Java tutorial
//package com.java2s; import android.graphics.Bitmap; import android.net.Uri; import java.io.ByteArrayOutputStream; import java.io.FileInputStream; import java.io.IOException; import java.io.InputStream; import java.net.URL; public class Main { public static byte[] toByteArray(final Bitmap bmp, boolean recycle) { byte[] result = null; if (bmp != null) { ByteArrayOutputStream output = new ByteArrayOutputStream(); bmp.compress(Bitmap.CompressFormat.JPEG, 85, output); result = output.toByteArray(); if (recycle) { bmp.recycle(); } } return result; } public static byte[] toByteArray(final String uri) { try { if (Uri.parse(uri).getScheme() != null) { return toByteArray(new URL(uri).openStream()); } else { return toByteArray(new FileInputStream(uri)); } } catch (Exception e) { } return null; } public static byte[] toByteArray(InputStream is) { byte[] ret = null; try { ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream(); int ch; while ((ch = is.read()) != -1) { byteArrayOutputStream.write(ch); } ret = byteArrayOutputStream.toByteArray(); byteArrayOutputStream.close(); } catch (Exception e) { } finally { try { is.close(); } catch (IOException e) { } } return ret; } }