动画-layoutIfNeeded父控制器的self.view,子控制器的子视图如果重写了-layoutSubviews也将动画布局.
需求:导航栏根据子VC的tableview的位移动画.
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| if (contentOffsetY > 0) {
[self.headerContainerView mas_updateConstraints:^(MASConstraintMaker *make) {
make.top.equalTo(self.view.mas_topMargin).with.offset(startY - endY);
}];
[self.view setNeedsUpdateConstraints];
[self.view updateConstraintsIfNeeded];
[UIView animateWithDuration:0.3 animations:^{
self.contentScrollView.contentInset = UIEdgeInsetsMake(-endY, 0, 0, 0);
[self.view layoutIfNeeded];
self.headerContainerView.headerView.matchOtherDesBgView.alpha = 0;
self.headerContainerView.headerView.team1NameLabel.alpha = 0;
self.headerContainerView.headerView.team2NameLabel.alpha = 0;
self.headerContainerView.headerView.teamLogoBgView.transform = CGAffineTransformMakeScale(0.5, 0.5);
CGAffineTransform currentT = self.headerContainerView.headerView.teamLogoBgView.transform;
CGAffineTransform translation = CGAffineTransformTranslate(currentT, 0, teamLogoBgViewOffsetY);
self.headerContainerView.headerView.teamLogoBgView.transform = translation;
}];
}
|
由于需要动画的改变父控制器里的view位移,又因为使用了xib,所以动画时需要在动画block里写[self.view layoutIfNeeded];但这句代码导致了子控制器的视图的-layoutSubviews方法被调用.于是子控制器的视图在布局时也会动画的进行(而这种效果不是你需要的从而变成了bug.)
这里的bug就是:子控制器里的tableViewCell因为重写了-layoutSubviews,而cell上的子控件KDGMatchDetailItemView也重写了-layoutSubviews.所以KDGMatchDetailItemView在布局时出现动画的往右移动.
解决办法:当导航栏收缩后,就不要执行[self.view layoutIfNeeded];加个判断条件:
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| if (contentOffsetY > 0 && self.contentScrollView.contentInset.top != -endY) {
}
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系统的-layoutIfNeeded的实现应该是调用了视图的-layoutSubviews方法.父视图-layoutSubviews方法的调用可能会引起子视图-layoutSubviews方法的调用.
