arrowdecoratorlistener.java

java绘图 java awt 经典绘图的例子,对于初学awt模块的人非常有帮助.

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package arrow;

import java.awt.event.KeyEvent;
import java.awt.event.KeyListener;

/**
 *
 * @author zhaolin
 */
public class ArrowDecoratorListener implements KeyListener {
    public static final int LEFT_ARROW=0;
    public static final int RIGHT_ARROW=1;
    public static final int UP_ARROW=2;
    public static final int DOWN_ARROW=3;
    
    //保存每一个方向的状态
    private boolean arrowStatus[];
    private ArrowKeyListener akl;
    public ArrowDecoratorListener(ArrowKeyListener akl){
        this.akl = akl;
        arrowStatus = new boolean[4];
    }
    
    public void keyTyped(KeyEvent e) {
        
    }

    public void keyPressed(KeyEvent e) {
        changeArrowStatus(e.getKeyCode(),true);
        invokeArrow(e);
    }

    public void keyReleased(KeyEvent e) {
        changeArrowStatus(e.getKeyCode(),false);
        invokeArrow(e);
    }
    
    private void changeArrowStatus(int keyCode,boolean value){
        switch(keyCode){
            case KeyEvent.VK_UP:arrowStatus[UP_ARROW]=value;break;
            case KeyEvent.VK_DOWN:arrowStatus[DOWN_ARROW]=value;break;
            case KeyEvent.VK_LEFT:arrowStatus[LEFT_ARROW]=value;break;
            case KeyEvent.VK_RIGHT:arrowStatus[RIGHT_ARROW]=value;break;
        }
    }
    
    private void invokeArrow(KeyEvent event){
        if(arrowStatus[UP_ARROW]&&arrowStatus[LEFT_ARROW]){
            akl.upLeftArrowPressed(event);
        }else if(arrowStatus[UP_ARROW]&&arrowStatus[RIGHT_ARROW]){
            akl.upRightArrowPressed(event);
        }else if(arrowStatus[DOWN_ARROW]&&arrowStatus[LEFT_ARROW]){
            akl.downLeftArrowPressed(event);
        }else if (arrowStatus[DOWN_ARROW] && arrowStatus[RIGHT_ARROW]) {
            akl.downRightArrowPressed(event);
        } else if(arrowStatus[UP_ARROW]){
            akl.upArrowPressed(event);
        } else if(arrowStatus[DOWN_ARROW]){
            akl.downArrowPressed(event);
        } else if(arrowStatus[LEFT_ARROW]){
            akl.leftArrowPressed(event);
        } else if(arrowStatus[RIGHT_ARROW]){
            akl.rightArrowPressed(event);
        } 
    }

}