HarmonyOS —常用布局开发指导-AdaptiveBoxLayout

AdaptiveBoxLayout是自适应盒子布局，该布局提供了在不同屏幕尺寸设备上的自适应布局能力，主要用于相同级别的多个组件需要在不同屏幕尺寸设备上自动调整列数的场景。

1. 该布局中的每个子组件都用一个单独的“盒子”装起来，子组件设置的布局参数都是以盒子作为父布局生效，不以整个自适应布局为生效范围。
2. 该布局中每个盒子的宽度固定为布局总宽度除以自适应得到的列数，高度为match_content，每一行中的所有盒子按高度最高的进行对齐。
3. 该布局水平方向是自动分块，因此水平方向不支持match_content，布局水平宽度仅支持match_parent或固定宽度。
4. 自适应仅在水平方向进行了自动分块，纵向没有做限制，因此如果某个子组件的高设置为match_parent类型，可能导致后续行无法显示。

图1 AdaptiveBoxLayout示意图

常用方法

AdaptiveBoxLayout布局常用方法如下。

场景示例

在AdaptiveBoxLayout中添加和删除自适应盒子布局规则的效果对比如下。图2 添加和删除一个规则的效果对比

XML布局示例代码：

<?xml version="1.0" encoding="utf-8"?>

<DirectionalLayout
    xmlns:ohos="http://schemas.huawei.com/res/ohos"
    ohos:height="match_parent"
    ohos:width="match_parent"
    ohos:orientation="vertical">

    <AdaptiveBoxLayout
        xmlns:ohos="http://schemas.huawei.com/res/ohos"
        ohos:height="0vp"
        ohos:width="match_parent"
        ohos:weight="1"
        ohos:id="$+id:adaptive_box_layout">

        <Text
            ohos:height="40vp"
            ohos:width="80vp"
            ohos:background_element="#EC9DAA"
            ohos:margin="10vp"
            ohos:padding="10vp"
            ohos:text="NO 1"
            ohos:text_size="18fp" />

        <Text
            ohos:height="40vp"
            ohos:width="80vp"
            ohos:background_element="#EC9DAA"
            ohos:margin="10vp"
            ohos:padding="10vp"
            ohos:text="NO 2"
            ohos:text_size="18fp" />

        <Text
            ohos:height="match_content"
            ohos:width="match_content"
            ohos:background_element="#EC9DAA"
            ohos:margin="10vp"
            ohos:padding="10vp"
            ohos:multiple_lines="true"
            ohos:text="AdaptiveBoxLayout, where a number of boxes with the same width but varied heights are laid out. The height of a row is determined by the highest box."
            ohos:text_size="18fp" />

        <Text
            ohos:height="40vp"
            ohos:width="80vp"
            ohos:background_element="#EC9DAA"
            ohos:margin="10vp"
            ohos:padding="10vp"
            ohos:text="NO 4"
            ohos:text_size="18fp" />

        <Text
            ohos:height="40vp"
            ohos:width="match_parent"
            ohos:background_element="#EC9DAA"
            ohos:margin="10vp"
            ohos:padding="10vp"
            ohos:text="Add"
            ohos:text_size="18fp" />



        <Text
            ohos:height="40vp"
            ohos:width="80vp"
            ohos:background_element="#EC9DAA"
            ohos:margin="10vp"
            ohos:padding="10vp"
            ohos:text="NO 5"
            ohos:text_size="18fp" />

        <Text
            ohos:height="160vp"
            ohos:width="80vp"
            ohos:background_element="#EC9DAA"
            ohos:margin="10vp"
            ohos:padding="10vp"
            ohos:text="NO 6"
            ohos:text_size="18fp" />
    </AdaptiveBoxLayout>

    <Button
        ohos:id="$+id:add_rule_btn"
        ohos:layout_alignment="horizontal_center"
        ohos:top_margin="10vp"
        ohos:padding="10vp"
        ohos:background_element="#A9CFF0"
        ohos:height="match_content"
        ohos:width="match_content"
        ohos:text_size="22fp"
        ohos:text="adaptiveBoxLayout.addAdaptiveRule(100, 2000, 3);"/>

    <Button
        ohos:id="$+id:remove_rule_btn"
        ohos:padding="10vp"
        ohos:top_margin="10vp"
        ohos:layout_alignment="horizontal_center"
        ohos:bottom_margin="10vp"
        ohos:background_element="#D5D5D5"
        ohos:height="match_content"
        ohos:width="match_content"
        ohos:text_size="22fp"
        ohos:text="adaptiveBoxLayout.removeAdaptiveRule(100, 2000, 3);"/>

</DirectionalLayout>

Java关键代码：

AdaptiveBoxLayout adaptiveBoxLayout = (AdaptiveBoxLayout)findComponentById(ResourceTable.Id_adaptive_box_layout);

findComponentById(ResourceTable.Id_add_rule_btn).setClickedListener((component-> {
    // 添加规则
    adaptiveBoxLayout.addAdaptiveRule(100, 2000, 3);
    // 更新布局
    adaptiveBoxLayout.postLayout();
}));

findComponentById(ResourceTable.Id_remove_rule_btn).setClickedListener((component-> {
    // 移除规则
    adaptiveBoxLayout.removeAdaptiveRule(100, 2000, 3);
    // 更新布局
    adaptiveBoxLayout.postLayout();
}));