Simple SendInput example with Virtual Keys

[Ken F]

Hi, I am just trying to do a simple SendInput command to Notepad so
that is writes characters to the application. I have explained below
in code why I want to do this. The end of the internet has been
unable to supply me a clear and simple explanation. So, I pieced
together what I could.



package main;

import java.awt.GraphicsDevice;
import java.awt.GraphicsEnvironment;

import com.sun.jna.platform.win32.User32;
import com.sun.jna.platform.win32.WinDef.DWORD;
import com.sun.jna.platform.win32.WinDef.HWND;
import com.sun.jna.platform.win32.WinUser;
import com.sun.jna.platform.win32.WinUser.INPUT;
import com.sun.jna.platform.win32.WinUser.*;
import com.sun.jna.platform.win32.WinDef;

public class Main
{
public static GraphicsEnvironment environment =
GraphicsEnvironment.getLocalGraphicsEnvironment();
public static GraphicsDevice[] devices =
environment.getScreenDevices();
public static GraphicsDevice screen = devices[0];

public static final User32 lib = User32.INSTANCE;


/*
* I can use java robot to send keyboard input. This is a bit of a
problem since this is a desktop app.
* Each user can arrange the app in differnt locations, and screens,
and can adjust font size.
* I know I can resize and reposition the app using windows API, but
this is a bit annoying to some.
* This makes absolute screen positioning an issue. So, I want to
use SendInput to a Windows Handle App.
* Ironically this is a pre windows 95 app. I am using Notepad to
test the SendInput function.
* IDE Eclipse Indigo and also MyEclipse 10.
*
* Jna 3.40 from github twal
*
* OS Windows XP
* 32 bit
* 4G Ram
* Dual Core
*
*/

public static void main (String[] args)
{
HWND hwnd_Notepad = User32.INSTANCE.FindWindow(null, "Untitled -
Notepad");
User32.INSTANCE.SetForegroundWindow(hwnd_Notepad);
User32.INSTANCE.SetFocus(hwnd_Notepad);

INPUT in = new INPUT();
in.input.setType(KEYBDINPUT.class);
in.type = new DWORD(1);
//Lets say I want to send keyboard input of a character to the app
'a' or simulate the input with a virtual key
// below does not work
in.input.ki.wScan = 'a'; // error here
// how do I translate this to from a ascii to a keycode to send to
a window Handle?
in.input.ki.dwFlags = new
DWORD(WinUser.KEYBDINPUT.KEYEVENTF_SCANCODE);

INPUT[] inputs = (INPUT[])in.input.toArray(1);
int out = User32.SendInput(inputs.length, inputs,28); //error here

// do I now need to send a keyup/ down since I am using scancode?

}
}

[Ken F]

Update:

I found java robot does fine and I do not need to send virtual
codes. Just make sure your windows Handle has focus. Then it is
just a matter of doing your robot.keypress . This brings me to me
to a new issue.

I have a program that is a child of another program. There is no
window text in the child progam ( setMenu null ?) Anywho, can you
suggest anyplace where I can find an implementation of
EnumChildWindows so that I can get the handle of a child that has no
window text? I have a sneaking suspicion that the child handle I want
is actually a grandchild.

[Kamran Wali]

Hi Ken F.

I was having the same problem by sending input through SendInput(). I tried to use Robot but it looks like some softwares can't detect Robot. Is there any chance that you solved the problem for the SendInput() in JNA?

Thanks

Kamran Wali

[Ken F]

Tim did post some pseudo code on a different thread  about this.   I do not have much experience in C so I had trouble implementing the solution.  But, Tim pointed out the Windows 7 OS should be blocking the send Input from another application.  For those two reasons, I went to Robot.  What type of system are you on?  I have had good luck with Robot on a few OS types.   My Windows 7 implementation works well with JNA to grab focus, re-size,  make a view  area ( think of it as a box within a box) ,  and click so to type. The downside is that the Robot is screen location dependent. (( Multiple Monitors can get a bit hectic along with non standard  resolutions))       One issue I noted was that if you have Windows Explorer open and the title bar has the same name as the window you want; the OS might grab Windows Explorer instead of the one you want.