问题描述：
今天做AD杂志(iPad)LEGO功能点，需要在UIScrollView中让UIView移动。加了正确代码，结果却不好。
结果是这样的：点击不移动，运行touchesBegan和touchesEnded，一切正常。但是点下移动释放，touchesBegan会100%运行，然后三两个touchesMoved，move效果也跟不上，touchesEnded也没有触发。
在UIView用了如下代码实现：
#pragma mark --
#pragma mark touch
- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
{
NSLog(@"touchesBegan");
UITouch *touch = [touches anyObject];
UIScrollView *parentView = (UIScrollView *)[[[touch view] superview]superview];
parentView.scrollEnabled=NO;
// Calculate and store offset, and pop view into front if needed
CGPoint pt = [[touches anyObject] locationInView:self];
startLocation = pt;
}
- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event
{
NSLog(@"touchesMoved");
// Calculate offset
CGPoint pt = [[touches anyObject] locationInView:self];
float dx = pt.x - startLocation.x;
float dy = pt.y - startLocation.y;
CGPoint newcenter = CGPointMake(self.center.x + dx, self.center.y + dy);
// Bound movement into parent bounds
float halfx = CGRectGetMidX(self.bounds);
newcenter.x = MAX(halfx, newcenter.x);
newcenter.x = MIN(self.superview.bounds.size.width - halfx, newcenter.x);
float halfy = CGRectGetMidY(self.bounds);
newcenter.y = MAX(halfy, newcenter.y);
newcenter.y = MIN(self.superview.bounds.size.height - halfy, newcenter.y);
// Set new location
self.center = newcenter;
}
- (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event
{
NSLog(@"touchesEnded");
UITouch *touch = [touches anyObject];
UIScrollView *parentView = (UIScrollView *)[[[touch view] superview]superview];
parentView.scrollEnabled=YES;
}
问题分析：
最后一段一段检查，应该是parentView.scrollEnabled=NO;这句有问题。
可能是iOS的一个Bug。
问题解决：
在另一台Mac上做了一个Demo，一切OK。细细检查，唯一不同就是SDK版本不一样。出问题的那台是4.1，而做Demo一切OK的那台是4.2.1。把出问题的代码copy给4.2.1，一切安逸了。