通知不显示

Question

我试图向手机发送通知，但它没有发送

进口：

import androidx.core.app.NotificationCompat;
import android.content.Context;
import android.app.NotificationManager;

我的代码：

public void sendNotification(){
    NotificationCompat.Builder builder = new NotificationCompat.Builder(this, NotificationChannel.DEFAULT_CHANNEL_ID)
            .setSmallIcon(R.mipmap.ic_launcher_round)
            .setContentTitle("Title")
            .setContentText("Content");

    Intent notificationIntent = new Intent(this, MainActivity.class);
    PendingIntent contentIntent =  PendingIntent.getActivity(this, 0, notificationIntent, PendingIntent.FLAG_UPDATE_CURRENT);
    builder.setContentIntent(contentIntent);

    NotificationManager mNotificationManager = (NotificationManager) getSystemService(Context.NOTIFICATION_SERVICE);
    mNotificationManager.notify(0, builder.build());
}

为什么不显示？ 是否需要意图？ 渠道应该是什么？ 谢谢！

Answer 1

如果您使用 firebase 发送通知，则需要使用 firebase 消息服务活动来接收通知。 并将数据添加到您的清单文件以接收通知。

Answer 2

如果您正在使用服务

从 Android 8.0（API 级别 26）开始，所有通知都必须分配给一个频道。

NotificationCompat.Builder builder = new NotificationCompat.Builder(this, 100);
    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
        NotificationChannel notificationChannel =
                new NotificationChannel(
                        100,
                        "Media PlayBack",
                        NotificationManager.IMPORTANCE_LOW);
        NotificationManager notificationManager = (NotificationManager) getSystemService(Context.NOTIFICATION_SERVICE);
        if (notificationManager != null) {
            notificationManager.createNotificationChannel(notificationChannel);
        }
 }

Intent notificationIntent = new Intent(this, MainActivity.class);
PendingIntent contentIntent =  PendingIntent.getActivity(this, 0, notificationIntent, PendingIntent.FLAG_UPDATE_CURRENT);

builder.setSmallIcon(R.mipmap.ic_launcher_round)
.setContentTitle("Title")
.setContentText("Content")
.setContentIntent(contentIntent); 

Notification notification = builder.build();
startForeground(101, notification);