Java tutorial
//package com.java2s; import java.io.FileNotFoundException; import java.io.IOException; import android.content.ContentResolver; import android.content.ContentUris; import android.content.Context; import android.graphics.Bitmap; import android.graphics.BitmapFactory; import android.net.Uri; import android.os.ParcelFileDescriptor; public class Main { private static final BitmapFactory.Options sBitmapOptionsCache = new BitmapFactory.Options(); private static final Uri sArtworkUri = Uri.parse("content://media/external/audio/albumart"); public static Bitmap getArtworkQuick(Context context, long album_id, int w, int h) { // NOTE: There is in fact a 1 pixel border on the right side in the // ImageView // used to display this drawable. Take it into account now, so we don't // have to // scale later. w -= 1; ContentResolver res = context.getContentResolver(); Uri uri = ContentUris.withAppendedId(sArtworkUri, album_id); if (uri != null) { ParcelFileDescriptor fd = null; try { fd = res.openFileDescriptor(uri, "r"); int sampleSize = 1; // Compute the closest power-of-two scale factor // and pass that to sBitmapOptionsCache.inSampleSize, which will // result in faster decoding and better quality sBitmapOptionsCache.inJustDecodeBounds = true; BitmapFactory.decodeFileDescriptor(fd.getFileDescriptor(), null, sBitmapOptionsCache); int nextWidth = sBitmapOptionsCache.outWidth >> 1; int nextHeight = sBitmapOptionsCache.outHeight >> 1; while (nextWidth > w && nextHeight > h) { sampleSize <<= 1; nextWidth >>= 1; nextHeight >>= 1; } sBitmapOptionsCache.inSampleSize = sampleSize; sBitmapOptionsCache.inJustDecodeBounds = false; Bitmap b = BitmapFactory.decodeFileDescriptor(fd.getFileDescriptor(), null, sBitmapOptionsCache); if (b != null) { // finally rescale to exactly the size we need if (sBitmapOptionsCache.outWidth != w || sBitmapOptionsCache.outHeight != h) { Bitmap tmp = Bitmap.createScaledBitmap(b, w, h, true); // Bitmap.createScaledBitmap() can return the same // bitmap if (tmp != b) b.recycle(); b = tmp; } } return b; } catch (FileNotFoundException e) { } finally { try { if (fd != null) fd.close(); } catch (IOException e) { } } } return null; } }