部分场景，基本动画不执行：
[UIView animateWithDuration:animationDuration animations:^{ } completion:^(BOOL finished) { }];
其实想解决很简单，就是调用布局重新绘制函数：[self layoutIfNeeded];
具体的例子是：
[_comTool setKeyBoardChangeBlock:^(CGFloat height, CGFloat animationDuration) { if (DYGlobleData.isLogin) { if(animationDuration <= 0) { //防范式编程，理论不会出现 weakSelf.bgV.hidden = NO; } else { weakSelf.bgV.hidden = (height<=0); [UIView animateWithDuration:animationDuration animations:^{ if((height<=0)) { [weakSelf.comTool mas_updateConstraints:^(MASConstraintMaker *make) { make.height.mas_equalTo(BaseSize(100)); make.width.mas_equalTo(KScreenW); make.bottom.mas_equalTo(BaseSize(100) -(49+(BR_BOTTOM_MARGIN?24:0))); }]; [weakSelf.comTool updateCommentTVWithShift:(BaseSize(100) -(49+(BR_BOTTOM_MARGIN?24:0))+(BR_BOTTOM_MARGIN?24:0))]; } else { [weakSelf.comTool mas_updateConstraints:^(MASConstraintMaker *make) { make.height.mas_equalTo(BaseSize(100)); make.width.mas_equalTo(KScreenW); make.bottom.mas_equalTo(-height); }]; [weakSelf.comTool updateCommentTVWithShift:0]; } [weakSelf layoutIfNeeded]; } completion:^(BOOL finished) { }]; } } else { weakSelf.bgV.hidden = YES; [weakSelf.comTool mas_updateConstraints:^(MASConstraintMaker *make) { make.height.mas_equalTo(BaseSize(100)); make.width.mas_equalTo(KScreenW); make.bottom.mas_equalTo(BaseSize(100) -(49+(BR_BOTTOM_MARGIN?24:0))); }]; [weakSelf.comTool updateCommentTVWithShift:(BaseSize(100) -(49+(BR_BOTTOM_MARGIN?24:0))+(BR_BOTTOM_MARGIN?24:0))]; }; }];
