Develop Reference

Android: Display image in imageview by SimpleAdapter

I am new android now I want to display image from an url. I am using imageview in listview. I want to add the list of images into the each row of the list item. I used SimpleAdapter but the imageview shows blank.
Here's the main activity:
package com.example.mysqltest;
import java.util.ArrayList;
import java.util.HashMap;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
import android.app.ListActivity;
import android.app.ProgressDialog;
import android.content.Intent;
import android.os.AsyncTask;
import android.os.Bundle;
import android.view.View;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.ListAdapter;
import android.widget.ListView;
import android.widget.SimpleAdapter;
public class ReadComments extends ListActivity {
// Progress Dialog
private ProgressDialog pDialog;
// testing on Emulator:
private static final String READ_COMMENTS_URL = "http://192.168.30.198/test/webservice/comments.php";
// JSON IDS:
private static final String TAG_SUCCESS = "success";
private static final String TAG_TITLE = "title";
private static final String TAG_POSTS = "posts";
private static final String TAG_POST_ID = "post_id";
private static final String TAG_USERNAME = "username";
private static final String TAG_MESSAGE = "message";
private static final String TAG_IMAGE = "image";
// An array of all of our comments
private JSONArray mComments = null;
// manages all of our comments in a list.
private ArrayList<HashMap<String, String>> mCommentList;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
// note that use read_comments.xml instead of our single_post.xml
setContentView(R.layout.read_comments);
}
#Override
protected void onResume() {
// TODO Auto-generated method stub
super.onResume();
// loading the comments via AsyncTask
new LoadComments().execute();
}
public void addComment(View v) {
Intent i = new Intent(ReadComments.this, AddComment.class);
startActivity(i);
}
/**
* Retrieves recent post data from the server.
*/
public void updateJSONdata() {
mCommentList = new ArrayList<HashMap<String, String>>();
JSONParser jParser = new JSONParser();
JSONObject json = jParser.getJSONFromUrl(READ_COMMENTS_URL);
try {
mComments = json.getJSONArray(TAG_POSTS);
for (int i = 0; i < mComments.length(); i++) {
JSONObject c = mComments.getJSONObject(i);
// gets the content of each tag
String title = c.getString(TAG_TITLE);
String content = c.getString(TAG_MESSAGE);
String username = c.getString(TAG_USERNAME);
String image = c.getString(TAG_IMAGE);
// creating new HashMap
HashMap<String, String> map = new HashMap<String, String>();
map.put(TAG_TITLE, title);
map.put(TAG_MESSAGE, content);
map.put(TAG_USERNAME, username);
map.put(TAG_IMAGE, image);
// adding HashList to ArrayList
mCommentList.add(map);
}
} catch (JSONException e) {
e.printStackTrace();
}
}
/**
* Inserts the parsed data into the listview.
*/
private void updateList() {
ListAdapter adapter = new SimpleAdapter(this, mCommentList,
R.layout.single_post, new String[] { TAG_TITLE, TAG_MESSAGE,
TAG_USERNAME,TAG_IMAGE }, new int[] { R.id.title, R.id.message,
R.id.username, R.id.imageView1 });
// I shouldn't have to comment on this one:
setListAdapter(adapter);
ListView lv = getListView();
lv.setOnItemClickListener(new OnItemClickListener() {
#Override
public void onItemClick(AdapterView<?> parent, View view,
int position, long id) {}
});
}
public class LoadComments extends AsyncTask<Void, Void, Boolean> {
#Override
protected void onPreExecute() {
super.onPreExecute();
pDialog = new ProgressDialog(ReadComments.this);
pDialog.setMessage("Loading Comments...");
pDialog.setIndeterminate(false);
pDialog.setCancelable(true);
pDialog.show();
}
#Override
protected Boolean doInBackground(Void... arg0) {
updateJSONdata();
return null;
}
#Override
protected void onPostExecute(Boolean result) {
super.onPostExecute(result);
pDialog.dismiss();
updateList();
}
}
}

Okay. So I assume here that you insist on using SimpleAdapter. No probem, problem solved, just follow the steps:
First lets create our custom row.xml for our ListView which will consist of only one ImageView.(You can add whatever you like to it later on but now i'll assume that you only wanna load the ImageView)
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical" >
<ImageView
android:id="#+id/imageView1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true"
android:layout_alignParentTop="true"
android:layout_marginLeft="5dp"
android:layout_marginTop="5dp"
android:src="#drawable/ic_launcher" />
</RelativeLayout>
Second lets create our custom SimpleAdapter
package com.example.helpstack;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ImageView;
import android.widget.SimpleAdapter;
public class MySimpleAdapter extends SimpleAdapter {
private Context mContext;
public LayoutInflater inflater = null;
public MySimpleAdapter(Context context,
List<? extends Map<String, ?>> data, int resource, String[] from,
int[] to) {
super(context, data, resource, from, to);
mContext = context;
inflater = (LayoutInflater) mContext
.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
}
#Override
public View getView(int position, View convertView, ViewGroup parent) {
View vi = convertView;
if (convertView == null)
vi = inflater.inflate(R.layout.row, null);
HashMap<String, Object> data = (HashMap<String, Object>) getItem(position);
new DownloadTask((ImageView) vi.findViewById(R.id.imageView1))
.execute((String) data.get("uri"));
return vi;
}
}
Third lets create our DownloadTask, this class will download the image:
package com.example.helpstack;
import java.io.IOException;
import java.net.MalformedURLException;
import java.net.URL;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.os.AsyncTask;
import android.widget.ImageView;
public class DownloadTask extends AsyncTask<String, Void, Boolean> {
ImageView v;
String url;
Bitmap bm;
public DownloadTask(ImageView v) {
this.v = v;
}
#Override
protected Boolean doInBackground(String... params) {
url = params[0];
bm = loadBitmap(url);
return true;
}
#Override
protected void onPostExecute(Boolean result) {
// TODO Auto-generated method stub
super.onPostExecute(result);
v.setImageBitmap(bm);
}
public static Bitmap loadBitmap(String url) {
try {
URL newurl = new URL(url);
Bitmap b = BitmapFactory.decodeStream(newurl.openConnection()
.getInputStream());
return b;
} catch (MalformedURLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return null;
}
}
Now the DownloadTask is being used from inside the getView() in SimpleAdapter
Fourth lets run our amazing small project from our MainActivity.java
package com.example.helpstack;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import android.app.Activity;
import android.os.Bundle;
import android.widget.ListView;
public class MainActivity extends Activity {
ListView lv;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
lv = (ListView) findViewById(R.id.listView1);
List<Map<String, Object>> data = new ArrayList<Map<String, Object>>();
Map<String, Object> map = new HashMap<String, Object>();
map.put("uri",
"http://upload.wikimedia.org/wikipedia/commons/thumb/f/f9/Wiktionary_small.svg/350px-Wiktionary_small.svg.png");
//here u can add as many uri as u want
data.add(map);
MySimpleAdapter adapter = new MySimpleAdapter(MainActivity.this, data,
R.layout.row, new String[] {}, new int[] {});
lv.setAdapter(adapter);
}
}

You can use any image cache library. Example, Picasa, Universal Image Loader..
You can cache the images from the URL and then you can use the images in your app.
You can find the libraries in the following links
http://square.github.io/picasso/ and https://github.com/nostra13/Android-Universal-Image-Loader

You can use multiple thread to download and decode bitmap .please follow this website and try to learn how android Developer use thread pool executer to execute different image in thread.
http://developer.android.com/training/multiple-threads/create-threadpool.html

1) To set the image Uri to the ImageView you can use a ViewBinder
You have to implement the abstract class and override setViewValue
2) You can use Picasso to load the images in a background thread and cache them.
The setViewValue method would look like this:
boolean setViewValue (View view, Object data, String textRepresentation) {
if(view.getId() == R.id.imageView1) {
Picasso.with(view.getContext()).load(textRepresentation).into((ImageView) view);
return true;
}
return false;
}
You return true if you want to take care of the binding. You return false for the default behavior.
3) Set your adapter to use the ViewBinder by calling adapter.setViewBinder(ViewBinder);

for now, my suggestion for you is:
1. download the image from url
2. save it as drawable in the storage
3. set this drawable to the image src of imageview
(I didn't see you do this part of job from your code...)

This tutorial is the best example to parse image using json parsing and show it in a listview: http://www.androidbegin.com/tutorial/android-json-parse-images-and-texts-tutorial/
Some other:
http://imagelistviewdynamic.blogspot.in/2012/12/image-parsed-from-json-using-async-into.html
http://www.java2s.com/Open-Source/Android_Free_Code/JSON/Download_Free_code_Android_JSON_Parse_Images_and_Texts_Tutorial.htm

I suggest you use Universal Image Loader, it uses asynchronous image downloading, caching and displaying, there you can find examples how to implement it. After you do it you dont have to concern about the number of images, or its size.
If you download the project you will find this example that does all the work you want:
/**
* #author Sergey Tarasevich (nostra13[at]gmail[dot]com)
*/
public class ImageListActivity extends AbsListViewBaseActivity {
DisplayImageOptions options;
String[] imageUrls;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.ac_image_list);
// here you get a String array with images URL
Bundle bundle = getIntent().getExtras();
imageUrls = bundle.getStringArray(Extra.IMAGES);
options = new DisplayImageOptions.Builder()
.showImageOnLoading(R.drawable.ic_stub)
.showImageForEmptyUri(R.drawable.ic_empty)
.showImageOnFail(R.drawable.ic_error)
.cacheInMemory(true)
.cacheOnDisc(true)
.considerExifParams(true)
.displayer(new RoundedBitmapDisplayer(20))
.build();
listView = (ListView) findViewById(android.R.id.list);
((ListView) listView).setAdapter(new ItemAdapter());
listView.setOnItemClickListener(new OnItemClickListener() {
#Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
startImagePagerActivity(position);
}
});
}
#Override
public void onBackPressed() {
AnimateFirstDisplayListener.displayedImages.clear();
super.onBackPressed();
}
// it gets the position of listView and opens that image in a new Activity
private void startImagePagerActivity(int position) {
Intent intent = new Intent(this, ImagePagerActivity.class);
intent.putExtra(Extra.IMAGES, imageUrls);
intent.putExtra(Extra.IMAGE_POSITION, position);
startActivity(intent);
}
class ItemAdapter extends BaseAdapter {
private ImageLoadingListener animateFirstListener = new AnimateFirstDisplayListener();
private class ViewHolder {
public TextView text;
public ImageView image;
}
#Override
public int getCount() {
return imageUrls.length;
}
#Override
public Object getItem(int position) {
return position;
}
#Override
public long getItemId(int position) {
return position;
}
#Override
public View getView(final int position, View convertView, ViewGroup parent) {
View view = convertView;
final ViewHolder holder;
if (convertView == null) {
view = getLayoutInflater().inflate(R.layout.item_list_image, parent, false);
holder = new ViewHolder();
holder.text = (TextView) view.findViewById(R.id.text);
holder.image = (ImageView) view.findViewById(R.id.image);
view.setTag(holder);
} else {
holder = (ViewHolder) view.getTag();
}
holder.text.setText("Item " + (position + 1));
// here is the place where is loaded the image using Universal ImageLoader , imageUrls[position] is a list of images URL
imageLoader.displayImage(imageUrls[position], holder.image, options, animateFirstListener);
return view;
}
}
private static class AnimateFirstDisplayListener extends SimpleImageLoadingListener {
static final List<String> displayedImages = Collections.synchronizedList(new LinkedList<String>());
#Override
public void onLoadingComplete(String imageUri, View view, Bitmap loadedImage) {
if (loadedImage != null) {
ImageView imageView = (ImageView) view;
boolean firstDisplay = !displayedImages.contains(imageUri);
if (firstDisplay) {
FadeInBitmapDisplayer.animate(imageView, 500);
displayedImages.add(imageUri);
}
}
}
}
}

NullPointerException android crash

Hi guys i have this problem:
Caused by: java.lang.NullPointerException
at com.example.myapplication.Foto$ImageAdapter.getCount(Foto.java:65)//error1
at android.widget.GridView.setAdapter(GridView.java:182)
at com.example.myapplication.Foto.onCreate(Foto.java:46)//error2
Here is my code:
import android.content.Intent;
import android.graphics.Bitmap;
import android.os.Bundle;
import android.view.View;
import android.view.ViewGroup;
import android.widget.AdapterView;
import android.widget.BaseAdapter;
import android.widget.GridView;
import android.widget.ImageView;
import com.example.myapplication.universalimageloader.AbsListViewBaseActivity;
import com.example.myapplication.universalimageloader.Constants;
import com.example.myapplication.universalimageloader.ImagePagerActivity;
import com.nostra13.universalimageloader.core.DisplayImageOptions;
public class Foto extends AbsListViewBaseActivity {
String[] imageUrls;
DisplayImageOptions options;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.ac_image_grid);
Bundle bundle = getIntent().getExtras();
if (bundle != null) {
imageUrls = bundle.getStringArray(Constants.Extra.IMAGES);
}
options = new DisplayImageOptions.Builder()
.showStubImage(R.drawable.ic_stub)
.showImageForEmptyUri(R.drawable.ic_empty)
.showImageOnFail(R.drawable.ic_error)
.cacheInMemory()
.cacheOnDisc()
.bitmapConfig(Bitmap.Config.RGB_565)
.build();
listView = (GridView) findViewById(R.id.gridview);
((GridView) listView).setAdapter(new ImageAdapter()); //ERROR 2
listView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
#Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
startImagePagerActivity(position);
}
});
}
private void startImagePagerActivity(int position) {
Intent intent = new Intent(this, ImagePagerActivity.class);
intent.putExtra(Constants.Extra.IMAGES, imageUrls);
intent.putExtra(Constants.Extra.IMAGE_POSITION, position);
startActivity(intent);
}
public class ImageAdapter extends BaseAdapter {
#Override
public int getCount() {
return imageUrls.length; //ERROR 1
}
#Override
public Object getItem(int position) {
return null;
}
#Override
public long getItemId(int position) {
return position;
}
#Override
public View getView(int position, View convertView, ViewGroup parent) {
final ImageView imageView;
if (convertView == null) {
imageView = (ImageView) getLayoutInflater().inflate(R.layout.item_grid_image, parent, false);
} else {
imageView = (ImageView) convertView;
}
imageLoader.displayImage(imageUrls[position], imageView, options);
return imageView;
}
}
}
What Can i do?
public final class Constants {
public static final String[] IMAGES = new String[] {
// Heavy images
"https://lh6.googleusercontent.com/-jZgveEqb6pg/T3R4kXScycI/AAAAAAAAAE0/xQ7CvpfXDzc/s1024/sample_image_01.jpg",
"https://lh4.googleusercontent.com/-K2FMuOozxU0/T3R4lRAiBTI/AAAAAAAAAE8/a3Eh9JvnnzI/s1024/sample_image_02.jpg",
"https://lh5.googleusercontent.com/-SCS5C646rxM/T3R4l7QB6xI/AAAAAAAAAFE/xLcuVv3CUyA/s1024/sample_image_03.jpg",
"https://lh6.googleusercontent.com/-f0NJR6-_Thg/T3R4mNex2wI/AAAAAAAAAFI/45oug4VE8MI/s1024/sample_image_04.jpg",
"https://lh3.googleusercontent.com/-n-xcJmiI0pg/T3R4mkSchHI/AAAAAAAAAFU/EoiNNb7kk3A/s1024/sample_image_05.jpg",
"https://lh3.googleusercontent.com/-X43vAudm7f4/T3R4nGSChJI/AAAAAAAAAFk/3bna6D-2EE8/s1024/sample_image_06.jpg",
"https://lh5.googleusercontent.com/-MpZneqIyjXU/T3R4nuGO1aI/AAAAAAAAAFg/r09OPjLx1ZY/s1024/sample_image_07.jpg",
"https://lh6.googleusercontent.com/-ql3YNfdClJo/T3XvW9apmFI/AAAAAAAAAL4/_6HFDzbahc4/s1024/sample_image_08.jpg",
"https://lh5.googleusercontent.com/-Pxa7eqF4cyc/T3R4oasvPEI/AAAAAAAAAF0/-uYDH92h8LA/s1024/sample_image_09.jpg",
"https://lh4.googleusercontent.com/-Li-rjhFEuaI/T3R4o-VUl4I/AAAAAAAAAF8/5E5XdMnP1oE/s1024/sample_image_10.jpg",
"https://lh5.googleusercontent.com/-_HU4fImgFhA/T3R4pPVIwWI/AAAAAAAAAGA/0RfK_Vkgth4/s1024/sample_image_11.jpg",
"https://lh6.googleusercontent.com/-0gnNrVjwa0Y/T3R4peGYJwI/AAAAAAAAAGU/uX_9wvRPM9I/s1024/sample_image_12.jpg",
"https://lh3.googleusercontent.com/-HBxuzALS_Zs/T3R4qERykaI/AAAAAAAAAGQ/_qQ16FaZ1q0/s1024/sample_image_13.jpg",
"https://lh4.googleusercontent.com/-cKojDrARNjQ/T3R4qfWSGPI/AAAAAAAAAGY/MR5dnbNaPyY/s1024/sample_image_14.jpg",
"https://lh3.googleusercontent.com/-WujkdYfcyZ8/T3R4qrIMGUI/AAAAAAAAAGk/277LIdgvnjg/s1024/sample_image_15.jpg",
"https://lh6.googleusercontent.com/-FMHR7Vy3PgI/T3R4rOXlEKI/AAAAAAAAAGs/VeXrDNDBkaw/s1024/sample_image_16.jpg",
"https://lh4.googleusercontent.com/-mrR0AJyNTH0/T3R4rZs6CuI/AAAAAAAAAG0/UE1wQqCOqLA/s1024/sample_image_17.jpg",
"https://lh6.googleusercontent.com/-z77w0eh3cow/T3R4rnLn05I/AAAAAAAAAG4/BaerfWoNucU/s1024/sample_image_18.jpg",
"https://lh5.googleusercontent.com/-aWVwh1OU5Bk/T3R4sAWw0yI/AAAAAAAAAHE/4_KAvJttFwA/s1024/sample_image_19.jpg",
"https://lh6.googleusercontent.com/-q-js52DMnWQ/T3R4tZhY2sI/AAAAAAAAAHM/A8kjp2Ivdqg/s1024/sample_image_20.jpg",
"https://lh5.googleusercontent.com/-_jIzvvzXKn4/T3R4t7xpdVI/AAAAAAAAAHU/7QC6eZ10jgs/s1024/sample_image_21.jpg",
"https://lh3.googleusercontent.com/-lnGi4IMLpwU/T3R4uCMa7vI/AAAAAAAAAHc/1zgzzz6qTpk/s1024/sample_image_22.jpg",
"https://lh5.googleusercontent.com/-fFCzKjFPsPc/T3R4u0SZPFI/AAAAAAAAAHk/sbgjzrktOK0/s1024/sample_image_23.jpg",
"https://lh4.googleusercontent.com/-8TqoW5gBE_Y/T3R4vBS3NPI/AAAAAAAAAHs/EZYvpNsaNXk/s1024/sample_image_24.jpg",
"https://lh6.googleusercontent.com/-gc4eQ3ySdzs/T3R4vafoA7I/AAAAAAAAAH4/yKii5P6tqDE/s1024/sample_image_25.jpg",
"https://lh5.googleusercontent.com/--NYOPCylU7Q/T3R4vjAiWkI/AAAAAAAAAH8/IPNx5q3ptRA/s1024/sample_image_26.jpg",
"https://lh6.googleusercontent.com/-9IJM8so4vCI/T3R4vwJO2yI/AAAAAAAAAIE/ljlr-cwuqZM/s1024/sample_image_27.jpg",
"https://lh4.googleusercontent.com/-KW6QwOHfhBs/T3R4w0RsQiI/AAAAAAAAAIM/uEFLVgHPFCk/s1024/sample_image_28.jpg",
"https://lh4.googleusercontent.com/-z2557Ec1ctY/T3R4x3QA2hI/AAAAAAAAAIk/9-GzPL1lTWE/s1024/sample_image_29.jpg",
"https://lh5.googleusercontent.com/-LaKXAn4Kr1c/T3R4yc5b4lI/AAAAAAAAAIY/fMgcOVQfmD0/s1024/sample_image_30.jpg",
"https://lh4.googleusercontent.com/-F9LRToJoQdo/T3R4yrLtyQI/AAAAAAAAAIg/ri9uUCWuRmo/s1024/sample_image_31.jpg",
"https://lh4.googleusercontent.com/-6X-xBwP-QpI/T3R4zGVboII/AAAAAAAAAIs/zYH4PjjngY0/s1024/sample_image_32.jpg",
"https://lh5.googleusercontent.com/-VdLRjbW4LAs/T3R4zXu3gUI/AAAAAAAAAIw/9aFp9t7mCPg/s1024/sample_image_33.jpg",
"https://lh6.googleusercontent.com/-gL6R17_fDJU/T3R4zpIXGjI/AAAAAAAAAI8/Q2Vjx-L9X20/s1024/sample_image_34.jpg",
"https://lh3.googleusercontent.com/-1fGH4YJXEzo/T3R40Y1B7KI/AAAAAAAAAJE/MnTsa77g-nk/s1024/sample_image_35.jpg",
"https://lh4.googleusercontent.com/-Ql0jHSrea-A/T3R403mUfFI/AAAAAAAAAJM/qzI4SkcH9tY/s1024/sample_image_36.jpg",
"https://lh5.googleusercontent.com/-BL5FIBR_tzI/T3R41DA0AKI/AAAAAAAAAJk/GZfeeb-SLM0/s1024/sample_image_37.jpg",
"https://lh4.googleusercontent.com/-wF2Vc9YDutw/T3R41fR2BCI/AAAAAAAAAJc/JdU1sHdMRAk/s1024/sample_image_38.jpg",
"https://lh6.googleusercontent.com/-ZWHiPehwjTI/T3R41zuaKCI/AAAAAAAAAJg/hR3QJ1v3REg/s1024/sample_image_39.jpg",
// Light images
"http://tabletpcssource.com/wp-content/uploads/2011/05/android-logo.png",
"http://simpozia.com/pages/images/stories/windows-icon.png",
"https://si0.twimg.com/profile_images/1135218951/gmail_profile_icon3_normal.png",
"http://www.krify.net/wp-content/uploads/2011/09/Macromedia_Flash_dock_icon.png",
"http://radiotray.sourceforge.net/radio.png",
"http://www.bandwidthblog.com/wp-content/uploads/2011/11/twitter-logo.png",
"http://weloveicons.s3.amazonaws.com/icons/100907_itunes1.png",
"http://weloveicons.s3.amazonaws.com/icons/100929_applications.png",
"http://www.idyllicmusic.com/index_files/get_apple-iphone.png",
"http://www.frenchrevolutionfood.com/wp-content/uploads/2009/04/Twitter-Bird.png",
"http://3.bp.blogspot.com/-ka5MiRGJ_S4/TdD9OoF6bmI/AAAAAAAAE8k/7ydKtptUtSg/s1600/Google_Sky%2BMaps_Android.png",
"http://www.desiredsoft.com/images/icon_webhosting.png",
"http://goodereader.com/apps/wp-content/uploads/downloads/thumbnails/2012/01/hi-256-0-99dda8c730196ab93c67f0659d5b8489abdeb977.png",
"http://1.bp.blogspot.com/-mlaJ4p_3rBU/TdD9OWxN8II/AAAAAAAAE8U/xyynWwr3_4Q/s1600/antivitus_free.png",
"http://cdn3.iconfinder.com/data/icons/transformers/computer.png",
"http://cdn.geekwire.com/wp-content/uploads/2011/04/firefox.png?7794fe",
"https://ssl.gstatic.com/android/market/com.rovio.angrybirdsseasons/hi-256-9-347dae230614238a639d21508ae492302340b2ba",
"http://androidblaze.com/wp-content/uploads/2011/12/tablet-pc-256x256.jpg",
"http://www.theblaze.com/wp-content/uploads/2011/08/Apple.png",
"http://1.bp.blogspot.com/-y-HQwQ4Kuu0/TdD9_iKIY7I/AAAAAAAAE88/3G4xiclDZD0/s1600/Twitter_Android.png",
"http://3.bp.blogspot.com/-nAf4IMJGpc8/TdD9OGNUHHI/AAAAAAAAE8E/VM9yU_lIgZ4/s1600/Adobe%2BReader_Android.png",
"http://cdn.geekwire.com/wp-content/uploads/2011/05/oovoo-android.png?7794fe",
"http://icons.iconarchive.com/icons/kocco/ndroid/128/android-market-2-icon.png",
"http://thecustomizewindows.com/wp-content/uploads/2011/11/Nicest-Android-Live-Wallpapers.png",
"http://c.wrzuta.pl/wm16596/a32f1a47002ab3a949afeb4f",
"http://macprovid.vo.llnwd.net/o43/hub/media/1090/6882/01_headline_Muse.jpg",
// Special cases
"file:///sdcard/Universal Image Loader ##&=+-_.,!()~'%20.png", // Image from SD card with encoded symbols
"assets://Living Things ##&=+-_.,!()~'%20.jpg", // Image from assets
"drawable://" + R.drawable.ic_launcher, // Image from drawables
"https://www.eff.org/sites/default/files/chrome150_0.jpg", // Image from HTTPS
"http://bit.ly/soBiXr", // Redirect link
"http://img001.us.expono.com/100001/100001-1bc30-2d736f_m.jpg", // EXIF
"", // Empty link
"http://wrong.site.com/corruptedLink", // Wrong link
};
private Constants() {
}
public static class Config {
public static final boolean DEVELOPER_MODE = false;
}
public static class Extra {
public static final String IMAGES = "com.example.myapplication.universalimageloader.IMAGES";
public static final String IMAGE_POSITION = "com.example.myapplication.universalimageloader.IMAGE_POSITION";
}
}

imageUrls is only initialized if there is bundle data, if there isn't then when you set the adapter, the data is null. What you need to do is ensure (or check) if imageUrls is null before trying to access the properties (for example on the imageUrls.length call).
To be more specific, those lines:
if (bundle != null) {
imageUrls = bundle.getStringArray(Constants.Extra.IMAGES);
}
Will initilize the imageUrls array only if the bundle is not null, but if it is.. it breaks.

CustomAdapter with multiple getView in android

I have an activity, where in i display list of media files i.e Video, Audio, Images and Animations. On clicking the list item, (as of now Images), the activity must display all the images in the local assets folder in grid View. To do so, i use a single adapter and have a switch case in my getView() function. Depending on the options that is set in the constructor, the switch cases would execute. It works fine for the ListView display, but i am unable to display list of images in grid View. Any help would be apprecaited. Thanks in advance. Here is my code:
package com.bookshelf;
import java.io.File;
import java.io.FilenameFilter;
import java.io.IOException;
import java.util.ArrayList;
import android.app.Activity;
import android.app.AlertDialog;
import android.content.Context;
import android.content.DialogInterface;
import android.content.DialogInterface.OnClickListener;
import android.content.res.AssetManager;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.media.ThumbnailUtils;
import android.os.Bundle;
import android.provider.MediaStore;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.BaseAdapter;
import android.widget.Gallery;
import android.widget.GridView;
import android.widget.ImageView;
import android.widget.ListAdapter;
import android.widget.ListView;
import android.widget.TextView;
import android.widget.Toast;
public class MediaGalaryListActivity extends Activity implements
OnItemClickListener {
private ArrayList<String> mGalary = new ArrayList<String>();
private Bitmap mBitArray[];
private Gallery mMediaGallery;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.mediagalary);
mGalary.add("Videos");
mGalary.add("Audios");
mGalary.add("Images");
mGalary.add("Animation");
ListView lv = (ListView) findViewById(R.id.mediaGal);
mMediaGallery = (Gallery) findViewById(R.id.mediaGallery);
lv.setAdapter(new MediaGalaryAdapter(this, mGalary, 1));
lv.setOnItemClickListener(this);
}
class MediaGalaryAdapter extends BaseAdapter {
private ArrayList<String> mGal = new ArrayList<String>();
private Bitmap[] mImgArray;
private Context context;
private LayoutInflater mInflate;
private int mAdapterOpt;
public MediaGalaryAdapter(Context ctx, ArrayList<String> gal,
int adapOpt) {
context = ctx;
mGal = gal;
mAdapterOpt = adapOpt;
mInflate = (LayoutInflater) context
.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
}
public MediaGalaryAdapter(Context ctx, Bitmap[] imgArray, int adapOpt) {
context = ctx;
mImgArray = imgArray;
mInflate = (LayoutInflater) context
.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
mAdapterOpt = adapOpt;
}
public int getCount() {
int size = 0;
switch (mAdapterOpt) {
case 1:
size = mGal.size();
break;
case 2:
size = mImgArray.length;
break;
}
return size;
}
public Object getItem(int position) {
return null;
}
public long getItemId(int position) {
return 0;
}
public View getView(int position, View convertView, ViewGroup parent) {
switch (mAdapterOpt) {
case 1:
convertView = mInflate.inflate(R.layout.medialayout, null);
TextView tv = (TextView) convertView.findViewById(R.id.text);
tv.setText(mGal.get(position));
break;
case 2:
ImageView imgView;
convertView = mInflate.inflate(R.layout.image_gallery, null);
imgView = new ImageView(context);
imgView.setImageBitmap(mImgArray[position]);
imgView.setScaleType(ImageView.ScaleType.CENTER_CROP);
imgView.setLayoutParams(new GridView.LayoutParams(100, 100));
imgView.setPadding(8, 8, 8, 8);
break;
}
return convertView;
}
}
// For filtering the filename with extensions
class FileNamFilter implements FilenameFilter {
private String mFileExtn;
public FileNamFilter(String extn) {
mFileExtn = "." + extn;
}
public boolean accept(File dir, String filename) {
return filename.endsWith(mFileExtn);
}
}
public void onItemClick(AdapterView<?> parent, View view, int pos, long id) {
String mediaType = mGalary.get(pos);
String list[] = null;
AssetManager assetManager = getAssets();
try {
list = assetManager.list("Immersive");
mBitArray = new Bitmap[list.length];
System.out.println("Length of list ="+list.length);
for (int i = 0, idx = 0; i < list.length; i++)
{
if (list[i].endsWith(".png") || list[i].endsWith(".gif")
|| list[i].endsWith(".jpeg")
|| list[i].endsWith(".jpg"))
{
mBitArray[idx++] = BitmapFactory.decodeStream(assetManager
.open("Immersive/" + list[i]));
System.out.println("Image at position "+i+" is "+list[i]);
}
;
}
mMediaGallery
.setAdapter(new MediaGalaryAdapter(this, mBitArray, 2));
} catch (IOException e) {
e.printStackTrace();
}
AlertDialog.Builder build = new AlertDialog.Builder(this);
build.setTitle("InProgress....");
// build.setIcon(android.R.drawable.)
build.setMessage(mediaType + " is Inprogress...");
build.setPositiveButton("Ok", new OnClickListener() {
public void onClick(DialogInterface dialog, int which) {
// finish();
}
});
AlertDialog alert = build.create();
alert.show();
// Toast.makeText(getApplicationContext(), mediaType, 30).show();
}
class MediaGalary {
private ImageView mImage;
private TextView mName;
public MediaGalary(ImageView img, TextView strName) {
mImage = img;
mName = strName;
}
public ImageView getmImage() {
return mImage;
}
public void setmImage(ImageView mImage) {
this.mImage = mImage;
}
public TextView getmName() {
return mName;
}
public void setmName(TextView mName) {
this.mName = mName;
}
}
}

each application in the device will be allocated some amount of memory by the DVM. you are getting out of memory error becoz your application is exceeding the memory the allocated by dvm to ur application. for example in froyo, memory allocated for an application is 16Mb. if your application exceeding more than 16Mb, you will get out of memory error. The solution for this is you have to compress the images you are using in your application, and you have to clear all the collection you are using. try clearing all collection you are using once there job is done. you can check how much memory has been consumed by your application in ddms using heap tool. hope this will be helpfull for you.

Loading image bitmap from content providers using asynctask

I have been trying to query for all images on sd card through MediaStore content provider and display their thumbnail on a GridView.
However, if i load the image thumbnail on the main thread, the scrolling gets incredibly slow...
So i tried to load the bitmap through asynctasks:
Scrolling performance got better, but now the grid items keep reloading their thumbnail until it gets the correct bitmap...
Here is my asynctask, which loads the bitmaps:
package x.y;
import java.lang.ref.WeakReference;
import android.content.ContentResolver;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory.Options;
import android.os.AsyncTask;
import android.provider.MediaStore;
import android.widget.ImageView;
public class ImageThumbnailLoader extends AsyncTask<Long, Void, Bitmap> {
private final Options mOptions;
private WeakReference<ImageView> mImageViewWeakReference;
private ContentResolver mContentResolver;
public ImageThumbnailLoader(ImageView imageView,
ContentResolver cr) {
mContentResolver = cr;
mImageViewWeakReference = new WeakReference<ImageView>(imageView);
mOptions = new Options();
mOptions.inSampleSize = 4;
}
#Override
protected Bitmap doInBackground(Long... params) {
Bitmap result;
result = MediaStore.Images.Thumbnails.getThumbnail(
mContentResolver, params[0],
MediaStore.Images.Thumbnails.MINI_KIND, mOptions);
return result;
}
#Override
protected void onPostExecute(Bitmap result) {
super.onPostExecute(result);
if (mImageViewWeakReference != null
&& mImageViewWeakReference.get() != null)
mImageViewWeakReference.get().setImageBitmap(result);
}
}
And here is my custom cursor adapter:
package x.y;
import android.content.Context;
import android.database.Cursor;
import android.graphics.BitmapFactory.Options;
import android.provider.MediaStore;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.CursorAdapter;
import android.widget.ImageView;
public class MediaCursorAdapter extends CursorAdapter {
private LayoutInflater mInflater;
private final static int mColumnID = 0;
private Options mOptions;
public MediaCursorAdapter(Context context, Cursor c) {
super(context, c);
mInflater = LayoutInflater.from(context);
mOptions = new Options();
mOptions.inSampleSize = 4;
}
#Override
public void bindView(View view, Context context, Cursor cursor) {
ViewHolder holder = (ViewHolder) view.getTag();
ImageThumbnailLoader imageLoader = new ImageThumbnailLoader(holder.thumbImg,
context.getContentResolver());
imageLoader.execute(cursor.getLong(mColumnID));
// holder.thumbImg.setImageBitmap(MediaStore.Images.Thumbnails.getThumbnail(
// context.getContentResolver(), cursor.getLong(mColumnID),
// MediaStore.Images.Thumbnails.MINI_KIND, mOptions));
Log.i("Prototype", "bindView : " + cursor.getPosition());
}
#Override
public View newView(Context context, Cursor cursor, ViewGroup parent) {
Log.i("Prototype", "newView : " + cursor.getPosition());
View view = mInflater.inflate(R.layout.grid_item, null);
ViewHolder holder = new ViewHolder(view);
view.setTag(holder);
return view;
}
private static class ViewHolder {
ImageView thumbImg, dragImg;
ViewHolder(View base) {
thumbImg = (ImageView) base.findViewById(R.id.thumbImage);
dragImg = (ImageView) base.findViewById(R.id.dragImage);
}
}
}
I query the cursor with this code and send it to the adapter:
query(MediaStore.Images.Media.EXTERNAL_CONTENT_URI, new String[] { MediaStore.Images.Media._ID,
MediaStore.Images.Media.DATA }, null, null,
MediaStore.Images.Media._ID);
Looks like the bindview() on my custom cursor adapter gets called more often than it is supposed to... Anyone knows how can i make the images on my gridview stop reloading while mantaining the scrolling performance??
Thanks in advance.

Problem solved, had to check if image at the start of async task was the same as the image at the end of it, on onPostExecute().
new bindView:
#Override
public void bindView(View view, Context context, Cursor cursor) {
ViewHolder holder = (ViewHolder) view.getTag();
holder.thumbImg.setId(cursor.getPosition());
ImageThumbnailLoader imageLoader = new ImageThumbnailLoader(holder.thumbImg,
context.getContentResolver());
imageLoader.execute(cursor.getLong(mColumnID));
Log.i("Prototype", "bindView : " + cursor.getPosition());
}
new Async:
public class ImageThumbnailLoader extends AsyncTask<Long, Void, Bitmap> {
private final Options mOptions;
private WeakReference<ImageView> mImageViewWeakReference;
private ContentResolver mContentResolver;
private int mPosition;
public ImageThumbnailLoader(ImageView imageView,
ContentResolver cr) {
mContentResolver = cr;
mImageViewWeakReference = new WeakReference<ImageView>(imageView);
mOptions = new Options();
mOptions.inSampleSize = 4;
mPosition = imageView.getId();
}
#Override
protected Bitmap doInBackground(Long... params) {
Bitmap result;
result = MediaStore.Images.Thumbnails.getThumbnail(
mContentResolver, params[0],
MediaStore.Images.Thumbnails.MINI_KIND, mOptions);
return result;
}
#Override
protected void onPostExecute(Bitmap result) {
super.onPostExecute(result);
if (mImageViewWeakReference != null
&& mImageViewWeakReference.get() != null
&& mPosition == mImageViewWeakReference.get().getId())
mImageViewWeakReference.get().setImageBitmap(result);
}
}

Slow scrolling when populating gridview of images with AsyncTask

good day, i am having a bit of a problem here. i am using and async task to display images from external or internal storage.Now it works but the problem is, it is very slow and slightly jerky in scrolling. I have no idea why? please any solution or an idea how to do this.
import java.io.IOException;
import java.util.ArrayList;
import android.app.Activity;
import android.content.Context;
import android.content.Intent;
import android.database.Cursor;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.drawable.BitmapDrawable;
import android.net.Uri;
import android.os.AsyncTask;
import android.os.Bundle;
import android.os.Debug;
import android.os.Environment;
import android.provider.MediaStore;
import android.view.Display;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.view.Window;
import android.view.WindowManager;
import android.widget.AdapterView;
import android.widget.BaseAdapter;
import android.widget.GridView;
import android.widget.ImageView;
import android.widget.Toast;
import android.widget.AdapterView.OnItemClickListener;
public class Wallpaper extends Activity implements OnItemClickListener{
/*Instance variables*/
private GridView grid;
private ImageAdapter imageAdapter;
private Display display;
Cursor cursor;
boolean inInternalStorage = false;
public void onCreate(Bundle savedInstanceState){
super.onCreate(savedInstanceState);
requestWindowFeature(Window.FEATURE_INDETERMINATE_PROGRESS);
setContentView(R.layout.wallpaper_images);
display = ((WindowManager) getSystemService(Context.WINDOW_SERVICE)).getDefaultDisplay();
setupViews();
setProgressBarIndeterminateVisibility(true);
loadImages();
}
#Override
protected void onStop(){
super.onStop();
}
/*methods called from AsyncTask as appropriate when its querying and processing the images from the MediaStore*/
private void loadImages() {
final Object data = getLastNonConfigurationInstance();
if(data == null){
new LoadImagesFromSDCard().execute();
}else {
final LoadedImage[] photos = (LoadedImage[])data;
if(photos.length == 0){
new LoadImagesFromSDCard().execute();
}
for(LoadedImage photo:photos){
addImage(photo);
}
}
}
private void addImage(LoadedImage... value) {
for(LoadedImage photo: value){
imageAdapter.addPhotos(photo);
imageAdapter.notifyDataSetChanged();
}
}
private void setupViews() {
grid = (GridView)findViewById(R.id.gridview);
grid.setNumColumns(display.getWidth()/95);
grid.setClipToPadding(false);
imageAdapter = new ImageAdapter(getApplicationContext());
grid.setAdapter(imageAdapter);
grid.setOnItemClickListener(this);
}
protected void onDestroy() {
super.onDestroy();
final GridView gridview = grid;
final int count = grid.getChildCount();
ImageView v = null;
for (int i = 0; i < count; i++) {
v = (ImageView) grid.getChildAt(i);
((BitmapDrawable) v.getDrawable()).setCallback(null);
}
unbindDrawables(findViewById(R.id.gridview));
System.gc();
}
/*public Object onRetainNonConfigurationInstance(){
final GridView gridview = grid;
final int count = grid.getChildCount();
final LoadedImage[] list = new LoadedImage[count];
for(int i = 0; i < count; i++){
final ImageView v = (ImageView)grid.getChildAt(i);
list[i] = new LoadedImage(((BitmapDrawable) v.getDrawable()).getBitmap());
}
return list;
}*/
/*utility method called that prevents screen from crashing when screen orientation changes*/
private void unbindDrawables(View view){
if(view.getBackground() != null){
view.getBackground().setCallback(null);
}
if(view instanceof ViewGroup){
for(int i = 0; i < ((ViewGroup) view).getChildCount(); i++){
unbindDrawables(((ViewGroup)view).getChildAt(i));
}
try{
((ViewGroup)view).removeAllViews();
}catch(Exception e){
e.printStackTrace();
}
}
}
/*AsyncTask thats queries the MediaStore for images and creates thumbnail images from bitmaps*/
class LoadImagesFromSDCard extends AsyncTask<Object, LoadedImage, Object> {
#Override
protected Object doInBackground(Object... params) {
Cursor cursor;
Bitmap bitmap = null;
Bitmap newbitmap = null;
Uri uri = null;
String [] img = {MediaStore.Images.Media._ID};
String state = Environment.getExternalStorageState();
if(Environment.MEDIA_MOUNTED.equals(state)){
cursor = getContentResolver().query(MediaStore.Images.Media.EXTERNAL_CONTENT_URI, img,
MediaStore.Images.Media.DATA + " like ? " , new String[]{ "%dcim%"}, null);
} else {
cursor = getContentResolver().query(MediaStore.Images.Media.INTERNAL_CONTENT_URI, img, null, null, null);
inInternalStorage = true;
}
int column_index = cursor.getColumnIndexOrThrow(MediaStore.Images.Media._ID);
int size = cursor.getCount();
if(size == 0){
Toast.makeText(getApplicationContext(), "There are no Images on the sdcard", Toast.LENGTH_SHORT).show();
}else {
}
for(int i = 0; i < size; i++){
cursor.moveToPosition(i);
int ImageId = cursor.getInt(column_index);
if(inInternalStorage == true){
uri = Uri.withAppendedPath(MediaStore.Images.Media.INTERNAL_CONTENT_URI, "" + ImageId);
}else {
uri = Uri.withAppendedPath(MediaStore.Images.Media.EXTERNAL_CONTENT_URI, "" + ImageId);
}
try {
BitmapFactory.Options options = new BitmapFactory.Options();
options.inSampleSize=4;
bitmap = BitmapFactory.decodeStream(getContentResolver().openInputStream(uri), null, options);
if(bitmap != null){
newbitmap = Bitmap.createScaledBitmap(bitmap, 100, 100, true);
bitmap.recycle();
}
if(newbitmap != null){
publishProgress(new LoadedImage(newbitmap));
}
}catch(IOException e){
}
}
cursor.close();
return null;
}
#Override
public void onProgressUpdate(LoadedImage... value){
addImage(value);
}
#Override
protected void onPostExecute(Object result) {
setProgressBarIndeterminateVisibility(false);
}
}
private static class LoadedImage {
Bitmap mBitmap;
LoadedImage(Bitmap bitmap) {
mBitmap = bitmap;
}
public Bitmap getBitmap() {
return mBitmap;
}
}
/*Image Adapter to populate grid view of images*/
public class ImageAdapter extends BaseAdapter {
private Context mContext;
private ArrayList<LoadedImage> photos = new ArrayList<LoadedImage>();
public ImageAdapter(Context context){
this.mContext = context;
}
public void addPhotos(LoadedImage photo){
photos.add(photo);
}
#Override
public int getCount() {
return photos.size();
}
#Override
public Object getItem(int position) {
return position;
}
#Override
public long getItemId(int position) {
return position;
}
#Override
public View getView(int position, View convertView, ViewGroup parent) {
System.gc();
ImageView image;
ViewHolder holder;
if(convertView == null){
LayoutInflater inflater = (LayoutInflater)mContext.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
convertView = inflater.inflate(R.layout.image_list,null);
holder = new ViewHolder();
holder.image = (ImageView)convertView.findViewById(R.id.image_list_id);
convertView.setTag(holder);
} else{
holder = (ViewHolder)convertView.getTag();
}
holder.image.setLayoutParams(new GridView.LayoutParams(100, 100));
holder.image.setImageBitmap(photos.get(position).getBitmap());
return convertView;
}
}
static class ViewHolder {
ImageView image;
}
#Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
Cursor cursor = null;
int image_column_index = 0;
String[] proj = {MediaStore.Images.Media.DATA};
String state = Environment.getExternalStorageState();
if(Environment.MEDIA_MOUNTED.equals(state)){
cursor = managedQuery(MediaStore.Images.Media.EXTERNAL_CONTENT_URI,proj, MediaStore.Images.Media.DATA + " like ? ", new String[]{"%dcim%"},null);
}else{
cursor = managedQuery(MediaStore.Images.Media.INTERNAL_CONTENT_URI,proj,null, null,null);
}
cursor.moveToPosition(position);
image_column_index = cursor.getColumnIndexOrThrow(MediaStore.Images.Media.DATA);
String info = cursor.getString(image_column_index);
Intent imageviewer = new Intent(getApplicationContext(), ViewImage.class);
imageviewer.putExtra("pic_name", info);
startActivity(imageviewer);
}
}
i think what i am after is a way to allow doBackground() to run for a while before i call publishProgress(). just like how the gallery app in android does.
Any ideas on why this could be slow or how to solve this problem will be greatly appreciated as i have been stuck on how to improve the perfomance for a while now.

The biggest bottleneck will be accessing the images from the device (internal or external). Therefore, you'll want to have as many images in memory as possible (within reason of course). You can do this in a number of ways:
Load perhaps 18 images first (as you said, prebuffer before displaying). Check to make sure the number of images doesn't exceed whatever number you choose though.
Create a 'thumbs.db' type file which will store 100x100 px thumbnails of the bitmaps. This will allow much faster reading since you'd only need to read in one file then extract each bitmap. If the user clicks an image, then request it from the storage. This method requires more work, but will be able to load the thumbnails really fast. You'd probably have to design your own simple file headers, such as:
<file header (size of file, number of images)>
<image header (img id, size in bytes)>
<image bitmap data>
<image header (img id, size in bytes)>
<image bitmap data>
<image header (img id, size in bytes)>
<image bitmap data>
...