Android saving Bitmap to external storage.

saveToExternalStorage.md

Source: StackOverflow

Question: How do I save Bitmap to extrenal storage in Android?

Answer:

Use this function to save your bitmap in SD card:

public void saveTempBitmap(Bitmap bitmap) {
        if (isExternalStorageWritable()) {
            saveImage(bitmap);
        }else{
        //prompt the user or do something
        }
    }

    private void saveImage(Bitmap finalBitmap) {

        String root = Environment.getExternalStorageDirectory().toString();
        File myDir = new File(root + "/saved_images");
        myDir.mkdirs();

        String timeStamp = new SimpleDateFormat("yyyyMMdd_HHmmss").format(new Date());
        String fname = "Shutta_"+ timeStamp +".jpg";

        File file = new File(myDir, fname);
        if (file.exists()) file.delete ();
        try {
            FileOutputStream out = new FileOutputStream(file);
            finalBitmap.compress(Bitmap.CompressFormat.JPEG, 100, out);
            out.flush();
            out.close();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    /* Checks if external storage is available for read and write */
    public boolean isExternalStorageWritable() {
        String state = Environment.getExternalStorageState();
        if (Environment.MEDIA_MOUNTED.equals(state)) {
            return true;
        }
        return false;
    }

and add this in manifest

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

EDIT: By using this line you can able to see saved images in the gallery view. [UNTESTED]

sendBroadcast(new Intent(
Intent.ACTION_MEDIA_MOUNTED,
            Uri.parse("file://" + Environment.getExternalStorageDirectory())));

look at this link also http://rajareddypolam.wordpress.com/?p=3&preview=true

How would you read it back in order to display it in an imageview?

public static Bitmap getBitmapThumbnail(Context context, Uri uri, double THUMBNAIL_SIZE) throws FileNotFoundException, IOException {
InputStream input = context.getContentResolver().openInputStream(uri);

        BitmapFactory.Options onlyBoundsOptions = new BitmapFactory.Options();
        onlyBoundsOptions.inJustDecodeBounds = true;
        onlyBoundsOptions.inDither=true;//optional
        onlyBoundsOptions.inPreferredConfig=Bitmap.Config.ARGB_8888;//optional
        BitmapFactory.decodeStream(input, null, onlyBoundsOptions);
        input.close();
        
        if ((onlyBoundsOptions.outWidth == -1) || (onlyBoundsOptions.outHeight == -1))
            return null;

        int originalSize = (onlyBoundsOptions.outHeight > onlyBoundsOptions.outWidth) ? onlyBoundsOptions.outHeight : onlyBoundsOptions.outWidth;

        double ratio = (originalSize > THUMBNAIL_SIZE) ? (originalSize / THUMBNAIL_SIZE) : 1.0;

        BitmapFactory.Options bitmapOptions = new BitmapFactory.Options();
        bitmapOptions.inSampleSize = getPowerOfTwoForSampleRatio(ratio);
        bitmapOptions.inDither=true;//optional
        bitmapOptions.inPreferredConfig=Bitmap.Config.ARGB_8888;//optional
        input = context.getContentResolver().openInputStream(uri);
        Bitmap bitmap = BitmapFactory.decodeStream(input, null, bitmapOptions);
        input.close();
        
        return bitmap;
    }

    private static int getPowerOfTwoForSampleRatio(double ratio){
        int k = Integer.highestOneBit((int)Math.floor(ratio));
        if(k==0) return 1;
        else return k;
    }

thumbnail_size_in_double = 50.00;
bitmap = getBitmapThumbnail(context, "the_path_where_the/image/is_located_as_a/an/Uri", thumbnail_size_in_double);
imageView.setImageBitmap(bitmap);

//Please do test for yourself too very well before usage, it worked perfectly for me