Screenshot from background service of another application (programmatically)

Question

When I use the browser I want to save screenshots of the site that I visited. Because some pages disappear in the future. So I decided to do a background service that would

Answer 1

 Process sh = Runtime.getRuntime().exec("su", null,null);

                        OutputStream  os = sh.getOutputStream();
                        os.write(("/system/bin/screencap -p " + "/sdcard/img.png").getBytes("ASCII"));
                        os.flush();

                        os.close();
                        sh.waitFor();

    then read img.png as bitmap and convert it jpg as follows 

Bitmap screen = BitmapFactory.decodeFile(Environment.getExternalStorageDirectory()+ File.separator +"img.png");

//my code for saving
        ByteArrayOutputStream bytes = new ByteArrayOutputStream();
        screen.compress(Bitmap.CompressFormat.JPEG, 15, bytes);

//you can create a new file name "test.jpg" in sdcard folder.

File f = new File(Environment.getExternalStorageDirectory()+ File.separator + "test.jpg");
                f.createNewFile();
//write the bytes in file
        FileOutputStream fo = new FileOutputStream(f);
        fo.write(bytes.toByteArray());
// remember close de FileOutput

        fo.close();