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我正在尝试构建一个从右到左GestureRecognizer拖动一个。UIView如果用户将 View 拖到屏幕的一半，View 会自动拖到左角丢弃它，但如果用户没有拖到一半屏幕，它会返回到屏幕的右角。这里有点迷失，任何教程或什么？谢谢

编辑：继承一些代码，它的a UIImageView，在a内UIScrollView，我需要拖动整个滚动或只是其中的图像：

_myScroll = [[UIScrollView alloc] initWithFrame:CGRectMake(0, 0, self.window.bounds.size.width, self.window.bounds.size.height)]; [_myScroll setContentSize:CGSizeMake(self.window.bounds.size.width , 1300)];

_tutorial = [[UIImageView alloc] initWithFrame:CGRectMake(0, 0, self.window.bounds.size.width, 1300)]; [_tutorial setImage:[UIImage imageNamed:@"Default"]];
_tutorial.contentMode = UIViewContentModeScaleAspectFit; [_myScroll addSubview:_tutorial];

_tutorial.userInteractionEnabled = YES;
    UIPanGestureRecognizer * recognizer = [[UIPanGestureRecognizer alloc]initWithTarget:_tutorial action:@selector(handlePan:)]; 
 [_tutorial addGestureRecognizer:recognizer];

    [self.window addSubview:_myScroll];

我尝试拖动的方法UIImageView

- (IBAction)handlePan:(UIPanGestureRecognizer *)recognizer {

    CGPoint translation = [recognizer translationInView:_myScroll];
    recognizer.view.center = CGPointMake(recognizer.view.center.x + translation.x,
                                         recognizer.view.center.y + translation.y);
    [recognizer setTranslation:CGPointMake(0, 0) inView:_myScroll];

}
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1 回答 1

33

看看这里。这是一个UIGestureRecognizer教程，它将为您提供处理捏合和平移手势的基础知识。一旦你学会了基础知识，就很容易实现你想要的。您只需在平移完成后检查视图的位置，以将其发送到正确的位置。看看这个其他教程，UIScrollViews它可能会帮助您找到通过第二部分的方式。

两个教程都来自raywenderlich.com，这可能是我所知道的最有用的 iOS 教程网站。

这是您可以使用的方法的一些代码handlePan:：

- (IBAction)handlePan:(UIPanGestureRecognizer *)recognizer {

    CGPoint translation = [recognizer translationInView:_myScroll];

    recognizer.view.center = CGPointMake(recognizer.view.center.x + translation.x,
                                         recognizer.view.center.y + translation.y);

    if (recognizer.state == UIGestureRecognizerStateEnded) {

        // Check here for the position of the view when the user stops touching the screen

        // Set "CGFloat finalX" and "CGFloat finalY", depending on the last position of the touch

        // Use this to animate the position of your view to where you want
        [UIView animateWithDuration: aDuration
                              delay: 0 
                            options: UIViewAnimationOptionCurveEaseOut 
                         animations:^{
            CGPoint finalPoint = CGPointMake(finalX, finalY);
            recognizer.view.center = finalPoint; } 
                         completion:nil];
    }


    [recognizer setTranslation:CGPointMake(0, 0) inView:_myScroll];

}

我不会在这里给你完美的答案，你必须在代码上工作才能找到一种方法让它按照你的意愿工作。

这是最后一个提示。您可以使用 slideFactor 来制作某种“平滑”动画。它将帮助您的动画更加“逼真”。处理这段代码，你在“if”的开头添加：

CGPoint velocity = [recognizer velocityInView:self.view];
CGFloat magnitude = sqrtf((velocity.x * velocity.x) + (velocity.y * velocity.y));
CGFloat slideMult = magnitude / 200;

float slideFactor = 0.1 * slideMult; // Increase for more slide

然后在 UIView 中animateWithDuration:，slideFactor用作持续时间。

于 2012-12-14T13:52:42.770 回答