How to execute shell commands through su?

Question

I tried following way but its not working for me :

public void RunAsRoot(String cmnd){
        Process p = Runtime.getRuntime().exec("su");
        DataOutputStream os = new DataOutputStream(p.getOutputStream());                        
        os.writeBytes(cmnd +"\n");                     
        os.writeBytes("exit\n");  
        os.flush();
        p.waitFor();
}

I tried this as well :

public void RunAsRoot(String cmds){
        Process p = Runtime.getRuntime().exec("su -c " + cmds);
        p.waitFor();
}

But none of the above method is working. However following command is working for me in shell through adb :

 su -c "input" " keyevent" " 3"

So I even tried this :

public void RunAsRoot(String cmds){
        Process p = Runtime.getRuntime().exec("su -c \"input\" \" keyevent\" \" 3\"");
        p.waitFor();
}

But even this didn't work. Can anyone please help me!!!!

Answer 1

I use an OutputStream instead of a DataOutputStream

sh = Runtime.getRuntime().exec("su", null,null);
String now =  c.get(Calendar.YEAR) + "-" + c.get(Calendar.MONTH) + "-" + c.get(Calendar.DAY_OF_MONTH) + "-" + c.get(Calendar.HOUR)+":"+c.get(Calendar.MINUTE);
Log.d(TAG, "Creating screenshot " + now +".png");
OutputStream  os = sh.getOutputStream();
os.write(("/system/bin/screencap -p " + "/data/local/" + now +".png").getBytes("ASCII"));
os.flush();
os.close();
sh.waitFor();