点击 Android 通知后如何打开上一个 Activity？

此示例演示了点击 Android 通知后如何打开上一个 Activity。

步骤 1 - 在 Android Studio 中创建一个新项目，转到文件 ⇒ 新建项目，并填写所有必需的详细信息以创建新项目。

步骤 2 - 将以下代码添加到 res/layout/activity_main.xml 中。

<?xml version = "1.0" encoding = "utf-8" ?>
<android.support.constraint.ConstraintLayout
   xmlns: android = "http://schemas.android.com/apk/res/android"
   xmlns: app = "http://schemas.android.com/apk/res-auto"
   xmlns: tools = "http://schemas.android.com/tools"
   android :layout_width = "match_parent"
   android :layout_height = "match_parent"
   android :padding = "16dp"
   tools :context = ".MainActivity" >
   <Button
      android :id = "@+id/btnCreateNotification"
      android :layout_width = "0dp"
      android :layout_height = "wrap_content"
      android :text = "Create notification"
      app :layout_constraintBottom_toBottomOf = "parent"
      app :layout_constraintEnd_toEndOf = "parent"
      app :layout_constraintStart_toStartOf = "parent"
      app :layout_constraintTop_toTopOf = "parent" />
</android.support.constraint.ConstraintLayout>

步骤 3 - 将以下代码添加到 src/MainActivity.java 中。

package app.tutorialspoint.com.notifyme ;
import android.app.NotificationChannel ;
import android.app.NotificationManager ;
import android.app.PendingIntent ;
import android.content.Context ;
import android.content.Intent ;
import android.support.v4.app.NotificationCompat ;
import android.support.v7.app.AppCompatActivity ;
import android.os.Bundle ;
import android.view.View ;
import android.widget.Button ;
public class MainActivity extends AppCompatActivity {
   public static final String NOTIFICATION_CHANNEL_ID = "10001" ;
   private final static String default_notification_channel_id = "default" ;
   @Override
   protected void onCreate (Bundle savedInstanceState) {
      super .onCreate(savedInstanceState) ;
      setContentView(R.layout. activity_main ) ;
      Button btnCreateNotification = findViewById(R.id. btnCreateNotification ) ;
      btnCreateNotification.setOnClickListener( new View.OnClickListener() {
         @Override
         public void onClick (View v) {
            Intent notificationIntent = new Intent(MainActivity. this, MainActivity. class );
            notificationIntent.addCategory(Intent. CATEGORY_LAUNCHER ) ;
            notificationIntent.setAction(Intent. ACTION_MAIN ) ;
            notificationIntent.setFlags(Intent. FLAG_ACTIVITY_CLEAR_TOP | Intent. FLAG_ACTIVITY_SINGLE_TOP );
            PendingIntent resultIntent = PendingIntent. getActivity (MainActivity. this, 0 , notificationIntent , 0 ) ;
            NotificationCompat.Builder mBuilder = new NotificationCompat.Builder(MainActivity. this, default_notification_channel_id )
               .setSmallIcon(R.drawable. ic_launcher_foreground )
               .setContentTitle( "Test" )
               .setContentIntent(resultIntent)
               .setStyle( new NotificationCompat.InboxStyle())
               .setContentText( "Hello! This is my first push notification" ) ;
            NotificationManager mNotificationManager = (NotificationManager) 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) ;
               mBuilder.setChannelId( NOTIFICATION_CHANNEL_ID ) ;
               assert mNotificationManager != null;
               mNotificationManager.createNotificationChannel(notificationChannel) ;
            }
            assert mNotificationManager != null;
            mNotificationManager.notify(( int ) System. currentTimeMillis () , mBuilder.build()) ;
         }
      }) ;
   }
}

步骤 4 - 将以下代码添加到 androidManifest.xml 中。

<? xml version = "1.0" encoding = "utf-8" ?>
<manifest xmlns: android = "http://schemas.android.com/apk/res/android"
   package = "app.tutorialspoint.com.notifyme" >
   <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>
   </application>
</manifest>

让我们尝试运行您的应用程序。我假设您已将您的实际 Android 移动设备连接到您的计算机。要从 Android Studio 运行应用程序，请打开您的一个项目活动文件，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，然后检查您的移动设备，它将显示您的默认屏幕 -