UIImageView 点击放大缩小

static CGRect oldframe;

-(void)showImage:(UIImageView *)avatarImageView{

UIImage *image=avatarImageView.image;

UIWindow *window=[UIApplication sharedApplication].keyWindow;

UIView *backgroundView=[[UIView alloc]initWithFrame:CGRectMake(0, 0, [UIScreen mainScreen].bounds.size.width, [UIScreen mainScreen].bounds.size.height)];

oldframe=[avatarImageView convertRect:avatarImageView.bounds toView:window];

backgroundView.backgroundColor=[UIColor blackColor];

backgroundView.alpha=0;

UIImageView *imageView=[[UIImageView alloc]initWithFrame:oldframe];

imageView.image=image;

imageView.tag=1;

[backgroundView addSubview:imageView];

[window addSubview:backgroundView];

UITapGestureRecognizer *tap=[[UITapGestureRecognizer alloc]initWithTarget:self action:@selector(hideImage:)];

[backgroundView addGestureRecognizer: tap];

[UIView animateWithDuration:0.3 animations:^{

imageView.frame=CGRectMake(0,([UIScreen mainScreen].bounds.size.height-image.size.height*[UIScreen mainScreen].bounds.size.width/image.size.width)/2, [UIScreen mainScreen].bounds.size.width, image.size.height*[UIScreen mainScreen].bounds.size.width/image.size.width);

backgroundView.alpha=1;

} completion:^(BOOL finished) {

}];

}

-(void)hideImage:(UITapGestureRecognizer*)tap{

UIView *backgroundView=tap.view;

UIImageView *imageView=(UIImageView*)[tap.view viewWithTag:1];

[UIView animateWithDuration:0.3 animations:^{

imageView.frame=oldframe;

backgroundView.alpha=0;

} completion:^(BOOL finished) {

[backgroundView removeFromSuperview];

}];

}