Develop Reference

Album art is not displaying correct when I use AsyncTask class

When I display album art directly in my music app, it hangs. In stackoverflow, someone suggested me to implemented AsyncTask. So, I implemented AsyncTask to make my app faster. Right now, my app is not hanging but it is not displaying correct album art. And album arts are random means changing frequently when I scroll my listview.
Please help me.
Here is AsyncTask class :
class BitmapWorkerTask extends AsyncTask<Integer, Void, Bitmap> {
private final WeakReference<ImageView> imageViewReference;
private int data = 0;
private long l;
public BitmapWorkerTask(ImageView imageView) {
// Use a WeakReference to ensure the ImageView can be garbage collected
imageViewReference = new WeakReference<ImageView>(imageView);
}
public BitmapWorkerTask(ImageView imageView, long l) {
// Use a WeakReference to ensure the ImageView can be garbage collected
imageViewReference = new WeakReference<ImageView>(imageView);
this.l = l;
}
// Decode image in background.
#Override
protected Bitmap doInBackground(Integer... params) {
//Bitmap art = getAlbumart(songlist.this, l);
Context context = songlist.this;
Bitmap bm = null;
BitmapFactory.Options options = new BitmapFactory.Options();
try {
final Uri sArtworkUri = Uri.parse("content://media/external/audio/albumart");
Uri uri = ContentUris.withAppendedId(sArtworkUri, l);
ParcelFileDescriptor pfd = context.getContentResolver().openFileDescriptor(uri, "r");
if (pfd != null) {
FileDescriptor fd = pfd.getFileDescriptor();
bm = BitmapFactory.decodeFileDescriptor(fd, null, options);
pfd = null;
fd = null;
}
} catch (Error ee) {
} catch (Exception e) {
}
return bm;
}
// Once complete, see if ImageView is still around and set bitmap.
#Override
protected void onPostExecute(Bitmap bitmap) {
if (imageViewReference != null && bitmap != null) {
final ImageView imageView = imageViewReference.get();
if (bitmap != null) {
iv_art.setImageBitmap(bitmap);
} else {
iv_art.setImageResource(R.mipmap.app_splash_screen_icon);
}
}
}
}
My class which displays song in the listview :
public class MediaCursorAdapter extends SimpleCursorAdapter {
String backgroundColor = "white";
String someOtherBackgroundColor = "#FAFAFA";
public MediaCursorAdapter(Context context, int layout, Cursor c) {
super(context, layout, c,
new String[]{MediaStore.MediaColumns.DISPLAY_NAME, MediaStore.MediaColumns.TITLE, MediaStore.Audio.AudioColumns.DURATION, MediaStore.Audio.Media.ALBUM_ID},
new int[]{R.id.displayname, R.id.title, R.id.duration, R.id.iv_art});
}
#Override
public void bindView(View view, Context context, Cursor cursor) {
if (cursor.getPosition() % 2 == 0) {
view.setBackgroundColor(
Color.parseColor(backgroundColor));
} else {
view.setBackgroundColor(
Color.parseColor(someOtherBackgroundColor));
}
TextView title = (TextView) view.findViewById(R.id.title);
TextView name = (TextView) view.findViewById(R.id.displayname);
TextView duration = (TextView) view.findViewById(R.id.duration);
iv_art = (ImageView) view.findViewById(R.id.iv_art);
String a = cursor.getString(cursor.getColumnIndex(MediaStore.Audio.Media.ALBUM_ID));
l = Long.parseLong(a);
bwc = new BitmapWorkerTask(iv_art,l);
bwc.execute();
long durationInMs = Long.parseLong(cursor.getString(
cursor.getColumnIndex(MediaStore.Audio.AudioColumns.DURATION)));
name.setText(cursor.getString(
cursor.getColumnIndex(MediaStore.MediaColumns.DISPLAY_NAME)));
title.setText(cursor.getString(
cursor.getColumnIndex(MediaStore.MediaColumns.TITLE)));
Utility d = new Utility();
String durationInMin = d.convertDuration(durationInMs);
duration.setText("" + durationInMin);
view.setTag(cursor.getString(cursor.getColumnIndex(MediaStore.MediaColumns.DATA)));
}
#Override
public View newView(Context context, Cursor cursor, ViewGroup parent) {
LayoutInflater inflater = LayoutInflater.from(context);
View v = inflater.inflate(R.layout.songlist_listitem, parent, false);
bindView(v, context, cursor);
return v;
}
}

Its because of row reordering. The image view you want to load it into when you start a fetch is not necessarily where you want to load it at the end. The weak reference isn't helping because the view isn't being destroyed, its just not the right one anymore.
Instead of loading the data directly into the view, store it in a cache, then call notifyDataSetChanged. When you bind the row, check and see if the image is int he cache. If so, use it. If not, send the request. That will fix the majority of the issues you see, and prevent OOM errors (you can put a max memory usage on the cache).
Or use a library that does all this for you, like Volley.

Make adapter more efficient

I tried to make a custom Adapter and I made it functionall maybe not the best way and may be not the intelligentes Way so I ask here what I can do to make this a little more efficient
public class MovieDataAdapter extends BaseAdapter implements FetchImage.AsyncResponse {
private Context mContext;
public MovieDataAdapter(Context context) {
mContext = context;
}
#Override
public int getCount() { // get coutn Method
SQLiteDatabase db = new MvDBHelper(mContext).getReadableDatabase();
Cursor cur = db.query(MovieContract.MovieEntry.TABLE_NAME, null, null, null, null, null, null);
return cur.getCount();
}
#Override
public Object getItem(int position) {
return null;
}//Not needed at the moment
#Override
public long getItemId(int position) {
return 0;
}// Not needed at the moment
#Override
public View getView(int position, View convertView, ViewGroup parent) {
final ImageView imageview;
if (convertView != null) {
imageview = (ImageView) convertView; //if used view just use ist again
} else {//if new view set the fitting parameters
imageview = new ImageView(mContext);
imageview.setLayoutParams(new GridView.LayoutParams(getw('w'), getw('h')));
imageview.setScaleType(ImageView.ScaleType.FIT_XY);
}
SQLiteDatabase picturedb = new MvDBHelper(mContext).getReadableDatabase();
Cursor cur = picturedb.query(MovieContract.MovieEntry.TABLE_NAME,
null, null, null, null, null, null
);//get the entries from the db
if (cur != null && cur.moveToFirst()) {
cur.moveToPosition(position); // move to the appropriate position
//defining nessesary Variables
int index_PosterPath = cur.getColumnIndex(MovieContract.MovieEntry.COL_POSTERPATH);
int index_FilePath = cur.getColumnIndex(MovieContract.MovieEntry.COL_FILE);
int index_ortTitel = cur.getColumnIndex(MovieContract.MovieEntry.COL_ORTITEL);
final String Filename = cur.getString(index_ortTitel) + ".jpg";
final String selection = MovieContract.MovieEntry.COL_ORTITEL + " = ?";
final String[] where = {cur.getString(index_ortTitel)};
picturedb.close();// db not needed so is closed
if (cur.isNull(index_FilePath)) {//if file not already saved in the storage save it there
FetchImage getImage = new FetchImage(mContext, new FetchImage.AsyncResponse() {
#Override
public void processfinished(Bitmap output) { // get the image as an Bitmap in asynchronus task throug interface callback
FileOutputStream fos = null;
try {
fos = mContext.openFileOutput(Filename, Context.MODE_PRIVATE);
if (fos != null)
output.compress(Bitmap.CompressFormat.PNG, 100, fos); //put bitmap in file
} catch (IOException e) {
e.printStackTrace();
} finally {
if (fos != null) {
try {
fos.close();
} catch (IOException e) {
e.printStackTrace();
}
}
ContentValues values = new ContentValues();
values.put(MovieContract.MovieEntry.COL_FILE, Filename);
SQLiteDatabase picwr = new MvDBHelper(mContext).getWritableDatabase();
int updated = picwr.update(MovieContract.MovieEntry.TABLE_NAME, values, selection, where);
//put the filname in the db for later use
picwr.close();
}
BitmapDrawable draw = new BitmapDrawable(mContext.getResources(), output);
Drawable gridimag = draw;
imageview.setImageDrawable(gridimag); // set the drawable as an image
}
});
String[] ptg = {cur.getString(index_PosterPath)};
getImage.execute(ptg);
} else { // if pic already saved in the internal storage get it from there
FileInputStream fis = null;
try {
fis = mContext.openFileInput(Filename);
Bitmap pic = BitmapFactory.decodeStream(fis);
BitmapDrawable draw = new BitmapDrawable(mContext.getResources(), pic);
Drawable gridimag = draw;
imageview.setImageDrawable(gridimag);
} catch (IOException e) {
e.printStackTrace();
} finally {
try {
fis.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
cur.close();
}
return imageview;
}
public int getw(char c) {
int DisplayWidth = mContext.getResources().getDisplayMetrics().widthPixels;
if (c == 'w') {
return (int) (DisplayWidth / 2);
} else {
return DisplayWidth;
}
}
public static float convertDpToPixel(float dp, Context context) {
Resources resources = context.getResources();
DisplayMetrics metrics = resources.getDisplayMetrics();
float px = dp * ((float) metrics.densityDpi / DisplayMetrics.DENSITY_DEFAULT);
return px;
}
#Override
public void processfinished(Bitmap output) {
}
}
Would be happy about every help I can get even if it's a complet new Way because at the moment the grid view does not work fluently

You should avoid close cursor each time you draw a cell. You can close it only when you done with your activity.
Also you need to avoid using cur.moveToFirst(). Because you are already moving your cursor to given position, why should i moving it first before?
Another trick to use a image loader library (Picasso is one of the best) to load it async and faster. It also handles to stop threads if view is not shown. More optimized.
You dont need to find indexs of coloumn each time you want a new cell. Find them once, use them everytime :)
Also you can use CursorAdapter class to implement it way better :)

Images from server does not show in listview

Hello I am using listview and display images from server into it.
But the problem is that all loaded images are displayed in last item one by one instead display on respective position.
please help me to display that images in respective position
public class Offer_adapter extends ArrayAdapter<String> {
Context context1;
String[] offer_title;
String[] offerimg1;
String[] mrp;
String[] offerprice;
String[] you_save;
String[] imgURLArray;
Bitmap bitmap;
ImageView offerimg;
int a;
LayoutInflater inflater1;
public Offer_adapter(Context context1, String[] offer_title, String[] offerimg1, String[] mrp, String[] you_save, String[] offerprice) {
super(context1, R.id.offer_list, offer_title);
this.context1 = context1;
this.offer_title = offer_title;
this.offerimg1 = offerimg1;
this.mrp = mrp;
this.offerprice = offerprice;
this.you_save = you_save;
}
private static class ViewHolder {
String offerimg;
}
#Override
public View getView(int position, View convertView, ViewGroup parent) {
ViewHolder viewHolder = null;
if (convertView == null) {
inflater1 = (LayoutInflater) context1.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
convertView = inflater1.inflate(R.layout.offer_list, null);
viewHolder = new ViewHolder();
}
android.util.Log.v("abhi", "" + position);
imgURLArray = new String[position + 1];
for (int i = 0; i <= position; i++) {
android.util.Log.v("abhijit", "" + position);
imgURLArray[i] = "http://www.surun.co/preost/mod_offer/images/" + offerimg1[position];
android.util.Log.v("abhi", "" + imgURLArray[position]);
}
a=position;
viewHolder = (ViewHolder) convertView.getTag();
TextView offertitle = (TextView) convertView.findViewById(R.id.ofrtitle);
TextView offermrp = (TextView) convertView.findViewById(R.id.offeroriginal);
offermrp.setPaintFlags(offermrp.getPaintFlags() | Paint.STRIKE_THRU_TEXT_FLAG);
TextView offersave = (TextView) convertView.findViewById(R.id.saveoffer);
TextView ofrprice = (TextView) convertView.findViewById(R.id.priceoffer);
offerimg = (ImageView) convertView.findViewById(R.id.ofr_img);
offertitle.setText(offer_title[position]);
offermrp.setText("Original Price: \u20B9" + mrp[position]);
offersave.setText("You Save: \u20B9" + you_save[position]);
ofrprice.setText("Offer Price: \u20B9" + offerprice[position]);
// Bitmap imageBitmap = null;
new DownloadAsyncTask().execute(imgURLArray[position]);
Log.v("abhi","async");
return convertView;
}
private class DownloadAsyncTask extends AsyncTask<String, String, Bitmap> {
protected Bitmap doInBackground(String... args) {
try {
Log.v("abhi","in do background");
bitmap = BitmapFactory.decodeStream((InputStream) new URL(args[0]).getContent());
bitmap = Bitmap.createScaledBitmap(bitmap, 270, 375, true);
} catch (Exception e) {
e.printStackTrace();
}
return bitmap;
}
#Override
protected void onPostExecute(Bitmap bitmap) {
super.onPostExecute(bitmap);
if (bitmap !=null) {
offerimg.setImageBitmap(bitmap);
} else {
offerimg.setImageResource(R.drawable.nooffer);
}
}
}
}
All images are shown in last item one after another. I just want to show it on respective position.

you should use lazyloading instead of downloading image as bitmap.
Bitmap will create problem sometime or will give you outofmemory error in some devices
There are lots of image loading library available for android.
Have a look at these
https://github.com/square/picasso
https://github.com/nostra13/Android-Universal-Image-Loader
https://code.google.com/p/android-query/wiki/ImageLoading
https://android.googlesource.com/platform/frameworks/volley
https://github.com/koush/UrlImageViewHelper
https://github.com/novoda/image-loader

CustomListView : Image is changing when scrolling a ListView

I know that this question is asked many times.. But I cant get any proper solution, In my app I use AsyncTask for loading a image. I use AsyncTask because I want smooth scrolling listview.. and after implement AsyncTask My listView get smoothly scrolling.. But now problem is that Image is changing after scrolling... What should I do?
MyAdapter Class
package com.example.adapter;
public class DisplayAllFeedAdapter extends ArrayAdapter<DisplayAllFeedItem> {
private final List<DisplayAllFeedItem> list;
private final Activity context;
ExifInterface exif;
public DisplayAllFeedAdapter(Activity context, List<DisplayAllFeedItem> list) {
super(context, R.layout.feed_screen, list);
this.context = context;
this.list = list;
}
static class ViewHolder {
public TextView optionalDesc, reportedBy;
public LinearLayout layout;
public ImageView displayFeedimg, channelIcon;
}
#Override
public View getView(int position, View convertView, ViewGroup parent) {
ViewHolder viewHolder = null;
if (convertView == null) {
LayoutInflater inflater = context.getLayoutInflater();
convertView = inflater.inflate(R.layout.display_all_feed_listitem, null);
viewHolder = new ViewHolder();
viewHolder.optionalDesc = (TextView) convertView.findViewById(R.id.txtFeedOptionalDesc);
viewHolder.reportedBy = (TextView) convertView.findViewById(R.id.txtFeedReportedBy);
viewHolder.displayFeedimg = (ImageView) convertView
.findViewById(R.id.imgFeedDisplayImage);
viewHolder.layout = (LinearLayout) convertView.findViewById(R.id.layoutChannelImgView);
convertView.setTag(viewHolder);
convertView.setTag(R.id.txtFeedOptionalDesc, viewHolder.optionalDesc);
convertView.setTag(R.id.txtFeedReportedBy, viewHolder.reportedBy);
convertView.setTag(R.id.imgFeedDisplayImage, viewHolder.displayFeedimg);
convertView.setTag(R.id.layoutChannelImgView, viewHolder.layout);
} else {
viewHolder = (ViewHolder) convertView.getTag();
}
String temp;
String drawableImagePath = list.get(position).getMediaChannelName();
List<String> channelList = new ArrayList<String>();
while (drawableImagePath.length() > 0) {
if (drawableImagePath.indexOf(",") == -1) {
temp = drawableImagePath.substring(0);
channelList.add(temp);
break;
} else {
temp = drawableImagePath.substring(0, drawableImagePath.indexOf(","));
}
channelList.add(temp);
drawableImagePath = drawableImagePath.substring(drawableImagePath.indexOf(",") + 1);
}
viewHolder.layout.removeAllViews();
for (int i = 0; i < channelList.size(); i++) {
LinearLayout.LayoutParams layoutParams = new LinearLayout.LayoutParams(dpToPx(30),
dpToPx(30));
ImageView imageView = new ImageView(context);
layoutParams.setMargins(0, 0, 10, 0);
imageView.setLayoutParams(layoutParams);
imageView.setImageResource(Integer.parseInt(channelList.get(i)));
viewHolder.layout.addView(imageView);
}
String tempPath = list.get(position).getMediaPath();
File mediaFile = new File(tempPath);
Bitmap bitmap;
viewHolder.optionalDesc.setText(list.get(position).getMediaDesc());
viewHolder.reportedBy.setText("Reported By " + list.get(position).getMediaDisplayName());
if (viewHolder != null) {
new LoadImage(viewHolder).execute(tempPath);
}
return convertView;
}
private class LoadImage extends AsyncTask<String, String, Bitmap> {
// File mediaFile = new File(tempPath);
Bitmap bitmap, displayBitmap;
File mediaFile;
String mediaPath;
private final ViewHolder imageViewReference;
public LoadImage(ViewHolder viewHolder) {
imageViewReference = viewHolder;
}
#Override
protected Bitmap doInBackground(String... params) {
// File f = new File(params[0]);
mediaPath = params[0];
mediaFile = new File(mediaPath);
if (mediaFile.exists()) {
if (isImage(mediaPath)) {
Bitmap myBitmap = BitmapFactory.decodeFile(mediaFile.getAbsolutePath());
int height = (myBitmap.getHeight() * 512 / myBitmap.getWidth());
Bitmap scale = Bitmap.createScaledBitmap(myBitmap, 512, height, true);
int rotate = 0;
try {
exif = new ExifInterface(mediaFile.getAbsolutePath());
} catch (IOException e) {
e.printStackTrace();
}
int orientation = exif.getAttributeInt(ExifInterface.TAG_ORIENTATION,
ExifInterface.ORIENTATION_UNDEFINED);
switch (orientation) {
case ExifInterface.ORIENTATION_NORMAL:
rotate = 0;
break;
case ExifInterface.ORIENTATION_ROTATE_270:
rotate = 270;
break;
case ExifInterface.ORIENTATION_ROTATE_180:
rotate = 180;
break;
case ExifInterface.ORIENTATION_ROTATE_90:
rotate = 90;
break;
}
Matrix matrix = new Matrix();
matrix.postRotate(rotate);
displayBitmap = Bitmap.createBitmap(scale, 0, 0, scale.getWidth(),
scale.getHeight(), matrix, true);
} else {
displayBitmap = ThumbnailUtils.createVideoThumbnail(mediaPath,
Thumbnails.MICRO_KIND);
}
}
return displayBitmap;
}
#Override
protected void onPostExecute(Bitmap result) {
// TODO Auto-generated method stub
super.onPostExecute(result);
if (imageViewReference != null) {
imageViewReference.displayFeedimg.setImageBitmap(result);
}
// tempView.displayFeedimg.setImageBitmap(result);
}
}
public int dpToPx(int dp) {
DisplayMetrics displayMetrics = getContext().getResources().getDisplayMetrics();
int px = Math.round(dp * (displayMetrics.xdpi / DisplayMetrics.DENSITY_DEFAULT));
return px;
}
public static boolean isImage(String str) {
boolean temp = false;
String[] arr = { ".jpeg", ".jpg", ".png", ".bmp", ".gif" };
for (int i = 0; i < arr.length; i++) {
temp = str.endsWith(arr[i]);
if (temp) {
break;
}
}
return temp;
}
}

I am not clear on your problem (need better clarification) but I know there are issues on loading images about the lag in performance.
Please Look at Google's web Making a Standard Request.
Search for (Universal) Image Loader, text "Use ImageLoader and NetworkImageView".
You can further improve performance by caching, located below that text.
Code snippet from the webpage:
ImageLoader mImageLoader;
ImageView mImageView;
// The URL for the image that is being loaded.
private static final String IMAGE_URL =
"http://developer.android.com/images/training/system-ui.png";
...
mImageView = (ImageView) findViewById(R.id.regularImageView);
// Get the ImageLoader through your singleton class.
mImageLoader = MySingleton.getInstance(this).getImageLoader();
mImageLoader.get(IMAGE_URL, ImageLoader.getImageListener(mImageView,
R.drawable.def_image, R.drawable.err_image));
There seems a good tutorial in Solving the Android image loading problem... by a knowledgeable author.
Have fun with this. And someday I may have to solve this problem as well. Pls keep us posted.

Besides my previous answer, there is another possible solution. But it is somewhat different than Google's recommendation, so beware...
Look at Stackoverflow discussion ListView like in universal image loader sample app. Checkout code in that page. In CarListAdapter:
ImageLoader = ImageLoader.getInstance();
imageLoader.init(ImageLoaderConfiguration.createDefault(context));
...In another method:
imageLoader.displayImage(...);
Both of my answers lead to one point, use the (Universal) Image Loader.

Get the LinearLayout inside a ListView from an Async Task onRetainNonConfigurationInstance()

I hope the title is not mis-leading. I am trying to implement onRetainNonConfigurationInstance() of an AsyncTask of loading images and am getting this error "Java.lang.RuntimeException:Unable to retain Activity". Here is my code for onRetainNonConfigurationInstance():
public Object onRetainNonConfigurationInstance(){
//final ListView listview = list;
final int count = list.getChildCount();
final LoadedImage[] mylist = new LoadedImage[count];
for(int i = 0; i < count; i++){
final ImageView v = (ImageView)list.getChildAt(i); // getting error here
mylist[i] = new LoadedImage(((BitmapDrawable) v.getDrawable()).getBitmap());
}
return mylist;
}
Here is the Logcat:
05-18 08:43:15.385: E/AndroidRuntime(28130): java.lang.RuntimeException: Unable to retain activity {com.MyApps.ImageGen/com.MyApps.ImageGen.Wallpapers}: java.lang.ClassCastException: android.widget.LinearLayout
05-18 08:43:15.385: E/AndroidRuntime(28130): at android.app.ActivityThread.performDestroyActivity(ActivityThread.java:2989)
05-18 08:43:15.385: E/AndroidRuntime(28130): at android.app.ActivityThread.handleDestroyActivity(ActivityThread.java:3100)
05-18 08:43:15.385: E/AndroidRuntime(28130): at android.app.ActivityThread.handleRelaunchActivity(ActivityThread.java:3216)
05-18 08:43:15.385: E/AndroidRuntime(28130): at android.app.ActivityThread.access$1600(ActivityThread.java:132)
Here is my layout with the ListView:
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent">
<ListView
android:id="#android:id/list"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:cacheColorHint="#00000000"
android:listSelector="#android:color/transparent" >
</ListView>
</LinearLayout>
Here is how I setup the ListView:
private void setupViews() {
list = (ListView)findViewById(android.R.id.list);
list.setDivider(null);
list.setDividerHeight(0);
imageAdapter = new ImageAdapter(getApplicationContext());
list.setAdapter(imageAdapter);
list.setOnItemClickListener(this);
}
my async task and Item Adapter:
class LoadImagesFromSDCard extends AsyncTask<Object, LoadedImage, Object> {
#Override
protected Object doInBackground(Object... params) {
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, null, null, 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();
//System.out.println("size equals zero");
Wallpaper.this.runOnUiThread(new Runnable() {
public void run() {
Toast.makeText(getApplicationContext(), "There are no Images on the sdcard", Toast.LENGTH_SHORT).show();
}
});
return params;
}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.inJustDecodeBounds = true;
BitmapFactory.decodeStream(getContentResolver().openInputStream(uri), null, options);
int imageHeight = options.outHeight;
int imageWidth = options.outWidth;
String imageType = options.outMimeType;
Log.i(TAG, "imageheight = " + imageHeight);
Log.i(TAG, "imagewidth = " + imageWidth);
Log.i(TAG, "imageType = " + imageType);
//options.inSampleSize=4;
options.inSampleSize = calculateInSampleSize(options, imageWidth, imageHeight);
options.inJustDecodeBounds = false;
//bitmap = BitmapFactory.decodeStream(getContentResolver().openInputStream(uri));
bitmap = BitmapFactory.decodeStream(getContentResolver().openInputStream(uri), null, options);
if(bitmap != null){
newbitmap = Bitmap.createScaledBitmap(bitmap, 180, 180, true);
bitmap.recycle();
}
if(newbitmap != null){
publishProgress(new LoadedImage(newbitmap));
}
}catch(IOException e){
}
//cursor.close();
}
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) {
ImageView image;
ViewHolder holder;
if(convertView == null){
LayoutInflater inflater = (LayoutInflater)mContext.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
//convertView = inflater.inflate(R.layout.image_list,null);
convertView = inflater.inflate(R.layout.media_view, null);
holder = new ViewHolder();
holder.image = (ImageView)convertView.findViewById(R.id.media_image_id);
//holder.item_name = (TextView)convertView.findViewById(R.id.media_image_id);
convertView.setTag(holder);
} else{
holder = (ViewHolder)convertView.getTag();
}
//holder.image.setLayoutParams(new GridView.LayoutParams(100, 100));
//String item_name = cursor.getString(cursor.getColumnIndexOrThrow(MediaStore.Images.Media.DISPLAY_NAME));
holder.image.setImageBitmap(photos.get(position).getBitmap());
//holder.item_name.setText(item_name);
return convertView;
}
}
static class ViewHolder {
ImageView image;
TextView item_name;
}
#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,null, null,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);
cursor.close();
}
public static int calculateInSampleSize(
BitmapFactory.Options options, int reqWidth, int reqHeight) {
// Raw height and width of image
final int height = options.outHeight;
final int width = options.outWidth;
int inSampleSize = 2;
if (height > reqHeight || width > reqWidth) {
if (width > height) {
inSampleSize = Math.round((float)height / (float)reqHeight);
} else {
inSampleSize = Math.round((float)width / (float)reqWidth);
}
}
/*final int REQUIRED_SIZE = 180;
int scale = 1;
if(reqWidth > REQUIRED_SIZE || reqHeight > REQUIRED_SIZE){
scale = (int)Math.pow(2, (int)Math.round(Math.log(REQUIRED_SIZE/(double)Math.max(reqHeight, reqWidth)) / Math.log(0.5)));
}*/
return inSampleSize;
}
other Methods within Async Task:
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();
}
}
I am assuming I should first get the root element before I get the ListView from the logcat error, but I don't know how, I can't seem to find a suitable method from the documentation.
P.S: I am using an Activity and not a ListActivity.

The exception tells you that you try to do an invalid cast. My guess is that your row layout isn't a simple ImageView like you assume with the cast in the onRetainNonConfigurationInstance(), instead your row layout probably has a parent Linearlayout that wraps the ImageView(and other views?!). When you call the method getChildAt you get that parent Linearlayout which you try to cast to a ImageView. Instead you should do this:
//...
for(int i = 0; i < count; i++){
LinearLayout parent = (LinearLayout)list.getChildAt(i);
final ImageView v = (ImageView) parent.findViewById(R.id.the_id_of_the_imageview_from_theRow_layout);
mylist[i] = new LoadedImage(((BitmapDrawable) v.getDrawable()).getBitmap());
}
Note: The getChildAt method returns the rows views for the visible rows only so if you try to access the View for a row that isn't currently visible you'll most likely end up with a NullPointerException(you should get the drawables directly from the adapter and not from parsing all the rows Views).
Edit based on the comments:
If I understood your problem, the behavior you see it's normal. You didn't say how you ended up getting the bitmaps in the onRetainNonConfigurationInstance but my guess is that you just save the images from the ListView rows that are currently visible to the user. When it's time to restore the adapter with the images from getLastNonConfigurationInstance() you end up getting only those images which were previously visible. This will get worse if you rotate the phone again as, most likely, there are fewer images visible in landscape orientation then in the portrait orientation.
I don't know if this will work but you could try to modify the LoadedImage class to store the id of the image from MediaStore.Images.Media. When it's time to save the configuration, stop the LoadImagesFromSDCard task and nullify all the images(remove the Bitmap to which LoadedImage points)from the LoadedImages ArrayList(in the adapter) except the ones that are currently visible to the user. Send the photos ArrayList from your adapter through
onRetainNonConfigurationInstance.
When it's time to restore the adapter set the photos ArrayList of your new adapter to the one you got back and put the ListView to the position of the visible images(so the user sees the sent images). In the getView method of your adapter you'll put a default image(like loading...) when you have a null value for the Bitmap in the associated LoadedImage class. Start a new LoadImagesFromSDCard task to get the images and parse them again. When you get the id from MediaStore.Images.Media you'll check if a LoadedImage with this id exists in the adapter and if it has a Bitmap set to it. If it doesn't exist(or it doesn't have a Bitmap associated) then load the image and put it in the adapter, if not the image already exists and move to the next one.
I don't know if the solution above will work or if it's efficient. I would recommend you to modify the code and load images on demand instead of loading all up in a big task.