android - 以编程方式取消(和隐藏)Android 通知

Question

我有一个与通知(系统)一起运行的服务。当服务停止(和/或应用程序停止)时，应取消通知(即不再显示在状态栏上)。

正在通过提供 Android Dev guide of Notifications ，我没有找到有关如何关闭通知的任何信息。

去SO，我发现了一些问题。

1.

总结 @nipun.birla的 answer应该如何取消 Android 通知:

致 取消通知 ，按顺序尝试:

NotifcationManager.cancel(int)与 notificationID

NotificationManager.cancel(String, int)与 notificationID和 notificationTag

NotificationManager.cancelAll()作为最后的尝试

但是没有提到的是，如果这些都不起作用，应该怎么做。

2.

应该使用 cancelAll suggestion

3.

This SO thread包含启动服务示例的一个很好的示例，其中包含在服务生命周期中实现的关联通知(通知也被终止) - 请参阅此处了解 Started Service details

4.

Here有人建议删除 PendingIntent与通知相关

5.

还有几个问题和解决方案反射(reflect)了上述相同的信息:
见 this , 和 this ， 还有很多...

6.

安 very interesting question and solution以编程方式在状态栏中隐藏通知图标

我的问题

现在应该是相当明显的，我的通知并没有取消自己要求这样做。

实现:

完整的实现见下文，虽然我会发布辅助类和核心函数的一般用法

- 创建通知

private Context context;
private NotificationManager notificationManager;
private NotificationChannel notificationChannel;
private NotificationCompat.Builder notificationBuilder;

public NotificationHelper(Context context) {
    this.context = context;

    // Init notification

    // onNotificationCreate()
    {
        // get notification manager system service
        notificationManager = (NotificationManager) context.getSystemService(Context.NOTIFICATION_SERVICE);

        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
            // Create notification channel
            createNotificationChannel();

            //Register notification channel with notification manager
            notificationManager.createNotificationChannel(notificationChannel);
        }

    }

    // Init Notification Builder

    // createNotificationChannel() 
    {
        Log.d(TAG, "createNotificationChannel: Creating notification channel");

        // Define notification channel ID, Channel Name and description
        String channelName = BuildConfig.FLAVOR.concat(" Notifier");
        String channelDescription = context.getString(R.string.notification_description);

        // Create notification channel
        notificationChannel = new NotificationChannel(channelId, channelName, NotificationManager.IMPORTANCE_LOW);
        // Set description of notification channel
        notificationChannel.setDescription(channelDescription);
    }
}

这是由 new NotificationHelper(getApplicationContext) 调用的其中上下文是 Application使用的上下文(也用作许多其他功能的上下文)

我的助手类背后的方法是简单地使用 method chaining允许使用更吸引人的方法来创建、修改和取消通知。

- NotificationHelper 用法:

设置通知 contentText调用 setTextContent(String) :

public NotificationHelper setTextContent(String text){
    notificationBuilder.setContentText(text);
    return this;
}

设置 contentTitle通过`setTitle(字符串):

public NotificationHelper setTitle(String format) {
    notificationBuilder.setContentTitle(format);
    return this;
}

并设置 smallIcon (状态图标)通过拨打 setStatusIcon(int) :

public NotificationHelper setStatusIcon(int res_id) {
    notificationBuilder.setSmallIcon(res_id);
    return this;
}

最后，通过以下方式更新通知以显示结果设置:

public void update() {
    Log.d(TAG, "update: Updating notification");
    Notification notification = notificationBuilder.build();

    // Set notification flags
    notification.flags |= Notification.FLAG_NO_CLEAR;
    notification.flags |= Notification.FLAG_ONGOING_EVENT;
    notification.flags |= Notification.FLAG_FOREGROUND_SERVICE;

    // Notify update
    notificationManager.notify(TAG, notificationId, notification);
}

- 取消通知

正如预期的那样，取消通知就像拨打 cancelNotification() 一样简单。 :

public void cancelNotification() {
    Log.d(TAG, "cancelNotification: Cancelling notification");
    notificationManager.cancel(TAG, notificationId);
}

但是，这对取消通知没有影响。

通知取消时 ，在取消之前发生了以下情况。

应用程序导出已启动。

Bound Service未绑定(bind) - 确保没有客户端绑定(bind)到它。unbindService用 getApplicationContext() 调用在拥有上下文如 unbindService(ServiceConnection)使用相同的 ServiceConnection作为原来的绑定(bind)。

完成所有这些后，通知仍然存在。

我试过什么

notificationManger.cancel(int)

notificationManger.cancel(String, int)

notificationManger.cancelAll

这不起作用，所以我有创意:

此外:
创建一个单独的 NotificationManager发布这些更新的方法(即这里没有设置标志，但使用了相同的 notificationmanager)

public void updateCancelable() {
    Log.d(TAG, "update: Updating notification to cancel");
    Notification notification = notificationBuilder
            .setContentIntent(null)
            .setOngoing(false)
            .setAutoCancel(true)
            .build();
    // Notify update
    notificationManager.notify(TAG, notificationId, notification);
}

清除 setContentIntent()调用 setContentIntent(null)并重新通知更新

我也试过创建一个新的通知 cancelable与 setAutoCancel(true) ，并设置 ongoing state与 setOngoing(false)并重新通知更新

这也没有帮助。有什么我可能会遗漏的吗？

我还应该提到这一点:在调试我的应用程序时，我注意到当我退出应用程序时(绑定(bind)服务停止并调用 cancelNotification() ，尽管 Android Studio 仍然保持 Activity 的调试 session ，但应用程序绝不应该再运行当应用程序仍在运行时，像人们期望的那样打开。不确定这是否与它有关

NotificationHelper 类(完整实现)

import android.app.Notification;
import android.app.NotificationChannel;
import android.app.NotificationManager;
import android.app.PendingIntent;
import android.content.Context;
import android.os.Build;
import android.support.annotation.RequiresApi;
import android.support.v4.app.NotificationCompat;
import android.util.Log;

import com.connectedover.BuildConfig;
import com.connectedover.R;
import com.connectedover.listeners.NotificationUpdateListener;

/**
 * Class aimed at providing helper method for creating, maintaining and destroying notifications in conjunction with {@link de.blinkt.openvpn.core.OpenVPNService}
 *
 * @author cybex
 * @since 1.5.1
 */
public class NotificationHelper implements NotificationUpdateListener {

    private static final String TAG = NotificationManager.class.getSimpleName();
    private static final String channelId = BuildConfig.APPLICATION_ID.concat(".").concat(TAG);
    private static final int notificationId = 42;

    private Context context;
    private NotificationManager notificationManager;
    private NotificationChannel notificationChannel;

    private NotificationCompat.Builder notificationBuilder;

    public NotificationHelper(Context context) {
        this.context = context;

        // Init notification
        onNotificationCreate();

        // Init Notification Builder
        createBasicNotification();
    }

    /**
     * Initialize {@link NotificationChannel} and register channel with {@link NotificationManager} service if API is Android Orea (API 26 or higher), else initializes the notification manager
     */
    private void onNotificationCreate() {
        Log.d(TAG, "onNotificationCreate: Initializing notification helper");

        // get notification manager system service
        notificationManager = (NotificationManager) context.getSystemService(Context.NOTIFICATION_SERVICE);

        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
            // Create notification channel
            createNotificationChannel();

            //Register notification channel with notification manager
            notificationManager.createNotificationChannel(notificationChannel);
        }
    }

    /**
     * Creates a notification channel required by devices running Android SDK 26 and higher.
     * The notification  channel is set to {@link NotificationManager#IMPORTANCE_LOW} which should have no sound and appear right at the top of the status bar
     */
    @RequiresApi(api = Build.VERSION_CODES.O)
    private void createNotificationChannel() {
        Log.d(TAG, "createNotificationChannel: Creating notification channel");

        // Define notification channel ID, Channel Name and description
        String channelName = BuildConfig.FLAVOR.concat(" Notifier");
        String channelDescription = context.getString(R.string.notification_description);

        // Create notification channel
        notificationChannel = new NotificationChannel(channelId, channelName, NotificationManager.IMPORTANCE_LOW);
        // Set description of notification channel
        notificationChannel.setDescription(channelDescription);
    }

    /**
     * Creates a basic notification using {@link android.support.v4.app.NotificationCompatBuilder} for use throughout the application
     */
    private void createBasicNotification() {
        // Instantiate Notification Builder
        notificationBuilder = new NotificationCompat
                .Builder(context, channelId)
                .setContentTitle(context.getString(R.string.app_name))
                .setSmallIcon(R.drawable.ic_logo_disconnected)
                .setWhen(System.currentTimeMillis())
                .setAutoCancel(false)
                .setOngoing(true);
    }

    /**
     * Set the pending intent of a clickable {@link android.app.Notification} held by {@link NotificationHelper#notificationBuilder}
     * @param pendingIntent Pending intent to connect to activity
     * @return returns an instance of {@link NotificationHelper}
     */
    public NotificationHelper setPendingIntent(PendingIntent pendingIntent){
        Log.d(TAG, "setPendingIntent: Setting notification Pending intent");
        notificationBuilder.setContentIntent(pendingIntent);
        return this;
    }

    /**
     * Updates the notification which is displayed for the user.
     */
    public void update() {
        Log.d(TAG, "update: Updating notification");
        Notification notification = notificationBuilder.build();

        // Set notification flags
        notification.flags |= Notification.FLAG_NO_CLEAR;
        notification.flags |= Notification.FLAG_ONGOING_EVENT;
        notification.flags |= Notification.FLAG_FOREGROUND_SERVICE;

        // Notify update
        notificationManager.notify(TAG, notificationId, notification);
    }

    /**
     * Updates the notification {@link NotificationHelper#notificationBuilder} with new text and displays it to the user
     *
     * @param text new text to display
     * @return returns current {@link NotificationHelper} instance for method chaining.
     */
    public NotificationHelper setTextContent(String text){
        notificationBuilder.setContentText(text);
        return this;
    }

    @Override
    public void onUpdate(String update) {
        Log.d(TAG, "onUpdate: updating notification via callback");
        this.setTextContent(update)
                .update();
    }

    /**
     * Sets a new icon for the notification displayed to the user
     * @param res_id icon resource
     * @return current instance
     */
    public NotificationHelper setLargeIcon(int res_id) {
        notificationBuilder.setLargeIcon(ImageUtils.toBitmap(context, res_id));
        return this;
    }

    /**
     * Sets a new icon for the notification displayed to the user show in the status bar (i.e. the small icon)
     * @param res_id icon resource
     * @return current instance
     */
    public NotificationHelper setStatusIcon(int res_id) {
        notificationBuilder.setSmallIcon(res_id);
        return this;
    }

    public NotificationHelper setTitle(String format) {
        notificationBuilder.setContentTitle(format);
        return this;
    }

    /**
     * Cancels the application notification
     */
    public void cancelNotification() {
        Log.d(TAG, "cancelNotification: Cancelling notification");
        notificationManager.cancelAll();
    }
}

Answer 1

如果您想使用您的 Notification作为前台服务的一部分，不要直接操作标志，使用 startForeground()和 stopForeground()在您的 Service .