android – 从另一个应用程序的后台服务截图(以编程方式)

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();