Question

我正在尝试在iPhone应用中进行拖放。我有一个包含多层视图的主视图。

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，我能够在视图上加载缩略图图像。我尝试拖动UIImageView，但touchesMoved:未被调用。

这里有一些代码:(这是当用户触摸视图时加载的拖动图像，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

这就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];

}

Answer 2

你可以做的是将UIImageView放在UIControl中（它将响应UIControlEventTouchDragInside）。

UIControl *dragImageControl = [[UIControl alloc] initWithFrame:dragImageView.frame];
        [dragImageControl addSubview:dragImageView];

[self.view addSubview:dragImageControl];

[dragImageControl addTarget:self action:@selector(imageTouch:withEvent:) forControlEvents:UIControlEventTouchDown];
[dragImageControl addTarget:self action:@selector(imageMoved:withEvent:) forControlEvents:UIControlEventTouchDragInside];

并且在imageMoved中，您可以拥有以下代码：

- (IBAction) imageMoved:(id) sender withEvent:(UIEvent *) event
{
    CGPoint point = [[[event allTouches] anyObject] locationInView:self.view];
    UIControl *control = sender;
    control.center = point;
}

iPhone应用程序：拖放UIImageView

2 个答案: