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POasynctask to download images then load images into horizontal gallery
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  1. POasynctask to download images then load images into horizontal gallery
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    copied!<p>I am using asynctask to download images and then once it has finished downloading, it should load the images into my horizontal gallery. is it possible? </p> <p>for now i have tried but it keeps crashing:</p> <pre><code>@Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); new downloadFile().execute(); gallery = (Gallery) findViewById(R.id.examplegallery); gallery.setAdapter(new AddImgAdp(this)); gallery.setOnItemClickListener(new OnItemClickListener() { public void onItemClick(AdapterView parent, View v, int position, long id) { // Displaying the position when the gallery item in clicked Toast.makeText(MainActivity.this, "Position=" + position, Toast.LENGTH_SHORT).show(); } }); } /** * Background Async Task to Load all product by making HTTP Request * */ class downloadFile extends AsyncTask&lt;String, String, String&gt; { /** * getting all magazines from url * */ protected String doInBackground(String... args) { URL myFileUrl = null; // Building Parameters List&lt;NameValuePair&gt; params = new ArrayList&lt;NameValuePair&gt;(); // getting JSON string from URL JSONObject json = jParser.makeHttpRequest(url_login, "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 &lt; mag.length(); i++) { JSONObject c = mag.getJSONObject(i); // Storing each json item in variable String magLink = c.getString(TAG_MAGAZINE_URL); String magThumb = c.getString(TAG_MAGAZINE_THUMBNAIL); //String magazineIssue = c.getString(TAG_MAGAZINE_ISSUE); urlList.add(magLink); //urlList.add(magazineIssue); thumbnailList.add(magThumb); System.out.println(thumbnailList); } } else { } } catch (JSONException e) { e.printStackTrace(); } for (int i = 0; i &lt; thumbnailList.size(); i ++) { thumbnail = thumbnailList.get(i).toString(); Log.d("thumbnail", thumbnail); number = i; try { myFileUrl = new URL(thumbnail); // 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("im connected", "Download"); bmImg = BitmapFactory.decodeStream(in); File filename; try { // GET EXTERNAL STORAGE, SAVE FILE THERE File storagePath = new File(Environment.getExternalStorageDirectory(),"Covers"); storagePath.mkdirs(); filename = new File(storagePath + "/photo"+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()); // displayImage(); } catch (Exception e) { e.printStackTrace(); } } catch (IOException e) { e.printStackTrace(); } } return null; } /** * After completing background task Dismiss the progress dialog * **/ protected void onPostExecute() { runOnUiThread(new Runnable() { public void run() { ArrayList&lt;String&gt; mStringList= new ArrayList&lt;String&gt;(); File strPath = new File(Environment.getExternalStorageDirectory() + "/Covers"); int lists = strPath.listFiles().length; Log.d("number of items in array ",String.valueOf(lists)); File yourDir = new File(strPath, ""); for (File f : yourDir.listFiles()) { if (f.isFile()) { String name = f.getName(); String v = strPath + "/" + name; mStringList.add(v); } } mImageIds = new String[mStringList.size()]; mImageIds = mStringList.toArray(mImageIds); for(int a = 0; a &lt; mImageIds.length ; a++){ Log.d("string is",(mImageIds[a])); } } }); } } public class AddImgAdp extends BaseAdapter { int GalItemBg; private Context cont; public AddImgAdp(Context c) { cont = c; TypedArray typArray = obtainStyledAttributes(R.styleable.GalleryTheme); GalItemBg = typArray.getResourceId(R.styleable.GalleryTheme_android_galleryItemBackground, 0); typArray.recycle(); } public int getCount() { return mImageIds.length; } public Object getItem(int position) { return position; } public long getItemId(int position) { return position; } public View getView(int position, View convertView, ViewGroup parent) { ImageView imgView = new ImageView((Context) cont); imgView.setImageDrawable(Drawable.createFromPath(mImageIds[position])); // Fixing width &amp; height for image to display imgView.setLayoutParams(new Gallery.LayoutParams(80, 70)); imgView.setScaleType(ImageView.ScaleType.FIT_XY); imgView.setBackgroundResource(GalItemBg); return imgView; } } } </code></pre> <p>this is my logcat output:</p> <pre><code>12-28 12:08:10.510: E/AndroidRuntime(5567): FATAL EXCEPTION: main 12-28 12:08:10.510: E/AndroidRuntime(5567): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.horizontalviewing/com.example.horizontalviewing.MainActivity}: java.lang.NullPointerException 12-28 12:08:10.510: E/AndroidRuntime(5567): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1978) 12-28 12:08:10.510: E/AndroidRuntime(5567): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2003) 12-28 12:08:10.510: E/AndroidRuntime(5567): at android.app.ActivityThread.access$600(ActivityThread.java:123) 12-28 12:08:10.510: E/AndroidRuntime(5567): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1169) 12-28 12:08:10.510: E/AndroidRuntime(5567): at android.os.Handler.dispatchMessage(Handler.java:99) 12-28 12:08:10.510: E/AndroidRuntime(5567): at android.os.Looper.loop(Looper.java:137) 12-28 12:08:10.510: E/AndroidRuntime(5567): at android.app.ActivityThread.main(ActivityThread.java:4446) 12-28 12:08:10.510: E/AndroidRuntime(5567): at java.lang.reflect.Method.invokeNative(Native Method) 12-28 12:08:10.510: E/AndroidRuntime(5567): at java.lang.reflect.Method.invoke(Method.java:511) 12-28 12:08:10.510: E/AndroidRuntime(5567): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:784) 12-28 12:08:10.510: E/AndroidRuntime(5567): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:551) 12-28 12:08:10.510: E/AndroidRuntime(5567): at dalvik.system.NativeStart.main(Native Method) 12-28 12:08:10.510: E/AndroidRuntime(5567): Caused by: java.lang.NullPointerException 12-28 12:08:10.510: E/AndroidRuntime(5567): at com.example.horizontalviewing.MainActivity$AddImgAdp.getCount(MainActivity.java:247) 12-28 12:08:10.510: E/AndroidRuntime(5567): at android.widget.AbsSpinner.setAdapter(AbsSpinner.java:113) 12-28 12:08:10.510: E/AndroidRuntime(5567): at com.example.horizontalviewing.MainActivity.onCreate(MainActivity.java:69) 12-28 12:08:10.510: E/AndroidRuntime(5567): at android.app.Activity.performCreate(Activity.java:4465) 12-28 12:08:10.510: E/AndroidRuntime(5567): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1049) 12-28 12:08:10.510: E/AndroidRuntime(5567): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1942) 12-28 12:08:10.510: E/AndroidRuntime(5567): ... 11 more </code></pre>
 

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