当使用- transitionFromViewController:toViewController:duration:options:animations:completion:进行子viewcontroller之后，发现子controller的view比父controller的view要长一些 暂时还不知道什么原因
- 使他们在同一位置的解决方法:transitionFromViewController完成之后，重新设置子view的位置
[self transitionFromViewController:self.currentVC toViewController:self.oneTimeVC duration:0.1 options:UIViewAnimationOptionTransitionNone animations:^{
} completion:^(BOOL finished) {
if (finished) {
self.currentVC = self.oneTimeVC;
[self.currentVC.view mas_makeConstraints:^(MASConstraintMaker *make) {
make.edges.equalTo(self.view);
}];
}
}];
