Question

我创建了一个基本的解锁滑块，就像你用来解锁iPhone一样。

在我的touchesEnded函数中，我使用动画将滑块移回原位。

用户第一次移动滑块（并且实际上没有点击结束以解锁），动画工作正常，滑块移回原位。

但是，下次用户尝试移动滑块（并且会调用touchesMoved）时，滑块会被推离屏幕（向左），因为它们之前滑动了滑块。

那么，发生了什么？

- (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event {
  self.dragging = NO;
  self.startX = 0; 
  [UIView beginAnimations:nil context:nil];
  [UIView setAnimationDuration:0.5];
  self.unlock.frame = CGRectMake(0, 0, 75, 35);
  [UIView commitAnimations];
}

- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event {
  if (!self.dragging ) { return; }
  UITouch *touch = [[event allTouches] anyObject];
  CGPoint point = [touch locationInView:self];
  int offset = point.x - self.startX;
  NSLog(@"%i", offset);
  if (offset > (LENGTH-SIZE)) {
    offset = (LENGTH-SIZE);
  }
  CGAffineTransform myTransform = CGAffineTransformMakeTranslation(offset, 0.0);
  [self.unlock setTransform:myTransform];
  if (point.x >= (LENGTH-(SIZE-self.startX))) {
    NSLog(@"Slider reached end");
    [self.sliderView removeFromSuperview];
  }
}

修改

这是工作功能，清理了一下，虽然它可能会更好（感谢几个来自一个黑客的SO回答问题）。我将博客完整的模块，因为似乎没有标准的小部件：

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

  if (!self.dragging ) { return; }

  UITouch *touch = [[event allTouches] anyObject];
  CGPoint point = [touch locationInView:self];  

  if (point.x >= (LENGTH-(SIZE-self.startX))) {
    NSLog(@"Slider reached end");
    [self.sliderView removeFromSuperview];
  }

  // offset based on where the user clicked the slider
  int offset = point.x - self.startX;
  if (offset > (LENGTH-SIZE)) {
    offset = (LENGTH-SIZE);
  }

  //move the slider
  CGRect oldFrame = self.unlock.frame;
  CGRect newFrame = CGRectMake(self.frame.origin.x+offset, self.frame.origin.y-5, oldFrame.size.width, oldFrame.size.height);
  self.unlock.frame = newFrame; 
}

Answer 1

在您之前的问题中，我没有意识到您通过更改其变换来移动滑块。通过改变帧和变换来混合运动将会变得相当复杂。

也许你可以尝试做更像这样的事情：

- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event {
  if (!self.dragging ) { return; }
  UITouch *touch = [[event allTouches] anyObject];
  CGPoint point = [touch locationInView:self];
  int offset = point.x - self.startX;
  NSLog(@"%i", offset);
  if (offset > (LENGTH-SIZE)) {
    offset = (LENGTH-SIZE);
  }

  CGRect oldFrame = self.frame;
  CGRect newFrame = CGRectMake(oldFrame.origin.x+offset, oldFrame.origin.y, oldFrame.size.width, oldFrame.size.height);
  self.frame = newFrame;

  if (point.x >= (LENGTH-(SIZE-self.startX))) {
    NSLog(@"Slider reached end");
    [self.sliderView removeFromSuperview];
  }
}

通过修改其框架而不是其平移来移动滑块，这应该使其与快照动画更好地交互。或者，不是在隐式动画师中重置帧，而是可以重置那里的翻译。

Answer 2

您需要在touchesEnded处理程序中重置视图转换：

[self.unlock setTransform:CGAffineTransformIdentity];

尝试使用{而不是动画frame属性。

iPhone / Cocoa动画有效我不明白

2 个答案: