[英]iPhone/Cocoa Animation having effect I don't understand
我已经创建了一个基本的解锁滑块,就像您用来解锁iPhone一样。
在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(并且实际上并没有将其解锁),动画效果很好,并且滑块移回了原位。
但是,下一次用户尝试移动滑块(并调用touchesMoved)时,滑块被推到屏幕外(向左),移动量为之前滑动滑块的量。
那么,发生了什么事?
- (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];
}
}
编辑
这是工作功能,需要进行一些整理,尽管可能会更好(这要归功于一对黑客回答了一对有关SO的问题)。 我将对整个模块进行博客撰写,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;
}
在上一个问题中,我没有意识到您是通过更改其变形来移动滑块的。 通过更改帧和变换来混合运动将变得相当复杂。
也许您可以尝试做更多这样的事情:
- (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];
}
}
通过修改滑块的框架(而不是平移)来移动滑块,这应使滑块与回弹动画更好地交互。 或者,您可以在此处重置转换,而不是在隐式动画师中重置框架。
您需要在touchesEnded处理程序中重置视图转换:
[self.unlock setTransform:CGAffineTransformIdentity];
尝试这样做,而不是对frame
属性设置动画。
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