Android getting path to image from Thumbnail?

问题

I'm trying to ship a pivotal update to my app currently on the market. I need to query the thumbnails in the MediaStore, and load the the thumbnails into a GridView. So far so good, now I just need to get the path of the actual fullsized image on the user's External Storage based only on what I have(which is the path to the thumbnail). I need to be able to perform 4 actions whenever a user clicks a thumbnail, Share, View, Move and Delete...but I can't do any of these with just the thumbnail path, I've tried everything, doesn't work :/. Here's a snippet of my implementation below, any help or guidance on this would be greatly appreciated!

public void onItemClick(AdapterView<?> parent, View v, int position, long id) {

    int columnIndex = 0;
    String[] projection = {MediaStore.Images.Media.DATA};
    Cursor cursor = managedQuery(MediaStore.Images.Thumbnails.EXTERNAL_CONTENT_URI, projection, null, null, null);

    if(cursor != null){
        columnIndex = cursor.getColumnIndexOrThrow(MediaStore.Images.Media.DATA);

        cursor.moveToPosition(position);
        imagePath = cursor.getString(columnIndex);

        FileInputStream is = null;
        BufferedInputStream bis = null;

        try{
            is = new FileInputStream(new File(imagePath));
            bis = new BufferedInputStream(is);
            Bitmap bitmap = BitmapFactory.decodeStream(bis);
            useThisBitmap = Bitmap.createScaledBitmap(bitmap, parent.getWidth(), parent.getHeight(), true);

            bitmap.recycle();
        }catch(Exception e){
            //Try to recover
        }
        finally{
            try{
                if(bis != null){
                    bis.close();
                }
                if(is != null){
                    is.close();
                }
                cursor.close();
                projection = null;
            }catch(Exception e){

            }
        }
    }
    Toast.makeText(this, "  " + imagePath, Toast.LENGTH_SHORT).show();

So far I've tried everything using the imagePath member, but that either causes exceptions to be thrown or other errors. Any suggestions?

回答1:

I've found the solution. Before I was querying the MediaStore Content Resolver and grabbing Thumbnails(not what I needed anyways). This optimization allows me to search the MediaStore in the same exact way, but this time I'm searching for the ACTUAL Images, and I'm returning the Thumbnail MICRO_KIND. The images are then cached in an array of Bitmaps and then used to populate the GridView. I am now able to get the path to the actual, full size image on the device..in case I need to create a URI instance or a File using that path, now I can easily. For anyone else having this or a similar issue Android getting path to image from Thumbnail?, here's the solution code below. Btw, I'm doing this in an AsyncTask and showing/dismissing a loading dialog after all images on device have been displayed.

  /*----------------------------ASYNC TASK TO LOAD THE    PHOTOS--------------------------------------------------------*/

public class LoadPhotos extends AsyncTask<Object, Object, Object>{

    @Override
    protected Object doInBackground(Object... params) {
        final String[] columns = { MediaStore.Images.Media._ID };
        final String orderBy = MediaStore.Images.Media._ID;

        Cursor imagecursor = managedQuery(
                MediaStore.Images.Media.EXTERNAL_CONTENT_URI, columns, null,
                null, orderBy);

        int image_column_index = imagecursor
                .getColumnIndex(MediaStore.Images.Media._ID);

        AllPhotosActivity.count = imagecursor.getCount();
        AllPhotosActivity.windows = new Bitmap[AllPhotosActivity.count];

        for (int i = 0; i < AllPhotosActivity.count; i++) {
            imagecursor.moveToPosition(i);
            //i = index;
            int id = imagecursor.getInt(image_column_index);
            windows[i] = MediaStore.Images.Thumbnails.getThumbnail(
                    getApplicationContext().getContentResolver(), id,
                    MediaStore.Images.Thumbnails.MICRO_KIND, null);
        }

        imagecursor.close();
        return null;

    }

    @Override
    protected void onPostExecute(Object result) {
        // TODO Auto-generated method stub
        super.onPostExecute(result);
        pd.dismiss();
        imagegrid.setAdapter(new ImageAdapter(getApplicationContext()));

    }

    @Override
    protected void onProgressUpdate(Object... values) {
        // TODO Auto-generated method stub
        super.onProgressUpdate(values);
    }



}

And here's my onItemClick() The "filename" member is what you would use to create instances of URIs or whatever you need to do with the image.

public void onItemClick(AdapterView<?> arg0, android.view.View v,
                int position, long id) {
            String[] columns = { MediaStore.Images.Media.DATA,
                    MediaStore.Images.Media._ID };
            Cursor actualimagecursor = managedQuery(
                    MediaStore.Images.Media.EXTERNAL_CONTENT_URI, columns,
                    null, null, null);

            final int dataColumnIndex = actualimagecursor
                    .getColumnIndex(MediaStore.Images.Media.DATA);
            final int idColumIndex = actualimagecursor
                    .getColumnIndex(MediaStore.Images.Media._ID);

            actualimagecursor.moveToPosition(position);

            filename = actualimagecursor.getString(dataColumnIndex);
            final long imageId = actualimagecursor.getLong(idColumIndex);

回答2:

Cursor cursor = managedQuery(MediaStore.Images.Media.EXTERNAL_CONTENT_URI, projection, null, null, null);

use this code, i think it will work. Basically its the same id for both thumbnail and the original image, so the position for both thumbnails and images will be the same.

来源：https://stackoverflow.com/questions/9279553/android-getting-path-to-image-from-thumbnail

标签

android

gridview

path

thumbnails