Android中百分比布局

百分比布局的出现主要是由于LinearLayout中能够经过android:layout_weight="1"这种方法来支持按比例指定控件大小

可是FrameLayout和RelativeLayout中并无这种实现比例分配的功能，所以引入了PercentFrameLayout和PercentRelativeLayout这两个全新的布局

接下来是PercentFrameLayout的具体应用，须要导入support库

在app的build.gradle中添加以下的包

dependencies { compile fileTree(dir: 'libs', include: ['*.jar']) androidTestCompile('com.android.support.test.espresso:espresso-core:2.2.2', { exclude group: 'com.android.support', module: 'support-annotations' }) compile 'com.android.support:appcompat-v7:25.3.1' compile 'com.android.support:percent:25.3.1' testCompile 'junit:junit:4.12' }

 

接下来对布局的安排代码为：

<?xml version="1.0" encoding="utf-8"?>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:app="http://schemas.android.com/apk/res-auto" xmlns:tools="http://schemas.android.com/tools" android:id="@+id/activity_main" android:orientation="horizontal" android:layout_width="match_parent" android:layout_height="match_parent" tools:context="com.itheima.album.uilayouttest.MainActivity">
    <android.support.percent.PercentFrameLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:app="http://schemas.android.com/apk/res-auto" android:layout_width="match_parent" android:layout_height="match_parent"
        >
        <Button android:id="@+id/button1" android:text="Button 1" android:layout_gravity="left|top" app:layout_widthPercent="50%" app:layout_heightPercent="50%"
            />
        <Button android:id="@+id/button2" android:text="Button 2" android:layout_gravity="right|top" app:layout_widthPercent="50%" app:layout_heightPercent="50%"
            />
        <Button android:id="@+id/button3" android:text="Button 3" android:layout_gravity="left|bottom" app:layout_widthPercent="50%" app:layout_heightPercent="50%"
            />
        <Button android:id="@+id/button4" android:text="Button 4" android:layout_gravity="right|bottom" app:layout_widthPercent="50%" app:layout_heightPercent="50%"
            />
    </android.support.percent.PercentFrameLayout>
</FrameLayout>

 

程序运行截图以下：

 PercentRelativeLayout实现上图所示：

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:app="http://schemas.android.com/apk/res-auto" xmlns:tools="http://schemas.android.com/tools" android:id="@+id/activity_main" android:orientation="horizontal" android:layout_width="match_parent" android:layout_height="match_parent" tools:context="com.itheima.album.uilayouttest.MainActivity">
    <android.support.percent.PercentRelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:app="http://schemas.android.com/apk/res-auto" android:layout_width="match_parent" android:layout_height="match_parent"
        >
        <Button android:id="@+id/button1" android:text="Button1" app:layout_widthPercent="50%" app:layout_heightPercent="50%"
            />
        <Button android:id="@+id/button2" android:text="Button2" android:layout_toRightOf="@id/button1" app:layout_widthPercent="50%" app:layout_heightPercent="50%"
            />
        <Button android:id="@+id/button3" android:text="Button3" android:layout_below="@id/button1" app:layout_widthPercent="50%" app:layout_heightPercent="50%"
            />
        <Button android:id="@+id/button4" android:text="Button4" android:layout_below="@id/button1" android:layout_toRightOf="@id/button3" app:layout_widthPercent="50%" app:layout_heightPercent="50%"
            />
    </android.support.percent.PercentRelativeLayout>
</RelativeLayout>

 

执行以下图所示：