[問題]下載多個檔案使用ProgressDialog問題

看板AndroidDev作者Dong0129 (阿東)時間6年前 (2018/08/21 08:09)推噓5(5推 0噓 4→)

留言9則, 4人參與討論串1/1

各位版友好，最近在寫透過ProgressDialog依序顯示多個URL下載檔案的APP時有個問題一直不知道該怎麼解，程式碼及敘述如下... 將多個url存入一個array list中，依序將這些url丟入function中可透過Progress Dialo g 讓使用者可以看到每個檔案的下載進度，每個檔案下載完後，Progress Dialog關閉，等到下一個url被傳入downloadFile(url)時，再開啟一個Progress Dialog顯示進度條，但目前只有第一筆url會正常顯示進度條，第二筆url的進度條一直停留在0%，但事實上檔案有被下載到目的地中...請問是否哪裡寫錯了呢? in Main: for(String url:urls) { downloadFile(url); } downloadFile() function: private void download(String data) { app_name=data .substring(data.indexOf("0%2F"),data.indexOf("apk")) .replace("0%2F","") .replace(".",".apk"); final DownloadTask downloadTask = new DownloadTask(MainActivity.this); downloadTask.execute(data); mProgressDialog.setOnCancelListener(new DialogInterface.OnCancelListener() { @Override public void onCancel(DialogInterface dialog) { downloadTask.cancel(true); } }); } private class DownloadTask extends AsyncTask<String, Integer, String> { private Context context; private PowerManager.WakeLock mWakeLock; public DownloadTask(Context context) { this.context = context; } @Override protected String doInBackground(String... sUrl) { InputStream input = null; OutputStream output = null; HttpURLConnection connection = null; try { URL url = new URL(sUrl[0]); Log.i("Eden","surl:"+sUrl[0]); app_name=sUrl[0] .substring(sUrl[0].indexOf("0%2F"),sUrl[0].indexOf("apk") ) .replace("0%2F","") .replace(".",".apk"); connection = (HttpURLConnection) url.openConnection(); connection.connect(); if (connection.getResponseCode() != HttpURLConnection.HTTP_OK) { return "Server returned HTTP " + connection.getResponseCode() + " " + connection.getResponseMessage(); } int fileLength = connection.getContentLength(); // download the file input = connection.getInputStream(); output = new FileOutputStream("/storage/emulated/0/Download/" +app_name); byte data[] = new byte[4096]; long total = 0; int count; while ((count = input.read(data)) != -1) { if (isCancelled()) { input.close(); return null; } total += count; if (fileLength > 0) publishProgress((int) (total * 100 / fileLength)); output.write(data, 0, count); } } catch (Exception e) { return e.toString(); } finally { try { if (output != null) output.close(); if (input != null) input.close(); } catch (IOException ignored) { } if (connection != null) connection.disconnect(); } return null; } @Override protected void onPreExecute() { super.onPreExecute(); mProgressDialog = new ProgressDialog(MainActivity.this); mProgressDialog.setTitle("Downloading..."); mProgressDialog.setMessage("Downloading "+app_name); mProgressDialog.setIndeterminate(false); mProgressDialog.setProgressStyle(ProgressDialog.STYLE_HORIZONTAL); mProgressDialog.setCancelable(true); mProgressDialog.setMax(100); PowerManager pm = (PowerManager) context .getSystemService(Context.POWER_SERVICE); mWakeLock = pm.newWakeLock(PowerManager.PARTIAL_WAKE_LOCK, getClass().getName()); mWakeLock.acquire(); mProgressDialog.show(); } @Override protected void onProgressUpdate(Integer... progress) { super.onProgressUpdate(progress); // if we get here, length is known, now set indeterminate to false mProgressDialog.setProgress(progress[0]); } @Override protected void onPostExecute(String result) { mWakeLock.release(); mProgressDialog.dismiss(); if (result != null) Toast.makeText(context,"Download error: "+result, Toast.LENGTH_LONG).show(); else Toast.makeText(context,"File downloaded", Toast.LENGTH_SHORT).show(); } } -- ※ 發信站: 批踢踢實業坊(ptt.cc), 來自: 36.227.181.38 ※ 文章網址: https://www.ptt.cc/bbs/AndroidDev/M.1534810195.A.020.html

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andy2151

08/21 22:10, 6年前 , 1^F

08/21 22:10, 1^F

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andy2151

08/21 22:11, 6年前 , 2^F

08/21 22:11, 2^F

是的，程式運作是非同步所以第二個ProgressDialog彈出來後它就收不到download task 的資料，因為第2個檔案已經下載完了...我想請問是否有方法能夠達成我要的效果呢? ※ 編輯: Dong0129 (36.227.181.38), 08/21/2018 23:19:33