Horizontale und vertikale Mitte zum übergeordneten Layout

Question

Ich erstelle einen Benutzerprofilbildschirm in Android. In diesem Bildschirm haben Benutzerprofil Hintergrund und Benutzerprofil Bild. Hier ist der graue Hintergrund Profiltapete und roter Hintergrund wird zum Profilbild. Ich brauche das rote bg Layout zur horizontalen und vertikalen Mitte des grauen bg Layouts einstellen ..

<?xml version="1.0" encoding="utf-8"?> 
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" 
xmlns:app="http://schemas.android.com/apk/res-auto" 
android:orientation="vertical" 
android:layout_width="match_parent" 
android:layout_height="match_parent" 
android:id="@+id/rlActivityNotificationsAndProfile"> 
<include layout="@layout/layout_tool_bar"/> 
<RelativeLayout 
    android:layout_width="match_parent" 
    android:layout_height="@dimen/profile_wallpaper_container_height" 
    android:id="@+id/rlProfileWallpaper" 
    android:layout_below="@+id/toolbar"> 
    <LinearLayout 
     android:layout_width="match_parent" 
     android:background="#646464" 
     android:orientation="vertical" 
     android:layout_height="@dimen/profile_wallpaper_height"> 
     <LinearLayout 
      android:layout_width="30dp" 
      android:layout_height="30dp" 
      android:layout_gravity="center" 
      android:background="#A52525"> 
     </LinearLayout> 
</LinearLayout> 
<android.support.design.widget.FloatingActionButton xmlns:android="http://schemas.android.com/apk/res/android" 
     xmlns:app="http://schemas.android.com/tools" 
     android:id="@+id/fabEditProfile" 
     android:layout_width="wrap_content" 
     android:layout_height="wrap_content" 
     android:layout_alignParentBottom="true" 
     android:layout_alignParentRight="true" 
     android:layout_margin="@dimen/base_ten_dp" 
     android:layout_marginEnd="@dimen/base_ten_dp" 
     android:layout_marginStart="@dimen/base_ten_dp" 
     android:scaleType="center" 
     android:src="@drawable/add" 
     app:elevation="@dimen/priority_1_elevation" 
     app:fabSize="1"/> 
</RelativeLayout> 
</LinearLayout> 

Answer 1

können Sie legen einfach Ihre Eltern Linearlayout Schwerkraft zum Zentrum (nur 1 Zeile hinzugefügt werden):

<?xml version="1.0" encoding="utf-8"?> 
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" 
xmlns:app="http://schemas.android.com/apk/res-auto" 
android:orientation="vertical" 
android:layout_width="match_parent" 
android:layout_height="match_parent" 
android:id="@+id/rlActivityNotificationsAndProfile"> 
<include layout="@layout/layout_tool_bar"/> 
<RelativeLayout 
    android:layout_width="match_parent" 
    android:layout_height="@dimen/profile_wallpaper_container_height" 
    android:id="@+id/rlProfileWallpaper" 
    android:layout_below="@+id/toolbar"> 
    <LinearLayout 
     android:layout_width="match_parent" 
     android:background="#646464" 
     android:orientation="vertical" 
     android:layout_height="@dimen/profile_wallpaper_height" 
     android:gravity="center"> 
     <LinearLayout 
      android:layout_width="30dp" 
      android:layout_height="30dp" 
      android:layout_gravity="center" 
      android:background="#A52525"> 
     </LinearLayout> 
</LinearLayout> 
<android.support.design.widget.FloatingActionButton xmlns:android="http://schemas.android.com/apk/res/android" 
     xmlns:app="http://schemas.android.com/tools" 
     android:id="@+id/fabEditProfile" 
     android:layout_width="wrap_content" 
     android:layout_height="wrap_content" 
     android:layout_alignParentBottom="true" 
     android:layout_alignParentRight="true" 
     android:layout_margin="@dimen/base_ten_dp" 
     android:layout_marginEnd="@dimen/base_ten_dp" 
     android:layout_marginStart="@dimen/base_ten_dp" 
     android:scaleType="center" 
     android:src="@drawable/add" 
     app:elevation="@dimen/priority_1_elevation" 
     app:fabSize="1"/> 
</RelativeLayout> 
</LinearLayout>