我添加了一个平移手势到我的按钮，当我移动它没有任何额外的代码，一切都很好，但是当我添加一些代码，这是在下面的例子中评论，按钮开始重置到它的原点位置。
为什么会这样？原因是什么？
- (IBAction)handlePan:(UIPanGestureRecognizer *)recognizer {
switch([recognizer state]){
case UIGestureRecognizerStateBegan: {
UIButton *on = [UIButton onWithType:UIButtonTypeRoundedRect];
[on setFrame:recognizer.view.frame];
[on setBackgroundColor: [UIColor redColor]];
// [self.view insertSubview:on belowSubview:recognizer.view];
_tempButton = on;
}break;
case UIGestureRecognizerStateChanged: {
CGPoint translation = [recognizer translationInView:self.view];
recognizer.view.center = CGPointMake(recognizer.view.center.x + translation.x, recognizer.view.center.y + translation.y);
[recognizer setTranslation:CGPointMake(0, 0) inView:self.view];
}break;
}
}
0
您在UIGestureRecognizerStateChanged案例中添加的代码，将其移动到操作方法的标题中：
CGPoint translation = [recognizer translationInView:self.view];
recognizer.view.center = CGPointMake(recognizer.view.center.x + translation.x,
recognizer.view.center.y + translation.y);
[recognizer setTranslation:CGPointMake(0, 0) inView:self.view];
在那之后，你要做的另一件事是在你的开关方法中制作另一个案例：
//This checks if you ended the pan gesture (removed finger from object)
case UIGestureRecognizerStateEnded:
{
CGPoint velocity = [recognizer velocityInView:self.view];
CGFloat magnitude = sqrtf((velocity.x * velocity.x) + (velocity.y * velocity.y));
CGFloat slideMult = magnitude / 200;
NSLog(@"magnitude: %f, slideMult: %f", magnitude, slideMult);
float slideFactor = 0.1 * slideMult; // Increase for more of a slide
CGPoint finalPoint = CGPointMake(recognizer.view.center.x + (velocity.x * slideFactor),
recognizer.view.center.y + (velocity.y * slideFactor));
finalPoint.x = MIN(MAX(finalPoint.x, 0), self.view.bounds.size.width);
finalPoint.y = MIN(MAX(finalPoint.y, 0), self.view.bounds.size.height);
[UIView animateWithDuration:slideFactor*2 delay:0 options:UIViewAnimationOptionCurveEaseOut animations:^{
recognizer.view.center = finalPoint;
} completion:nil];
}
所以我在上面的UIGestureRecognizerStateEnded状态中所做的是，我采取了用户发送图像的最后一点。之后，我将图像的中心设置为等于图像是最后一刻的点。
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