之前在寫代碼的時(shí)候發(fā)現(xiàn)使用了Masonry來(lái)做頁(yè)面布局的情況下，通過(guò)UIView的animateWithDuration 方法來(lái)添加動(dòng)畫是不會(huì)有效果的，那么應(yīng)該如何實(shí)現(xiàn)動(dòng)畫效果呢？

比如在點(diǎn)擊某個(gè)按鈕的時(shí)候需要更新約束，那么可以執(zhí)行下面的方法：

- (void)updateLayout {
    // 告訴當(dāng)前的頁(yè)面需要更新約束
    [self.view setNeedsUpdateConstraints];
    // 添加動(dòng)畫效果，3s執(zhí)行完畢
    [UIView animateWithDuration:3 animations:^{
        // 更新約束
        if (self.accountTextField.isShowKeyboard) {
            [self.titleImage mas_updateConstraints:^(MASConstraintMaker *make) {
                make.height.mas_equalTo(0.f);
            }];
            
            [self.accountTextField mas_updateConstraints:^(MASConstraintMaker *make) {
                make.top.equalTo(self.view.mas_top).with.offset(SCREEN_SIZE_HEIGHT * 0.198);
            }];
        } else {
            CGFloat scale = iPad ? 1.5f : 1.f;
            [self.titleImage mas_updateConstraints:^(MASConstraintMaker *make) {
                make.height.mas_equalTo(65.f * scale);
            }];
            
            [self.accountTextField mas_updateConstraints:^(MASConstraintMaker *make) {
                make.top.equalTo(self.view.mas_top).with.offset(SCREEN_SIZE_HEIGHT * 0.35);
            }];
        }
        // 告知發(fā)生變化的視圖的父視圖需要重新繪制
        [self.titleImage.superview layoutIfNeeded];
        [self.accountTextField.superview layoutIfNeeded];
    }];
}