Android通知是重建而不是更新? [英] Android notification rebuilds instead of updating?

问题描述

我正在下载文件，我想让用户了解进度，所以我创建了一个通知.问题是通知不断重建而不是更新.我在网上搜索了类似的行为，并且按照他们说的做了，但是我的问题仍然存在.

I'm downloading a file and i want to keep the user informed about the progress so i created a notification.The problem is that the notification keeps getting rebuild instead of updating. I searched for similar behaviours online and i did as they said but my problem persists.

每个人都在说要使用通知生成器，因此它第一次构建整个通知，然后仅更新我告诉它的内容.尝试过，仍然无法正常工作.

Everybody is saying to use a notification builder so the first time it builds the whole notification and then only updates what i tell it to.Tried it,still not working.

这里我要声明通知和NotificationManager.

Here i'm declaring the notification and the notificationManager.

private NotificationCompat.Builder notification;
private NotificationManager notificationManager;

这是创建通知的方法.DOWNLOAD_NOTIFICATION_ID是值为2的最终int

This is the method that creates the notification.DOWNLOAD_NOTIFICATION_ID is a final int with value 2

private void createDownloadNotification(){

        notificationManager = (NotificationManager) getSystemService(GuideSelected.this.NOTIFICATION_SERVICE);

            notification = new NotificationCompat.Builder(GuideSelected.this,CHANNEL_DOWNLOAD)
                    .setSmallIcon(android.R.drawable.stat_sys_download)  // here is the animated icon
                    .setLargeIcon(BitmapFactory.decodeResource(this.getResources(), android.R.drawable.stat_sys_download))
                    .setContentTitle("title")
                    .setContentText("Download starting...")
                    .setStyle(new NotificationCompat.BigTextStyle())

                    //.setContentIntent(pendingIntent)
                    //la notifica si cancella da sola dopo che clicco
                    .setOngoing(true)
                    .setPriority(NotificationCompat.PRIORITY_LOW)
                    .setProgress(100,0,false);
            notificationManager.notify(DOWNLOAD_NOTIFICATION_ID,notification.build());
        }
}

这是我要更新通知的异步任务

This is the asynctask where i'm updating the notification

private class DownloadFile extends AsyncTask<String, String, String> {
        final Handler handler = new Handler();

        @Override
        protected void onPreExecute() {
            super.onPreExecute();

        }

        @Override
        protected String doInBackground(String... f_url) {
            int count;
           // HERE I'M CREATING THE NOTIFICATION
                createDownloadNotification();

        //DOWNLOADING STUFF....

        }

        // Updating progress bar

        protected void onProgressUpdate(String... progress) {

            // UPDATING IT EVERY 5% SO I DON't MAKE TOO MANY CALLS

            currentPercentage=Integer.parseInt(progress[0]);

                if (previousPercentage != currentPercentage && currentPercentage%5==0) {// line : 6
                    notification.setProgress(100,previousPercentage, false).setContentText(previousPercentage+"%").setSubText("Downloading...");
                    notificationManager.notify(DOWNLOAD_NOTIFICATION_ID, notification.build());
                    previousPercentage=currentPercentage;
                }

        }


        @Override
        protected void onPostExecute(String message) {

            handler.postDelayed(new Runnable() {
                @Override
                public void run() {
                    notification.setProgress(0,0,false).setOngoing(false).setContentText("Download complete").setSubText(null);
                    notificationManager.notify(DOWNLOAD_NOTIFICATION_ID, notification.build());
                }
            }, 2000);


        }
    }

我只希望通知在每次更新时都无需重建，我可以从动画下载图标中看到它的重建，因为它一直在重新启动.

I just want the notification to update without rebuilding everytime, i can see it rebuilds from the animated download icon because it keeps restarting.

添加了通知和通知管理器的声明.

Added the declaration of notification and notification manager.

推荐答案

最后，我通过使用扩展了

In the end i solved it by using custom download intent service class which extends IntentService and when i'm updating the notification i'm controlling if the last % is different than the current one (since the updateProgress is called multiple times in a second) and i also added a timer so it only updates every 1.3 seconds (this is the time that the download icon aniamtion takes to complete) and in this way i finally achieved my goal and the notification doesn't continuously rebuild.

这是我更新通知的方式:

Here is how i'm updating the notification:

   while ((count = input.read(data)) != -1) {
                if (Constants.stopService) {
                    output.flush();
                    output.close();
                    input.close();
                    stopSelf();
                    return;
                }
                if (count != 0) {
                    total += count;

                    latestPercentDone = (int) Math.round(total / lengthOfFile * 100.0);
                    if (percentDone != latestPercentDone) {
                        percentDone = latestPercentDone;
                        if (SystemClock.elapsedRealtime() - mLastClickTime > 1300) { // 1000 = 1second
                            mLastClickTime = SystemClock.elapsedRealtime();
                            sendMessage(percentDone, idLesson);
                            notification.setProgress(100, percentDone, false);
                            notificationManager.notify(realNotificationID, notification.build());
                        }
                    }
                    output.write(data, 0, count);
                }
            }
            // flushing output
            output.flush();
            // closing streams
            output.close();
            input.close();

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