下载图像并将其保存到SD卡中

Question

I am trying to download and save the image into a sd card and sometimes it work, sometimes it doesn't. I need help trying to understand why and i tried to google but i couldn't find an answer.

so this is my code to retrieve the magazine issues and then loop through each item in json array then download and store them into the sd card. however some images doesn't get downloaded, it skips instead (view logcat)

    /**
     * Background Async Task to Load all product by making HTTP Request
     * */
    class downloadMagazine extends AsyncTask<String, String, String> {

         @Override
            protected void onPreExecute() {
                super.onPreExecute();
                progressDialog = new ProgressDialog(Store.this);
                progressDialog.setMessage("Loading.." + "\n" + "加载中..");
                progressDialog.setIndeterminate(false);
                progressDialog.setCancelable(false);
                progressDialog.show();
            } 
        /**
         * getting preview url and then load them
         * */
        protected String doInBackground(String... args) {
            URL myFileUrl = null;

            // Building Parameters
                List<NameValuePair> params = new ArrayList<NameValuePair>();
                // getting JSON string from URL
                JSONObject json = jParser.makeHttpRequest(url_magazine, "GET", params);

                // Check your log cat for JSON reponse
                //Log.d("All Products: ", json.toString());

                try {
                    // Checking for SUCCESS TAG
                    int success = json.getInt(TAG_SUCCESS);

                    if (success == 1) {
                        // products found
                        // Getting Array of Products
                        mag = json.getJSONArray(TAG_MAGAZINE);

                        for (int i = 0; i < mag.length(); i++) {
                            JSONObject c = mag.getJSONObject(i);

                            // Storing each json item in variable
                            String magazineUrl = c.getString(TAG_MAGAZINE_URL);
                            String issueName = c.getString(TAG_MAGAZINE_NAME);

                            urlList.add(magazineUrl);
                            issueNameList.add(issueName);
                            //System.out.println(urlList);
                        }                   
                    } 
                } catch (JSONException e) {
                    e.printStackTrace();
                }           

                // Building Parameters
                List<NameValuePair> param = new ArrayList<NameValuePair>();
                // getting JSON string from URL
                JSONObject json1 = jParser.makeHttpRequest(urlList.get(pos), "GET", param);

                // CHECKING OF JSON RESPONSE
                Log.d("All guide: ", json.toString());

                try {
                    issues = json1.getJSONArray(TAG_ISSUE);

                    for (int i = 0; i < issues.length(); i++) {
                        JSONObject c = issues.getJSONObject(i);

                        String image = c.getString(TAG_IMAGE);

                        imageList.add(image);
                        //System.out.println(imageList);
                    }   


                    // STOP THE LOOP
                    //break;

                } catch (JSONException e) {
                    e.printStackTrace();
                }

                for (int i = 0; i < imageList.size(); i ++)
                {
                imageUrl = imageList.get(i).toString();
                Log.d("thumbnail", imageUrl);
                number = i;
                try {
                    myFileUrl = new URL(imageUrl);    // RETRIEVE IMAGE URL
                    }
                 catch (MalformedURLException e) {
                    e.printStackTrace();
                }
                try {
                    HttpURLConnection conn = (HttpURLConnection) myFileUrl.openConnection();
                    conn.setDoInput(true);
                    conn.connect();
                    InputStream in = conn.getInputStream();
                    Log.i("I'm connected", "Download");
                    bmImg = BitmapFactory.decodeStream(in);

                    File filename;
                    // GET EXTERNAL STORAGE, SAVE FILE THERE
                    File storagePath = new File(Environment.getExternalStorageDirectory(),folderName+"issue"+issueNumber+"/");
                    storagePath.mkdirs();

                    filename = new File(storagePath + "/page"+number+".jpg");
                    FileOutputStream out = new FileOutputStream(filename);
                    bmImg.compress(Bitmap.CompressFormat.JPEG, 90, out);

                        out.flush();
                        out.close();

                        MediaStore.Images.Media.insertImage(getContentResolver(),filename.getAbsolutePath(), filename.getName(),
                                filename.getName());          
                        in.close();

                         // displayImage();
                } catch (IOException e) {
                    e.printStackTrace();
                }   
                }

                return null;

}

this is my logcat output whenever it skips download a page (i know it is similar to one of the question i posted but i really do need help in trouble shooting). I have no idea what happened, i googled and saw that many using android 4.0 onwards have faced this issue

01-23 17:09:29.120: W/System.err(24339): java.io.EOFException
01-23 17:09:29.120: W/System.err(24339):    at libcore.io.Streams.readAsciiLine(Streams.java:203)
01-23 17:09:29.120: W/System.err(24339):    at libcore.net.http.HttpEngine.readResponseHeaders(HttpEngine.java:544)
01-23 17:09:29.120: W/System.err(24339):    at libcore.net.http.HttpEngine.readResponse(HttpEngine.java:784)
01-23 17:09:29.120: W/System.err(24339):    at libcore.net.http.HttpURLConnectionImpl.getResponse(HttpURLConnectionImpl.java:274)
01-23 17:09:29.120: W/System.err(24339):    at libcore.net.http.HttpURLConnectionImpl.getInputStream(HttpURLConnectionImpl.java:168)
01-23 17:09:29.130: W/System.err(24339):    at libcore.net.http.HttpsURLConnectionImpl.getInputStream(HttpsURLConnectionImpl.java:270)
01-23 17:09:29.130: W/System.err(24339):    at com.sfcca.coverflow.Store$downloadMagazine.doInBackground(Store.java:881)
01-23 17:09:29.130: W/System.err(24339):    at com.sfcca.coverflow.Store$downloadMagazine.doInBackground(Store.java:1)
01-23 17:09:29.130: W/System.err(24339):    at android.os.AsyncTask$2.call(AsyncTask.java:264)
01-23 17:09:29.130: W/System.err(24339):    at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:305)
01-23 17:09:29.130: W/System.err(24339):    at java.util.concurrent.FutureTask.run(FutureTask.java:137)
01-23 17:09:29.130: W/System.err(24339):    at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:208)
01-23 17:09:29.130: W/System.err(24339):    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1076)
01-23 17:09:29.130: W/System.err(24339):    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:569)
01-23 17:09:29.130: W/System.err(24339):    at java.lang.Thread.run(Thread.java:856)

Answer 1

Check whether you have given appropriate permissions to the manifest

 <uses-permission android:name="android.permission.INTERNET"/>
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />

Answer 2

Have a look at this: http://code.google.com/p/google-http-java-client/issues/detail?id=116

I'd try the LAST comment there and see if the issue goes away:

System.setProperty("http.keepAlive", "false");

Now, you may not necessarily want that setting in the long term, but at least see if that's related.

And note that even though this question refers to Spring and a bunch of other stuff, it seems like the same root problem: Spring Rest Template usage causes EOFException

Lastly, I'm not exactly sure what you are trying to do there, but with one AsyncTask doing a lot of work (and not really dealing with contingencies like the network going away, and more) but you could get into trouble several others ways there (unrelated to your question). You might also want to consider a general purpose image download/cache library, if that might help, such as https://github.com/koush/UrlImageViewHelper . Even if you don't use one of those, digging through the source a bit you may see how they're making things a bit more robust.