如何让 Android 状态栏通知在手机重启后仍然保留?
androidapps/applicationsmobile development
本示例演示如何让 Android 状态栏通知在手机重启后仍然保留。
步骤 1 - 在 Android Studio 中创建一个新项目，依次点击"文件">"新建项目"，并填写所有必需信息以创建一个新项目。
步骤 2 - 将以下代码添加到 res/layout/activity_main.xml 文件中。
<? 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 :layout_width = "match_parent" android :layout_height = "match_parent" android :padding = "16dp" tools :context = ".MainActivity" / >
步骤 3 − 将以下代码添加到 src/MainActivity。
package app.tutorialspoint.com.notifyme ;
import android.os.Bundle ;
import android.support.v7.app.AppCompatActivity ;
public class MainActivity extends AppCompatActivity {
@Override
protected void onCreate (Bundle savedInstanceState) {
super .onCreate(savedInstanceState) ;
setContentView(R.layout. activity_main ) ;
}
}
步骤 4 将以下代码添加到 src/USBStateReceiver 文件中。
package app.tutorialspoint.com.notifyme ;
import android.annotation. SuppressLint ;
import android.app.Notification ;
import android.app.NotificationChannel ;
import android.app.NotificationManager ;
import android.content.BroadcastReceiver ;
import android.content.Context ;
import android.content.Intent ;
import android.support.v4.app.NotificationCompat ;
import android.util.Log ;
public class USBStateReceiver extends BroadcastReceiver {
public static final String NOTIFICATION_CHANNEL_ID = "10001" ;
private final static String default_notification_channel_id = "default" ;
boolean connected = true;
@SuppressLint ( "UnsafeProtectedBroadcastReceiver" )
@Override
public void onReceive (Context context , Intent intent) {
NotificationCompat.Builder builder = new NotificationCompat.Builder(context , default_notification_channel_id ) ;
builder.setContentTitle( "USB - Notification" ) ;
String action = intent.getAction() ;
Log. e ( "USB" , action) ;
assert action != null;
builder.setContentText( "Connected" ) ;
builder.setSmallIcon(R.drawable. ic_launcher_foreground ) ;
builder.setAutoCancel( true ) ;
builder.setChannelId( NOTIFICATION_CHANNEL_ID ) ;
Notification notification = builder.build() ;
NotificationManager notificationManager = (NotificationManager) context.getSystemService(Context. NOTIFICATION_SERVICE ) ;
if (android.os.Build.VERSION. SDK_INT >= android.os.Build.VERSION_CODES. O ) {
int importance = NotificationManager. IMPORTANCE_HIGH ;
NotificationChannel notificationChannel = new NotificationChannel( NOTIFICATION_CHANNEL_ID , "NOTIFICATION_CHANNEL_NAME" , importance) ;
assert notificationManager != null;
notificationManager.createNotificationChannel(notificationChannel) ;
}
assert notificationManager != null;
if ( connected ) {
notificationManager.notify( 1 , notification) ;
connected = false;
} else {
notificationManager.cancel( 1 ) ;
connected = true;
}
}
步骤 5 − 将以下代码添加到 AndroidManifest.xml
<? xml version= "1.0" encoding= "utf-8" ?> <manifest xmlns: android = "http://schemas.android.com/apk/res/android" package = "app.tutorialspoint.com.notifyme" > <uses-permission android :name = "android.permission.VIBRATE" /> <uses-permission android :name = "android.permission.RECEIVE_BOOT_COMPLETED" /> <application android :allowBackup= "true" android :icon = "@mipmap/ic_launcher" android :label = "@string/app_name" android :roundIcon = "@mipmap/ic_launcher_round" android :supportsRtl = "true" android :theme= "@style/AppTheme" > <activity android :name = ".MainActivity" > <intent-filter> <action android :name = "android.intent.action.MAIN" /> <category android :name = "android.intent.category.LAUNCHER" /> </intent-filter> </activity> <receiver android :name = ".USBStateReceiver" > <intent-filter> <action android :name = "android.intent.action.BOOT_COMPLETED" /> </intent-filter> </receiver> <application> </manifest>
让我们尝试运行您的应用程序。我假设您已将 Android 移动设备连接到计算机。要从 Android Studio 运行应用程序，请打开项目中的一个 Activity 文件，然后单击工具栏中的"运行"图标 
。选择您的移动设备作为选项，然后选中您的移动设备，它将显示您的默认屏幕。 −
