如果使用CGRect變量代替CGRectMake，動畫不起作用

Question

我有一個向右移動圖像的動畫，然後當我放開按鈕時停止。我需要圖像的幀在不同的時間是不同的，所以我用CGRect變量代替myImageView.frame = CGRectMake。但是當我使用可變圖像跳躍回到原來的位置時，每次我放開，而不是像往常一樣停下來。

if (myInt == 2) { 
    MyCGRect = CGRectMake(myImageView.frame.origin.x,myImageView.frame.origin.y,18,42); 
} else { 
    MyCGRect = CGRectMake(myImageView.frame.origin.x,myImageView.frame.origin.y,35,28); 
} 

-(IBAction)holdToMakeImageMove:(id)sender 
{ 
//!!!!!This Works!!!!!! 
myImageView.frame = CGRectMake(myImageView.frame.origin.x,myImageView.frame.origin.y,18,42); 

//!!!!!!THIS doesnt work 

myImageView.frame = MyCGRect; 

//...animation 

} 

Answer 1

例如，此代碼適用於我。將按鈕幀從（0,800,50,50）更改爲（0,0,100,100）

@interface ViewController() 
... 
@property (nonatomic, assign) CGRect myRect; 
... 
@end 

@implementation ViewController 
... 
@synthesize myRect = _myRect; 
... 
- (void)viewDidLoad { 
    [super viewDidLoad]; 

    UIButton *btn = [UIButton buttonWithType:UIButtonTypeRoundedRect]; 
    [btn setFrame:CGRectMake(0, 800, 50, 50)]; 
    [btn addTarget:self action:@selector(avvia:) forControlEvents:UIControlEventTouchUpInside]; 
    [self.view addSubview:btn]; 

    self.myRect = CGRectMake(100, 0, 100, 100); 
} 
... 
- (void)avvia:(id)sender { 
    ((UIButton *)sender).frame = self.myRect; 
} 
... 
@end