objective-c 動畫 花瓣飄落

//

//  ViewController.m

//  花瓣飄落

//

#import "ViewController.h"

@interface ViewController ()

{

    CALayer *_layer;//建立一個圖層

}

@end

@implementation ViewController

- (void)viewDidLoad {

    [super viewDidLoad];

    

    //設置背景

    UIImage *backgroundImage = [UIImage imageNamed:@"background"];

    self.view.backgroundColor = [UIColor colorWithPatternImage:backgroundImage];

    

    //自定義一個圖層（花瓣）

    _layer = [[CALayer alloc]init];

    _layer.bounds = CGRectMake(0, 0, 16, 30);

    _layer.position = CGPointMake(50, 200);

    _layer.contents = (id)[UIImage imageNamed:@"petal"].CGImage;

    [self.view.layer addSublayer:_layer];

    //執行動畫

    [self keyFrameAnimation];

}

#pragma mark 關鍵幀動畫

- (void)keyFrameAnimation

{

    //1.建立關鍵幀動畫

    CAKeyframeAnimation *keyframeAni = [CAKeyframeAnimation animationWithKeyPath:@"position"];

    

    //2.設置關鍵幀

    //繪製貝塞爾曲線

    CGMutablePathRef path = CGPathCreateMutable();

    CGPathMoveToPoint(path, NULL, _layer.position.x, _layer.position.y);//路徑移動到起點

    CGPathAddCurveToPoint(path, NULL, 160, 280, -30, 300, 50, 400);//繪製2次貝塞爾曲線

    keyframeAni.path = path;//設置動畫沿路徑進行

    

    //設置一些其它的屬性

    keyframeAni.duration = 10.0;

    keyframeAni.beginTime = CACurrentMediaTime() + 2;//設置延遲2秒執行

    keyframeAni.autoreverses = YES;

    keyframeAni.repeatCount = HUGE_VALF;

    //添加動畫到圖層

    [_layer addAnimation:keyframeAni forKey:@"keyFrameAnimation"];

}

//-(void)touchesBegan:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event

//{

//    //獲取點擊位置

//    UITouch *touch = [touches anyObject];

//    CGPoint location = [touch locationInView:self.view];

//    

//    //1.建立動畫並指定動畫屬性

//    CABasicAnimation *basicAnimation = [CABasicAnimation animationWithKeyPath:@"position"];

//    //2.設置動畫屬性初始值和結束值

//    //初始值能夠不設置，默認圖層初始位置

//    basicAnimation.toValue = [NSValue valueWithCGPoint:location];

//    //3.設置其餘動畫屬性

//    basicAnimation.duration = 5.0;//動畫時間

//    basicAnimation.repeatCount = 1;//循環次數

//    basicAnimation.delegate = self;

//    //記錄鼠標點擊位置,在動畫結束後使用

//    [basicAnimation setValue:[NSValue valueWithCGPoint:location] forKey:@"animationLocation"];

//    

//    //4.添加動畫。注意key至關於給動畫命名，之後可使用此名稱獲取該動畫

//    [_layer addAnimation:basicAnimation forKey:@"basicAnimation"];

//}

//

//#pragma mark 動畫代理方法

//#pragma mark 動畫結束

//-(void)animationDidStop:(CAAnimation *)anim finished:(BOOL)flag

//{

//    //開啓動畫事務

//    [CATransaction begin];

//    //禁用隱式動畫

//    [CATransaction setDisableActions:YES];

//    _layer.position = [[anim valueForKey:@"animationLocation"] CGPointValue];

//    //遞交動畫事務

//    [CATransaction commit];

//}

@end