How to scale UIImageView properly with UIView animateWithDuration?

问题

I'm scaling UIImageView and then reverting it using UIView animateWithDuration with UIViewAnimationOptionAutoreverse option. The problem is the image animation is a little bit jaggy (twitching) at the end of the animation. Here's my code:

[UIView animateWithDuration:0.25 delay:0 options:UIViewAnimationOptionAutoreverse 
  animations:^{

    myImage.transform = CGAffineTransformScale(CGAffineTransformIdentity, 0.9, 0.9);}  

  completion:^(BOOL finished){if (finished){

    myImage.transform = CGAffineTransformScale(CGAffineTransformIdentity, 1.0, 1.0);}}];

I know that I'm missing something but don't know where to start :(

UPDATE1: I'm performing nested 6 animations where each next animation performs after previous one. For that I'm using block animations and performing each next animation in complete block.

UPDATE2: I have tried with UIViewAnimationOptionRepeat option but there's still some flash effect after each scale animation.

回答1:

UIViewAnimationOptionAutoreverse does nothing without also using the UIViewAnimationOptionRepeat option. Your animation as written will shrink the image to 90%, then snap back to 100% in the completion block. Maybe you can follow this animation with another that scales back to 100% over a quarter second. Something like this:

    [UIView animateWithDuration:0.25 delay:0 options:UIViewAnimationOptionCurveEaseInOut 
                 animations:^{
                     myImage.transform = CGAffineTransformScale(CGAffineTransformIdentity, 0.9, 0.9);}  
                 completion:^(BOOL finished){if (finished){

    [UIView animateWithDuration:0.25 delay:0 options:UIViewAnimationOptionCurveEaseInOut 
                     animations:^{
                         myImage.transform = CGAffineTransformScale(CGAffineTransformIdentity, 1.0, 1.0);}  
                     completion:NULL];}}];

回答2:

.h file declerd.

NSInteger imgint;

.m file in code and try.

-(void) 
{
    [NSTimer scheduledTimerWithTimeInterval:(0.85f)target:self selector:@selector(play_btn_animation) userInfo:nil repeats:YES];   
}

-(void)play_btn_animation
{
    if(imgint == 0)
    {
        [UIView animateWithDuration:0.8
                              delay:0.0
                            options: UIViewAnimationOptionCurveEaseIn
                         animations:^{
                             img.transform = CGAffineTransformScale(CGAffineTransformIdentity, 0.8, 0.8);
                         }
                         completion:^(BOOL finished) {
                             img = 1;
                         }];

    }
    else
    {
        [UIView animateWithDuration:0.8
                              delay:0.0
                            options: UIViewAnimationOptionCurveEaseOut
                         animations:^{
                             img.transform = CGAffineTransformScale(CGAffineTransformIdentity, 1, 1);
                         }
                         completion:^(BOOL finished) {
                             imgint = 0;
                         }];
    }
}

来源：https://stackoverflow.com/questions/7081076/how-to-scale-uiimageview-properly-with-uiview-animatewithduration

标签

iphone

objective-c

animation

uiimageview

scaling