Java tutorial
//package com.java2s; //License from project: Apache License import java.io.FileNotFoundException; import java.io.IOException; import java.io.InputStream; import android.content.Context; import android.graphics.Bitmap; import android.graphics.Bitmap.Config; import android.graphics.BitmapFactory; import android.net.Uri; public class Main { public static Bitmap getThumbnail(Context context, Uri uri, int 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 = 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 > size) ? (originalSize / size) : 1.0; BitmapFactory.Options bitmapOptions = new BitmapFactory.Options(); bitmapOptions.inSampleSize = getPowerOfTwoForSampleRatio(ratio); bitmapOptions.inDither = true;//optional bitmapOptions.inPreferredConfig = 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; } }