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[操作系统]Android显示不重复通知的Notification


在Android开发中经常会用到Notification来展示通知,但是之前写出来的代码中一个APP只能有一个通知,有新的通知的时候自己会覆盖之前的通知,一直不知道为什么,好,话不多说,先贴我之前的代码

  private void showNotification(String title, Context context) {    NotificationManager notificationManager = (NotificationManager) context        .getSystemService(android.content.Context.NOTIFICATION_SERVICE);    Notification notification = new Notification(R.drawable.ic_launcher,        "XXX", System.currentTimeMillis());    notification.flags = Notification.FLAG_AUTO_CANCEL;    notification.defaults |= Notification.DEFAULT_VIBRATE;    notification.defaults |= Notification.DEFAULT_SOUND;    notification.defaults |= Notification.DEFAULT_LIGHTS;    notification.vibrate = new long[]{0, 100, 200, 300};    Intent intent = null;    if (pushType == 1) {      intent = new Intent(context, Advertisement.class);    } else if (pushType == 2) {      intent = new Intent(context, HomePage.class);    } else if (pushType == 3) {      intent = new Intent(context, OrderList.class);    }    PendingIntent contentIntent = PendingIntent.getActivity(context, 0,        intent, 0);    notification.setLatestEventInfo(context, "XXX", title, contentIntent);    notificationManager.notify(111, notification);  }

  这几天,看了Android关于Notification的源码,发现了notify函数的一段说明

 

/**   * Post a notification to be shown in the status bar. If a notification with   * the same id has already been posted by your application and has not yet been canceled, it   * will be replaced by the updated information.   *   * @param id An identifier for this notification unique within your   *    application.   * @param notification A {@link Notification} object describing what to show the user. Must not   *    be null.   */  public void notify(int id, Notification notification)  {    notify(null, id, notification);  }

  

在这里可以看到,Notification中的第一个参数id就是每一个通知的id,按照常理来推断,只要id一样,自然就会覆盖,既然这样,那就用时间戳来代替上面的写法好啦,新代码如下:

 

 private void showNotification(String title, Context context) {    int requestCode = (int) System.currentTimeMillis();    NotificationManager notificationManager = (NotificationManager) context        .getSystemService(android.content.Context.NOTIFICATION_SERVICE);    Notification notification = new Notification(R.drawable.ic_launcher,        "90上门洗车", System.currentTimeMillis());    notification.flags = Notification.FLAG_AUTO_CANCEL;    notification.defaults |= Notification.DEFAULT_VIBRATE;    notification.defaults |= Notification.DEFAULT_SOUND;    notification.defaults |= Notification.DEFAULT_LIGHTS;    notification.vibrate = new long[]{0, 100, 200, 300};    Intent intent = null;    if (pushType == 1) {      intent = new Intent(context, Advertisement.class);    } else if (pushType == 2) {      intent = new Intent(context, HomePage.class);    } else if (pushType == 3) {      intent = new Intent(context, OrderList.class);    }    PendingIntent contentIntent = PendingIntent.getActivity(context, 0,        intent, 0);    notification.setLatestEventInfo(context, "90上门洗车", title, contentIntent);    notificationManager.notify(requestCode, notification);  }

  

在这里,我把notify()里面的id参数变成了时间戳,编译,运行,好像成功了呢,这样,就可以显示不同的通知啦~

 

 =  =  虽然成功了,但是在源码里面可以看到,还有一种重载

 

 

 /**   * Post a notification to be shown in the status bar. If a notification with   * the same tag and id has already been posted by your application and has not yet been   * canceled, it will be replaced by the updated information.   *   * @param tag A string identifier for this notification. May be {@code null}.   * @param id An identifier for this notification. The pair (tag, id) must be unique   *    within your application.   * @param notification A {@link Notification} object describing what to   *    show the user. Must not be null.   */  public void notify(String tag, int id, Notification notification)  {    int[] idOut = new int[1];    INotificationManager service = getService();    String pkg = mContext.getPackageName();    if (notification.sound != null) {      notification.sound = notification.sound.getCanonicalUri();      if (StrictMode.vmFileUriExposureEnabled()) {        notification.sound.checkFileUriExposed("Notification.sound");      }    }    if (localLOGV) Log.v(TAG, pkg + ": notify(" + id + ", " + notification + ")");    Notification stripped = notification.clone();    Builder.stripForDelivery(stripped);    try {      service.enqueueNotificationWithTag(pkg, mContext.getOpPackageName(), tag, id,          stripped, idOut, UserHandle.myUserId());      if (id != idOut[0]) {        Log.w(TAG, "notify: id corrupted: sent " + id + ", got back " + idOut[0]);      }    } catch (RemoteException e) {    }  }

  

这个,才是之前的notifiy()方法调用的真实的函数,不过就是tag在之前的调用中被设置成了null,在这段代码的注释中说道tag和id都是可以拿来区分不同的通知的,我们可以把这两个混起来使用,实现类似于qq一样的效果