Android - Hide the status bar

发布日期：2021-05-06 23:02:42 浏览次数：21 分类：精选文章

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Hide the Status Bar on Android 4.1 and Higher

You can hide the status bar on Android 4.1 (API level 16) and higher by using setSystemUiVisibility(). This method sets UI flags at the individual view level; these settings are aggregated to the window level. Using setSystemUiVisibility() provides more granular control over the system bars compared to using WindowManager flags. The following snippet hides the status bar:

View decorView = getWindow().getDecorView();
int uiOptions = View.SYSTEM_UI_FLAG_FULLSCREEN;
decorView.setSystemUiVisibility(uiOptions);
// Remember that you should never show the action bar if the status bar is hidden, so hide that too if necessary
ActionBar actionBar = getActionBar();
actionBar.hide();

Notes:

Once UI flags have been cleared (for example, by navigating away from the activity), your app needs to reset them if you want to hide the bars again. See for a discussion of how to listen for UI visibility changes so that your app can respond accordingly.

Where you set the UI flags makes a difference. If you hide the system bars in your activity’s onCreate() method and the user presses Home, the system bars will reappear. When the user reopens the activity, onCreate() won’t get called, so the system bars will remain visible. If you want system UI changes to persist as the user navigates in and out of your activity, set UI flags in onResume() or onWindowFocusChanged().

The method setSystemUiVisibility() only has an effect if the view you call it from is visible.

Navigating away from the view causes flags set with setSystemUiVisibility() to be cleared.

Make Content Appear Behind the Status Bar

On Android 4.1 and higher, you can set your application’s content to appear behind the status bar, so that the content doesn’t resize as the status bar hides and shows. To do this, use SYSTEM_UI_FLAG_LAYOUT_FULLSCREEN. You may also need to use SYSTEM_UI_FLAG_LAYOUT_STABLE to help your app maintain a stable layout.

When using this approach, it becomes your responsibility to ensure that critical parts of your app’s UI (for example, the built-in controls in a Maps application) don’t end up getting covered by system bars. This could make your app unusable. In most cases, you can handle this by adding the android:fitsSystemWindows attribute to your XML layout file, set to true. This adjusts the padding of the parent ViewGroup to leave space for the system windows. This is sufficient for most applications.

In some cases, however, you may need to modify the default padding to get the desired layout for your app. To directly manipulate how your content lays out relative to the system bars (which occupy a space known as the window’s “content insets”), override fitSystemWindows(Rect insets). The fitSystemWindows() method is called by the view hierarchy when the content insets for a window have changed, allowing the window to adjust its content accordingly. By overriding this method, you can handle the insets (and hence your app’s layout) however you want.

Project Preparation

Development Environment:

IDE: Android Studio 4.1.1

Build #: #AI-201.8743.12.41.6953283, built on November 5, 2020

Runtime Version: 1.8.0_242-release-1644-b01 (AMD64)

VM: OpenJDK 64-Bit Server VM by JetBrains s.r.o

Operating System: Windows 10 10.0

Android Virtual Devices:

Name: Pixel 2

CPU/ABI: Google Play Intel Atom (x86)

Path: C:\Users\86188.android\avd\Pixel_2_API_28.avd

Target: google_apis_playstore [Google Play] (API level 28)

Skin: pixel_2

SD Card: 512MB

fastboot.chosenSnapshotFile: runtime.network.speed: full

hw.accelerometer: yes

hw.device.name: pixel_2

hw.lcd.width: 1080

hw.initialOrientation: Portrait

image.androidVersion.api: 28

tag.id: google_apis_playstore

hw.cpu.ncore: 4

hw.keyboard: yes

hw.sensors.proximity: yes

hw.dPad: no

hw.lcd.height: 1920

vm.heapSize: 256

skin.dynamic: yes

hw.device.manufacturer: Google

hw.gps: yes

audioInput: yes

image.sysdir.1: system-images\android-28\google_apis_playstore\x86

showDeviceFrame: yes

camera.back: virtual

sceneAvdId: Pixel_2_API_28

hw.lcd.density: 420

hw.arc: false

hw.device.hash2: MD5: 55acbc835978f326788ed66a5cd4c9a7

fastboot.forceColdBoot: no

fastboot.forceFastBoot: yes

hw.trackBall: no

hw.battery: yes

hw.sdCard: yes

tag.display: Google Play

runtime.network.latency: none

disk.dataPartition.size: 6442450944

hw.sensors.orientation: yes

avd.ini.encoding: UTF-8

hw.gpu.enabled: yes

Project Creation:

Effect: [Insert image link]

New Project: Select Empty Activity, and in project configuration, set Minimum SDK to API 16: Android 4.1 (Jelly Bean)

New Activity: Create a new Empty Activity, named SecondaryActivity

Layout File Editing: Modify src\main\res\layout\activity_secondary.xml to add Toolbar and Button components

Activity Configuration:

Layout File: src\main\res\layout\activity_secondary.xml
```
     
    
      
    
      
     
```

Activity Code: Modify SecondaryActivity.java

package com.mk;
import androidx.appcompat.app.AppCompatActivity;
import androidx.appcompat.widget.Toolbar;
import android.os.Build;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
public class SecondaryActivity extends AppCompatActivity {
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_secondary);
        Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
        setSupportActionBar(toolbar);
        getSupportActionBar().setDisplayHomeAsUpEnabled(true);
        Button buttonMakeContentAppearBehindTheStatusBar = (Button) findViewById(R.id.buttonMakeContentAppearBehindTheStatusBar);
        buttonMakeContentAppearBehindTheStatusBar.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN) {
                    View decorView = getWindow().getDecorView();
                    decorView.setSystemUiVisibility(View.SYSTEM_UI_FLAG_LAYOUT_FULLSCREEN);
                }
            }
        });
    }
}

Main Activity Configuration:

Layout File: src\main\res\layout\activity_main.xml

Activity Code: Modify MainActivity.java

package com.mk;
import androidx.appcompat.app.AppCompatActivity;
import androidx.appcompat.widget.Toolbar;
import android.content.Intent;
import android.os.Build;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
public class MainActivity extends AppCompatActivity {
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
        setSupportActionBar(toolbar);
        Button buttonHideTheStatusBar = (Button) findViewById(R.id.buttonHideTheStatusBar);
        buttonHideTheStatusBar.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN) {
                    View decorView = getWindow().getDecorView();
                    decorView.setSystemUiVisibility(View.SYSTEM_UI_FLAG_FULLSCREEN);
                    getSupportActionBar().hide();
                }
            }
        });
        Button buttonToSecondaryActivity = (Button) findViewById(R.id.buttonToSecondaryActivity);
        buttonToSecondaryActivity.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Intent intent = new Intent(MainActivity.this, SecondaryActivity.class);
                startActivity(intent);
            }
        });
    }
}