关于Notification的使用

Android8（包含8）以上需要创建channel id,否则无法弹出notification：

public class NotificationTest extends AppCompatActivity {

String channel_id="myChannelId"; //每个notification对应的channel_id是唯一的，一般用包名.channel命名
String channel_name="myChannelName";
String description = "this is myChannel's description";
NotificationManager notificationManager;
Button sendNotification;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_notification_test);
    sendNotification = findViewById(R.id.sendNotification);
    createNotificationChannel(); //为notification创建channel_id
    sendNotification.setOnClickListener(new View.OnClickListener() {

@Override
public void onClick(View v) {
    Intent intent = new Intent(NotificationTest.this, NotificationActivity.class);
    PendingIntent pi = PendingIntent.getActivity(NotificationTest.this, 0, intent, 0);
    Notification notification = new NotificationCompat.Builder(NotificationTest.this, channel_id)

.setContentTitle("Notification Title")
.setContentText("Notification Info")
.setWhen(System.currentTimeMillis())
.setSmallIcon(R.drawable.ic_launcher_background)
.setLargeIcon(BitmapFactory.decodeResource(getResources(), com.tripod.permission.R.drawable.ic_launcher_background))
.setContentIntent(pi) //设置pendingIntent ,是的Notification为可点击状态
.setAutoCancel(true) //设置notification点击查看后，后台显示的小图标自动取消
.build();//创建notification

notificationManager.notify(1,notification); //显示notification；每个notification对应的id都是唯一的

   }
});
}

/*Android 8.0（included）以上弹出Notification需要为其创建channel_id,否则存在Notification无法在后台显示的弹出*/
private void createNotificationChannel(){
    //Android8.0(API26)以上需要调用下列方法，但低版本由于支持库旧，不支持调用，需做判断
    if(Build.VERSION.SDK_INT >= Build.VERSION_CODES.O){
        int importance = NotificationManager.IMPORTANCE_DEFAULT;
        NotificationChannel channel = new NotificationChannel(channel_id,channel_name,importance);
        channel.setDescription(description);
        notificationManager = (NotificationManager)
                getSystemService(Context.NOTIFICATION_SERVICE);//获取notification服务
        notificationManager.createNotificationChannel(channel);//创建channel_id
    }

}

}
//NotificationTest.java  对应布局

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout 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"
    tools:context=".NotificationTest">

    <Button
        android:id="@+id/sendNotification"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="sendNotification " />

</LinearLayout>

public class NotificationActivity extends AppCompatActivity {

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

// NotificationActivity  对应布局 （下拉菜单，点击notification弹窗后，弹出的界面）

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout 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"
    tools:context=".NotificationActivity">

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="this is notofcation layout" />

</LinearLayout>