如何垂直居中两个视图并相对于超级视图平均划分宽度？

Posted 2023-02-23

【中文标题】如何垂直居中两个视图并相对于超级视图平均划分宽度？

【英文标题】：How to vertically center two views & divide the width equally relative to the super view?

【发布时间】：2015-06-10 11:35:23

【问题描述】：

我正在尝试将两个Buttons 对齐到一个View（以青色显示）。它们在View 中垂直对齐。当我尝试水平对齐它们时，它们的高度会改变。我希望它们的宽度应该根据超级视图的宽度相同，这与较小的 Next 按钮不同。这只能使用VFL来实现吗？

代码如下：

[self prepareButton:saveButton label:@"SAVE"];
[buttonContainerView addConstraint:[NSLayoutConstraint constraintWithItem:saveButton
                                                              attribute:NSLayoutAttributeCenterY
                                                              relatedBy:NSLayoutRelationEqual
                                                                 toItem:buttonContainerView
                                                              attribute:NSLayoutAttributeCenterY
                                                             multiplier:1.00f
                                                               constant:0]];
[saveButton layoutIfNeeded];

[self prepareButton:nextButton label:@"NEXT"];
[buttonContainerView addConstraint:[NSLayoutConstraint constraintWithItem:nextButton
                                                              attribute:NSLayoutAttributeCenterY
                                                              relatedBy:NSLayoutRelationEqual
                                                                 toItem:buttonContainerView
                                                              attribute:NSLayoutAttributeCenterY
                                                             multiplier:1.00f
                                                               constant:0]];
[nextButton layoutIfNeeded];
[buttonContainerView addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:@"H:|-[saveButton]-[nextButton]-|"
                                                                          options:0
                                                                          metrics:metrics
                                                                            views:viewDictionary]];
[saveButton layoutIfNeeded];
[nextButton layoutIfNeeded];

-(void)prepareButton:(UIButton *)button
           label:(NSString *) label

    [buttonContainerView addSubview:button];
    button.translatesAutoresizingMaskIntoConstraints = NO;
    button.backgroundColor = [UIColor redColor];
    button.layer.cornerRadius = 2.50f;
    [button setTitle:label forState:UIControlStateNormal];
    [button setTitleColor:[UIColor whiteColor] forState:UIControlStateNormal];

【参考方案1】：

通过在 VFL 中设置相等的高度和分配优先级解决了这个问题：

[buttonContainerView addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:@"H:|-[saveButton]-[nextButton(==saveButton@1000)]-|"
                                                                          options:0
                                                                          metrics:metrics
                                                                            views:viewDictionary]];