1. 技术文章
  2. KeyPress: How to detect if the user pressed the “Down” arrow key on their keyboard when the app is running

KeyPress: How to detect if the user pressed the “Down” arrow key on their keyboard when the app is running

由 谁说胖子不能爱 提交于 2019-12-21 02:51:37

问题


Here is what I've got so far.. I'm using this as a keybind. I want to press the "Down" arrow key anytime the app is running, and then make it auto press the "Down" arrow key 3 extra times then finish by pressing "Enter" in the code. I know this isn't the best explanation but sorry and I will try to explain it any better if you still didnt understand.

Here is the code: 

public class MyKeyListener extends KeyAdapter{ 
@Override
public void keyPressed(KeyEvent evt){  
}

KeyListener keyListener = new KeyListener() {
    @Override
  public void keyPressed(KeyEvent keyEvent) {
    int keyCode = keyEvent.getKeyCode();
        if(keyCode == 1005){
        System.out.println("So far, so good..");
        }

  }

    @Override
    public void keyTyped(KeyEvent e) {
        throw new UnsupportedOperationException("Not supported yet.");
    }

    @Override
    public void keyReleased(KeyEvent e) {
        throw new UnsupportedOperationException("Not supported yet.");
    }

};

I think the Key arrow down is 1005. I've so far wrote System.out.println("So far, so good.."); to see if the app even detects it when I press the down arrow key, but it doesn't...

Any ideas please?


回答1:


I'm just throwing this out there because I think it MAY be useful to you, this is a virtual Java keyboard, modified from some resource I found on the web years ago and which I no longer remember the link to:

import java.awt.AWTException;
import java.awt.Robot;
import java.awt.event.KeyEvent;

public class Keyboard {


    public void main (String[] args) throws InterruptedException {
        while(true) {
        type("

");
        }
    }


    private static Robot robot;
    static Random rand = new Random();

    public Keyboard() throws AWTException {
        this.robot = new Robot();
    }
    public Keyboard(Robot robot) {
        this.robot = robot;
    }
    public void type(CharSequence characters) throws InterruptedException {
        int length = characters.length();
        for (int i = 0; i < length; i++) {
                char character = characters.charAt(i);
                type(character);                

        }

         robot.keyPress(KeyEvent.VK_ENTER);
         robot.keyRelease(KeyEvent.VK_ENTER);
    }

    public void type(char character) {
        switch (character) {
        case 'a': doType(KeyEvent.VK_A); break;
        case 'b': doType(KeyEvent.VK_B); break;
        case 'c': doType(KeyEvent.VK_C); break;
        case 'd': doType(KeyEvent.VK_D); break;
        case 'e': doType(KeyEvent.VK_E); break;
        case 'f': doType(KeyEvent.VK_F); break;
        case 'g': doType(KeyEvent.VK_G); break;
        case 'h': doType(KeyEvent.VK_H); break;
        case 'i': doType(KeyEvent.VK_I); break;
        case 'j': doType(KeyEvent.VK_J); break;
        case 'k': doType(KeyEvent.VK_K); break;
        case 'l': doType(KeyEvent.VK_L); break;
        case 'm': doType(KeyEvent.VK_M); break;
        case 'n': doType(KeyEvent.VK_N); break;
        case 'o': doType(KeyEvent.VK_O); break;
        case 'p': doType(KeyEvent.VK_P); break;
        case 'q': doType(KeyEvent.VK_Q); break;
        case 'r': doType(KeyEvent.VK_R); break;
        case 's': doType(KeyEvent.VK_S); break;
        case 't': doType(KeyEvent.VK_T); break;
        case 'u': doType(KeyEvent.VK_U); break;
        case 'v': doType(KeyEvent.VK_V); break;
        case 'w': doType(KeyEvent.VK_W); break;
        case 'x': doType(KeyEvent.VK_X); break;
        case 'y': doType(KeyEvent.VK_Y); break;
        case 'z': doType(KeyEvent.VK_Z); break;
        case 'A': doType(KeyEvent.VK_SHIFT, KeyEvent.VK_A); break;
        case 'B': doType(KeyEvent.VK_SHIFT, KeyEvent.VK_B); break;
        case 'C': doType(KeyEvent.VK_SHIFT, KeyEvent.VK_C); break;
        case 'D': doType(KeyEvent.VK_SHIFT, KeyEvent.VK_D); break;
        case 'E': doType(KeyEvent.VK_SHIFT, KeyEvent.VK_E); break;
        case 'F': doType(KeyEvent.VK_SHIFT, KeyEvent.VK_F); break;
        case 'G': doType(KeyEvent.VK_SHIFT, KeyEvent.VK_G); break;
        case 'H': doType(KeyEvent.VK_SHIFT, KeyEvent.VK_H); break;
        case 'I': doType(KeyEvent.VK_SHIFT, KeyEvent.VK_I); break;
        case 'J': doType(KeyEvent.VK_SHIFT, KeyEvent.VK_J); break;
        case 'K': doType(KeyEvent.VK_SHIFT, KeyEvent.VK_K); break;
        case 'L': doType(KeyEvent.VK_SHIFT, KeyEvent.VK_L); break;
        case 'M': doType(KeyEvent.VK_SHIFT, KeyEvent.VK_M); break;
        case 'N': doType(KeyEvent.VK_SHIFT, KeyEvent.VK_N); break;
        case 'O': doType(KeyEvent.VK_SHIFT, KeyEvent.VK_O); break;
        case 'P': doType(KeyEvent.VK_SHIFT, KeyEvent.VK_P); break;
        case 'Q': doType(KeyEvent.VK_SHIFT, KeyEvent.VK_Q); break;
        case 'R': doType(KeyEvent.VK_SHIFT, KeyEvent.VK_R); break;
        case 'S': doType(KeyEvent.VK_SHIFT, KeyEvent.VK_S); break;
        case 'T': doType(KeyEvent.VK_SHIFT, KeyEvent.VK_T); break;
        case 'U': doType(KeyEvent.VK_SHIFT, KeyEvent.VK_U); break;
        case 'V': doType(KeyEvent.VK_SHIFT, KeyEvent.VK_V); break;
        case 'W': doType(KeyEvent.VK_SHIFT, KeyEvent.VK_W); break;
        case 'X': doType(KeyEvent.VK_SHIFT, KeyEvent.VK_X); break;
        case 'Y': doType(KeyEvent.VK_SHIFT, KeyEvent.VK_Y); break;
        case 'Z': doType(KeyEvent.VK_SHIFT, KeyEvent.VK_Z); break;
        case '`': doType(KeyEvent.VK_BACK_QUOTE); break;
        case '0': doType(KeyEvent.VK_0); break;
        case '1': doType(KeyEvent.VK_1); break;
        case '2': doType(KeyEvent.VK_2); break;
        case '3': doType(KeyEvent.VK_3); break;
        case '4': doType(KeyEvent.VK_4); break;
        case '5': doType(KeyEvent.VK_5); break;
        case '6': doType(KeyEvent.VK_6); break;
        case '7': doType(KeyEvent.VK_7); break;
        case '8': doType(KeyEvent.VK_8); break;
        case '9': doType(KeyEvent.VK_9); break;
        case '-': doType(KeyEvent.VK_MINUS); break;
        case '=': doType(KeyEvent.VK_EQUALS); break;
        case '~': doType(KeyEvent.VK_SHIFT, KeyEvent.VK_BACK_QUOTE); break;
        case '!': doType(KeyEvent.VK_EXCLAMATION_MARK); break;
        case '@': doType(KeyEvent.VK_AT); break;
        case '#': doType(KeyEvent.VK_NUMBER_SIGN); break;
        case '$': doType(KeyEvent.VK_DOLLAR); break;
        case '%': doType(KeyEvent.VK_SHIFT, KeyEvent.VK_5); break;
        case '^': doType(KeyEvent.VK_CIRCUMFLEX); break;
        case '&': doType(KeyEvent.VK_AMPERSAND); break;
        case '*': doType(KeyEvent.VK_ASTERISK); break;
        case '(': doType(KeyEvent.VK_LEFT_PARENTHESIS); break;
        case ')': doType(KeyEvent.VK_RIGHT_PARENTHESIS); break;
        case '_': doType(KeyEvent.VK_UNDERSCORE); break;
        case '+': doType(KeyEvent.VK_PLUS); break;
        case '\t': doType(KeyEvent.VK_TAB); break;
        case '\n': doType(KeyEvent.VK_ENTER); break;
        case '[': doType(KeyEvent.VK_OPEN_BRACKET); break;
        case ']': doType(KeyEvent.VK_CLOSE_BRACKET); break;
        case '\\': doType(KeyEvent.VK_BACK_SLASH); break;
        case '{': doType(KeyEvent.VK_SHIFT, KeyEvent.VK_OPEN_BRACKET); break;
        case '}': doType(KeyEvent.VK_SHIFT, KeyEvent.VK_CLOSE_BRACKET); break;
        case '|': doType(KeyEvent.VK_SHIFT, KeyEvent.VK_BACK_SLASH); break;
        case ';': doType(KeyEvent.VK_SEMICOLON); break;
        case ':': doType(KeyEvent.VK_COLON); break;
        case '\'': doType(KeyEvent.VK_QUOTE); break;
        case '"': doType(KeyEvent.VK_QUOTEDBL); break;
        case ',': doType(KeyEvent.VK_COMMA); break;
        case '<': doType(KeyEvent.VK_LESS); break;
        case '.': doType(KeyEvent.VK_PERIOD); break;
        case '>': doType(KeyEvent.VK_GREATER); break;
        case '/': doType(KeyEvent.VK_SLASH); break;
        case '?': doType(KeyEvent.VK_SHIFT, KeyEvent.VK_SLASH); break;
        case ' ': doType(KeyEvent.VK_SPACE); break;
        default:
                throw new IllegalArgumentException("Cannot type character " + character);
        }
    }

    private static void doType(int... keyCodes) {
        doType(keyCodes, 0, keyCodes.length);
    }

    private static void doType(int[] keyCodes, int offset, int length) {
        if (length == 0) {
                return;
        }

        robot.keyPress(keyCodes[offset]);
        doType(keyCodes, offset + 1, length - 1);
        robot.keyRelease(keyCodes[offset]);
    }

}

To modify this to your needs, you would do:

for(int i = 0; i != 3; ++i) {
doType(KeyEvent.VK_DOWN);
}

The doType(KeyEvent.VK_DOWN); would press down one time, and then also release it.

You would probably insert that after the "So far, so good..." part in your code.

Hope I helped!




回答2:


You can use Key Bindings instead. The tutorial is here, direct from the Sun Java tutorials. They are a newer (and I think better) way to do the above.

If you are set on using a key listener then go to this tutorial. It explains how to do it.

I have never created a listener the way you are doing it, so not 100% sure what is going wrong but I think it is because you are creating a class to listen for key events, but you need to use that class somewhere else, it doesn't just go. Not sure though.

UPDATE: As above, in the class that uses your key listener, are you adding it? addKeyListener( new MyKeyListener() );




回答3:


KeyEvent contains key code constants (static int) like VK_DOWN, .VK_A, VK_0, etc. If you are using an IDE like eclipse, it will show you a list as you start typing. Or you can view a complete list in the KeyEvent field summary. This may simplify this kind of coding in your future programs.

public void keyPressed(KeyEvent e) {
if(e.getKeyCode() == e.VK_DOWN){
System.out.println("So far, so good..");
}
}



回答4:


To people interested in global event handling I totally recommend my answer originally posted here: How to detect a key press in Java



来源：https://stackoverflow.com/questions/9832195/keypress-how-to-detect-if-the-user-pressed-the-down-arrow-key-on-their-keyboa

标签
java
key-bindings
keylistener
易学教程内所有资源均来自网络或用户发布的内容，如有违反法律规定的内容欢迎反馈！
该文章没有解决你所遇到的问题?点击提问,说说你的问题,让更多的人一起探讨吧!