirection) {
        case GestureDirectionUp:
            self.transition.subtype = kCATransitionFromTop;
            break;
        case GestureDirectionDown:
            self.transition.subtype = kCATransitionFromBottom;
           break;
        case GestureDirectionLeft:
            self.transition.subtype = kCATransitionFromRight;
            break;
        case GestureDirectionRight:
            self.transition.subtype = kCATransitionFromLeft;
            break;
        default:
            break;
    }
    self.transition.duration = 1.0f;
    self.imageView.image = [self getImage];
    [self.view.layer addAnimation:self.transition forKey:@"KCTransitionAnimation"];
}

- (UIImage *)getImage{
    self.currentIndex = (self.currentIndex + 1) % IMAGE_COUNT;
    NSString *imageName=[NSString stringWithFormat:@"%i.jpg",_currentIndex];
    return [UIImage imageNamed:imageName];
}

- (NSInteger)numberOfComponentsInPickerView:(UIPickerView *)pickerView{
    return 1;
}

- (NSInteger)pickerView:(UIPickerView *)pickerView numberOfRowsInComponent:(NSInteger)component{
    return self.transitions.count;
}

- (NSString *)pickerView:(UIPickerView *)pickerView titleForRow:(NSInteger)row forComponent:(NSInteger)component{
    return self.transitions[row];
}

- (void)pickerView:(UIPickerView *)pickerView didSelectRow:(NSInteger)row inComponent:(NSInteger)component{
    self.transition.type = self.transitions[row];
}

- (void)didReceiveMemoryWarning {
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}

@end

5.逐幀動畫

通過設置UIImageView的animationImages屬性，然后調用它的startAnimating方法去播放一組逐幀圖片，但是它存在著很大的性能問題，并且這種方法一旦設置完圖片中間的過程就無法控制了。使用CADisplayLink加入到主循環隊列中，循環調用目標方法，在這個方法中更新視圖內容就可以完成逐幀動畫。

- (void)runAnimationWithImageCount:(NSInteger)count AndImageName:(NSString *)name
{
    if (self.myImageView.isAnimating)
    {
        return;
    }
    NSMutableArray * pictArray = [NSMutableArray array];
    for (int i = 0; i < count; i++)
    {
        NSString * pictNum = [NSString stringWithFormat:@"%@_%02d.jpg",name,i];
        // 使用imageNamed的方式加載圖片會有緩存，使得占用的內存很大
        //[pictArray addObject:[UIImage imageNamed:pictNum]];
    
        // 直接從文件中讀取圖片就不會占用太大的內存
        NSBundle * boudle = [NSBundle mainBundle];
        NSString * path = [boudle pathForResource:pictNum ofType:nil];
        [pictArray addObject:[UIImage imageWithContentsOfFile:path]];
    }
    self.myImageView.animationImages = pictArray;
    self.myImageView.animationDuration = (self.myImageView.animationImages.count * 0.07);
    CGFloat delayTime = self.myImageView.animationDuration + 0.5;
    self.myImageView.animationRepeatCount = 1;
    [self.myImageView startAnimating];

    [self.myImageView performSelector:@selector(setAnimationImages:) withObject:nil afterDelay:delayTime];
}

6.UIView動畫封裝

UIView本身對于基本動畫和關鍵幀動畫、轉場動畫都有相應的封裝。

動畫使用block方式

UIViewAnimationCurve

UIViewAnimationOptions

UIViewKeyframeAnimationOptions
其中一部分值和 UIViewAnimationOptions 是一樣的，不一樣的如下：

7.彈簧動畫

[UIView animateWithDuration:5.0 delay:0 usingSpringWithDamping:0.1 initialSpringVelocity:1.0 options:UIViewAnimationOptionCurveLinear animations:^{
    self.imageView.center = CGPointMake(300, 300);
} completion:nil];