android 重叠view 重叠布局，按比例布局

 按比例布局

宽度满屏，高度9:16

<androidx.constraintlayout.widget.ConstraintLayout
    android:layout_width="match_parent"
    android:layout_height="wrap_content">

<RelativeLayout
    android:layout_width="match_parent"
    android:layout_height="0dp"
    app:layout_constraintTop_toTopOf="parent"
    app:layout_constraintDimensionRatio="w,9:16">

</RelativeLayout>

</androidx.constraintlayout.widget.ConstraintLayout>

 

 一分为二

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:id="@+id/mainLayout"
    android:layout_width="match_parent"
    android:layout_height="match_parent">
    <View
        android:id="@+id/view_top"
        android:layout_width="match_parent"
        android:layout_height="0dp"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintBottom_toTopOf="@+id/ll_headView"/>

    <LinearLayout
        android:id="@+id/ll_headView"
        android:layout_width="match_parent"
        android:layout_height="0dp"
        app:layout_constraintHeight_percent="0.58"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintBottom_toBottomOf="parent"
        android:background="@drawable/corners_white_top_bg"
        android:orientation="vertical">

使用RelativeLayout即可实现重叠布局——RelativeLayout标签内容里面的下层布局会浮现在上层布局之上；上层布局会被下层布局覆盖

实现layout：

<RelativeLayout
    android:layout_width="match_parent"
    android:layout_height="200dp"
    android:background="#FFE4C4">

    <LinearLayout
        android:layout_width="300dp"
        android:layout_height="100dp"
        android:background="#303F9F"></LinearLayout>
    <LinearLayout
        android:layout_width="200dp"
        android:layout_height="100dp"
        android:background="#FF4081"
        android:layout_marginLeft="50dp"
        android:layout_marginTop="50dp"></LinearLayout>
</RelativeLayout>

实现效果：