一、加载动画动作
/**
约束动画条件：
告知需要更改约束
[self.view setNeedsUpdateConstraints];
告知父类控件绘制
[self.view layoutIfNeeded];
*/
[self.view setNeedsUpdateConstraints];
@weakify(self)
[UIView animateWithDuration:0.3 animations:^{
@strongify(self);
[self.alertBgV mas_updateConstraints:^(MASConstraintMaker *make) {
make.height.mas_equalTo(0);
}];
[self.view layoutIfNeeded];
} completion:^(BOOL finished) {
@strongify(self);
[self dismissViewControllerAnimated:NO completion:nil];
}];
二、约束
[alertBgV mas_makeConstraints:^(MASConstraintMaker *make) {
make.left.right.mas_equalTo(0);
make.height.mas_equalTo(408);
make.bottom.mas_equalTo(8);
}];
三、更新约束
[self.alertBgV mas_updateConstraints:^(MASConstraintMaker *make) {
make.height.mas_equalTo(0);
}];
