How to Capture Global Key Presses in Java

How to capture global key presses in java

Jintellitype is a somewhat easy solution.

https://code.google.com/p/jintellitype/

The other easy solution would be to use a windows hook with JNA:

JNA Keyboard Hook in Windows

I have some experience with JNA and have really liked the api.

And a third solution would be to manage your own calls with JNI.

Portability-wise, as far as I know, windows dlls and api architecture as far as responding to user input, has been preserved in different OS versions. If memory serves, hooks for user input are in the user32 dll. Maybe you have to jump through some hoops for a x64 bit version, but I doubt it would be that hard.

capturing global keypresses in Java

I think you answered that yourself - yes I think you can find out the current element that has focus, and if it is an instanceof a certain field class, you ignore the space for the purpose of pause event. If it seams heavy handed, don't worry, instanceof is VERY fast for the JVM (and in any cause you are talking human scale events which are an eon to a processor).

Event listener in Java without app having focus? (Global keypress detection)

It's my understanding that this can't be done. At a fundamental level, the JVM only generates events for O/S events it receives, and it only receives O/S input events when it has focus.

I am sure you could use JNI to trigger the O/S to generate events for all input, but that would be very O/S dependent.

How can I listen for key presses (within Java Swing) across all components?

It is possible.

KeyboardFocusManager.getCurrentKeyboardFocusManager()
  .addKeyEventDispatcher(new KeyEventDispatcher() {
      @Override
      public boolean dispatchKeyEvent(KeyEvent e) {
        System.out.println("Got key event!");
        return false;
      }
});

That will grab all key events. Returning false allows the keyboard focus manager to resume normal key event dispatching to the various components.

If you want to catch key combos, you can keep a set of "pressed keys." Whenever a key is pressed, add it to the set and check what keys are already in the set. When a key is released, remove it from the set.

Capturing global key presses with java.awt.Toolkit

I may be wrong as I'm certainly not an expert, but as far as I know what you're trying to do isn't possible in Java.

Are you trying to capture a key click using a Java program, but without creating a window? Part of Java's security, and this is what I may be wrong on, is that it can only listen to events inside Java windows created by that particular Java program.

So if you were trying to make something key-logger-esque that runs in the background and captured a key press, it wouldn't be able to do that.

I wish I could give you a more concrete answer but I hope this helped.

Detect a key press in console

If you want to play with the console, you can start with this:

import java.util.Scanner;

public class ScannerTest {

    public static void main(String[] args) {
        Scanner keyboard = new Scanner(System.in);
        boolean exit = false;
        while (!exit) {
            System.out.println("Enter command (quit to exit):");
            String input = keyboard.nextLine();
            if(input != null) {
                System.out.println("Your input is : " + input);
                if ("quit".equals(input)) {
                    System.out.println("Exit programm");
                    exit = true;
                } else if ("x".equals(input)) {
                    //Do something
                }
            }
        }
        keyboard.close();
    }
}

Simply run ScannerTest and type any text, followed by 'enter'

Handle keypress in java (globally)

You are looking for this Key Bindings

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