學習練習--IOS雪花飄落的實現方法

學習練習--IOS雪花飄落的實現方法

方法一：利用NSMutableArray來實現

NSMutable *array;全域變數，在.m檔案中用定時器調用

-(void)down{    static int jianGe = 0;    jianGe++;    if (jianGe > 2) {        jianGe = 0;        [self snowState];    }    [self snowDown];}-(void)snowState{    for (int i  = 0; i < [array count]; i++) {        MyImageView *img = [array objectAtIndex:i];        if (img.tag == 0) {            img.tag = 1;            [self.view addSubview:img];            break;//提取雪花單片        }            }}-(void)snowDown{    for (int i = 0; i < [array count]; i++) {        MyImageView *img = [array objectAtIndex:i];        if (img.tag == 1) {            img.center = CGPointMake(img.center.x, img.center.y+10);            if (img.center.y > 480+25) {                img.tag = 0;                img.center = CGPointMake(arc4random()%370 - 50, -50);            }        }    }}

 

方法二：利用幀動畫

用定時器調用

 

//ViewController.m-(void)snowDown{//動畫效果    UIImageView *iv = [[UIImageView alloc]init];    int a = arc4random()%51;//雪花大小隨機（0~50）    iv.frame = CGRectMake(arc4random()%370 - 50, -50, a, a);    iv.image = [UIImage imageNamed:@"flake"];    [self.view addSubview:iv];        [UIView beginAnimations:nil context:(__bridge void *)(iv)];    [UIView setAnimationDuration:5];    [UIView setAnimationDelegate:self];    [UIView setAnimationDidStopSelector:@selector(animationDidStop:finished:context:)];    iv.frame = CGRectMake(arc4random()%370 - 50, 440, a, a);    [UIView commitAnimations];}-(void)animationDidStop:(NSString *)animationID finished:(NSNumber *)finished context:(void *)context//到底部消除{    UIImageView *image = (__bridge UIImageView *)context;    [image removeFromSuperview];}

 

幀動畫比用NSMutableArray要簡潔，易懂