Android O - Notification Channels and NotificationCompat

时间：2017-07-10 15:18:14

标签： java android-notifications android-support-library android-8.0-oreo

I cannot change this feeling: again, the Android developers came up with something new and leave everybody in the dark about how they would think the feature is used.

I am talking about Notification Channels in Android O.

For years I have been using the compatibility support libraries to avoid dealing with specific platform details. Namely: NotificationCompat.

Now, the Builder requires me to supply a notification channel id, which is nice, but completely leaves me alone with creating such a channel. I cannot find any compat support for creating channels. Nor can I find a reasonable way to create them at the right point.

The docs simply state that it should be done "somewhere" and "probably not when issuing a notification". But what exactly am I supposed to do? I hate writing version specific stuff for simple tasks - that's why I use the compat libraries.

Does anybody have a suggestion on how to handle it? Is it "expensive" to do the creating each and every time when I want a notification to be displayed?

7 个答案:

答案 0 :(得分：12)

这是我在Android O上生成通知并保持向后兼容性的解决方案：

c.isspace()

答案 1 :(得分：2)

它没有你想象的那么贵！ 您需要做的就是创建一个通知渠道并将其绑定到通知。

您可以通过两种方式解决此问题，但对于这两种方式，您需要创建具有特定渠道ID的通知渠道。

NotificationManager mNotificationManager = (NotificationManager) getSystemService(Context.NOTIFICATION_SERVICE);
String id = "my_channel_01";
int importance = NotificationManager.IMPORTANCE_LOW;
NotificationChannel mChannel = new NotificationChannel(id, name,importance);
mChannel.enableLights(true);
mNotificationManager.createNotificationChannel(mChannel);

第一种方法是在构造函数中设置通知通道：

Notification notification = new Notification.Builder(MainActivity.this , id).setContentTitle("Title");
mNotificationManager.notify("your_notification_id", notification);

第二种方法是通过Notificiation.Builder.setChannelId（）

设置频道 
Notification notification = new Notification.Builder(MainActivity.this).setContentTitle("Title").
setChannelId(id);
mNotificationManager.notify("your_notification_id", notification);

希望这有帮助

答案 2 :(得分：2)

以下是使用反射创建通知频道的替代解决方案，因此您可以将compileSdkVersion设置为低于26。

   private void createNotificationChannel(NotificationManager notificationManager) {
        // Channel details
        String channelId = "myChannelId";
        String channelName = "Notifications";

        // Channel importance (3 means default importance)
        int channelImportance = 3;

        try {
            // Get NotificationChannel class via reflection (only available on devices running Android O or newer)
            Class notificationChannelClass = Class.forName("android.app.NotificationChannel");

            // Get NotificationChannel constructor
            Constructor<?> notificationChannelConstructor = notificationChannelClass.getDeclaredConstructor(String.class, CharSequence.class, int.class);

            // Instantiate new notification channel
            Object notificationChannel = notificationChannelConstructor.newInstance(channelId, channelName, channelImportance);

            // Get notification channel creation method via reflection
            Method createNotificationChannelMethod =  notificationManager.getClass().getDeclaredMethod("createNotificationChannel", notificationChannelClass);

            // Invoke method on NotificationManager, passing in the channel object
            createNotificationChannelMethod.invoke(notificationManager, notificationChannel);

            // Log success to console
            Log.d("MyApp", "Notification channel created successfully");
        }
        catch (Exception exc) {
            // Log exception to console
            Log.e("MyApp", "Creating notification channel failed", exc);
        }
    }

然后，当您构建通知时，只需调用.setChannelId()的{​​{1}}方法：

NotificationCompat.Builder

注意：您需要将builder.setChannelId("myChannelId"); 库更新为appcompat-v7中的26.x.x版本：

build.gradle

答案 3 :(得分：0)

如果您的通知代码每次都具有相同的结构，那么您应该创建一个静态方法并传递所有您想要的内容并将其放入检查此方法中 API级别的代码。

答案 4 :(得分：0)

如果要支持早期版本的Android（NotificationManager中包装Notification.Builder来创建和构建NotificationHelper实例：

/**
 * Helper class to manage notification channels, and create notifications.
 * <p>
 * Created by teocci.
 *
 * @author teocci@yandex.com on 2018-Oct-02
 */
public class NotificationHelper extends ContextWrapper
{
    public static final String NOTIFICATION_CHANNEL_PRIMARY = "notification_channel_primary";
    public static final int NOTIFICATION_ID_PRIMARY = 1100;

    private NotificationManager manager;

    /**
     * Registers notification channels, which can be used later by individual notifications.
     *
     * @param ctx The application context
     */
    public NotificationHelper(Context ctx)
    {
        super(ctx);

        // For API 26+ create notification channels
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
            NotificationChannel channel = new NotificationChannel(NOTIFICATION_CHANNEL_PRIMARY,
                    getString(R.string.channel_name),
                    NotificationManager.IMPORTANCE_DEFAULT
            );
            channel.setLightColor(Color.BLUE);
            channel.setLockscreenVisibility(Notification.VISIBILITY_PRIVATE);
            channel.setDescription(getString(R.string.channel_description));
            getManager().createNotificationChannel(channel);
        }
    }
    /**
     * Cancel a previously shown notification.  If it's transient, the view
     * will be hidden.  If it's persistent, it will be removed from the status
     * bar.
     *
     * @param id    The ID of the notification
     */
    public void remove(int id){
        manager.cancel(id);
    }

    /**
     * Get a notification of type 1
     * <p>
     * Provide the builder rather than the notification it's self as useful for making notification
     * changes.
     *
     * @return the builder as it keeps a reference to the notification (since API 24)
     */
    public Notification getNotification()
    {
        return getNotification(getTitle(), getBody()).build();
    }

    /**
     * Get a notification of type 1
     * <p>
     * Provide the builder rather than the notification it's self as useful for making notification
     * changes.
     *
     * @param title the title of the notification
     * @param body  the body text for the notification
     * @return the builder as it keeps a reference to the notification (since API 24)
     */
    public Notification.Builder getNotification(String title, String body)
    {
        Notification.Builder builder = new Notification.Builder(getApplicationContext())
                .setOngoing(true)  // Persistent notification!
                .setAutoCancel(true)
                .setTicker(title)
                .setContentTitle(title)
                .setContentText(body)
                .setSmallIcon(getSmallIcon());

        // Set the Channel ID for Android O.
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
            builder.setChannelId(NOTIFICATION_CHANNEL_PRIMARY); // Channel ID
        }

        return builder;
    }

    /**
     * Send a notification.
     *
     * @param id           The ID of the notification
     * @param notification The notification object
     */
    public void notify(int id, Notification.Builder notification)
    {
        getManager().notify(id, notification.build());
    }

    /**
     * Get the notification manager.
     * <p>
     * Utility method as this helper works with it a lot.
     *
     * @return The system service NotificationManager
     */
    private NotificationManager getManager()
    {
        if (manager == null) {
            manager = (NotificationManager) getSystemService(NOTIFICATION_SERVICE);
        }

        return manager;
    }

    /**
     * Get the small icon for this app
     *
     * @return The small icon resource id
     */
    private int getSmallIcon()
    {
        return R.drawable.ic_smart_audio_noti_icon;
    }

    /**
     * Get the notification title for this app
     *
     * @return The notification title as string
     */
    private String getTitle()
    {
        return getString(R.string.notification_title);
    }

    /**
     * Get the notification content for this app
     *
     * @return The notification content as string
     */
    private String getBody()
    {
        return getString(R.string.notification_content);
    }
}

然后我们可以像这样轻松地使用它：

@Override
public void onCreate()
{
    ...
    notificationHelper = new NotificationHelper(this);
    notificationHelper.notify(NotificationHelper.NOTIFICATION_ID_PRIMARY, "App is running");
    ...
}

@Override
public void onDestroy()
{
    notificationHelper.remove(NotificationHelper.NOTIFICATION_ID_PRIMARY)
}

答案 5 :(得分：0)

下面的以下代码对我来说很好，希望对您有帮助

private void sendNotification(Context ctx, String title, int notificationNumber, String message, String subtext, Intent intent) {
        try {

            PendingIntent pendingIntent = PendingIntent.getActivity(ctx, notificationNumber, intent,
                    PendingIntent.FLAG_UPDATE_CURRENT);
            Uri url = your sound file from raw;
            NotificationCompat.Builder notificationBuilder = null;
            try {
                if (Build.VERSION.SDK_INT >= 26) {

                    try{
                        NotificationManager notificationManager = (NotificationManager)getApplicationContext().getSystemService(Context.NOTIFICATION_SERVICE);
                        notificationManager.deleteNotificationChannel(CHANNEL_ID_1);
                        notificationManager.deleteNotificationChannel(CHANNEL_ID_2);

                        if(!intent.getStringExtra("type").equalsIgnoreCase(""+TYPE_RIDE_REQUEST)){
                            NotificationChannel breaking = new NotificationChannel(CHANNEL_ID_1, CHANNEL_ID_1_NAME, NotificationManager.IMPORTANCE_HIGH);
                            breaking.setShowBadge(false);
                            breaking.enableLights(true);
                            breaking.enableVibration(true);
                            breaking.setLightColor(Color.WHITE);
                            breaking.setVibrationPattern(new long[]{100, 200, 100, 200, 100, 200, 100});
                            breaking.setSound(url,new AudioAttributes.Builder().build());

                            notificationBuilder = new NotificationCompat.Builder(this,CHANNEL_ID_1)
                                    .setSmallIcon(R.mipmap.ic_launcher);
                            notificationManager.createNotificationChannel(breaking);

                        }else{

                            NotificationChannel politics = new NotificationChannel(CHANNEL_ID_2,CHANNEL_ID_2_NAME, NotificationManager.IMPORTANCE_DEFAULT);
                            politics.setShowBadge(false);
                            politics.enableLights(true);
                            politics.enableVibration(true);
                            politics.setLightColor(Color.BLUE);
                            politics.setVibrationPattern(new long[]{100, 200, 100, 200, 100});
                            politics.setSound(url,new AudioAttributes.Builder().build());

                            notificationBuilder = new NotificationCompat.Builder(this,CHANNEL_ID_2)
                                    .setSmallIcon(R.mipmap.ic_launcher);
                            notificationManager.createNotificationChannel(politics);
                        }
                    }catch (Exception e){
                        e.printStackTrace();
                    }

                } else {
                    notificationBuilder = new NotificationCompat.Builder(ctx)
                            .setSmallIcon(R.mipmap.ic_launcher);
                }
            } catch (Exception e) {
                e.printStackTrace();
            }

            if (notificationBuilder == null) {
                notificationBuilder = new NotificationCompat.Builder(ctx)
                        .setSmallIcon(R.mipmap.ic_launcher);
            }


            notificationBuilder.setContentTitle(title);
            notificationBuilder.setSubText(subtext);
            notificationBuilder.setAutoCancel(true);

            notificationBuilder.setContentIntent(pendingIntent);
            notificationBuilder.setNumber(notificationNumber);
            NotificationManager notificationManager =
                    (NotificationManager) ctx.getSystemService(Context.NOTIFICATION_SERVICE);

            notificationManager.notify(notificationNumber, notificationBuilder.build());

        } catch (Exception e) {
            e.printStackTrace();
        }
    }

答案 6 :(得分：-1)

使用NotificationChannnel非常简单。

NotificationChannel实际上将多个通知分组到频道中。它基本上可以更好地控制用户的通知行为。您可以在Working with Notification Channel | With Example

了解有关通知渠道及其实施的更多信息

创建通知渠道

 // This is the Notification Channel ID. More about this in the next section
public static final String NOTIFICATION_CHANNEL_ID="channel_id";

//User visible Channel Name
public static final String CHANNEL_NAME="Notification Channel";

// Importance applicable to all the notifications in this Channel
int importance=NotificationManager.IMPORTANCE_DEFAULT;

//Notification channel should only be created for devices running Android 26
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {

      NotificationChannel notificationChannel = new NotificationChannel(NOTIFICATION_CHANNEL_ID, CHANNEL_NAME, importance);

      //Boolean value to set if lights are enabled for Notifications from this Channel
      notificationChannel.enableLights(true);

      //Boolean value to set if vibration is enabled for Notifications from this Channel
      notificationChannel.enableVibration(true);

      //Sets the color of Notification Light
      notificationChannel.setLightColor(Color.GREEN);

      //Set the vibration pattern for notifications. Pattern is in milliseconds with the format {delay,play,sleep,play,sleep...}
      notificationChannel.setVibrationPattern(new long[]{500,500,500,500,500});

      //Sets whether notifications from these Channel should be visible on Lockscreen or not
      notificationChannel.setLockscreenVisibility( 
 Notification.VISIBILITY_PUBLIC);
}
// Creating the Channel
NotificationManager notificationManager = (NotificationManager) getSystemService(NOTIFICATION_SERVICE);
notificationManager.createNotificationChannel(notificationChannel);

现在，在创建Notification时，只需将Channel ID传递给Notification Builder构造函数，如下所示

//We pass the unique channel id as the second parameter in the constructor
NotificationCompat.Builder notificationCompatBuilder=new NotificationCompat.Builder(this,NOTIFICATION_CHANNEL_ID);

//Title for your notification
notificationCompatBuilder.setContentTitle("This is title");

//Subtext for your notification
notificationCompatBuilder.setContentText("This is subtext");

//Small Icon for your notificatiom
notificationCompatBuilder.setSmallIcon(R.id.icon);

//Large Icon for your notification 
notificationCompatBuilder.setLargeIcon(  BitmapFactory.decodeResource(getResources(),R.id.icon));

notificationManager.notify( NOTIFICATION_ID,notificationCompatBuilder.build());

上述通知成为第一步中创建的通知频道的一部分，其行为现在将与频道设置相关

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