仅在横向模式下使用沉浸式模式(Using immersive mode only on landscape mode)

 我尝试使应用程序在横向上进入沉浸式模式（没有状态栏和导航栏），并禁用Portrate上的沉浸模式（使用返回状态栏和导航栏）。 没有重启活动（onCreate只调用一次）。 我写了一个小示例应用程序来显示我的问题。 
 
 AndroidManifest.xml中 
 
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="test.com.immersivetest">
    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:supportsRtl="true"
        android:theme="@style/AppTheme">
        <activity
            android:name=".MainActivity"
            android:configChanges="orientation|screenSize">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />
                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    &t;/application>
</manifest>
 
 activity_main.xml中 
 
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/activity_main"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:fitsSystemWindows="true"
    android:padding="0dp"
    tools:context="test.com.immersivetest.MainActivity">

    <RelativeLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:background="#ffff0000"
         />
</RelativeLayout>
 
 MainActivity.java 
 
package test.com.immersivetest;

import android.content.res.Configuration;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;

public class MainActivity extends AppCompatActivity {

    private View activity;
    private View decorView;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        activity = findViewById(R.id.activity_main);
        decorView = this.getWindow().getDecorView();
        System.out.println("On Crate");
    }

    @Override
    public void onConfigurationChanged(Configuration newConfig) {
        super.onConfigurationChanged(newConfig);
        updateForOrientation(newConfig.orientation);
    }

    public void updateForOrientation(int orientation) {
        if (orientation == Configuration.ORIENTATION_LANDSCAPE) {
            hideSystemUI();
        } else if (orientation == Configuration.ORIENTATION_PORTRAIT) {
            showSystemUI();
        }
    }



    private void hideSystemUI() {
        System.out.println("Hide UI");
        activity.setFitsSystemWindows(false);
        decorView.setSystemUiVisibility(
                View.SYSTEM_UI_FLAG_LAYOUT_STABLE
                        | View.SYSTEM_UI_FLAG_LAYOUT_HIDE_NAVIGATION
                        | View.SYSTEM_UI_FLAG_LAYOUT_FULLSCREEN
                        | View.SYSTEM_UI_FLAG_HIDE_NAVIGATION // hide nav bar
                        | View.SYSTEM_UI_FLAG_FULLSCREEN // hide status bar
                        | View.SYSTEM_UI_FLAG_IMMERSIVE_STICKY);

    }

    private void showSystemUI() {
        activity.setFitsSystemWindows(true);
        decorView.setSystemUiVisibility(
                View.SYSTEM_UI_FLAG_LAYOUT_STABLE
                        | View.SYSTEM_UI_FLAG_LAYOUT_HIDE_NAVIGATION
                        | View.SYSTEM_UI_FLAG_LAYOUT_FULLSCREEN);
    }


}
 
 查看我的问题的步骤： 
 
 1）启动应用程序（在肖像模式），并在结果我看到与全屏红色背景与标题栏，状态栏，导航栏的孩子RelativeLayout。 这是正确的。 截图 
 
 2）旋转到风景。 再次，我看到正确的结果：Child RelativeLayout红色背景沉浸模式没有标题栏，状态栏，导航栏。 
 
 3）旋转至肖像。 并看到正确的结果：如第一步的屏幕截图。 
 
 4）再次旋转到风景。 我看到不正确的结果。 Child RelativeLayout未拉伸到父级大小。 我们在屏幕的顶部和底部看到空的字段。 屏幕截图有问题 
 
 如何解决它？ 为什么所有的旋转将第一个不正确调整大小的孩子RelativeLayout调整为横向？ 
 
 Ps Min sdk版本19。 

I try make app that will go to immersive mode on landscape (without status bar and navigation bar) and disable immersive mode on portrate (with return status bar and navigation bar). Without restart activity (onCreate called only one time). I wrote small example app to show my problem.
 
AndroidManifest.xml
 
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="test.com.immersivetest">
    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:supportsRtl="true"
        android:theme="@style/AppTheme">
        <activity
            android:name=".MainActivity"
            android:configChanges="orientation|screenSize">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />
                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>
</manifest>
 
activity_main.xml
 
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/activity_main"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:fitsSystemWindows="true"
    android:padding="0dp"
    tools:context="test.com.immersivetest.MainActivity">

    <RelativeLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:background="#ffff0000"
         />
</RelativeLayout>
 
MainActivity.java
 
package test.com.immersivetest;

import android.content.res.Configuration;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;

public class MainActivity extends AppCompatActivity {

    private View activity;
    private View decorView;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        activity = findViewById(R.id.activity_main);
        decorView = this.getWindow().getDecorView();
        System.out.println("On Crate");
    }

    @Override
    public void onConfigurationChanged(Configuration newConfig) {
        super.onConfigurationChanged(newConfig);
        updateForOrientation(newConfig.orientation);
    }

    public void updateForOrientation(int orientation) {
        if (orientation == Configuration.ORIENTATION_LANDSCAPE) {
            hideSystemUI();
        } else if (orientation == Configuration.ORIENTATION_PORTRAIT) {
            showSystemUI();
        }
    }



    private void hideSystemUI() {
        System.out.println("Hide UI");
        activity.setFitsSystemWindows(false);
        decorView.setSystemUiVisibility(
                View.SYSTEM_UI_FLAG_LAYOUT_STABLE
                        | View.SYSTEM_UI_FLAG_LAYOUT_HIDE_NAVIGATION
                        | View.SYSTEM_UI_FLAG_LAYOUT_FULLSCREEN
                        | View.SYSTEM_UI_FLAG_HIDE_NAVIGATION // hide nav bar
                        | View.SYSTEM_UI_FLAG_FULLSCREEN // hide status bar
                        | View.SYSTEM_UI_FLAG_IMMERSIVE_STICKY);

    }

    private void showSystemUI() {
        activity.setFitsSystemWindows(true);
        decorView.setSystemUiVisibility(
                View.SYSTEM_UI_FLAG_LAYOUT_STABLE
                        | View.SYSTEM_UI_FLAG_LAYOUT_HIDE_NAVIGATION
                        | View.SYSTEM_UI_FLAG_LAYOUT_FULLSCREEN);
    }


}
 
Steps to see my problem:
 
1) Start app (in portrait mode) and in result i see child RelativeLayout with red background on fullscreen with titlebar, statusbar, navigationbar. It's correct. Screenshot
 
2) Rotate to landscape. And again i see correct result: Child RelativeLayout with red background on immersive mode without titlebar, statusbar, navigationbar.
 
3) Rotate to portrait. And see correct results: like on screenshot for the first step.
 
4) Rotate to landscape again. And i see not correct result. Child RelativeLayout not stretched to parent size. We see empty fields on top and bottom of screen. Screenshot with problem
 
How to fix it? Why all rotations to landscape intead of the first not correct resize child RelativeLayout ?
 
P.s. Min sdk version 19.

原文：https://stackoverflow.com/questions/39785977