Android 8.0中Notification的Progress每次更新进度，都会弹出提示，并且有提示音。原代码如下
public void notifyDownloading(long progress, long num, String file_name) {
Notification.Builder mBuilder;
mBuilder = new Notification.Builder(MainActivity.this, TAG);
NotificationChannel channel;
channel = new NotificationChannel(TAG , file_name, NotificationManager.IMPORTANCE_MAX);
mNotifyManager.createNotificationChannel(channel);
mBuilder.setSmallIcon(R.drawable.notification_download_icon);
mBuilder.setProgress((int) num, (int) progress, false);
mBuilder.setContentInfo(getPercent((int) progress, (int) num));
mBuilder.setOngoing(true);
mBuilder.setWhen(System.currentTimeMillis());
mBuilder.setContentTitle(file_name);
mBuilder.setContentText("download");
PendingIntent pendIntent = PendingIntent.getActivity(
MainActivity.this, NOTIFY_ID, getCurActivityIntent(), PendingIntent.FLAG_UPDATE_CURRENT);
mBuilder.setContentIntent(pendIntent);
mNotifyManager.notify(NOTIFY_ID, mBuilder.build());
}
这里需要修改NotificationChannel的importance属性：
/**
* Min notification importance: only shows in the shade, below the fold.
*/
public static final int IMPORTANCE_MIN = 1;
/**
* Low notification importance: shows everywhere, but is not intrusive.
*/
public static final int IMPORTANCE_LOW = 2;
/**
* Default notification importance: shows everywhere, makes noise, but does not visually
* intrude.
*/
public static final int IMPORTANCE_DEFAULT = 3;
/**
* Higher notification importance: shows everywhere, makes noise and peeks. May use full screen
* intents.
*/
public static final int IMPORTANCE_HIGH = 4;
/**
* Unused.
*/
public static final int IMPORTANCE_MAX = 5;
这里的IMPORTANCE_MAX应该和IMPORTANCE_HIGH属性类似，表示显示时有声音，且会出现弹框提示。在Android 8.0中，这样设置后，Progress每次更新都会有声音和弹框。
把IMPORTANCE_MAX修改为IMPORTANCE_LOW，则不会出现该现象。
修改后代码如下：
public void notifyDownloading(long progress, long num, String file_name) {
Notification.Builder mBuilder;
mBuilder = new Notification.Builder(MainActivity.this, TAG );
NotificationChannel channel;
channel = new NotificationChannel(TAG, file_name, NotificationManager.IMPORTANCE_LOW);
mNotifyManager.createNotificationChannel(channel);
mBuilder.setSmallIcon(R.drawable.notification_download_icon);
mBuilder.setProgress((int) num, (int) progress, false);
mBuilder.setContentInfo(getPercent((int) progress, (int) num));
mBuilder.setOngoing(true);
mBuilder.setWhen(System.currentTimeMillis());
mBuilder.setContentTitle(file_name);
mBuilder.setContentText("download");
PendingIntent pendIntent = PendingIntent.getActivity(
MainActivity.this, NOTIFY_ID, getCurActivityIntent(), PendingIntent.FLAG_UPDATE_CURRENT);
mBuilder.setContentIntent(pendIntent);
mNotifyManager.notify(NOTIFY_ID, mBuilder.build());
}
