February 12 relativelayout

1. Relative layout starts from the upper left corner of the interface , Therefore, the latter of two consecutive relative layouts will mask the former
for example , Red is covered by green

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <RelativeLayout
        android:background="#ff0000"
        android:layout_width="100dp"
        android:layout_height="100dp"/>

    <RelativeLayout
        android:background="#00ff00"
        android:layout_width="100dp"
        android:layout_height="100dp"/>

</RelativeLayout>

2. Locate according to the parent container （ Based on the outermost layer ）
Show the red

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <RelativeLayout
        android:background="#ff0000"
        android:layout_alignParentRight="true"
        android:layout_width="100dp"
        android:layout_height="100dp"/>

    <RelativeLayout
        android:background="#00ff00"
        android:layout_width="100dp"
        android:layout_height="100dp"/>

</RelativeLayout>

3. Locate according to the container
Because there are many brother containers , So which one should be set id

Set the red layout id

        android:id="@+id/rl1"

Note that @+id

The green layout is @id

        android:layout_toLeftOf="@id/rl1"

4. Set the margin between the component and the parent container
Distance from left 100dp

        android:layout_marginLeft="100dp"

Up, down, left and right offset 100dp

        android:layout_margin="100dp"

5. Set the margin of elements inside the component

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:padding="100dp"
    android:layout_width="match_parent"
    android:layout_height="match_parent">
    <RelativeLayout
        android:id="@+id/rl1"
        android:background="#ff0000"
        android:layout_centerInParent="true"
        android:layout_width="100dp"
        android:layout_height="100dp"/>

    <RelativeLayout
        android:background="#00ff00"
        android:layout_width="100dp"
        android:layout_height="100dp"/>

</RelativeLayout>