常见布局模式

提示

代码示例为通用内容，建议参阅英文版示例获取完整文档。

边缘固定

将视图固定到父视图的所有边缘：

::: code-group

[childView mas_makeConstraints:^(MASConstraintMaker *make) {
    make.edges.equalTo(superview);
}];

childView.mas.makeConstraints { make in
    make.edges.equalTo(superview)
}

:::

居中

在父视图中居中：

::: code-group

[childView mas_makeConstraints:^(MASConstraintMaker *make) {
    make.center.equalTo(superview);
    make.size.mas_equalTo(CGSizeMake(200, 100));
}];

childView.mas.makeConstraints { make in
    make.center.equalTo(superview)
    make.size.equalTo(CGSize(width: 200, height: 100))
}

:::

宽高比

保持宽高比：

::: code-group

[imageView mas_makeConstraints:^(MASConstraintMaker *make) {
    make.width.equalTo(superview);
    make.height.equalTo(imageView.mas_width).multipliedBy(9.0 / 16.0);
}];

imageView.mas.makeConstraints { make in
    make.width.equalTo(superview)
    make.height.equalTo(imageView.mas.width).multipliedBy(9.0 / 16.0)
}

:::

安全区域布局

固定到安全区域（iOS 11+）：

::: code-group

[contentView mas_makeConstraints:^(MASConstraintMaker *make) {
    make.top.equalTo(self.view.mas_safeAreaLayoutGuideTop);
    make.bottom.equalTo(self.view.mas_safeAreaLayoutGuideBottom);
    make.leading.equalTo(self.view.mas_safeAreaLayoutGuideLeading);
    make.trailing.equalTo(self.view.mas_safeAreaLayoutGuideTrailing);
}];

contentView.mas.makeConstraints { make in
    make.top.equalTo(view.mas.safeAreaLayoutGuideTop)
    make.bottom.equalTo(view.mas.safeAreaLayoutGuideBottom)
    make.leading.equalTo(view.mas.safeAreaLayoutGuideLeading)
    make.trailing.equalTo(view.mas.safeAreaLayoutGuideTrailing)
}

:::