objective-c - iphone 应用程序 : drag drop UIImageView

Question

我正在尝试在 iPhone 应用程序中执行拖放操作。我有一个包含多层 View 的主视图。

我放置了:

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

在主视图中，但这不会被调用。当用户第一次触摸时，我可以在 View 上加载缩略图。我尝试拖动 UIImageView，但未调用 touchesMoved:。

这是一些代码:(这是当用户触摸 View 时加载的拖动图像，它加载并放置在光标下方)

[dragImage addTarget:self action:@selector(endDrag) forControlEvents:UIControlEventTouchUpOutside];
[dragImage addTarget:self action:@selector(endDrag) forControlEvents:UIControlEventTouchUpInside];
[dragImage addTarget:self action:@selector(endDrag) forControlEvents:UIControlEventTouchDragInside];

Answer 1

这是我在屏幕上拖动图像的方法:

UIPanGestureRecognizer *panRecognizer = [[UIPanGestureRecognizer alloc] initWithTarget:self action:@selector(move:)];
[panRecognizer setMinimumNumberOfTouches:1];
[panRecognizer setMaximumNumberOfTouches:1];
[panRecognizer setDelegate:self];
[imageView_ addGestureRecognizer:panRecognizer];

然后:

-(void)move:(id)sender {

    CGPoint translatedPoint = [(UIPanGestureRecognizer*)sender translationInView:self.view];

    if([(UIPanGestureRecognizer*)sender state] == UIGestureRecognizerStateBegan) {

        firstX = [[sender view] center].x;
        firstY = [[sender view] center].y;
    }

    translatedPoint = CGPointMake(firstX+translatedPoint.x, firstY+translatedPoint.y);
    [[sender view] setCenter:translatedPoint];

}