如果检测到越界，则禁用Pan Gesture [英] Disabling Pan Gesture if out of bounds detected

问题描述

我有一个UIView我试图在屏幕上上下移动，但是我只希望它能够平移，这样当它处于正常位置（0,0）时你就无法将视图向下拖动

I have a UIView I am trying to move up and down the screen, however I only wish to enable it to pan so that you cannot drag the view down when it is in its normal position (0, 0)

我试图检测识别器的中心何时不是视图高度的一半，但视图是不可移动的，中心总是高度的一半（在这种情况下为230） 。

I tried to detect when the recognizer's center is not half the height of the view, however the view is then immovable, and the center is always half the height (230 in this case).

任何想法？

- (IBAction)panDetected:(UIPanGestureRecognizer *)recognizer {
    CGPoint translation = [recognizer translationInView:self.view];
    NSLog(@"\ncenter.y: %f\ntranslation.y: %f\n", recognizer.view.center.y, translation.y);
    if (recognizer.view.center.y > ([[UIScreen mainScreen] bounds].size.height - 20)/2) {
            return;
    }
    recognizer.view.center = CGPointMake(recognizer.view.center.x,
                                         recognizer.view.center.y + translation.y);
    [recognizer setTranslation:CGPointMake(0, 0) inView:self.view];
}

推荐答案

recognizer.view.center = CGPointMake(recognizer.view.center.x, MAX(recognizer.view.center.y + translation.y, ([[UIScreen mainScreen] bounds].size.height - 20)/2));

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