About Lesson
In Android, Notifications are a way to inform the user about events that are happening in your application. They are used to provide the user with reminders, communication from other people, or updates on ongoing tasks.
What are Notifications?
A Notification in Android is a message that appears outside of your application’s UI to provide the user with reminders, communication from other people, or other timely information from your app. Users can tap the notification to open your app or take an action directly from the notification.
Here’s an example of how to create a notification:
NotificationCompat.Builder builder = new NotificationCompat.Builder(this)
.setSmallIcon(R.drawable.notification_icon)
.setContentTitle("My notification")
.setContentText("Hello World!")
.setPriority(NotificationCompat.PRIORITY_DEFAULT);
NotificationManagerCompat notificationManager = NotificationManagerCompat.from(this);
// notificationId is a unique int for each notification that you must define
notificationManager.notify(notificationId, builder.build());
Why use Notifications?
Notifications are useful for several reasons:
-
User Engagement: Notifications can encourage the user to interact with your application when it’s not open.
-
Communication: Notifications allow your app to communicate with the user, even when the user is not actively using your app.
-
Updates: Notifications can provide the user with important updates, such as new messages or events.
Example
MainActivity.java
package in.infovistar.androidnotification;
import androidx.annotation.RequiresApi;
import androidx.appcompat.app.AppCompatActivity;
import androidx.core.app.ActivityCompat;
import androidx.core.app.NotificationCompat;
import androidx.core.app.NotificationManagerCompat;
import androidx.core.content.ContextCompat;
import android.annotation.SuppressLint;
import android.app.Notification;
import android.app.NotificationChannel;
import android.app.NotificationManager;
import android.content.Context;
import android.content.pm.PackageManager;
import android.graphics.Color;
import android.graphics.drawable.BitmapDrawable;
import android.media.RingtoneManager;
import android.os.Build;
import android.os.Bundle;
import android.Manifest;
public class MainActivity extends AppCompatActivity {
private final String ANDROID_CHANNEL_ID = "in.infovistar.androidnotification.MainActivity.ANDROID";
private final String ANDROID_CHANNEL_NAME = "ANDROID_CHANNEL";
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
checkNotificationPermission();
}
private void checkNotificationPermission() {
if (Build.VERSION.SDK_INT >= 33) {
if (ContextCompat.checkSelfPermission(this, Manifest.permission.POST_NOTIFICATIONS) != PackageManager.PERMISSION_GRANTED) {
ActivityCompat.requestPermissions(this, new String[]{Manifest.permission.POST_NOTIFICATIONS}, 101);
} else {
createChannel();
openNotification();
}
} else {
openNotification();
}
}
private void openNotification() {
if (android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.O) {
Notification.Builder notificationBuilder = new Notification.Builder(getApplicationContext(), ANDROID_CHANNEL_ID)
.setContentTitle("My Notification Title")
.setContentText("Notification Message")
.setSmallIcon(R.mipmap.ic_launcher)
.setPriority(Notification.PRIORITY_HIGH);
NotificationManager notificationManager =
(NotificationManager) getSystemService(Context.NOTIFICATION_SERVICE);
notificationManager.notify(102, notificationBuilder.build());
} else {
NotificationCompat.Builder mBuilder = new NotificationCompat.Builder(this, ANDROID_CHANNEL_ID);
@SuppressLint("UseCompatLoadingForDrawables")
Notification notification = mBuilder.setSmallIcon(R.mipmap.ic_launcher)
.setLargeIcon(((BitmapDrawable) getResources().getDrawable(R.mipmap.ic_launcher)).getBitmap())
.setContentTitle("My Notification Title")
.setContentText("Notification Message")
.setPriority(1)
.setSound(RingtoneManager.getDefaultUri(RingtoneManager.TYPE_NOTIFICATION))
.build();
notification.flags = Notification.FLAG_AUTO_CANCEL;
NotificationManager notificationManager =
(NotificationManager) getSystemService(Context.NOTIFICATION_SERVICE);
notificationManager.notify(103, notification);
}
}
@RequiresApi(api = Build.VERSION_CODES.O)
private void createChannel() {
// create android channel
NotificationChannel androidChannel = new NotificationChannel(ANDROID_CHANNEL_ID,
ANDROID_CHANNEL_NAME, NotificationManager.IMPORTANCE_DEFAULT);
// Sets whether notifications posted to this channel should display notification lights
androidChannel.enableLights(true);
// Sets whether notification posted to this channel should vibrate.
androidChannel.enableVibration(true);
// Sets the notification light color for notifications posted to this channel
androidChannel.setLightColor(Color.GREEN);
// Sets whether notifications posted to this channel appear on the lockscreen or not
androidChannel.setLockscreenVisibility(Notification.VISIBILITY_PRIVATE);
NotificationManagerCompat notificationManager = NotificationManagerCompat.from(this);
notificationManager.createNotificationChannel(androidChannel);
}
}
AndroidManifest.xml
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools">
<uses-permission android:name="android.permission.POST_NOTIFICATIONS"/>
<application
android:allowBackup="true"
android:dataExtractionRules="@xml/data_extraction_rules"
android:fullBackupContent="@xml/backup_rules"
android:icon="@mipmap/ic_launcher"
android:label="@string/app_name"
android:roundIcon="@mipmap/ic_launcher_round"
android:supportsRtl="true"
android:theme="@style/Theme.AndroidNotification"
tools:targetApi="31">
<activity
android:name=".MainActivity"
android:exported="true">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
<meta-data
android:name="android.app.lib_name"
android:value="" />
</activity>
</application>
</manifest>
Exercise Files