ios - TouchesMoved 与 UITouch

Question

我正在尝试创建一个简单的应用程序，您可以通过触摸 UIImageView 并拖动他来移动 UIImageView。

我的 UIImageView 叫做 imv

-(void ) touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event{

UITouch * touch = [touches anyObject];

if([touch view] == self.imv){
    CGPoint location = [touch locationInView:self.view];
    self.imv.center = location;

}
}

-(void ) touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event{
UITouch * touch = [touches anyObject];

if([touch view] == self.imv){
    CGPoint location = [touch locationInView:self.view];
    self.imv.center = location;

}
}

我一整天都在尝试解决这个问题，但我不知道出了什么问题。如果我禁用 if 语句，它就可以工作，否则就不行。我能做什么？

感谢您的回答

Answer 1

除非您将 UIImageView 子类化(不太可能)，否则您的 View 将接收触摸事件。

如今，使用 UIGestureRecognizer 来处理这种事情更简单也更常见，在本例中是 UIPanGestureRecognizer。

例如

UIPanGestureRecognizer *pan = [[UIPanGestureRecognizer alloc] initWithTarget:self action:@selector(dragImageView:)];
[self.imv addGestureRecognizer:pan];


- (void)dragImageView:(UIPanGestureRecognizer *)dragImageView {
    if(UIGestureRecognizerStateBegan  == state) {
        originalCenter = self.imv.center;    // add CGPoint originalCenter; member
    } else if(UIGestureRecognizerStateChanged == state) {
        CGPoint translate = [pan translationInView:self.imv.superview];
        self.imv.center = CGPointMake(originalCenter.x + translate.x, originalCenter.y + translate.y);
    }
}