From: Android APP_ Control (6) -- Notification notification
Author: and pursung
Release time: 2021-04-02 00:30:14
website: https://blog.csdn.net/weixin_44742824/article/details/115382674

<?xml version="1.0" encoding="utf-8"?>

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical">
    
<!--    Method name is sendNote，Shortcut key jump directly in java Specific implementation in-->
    <Button
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:onClick="sendNote"
        android:text="give an announcement" />

    <Button
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:onClick="canselNote"
        android:text="Cancellation notice" />

</LinearLayout>

MainAvtivity.java

public class MainActivity extends AppCompatActivity {

    //Create a global object: NotificationManager
    private NotificationManager manager;
    //Create a global object: notification
    private Notification notification;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        //Use the getSystemService method to get the NotificationManager object
        manager = (NotificationManager) getSystemService(NOTIFICATION_SERVICE);

        //If it is 8.0 or above, we can create this object; (I stepped on the pit before, and got a 4.0 version of the project. I couldn't get the notice)
        if(Build.VERSION.SDK_INT >= Build.VERSION_CODES.O){
            NotificationChannel channel = new NotificationChannel("zhua", "Test notification",NotificationManager.IMPORTANCE_HIGH);

            //Created how channel uses it: use the notification management class of NotificationManager
            manager.createNotificationChannel(channel);//Bind channelid to manager
        }
        
        //Create jump intent
        Intent intent = new Intent(this,NotificationActivity.class);
        //setContentIntent parameter to be passed in jump intention: pendingIntent 
        PendingIntent pendingIntent = PendingIntent.getActivities(this, 0, new Intent[]{intent}, 0);

        //Set the attribute of notification directly through the chain structure (set the attribute of notification)
        notification = new NotificationCompat.Builder(this,"zhua")
                //Title (required)
                .setContentTitle("official communication")
                //Notice content (required)
                .setContentText("Hua Tianzhu is here")
                
                //Notification small icon (required) this picture cannot be RGB
                .setSmallIcon(R.drawable.ic_baseline_account_box_24)

                //Large icon for notification: this parameter requires the bitmap type of the picture, so BitmapFactory conversion is required
                .setLargeIcon(BitmapFactory.decodeResource(getResources(),R.drawable.head))
				//Set the notification icon bar icon to red: setColor the incoming parameter is argb
                .setColor(Color.parseColor("#ff0000"))
                //Instead of ordinary intent, pandding intent is created on it
                .setContentIntent(pendingIntent)
                //After clicking the notification, the notification will be cancelled
                .setAutoCancel(true)
                .build();
    }

    public void sendNote(View view) {
        //Two parameters, the first is id. click in and find that there are no requirements. Just write a 1
        manager.notify(1,notification);
    }

    public void canselNote(View view) {
        manager.cancel(1); //The id of this cancellation notice should correspond to the one above
    }
}

NotificationActivity.java

//For the purpose of jump, the class created here must be associated with alt+enter in this place
public class NotificationActivity extends Activity {
    @Override
    protected void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        //Make a simple print to see the effect
        Log.e("zhua", "onCreate: get into NotificationActivity" );
    }
}