Java Android O-通知通道和通知兼容性

我无法改变这种感觉：再一次，Android开发人员想出了一些新的东西，让每个人都不知道他们认为该功能是如何使用的

我说的是Android O中的通知通道

多年来，我一直在使用兼容性支持库来避免处理特定的平台细节。即：

NotificationCompat

---

现在，

Builder

要求我提供一个通知频道id，这很好，但完全让我自己创建这样一个频道。我找不到任何compat支持创建频道。我也无法找到一种合理的方法在正确的位置创建它们

这些文件只是简单地说明应该在“某个地方”和“在发出通知时可能不这样做”。但我到底该怎么办呢？我讨厌为简单的任务编写特定于版本的东西——这就是我使用compat库的原因

---

有人对如何处理这件事有什么建议吗？每当我想要显示通知时，创建通知是否“昂贵”？

这并不像你想象的那么昂贵！ 您只需创建一个通知通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，您都需要创建具有特定通道id的通知通道

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notification.Builder.setChannelId（）设置通道

---

希望这有帮助

这是我在Android O上生成通知并保持向后兼容性的解决方案：

        String idChannel = "my_channel_01";
        Intent mainIntent;

        mainIntent = new Intent(context, LauncherActivity.class);

        PendingIntent pendingIntent = PendingIntent.getActivity(context, 0, mainIntent, 0);

        NotificationManager mNotificationManager = (NotificationManager) context.getSystemService(Context.NOTIFICATION_SERVICE);

        NotificationChannel mChannel = null;
        // The id of the channel.

        int importance = NotificationManager.IMPORTANCE_HIGH;

        NotificationCompat.Builder builder = new NotificationCompat.Builder(context, null);
        builder.setContentTitle(context.getString(R.string.app_name))
                .setSmallIcon(getNotificationIcon())
                .setContentIntent(pendingIntent)
                .setContentText(context.getString(R.string.alarm_notification) + ManagementDate.getIstance().hourFormat.format(getAlarm(context, 0)));

        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
            mChannel = new NotificationChannel(idChannel, context.getString(R.string.app_name), importance);
            // Configure the notification channel.
            mChannel.setDescription(context.getString(R.string.alarm_notification));
            mChannel.enableLights(true);
            mChannel.setLightColor(Color.RED);
            mChannel.setVibrationPattern(new long[]{100, 200, 300, 400, 500, 400, 300, 200, 400});
            mNotificationManager.createNotificationChannel(mChannel);
        } else {
            builder.setContentTitle(context.getString(R.string.app_name))
                    .setPriority(NotificationCompat.PRIORITY_HIGH)
                    .setColor(ContextCompat.getColor(context, R.color.transparent))
                    .setVibrate(new long[]{100, 250})
                    .setLights(Color.YELLOW, 500, 5000)
                    .setAutoCancel(true);
        }
        mNotificationManager.notify(1, builder.build());

---

这里有一个替代解决方案，它使用反射来创建通知通道，这样您就可以将

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);
        }
    }

注意：您需要在

build.gradle

中将

appcompat-v7

库更新为版本

26.x.x

：

compile 'com.android.support:appcompat-v7:26.1.0'

---

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，并将检查API级别的代码放入此方法中。

使用通知通道非常简单

NotificationChannel实际上将多个通知分组到多个通道中。它基本上为用户提供了更多的通知行为控制。有关通知通道及其实现的更多信息，请访问

创建通知通道

 // 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，在创建通知时，只需将通道ID传递给通知生成器构造函数，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());

---

随着上述通知成为第一步中创建的通知通道的一部分，如果您希望支持以前版本的Android（NotificationManager包装起来，在

NotificationHelper

中创建和构建

Notification.Builder

实例，如下所示：

/**
 * 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);
    }
}

@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)
}

---

“我也找不到一个合理的方法在正确的位置创建它们”——我会在你的应用程序第一次运行时创建，如果它们还不存在，我会根据需要懒洋洋地创建。“当我希望显示通知时，每次都创建频道是否“昂贵？”——每次创建相同的频道充其量是浪费，或者最坏的情况是为您提供N组频道，因为没有更新机制。“我找不到任何compat支持创建频道”--v26库处于测试阶段；也许他们会添加它。这是为了通知，而不是为了通知。如果我为应用程序设置了通知频道，是否可以获取我为特定应用程序更改的声音

URI

。借助渠道

/**
 * 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);
    }
}

@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)
}