屏幕上有一张图片需要在停留的时候全屏。
UILongPressGestureRecognizer *hold = [[UILongPressGestureRecognizer alloc] initWithTarget:self action:@selector(hold:)];
hold.minimumPressDuration = 0;
[self.photoImageView addGestureRecognizer:hold];
监听器:
-(void)hold:(UILongPressGestureRecognizer *)sender{
UIImageView *img = [[UIImageView alloc] initWithImage:self.photo];
img.userInteractionEnabled = NO;
if(sender.state == UIGestureRecognizerStateBegan){
NSLog(@"state began");
[self.view addSubview:img];
} else if (sender.state == UIGestureRecognizerStateEnded){
NSLog(@"state ended");
[img removeFromSuperview];
}
}
图片成功添加到屏幕中,只有 [img removeFromSuperview]
好像没有响应。
结束状态的NSlog
也正常。
-(void)hold:(UILongPressGestureRecognizer *)sender{
//每次响应函数 img都是一个新alloc出来的UIImageView
UIImageView *img = [[UIImageView alloc] initWithImage:self.photo];
img.userInteractionEnabled = NO;
if(sender.state == UIGestureRecognizerStateBegan){
NSLog(@"state began");
//添加新alloc出来的UIImageView,可以看到界面效果
[self.view addSubview:img];
} else if (sender.state == UIGestureRecognizerStateEnded){
NSLog(@"state ended");
//remove 新alloc出来的UIImageView当然没有效果,它还没有被add进去
[img removeFromSuperview];
}
}
改成这样
-(void)hold:(UILongPressGestureRecognizer *)sender{
if(sender.state == UIGestureRecognizerStateBegan){
NSLog(@"state began");
UIImageView *img = [[UIImageView alloc] initWithImage:self.photo];
img.userInteractionEnabled = NO;
img.tag = kTAG_PHOTO_IMAGE_VIEW
[self.view addSubview:img];
} else if (sender.state == UIGestureRecognizerStateEnded){
NSLog(@"state ended");
UIImageView *img = (UIImageView *)[self.view viewWithTag:kTAG_PHOTO_IMAGE_VIEW];
[img removeFromSuperview];
}
}
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