从Android中的服务发送通知

Question

我正在运行服务，并希望发送通知。太糟糕了，通知对象需要 Context ，比如 Activity ，而不是 Service 。

你知道通过什么方式吗？我尝试为每个通知创建一个 Activity ，但它看起来很难看，我找不到一种方法来启动 Activity 而不需要任何 View

Answer 1

Activity 和 Service 实际上 extend Context 所以你只需在中使用 this 作为 Context >服务

NotificationManager notificationManager =
    (NotificationManager) getSystemService(Service.NOTIFICATION_SERVICE);
Notification notification = new Notification(/* your notification */);
PendingIntent pendingIntent = /* your intent */;
notification.setLatestEventInfo(this, /* your content */, pendingIntent);
notificationManager.notify(/* id */, notification);

Answer 2

从文档中可以看到这种类型的通知：

@java.lang.Deprecated
public Notification(int icon, java.lang.CharSequence tickerText, long when) { /* compiled code */ }

public Notification(android.os.Parcel parcel) { /* compiled code */ }

@java.lang.Deprecated
public void setLatestEventInfo(android.content.Context context, java.lang.CharSequence contentTitle, java.lang.CharSequence contentText, android.app.PendingIntent contentIntent) { /* compiled code */ }

更好的方式
您可以发送如下通知：

// prepare intent which is triggered if the
// notification is selected

Intent intent = new Intent(this, NotificationReceiver.class);
PendingIntent pIntent = PendingIntent.getActivity(this, 0, intent, 0);

// build notification
// the addAction re-use the same intent to keep the example short
Notification n  = new Notification.Builder(this)
        .setContentTitle("New mail from " + "test@gmail.com")
        .setContentText("Subject")
        .setSmallIcon(R.drawable.icon)
        .setContentIntent(pIntent)
        .setAutoCancel(true)
        .addAction(R.drawable.icon, "Call", pIntent)
        .addAction(R.drawable.icon, "More", pIntent)
        .addAction(R.drawable.icon, "And more", pIntent).build();


NotificationManager notificationManager = 
  (NotificationManager) getSystemService(NOTIFICATION_SERVICE);

notificationManager.notify(0, n); 

最佳方式
上面的代码需要最低API级别11（Android 3.0）。
如果您的最低API级别低于11，则应使用支持库的NotificationCompat类像这样。

因此，如果您的最低目标API级别为4+（Android 1.6+），请使用：

    import android.support.v4.app.NotificationCompat;
    -------------
    NotificationCompat.Builder builder =
            new NotificationCompat.Builder(this)
                    .setSmallIcon(R.drawable.mylogo)
                    .setContentTitle("My Notification Title")
                    .setContentText("Something interesting happened");
    int NOTIFICATION_ID = 12345;

    Intent targetIntent = new Intent(this, MyFavoriteActivity.class);
    PendingIntent contentIntent = PendingIntent.getActivity(this, 0, targetIntent, PendingIntent.FLAG_UPDATE_CURRENT);
    builder.setContentIntent(contentIntent);
    NotificationManager nManager = (NotificationManager) getSystemService(Context.NOTIFICATION_SERVICE);
    nManager.notify(NOTIFICATION_ID, builder.build());

Answer 3

@TargetApi(Build.VERSION_CODES.JELLY_BEAN)
public void PushNotification()
{
    NotificationManager nm = (NotificationManager)context.getSystemService(NOTIFICATION_SERVICE);
    Notification.Builder builder = new Notification.Builder(context);
    Intent notificationIntent = new Intent(context, MainActivity.class);
    PendingIntent contentIntent = PendingIntent.getActivity(context,0,notificationIntent,0);

    //set
    builder.setContentIntent(contentIntent);
    builder.setSmallIcon(R.drawable.cal_icon);
    builder.setContentText("Contents");
    builder.setContentTitle("title");
    builder.setAutoCancel(true);
    builder.setDefaults(Notification.DEFAULT_ALL);

    Notification notification = builder.build();
    nm.notify((int)System.currentTimeMillis(),notification);
}

Answer 4

好吧，我不确定我的解决方案是否是最佳做法。使用 NotificationBuilder ，我的代码如下：

private void showNotification() {
    Intent notificationIntent = new Intent(this, MainActivity.class);

    PendingIntent contentIntent = PendingIntent.getActivity(
                this, 0, notificationIntent, PendingIntent.FLAG_UPDATE_CURRENT);
    builder.setContentIntent(contentIntent);
    NotificationManager notificationManager =
            (NotificationManager) getSystemService(Context.NOTIFICATION_SERVICE);
    notificationManager.notify(NOTIFICATION_ID, builder.build());
    }

清单：

    <activity
        android:name=".MainActivity"
        android:launchMode="singleInstance"
    </activity>

这里是服务：

    <service
        android:name=".services.ProtectionService"
        android:launchMode="singleTask">
    </service>

我不知道 Service 是否确实存在 singleTask ，但这在我的应用程序中正常运行...

Answer 5

如果这些都不起作用，请尝试 getBaseContext（），而不是 context 或 this 。