Java使用enter按钮打破while循环

时间:2015-02-25 22:48:10

标签: java swing if-statement break

问题在于我制作了一个JFrame,文字显示几乎像一部视觉小说。当JLabel中的文本完成时,闪烁的箭头符号">"显示在底部。我做到了这一点,但我如何制作'而#39;如果我按下回车键,循环中断。网上的所有答案都是关于JTextField和Console ......

public static void nextSymbol(boolean blink) {  
    ImageIcon nextIcon = null;
    boolean blinked = false;
    if(blink) {
        nextIcon = new ImageIcon("res/image/next.gif");
        while(blink){
            if (/* When ENTER is pressed */){
                System.out.println("Disabled");
                blink = false;
            }
            pause(0.01);
        }   
        blinked = true;
    }
    if(!blink && blinked)
        vnGame.nextSymbolIcon.setIcon(null);
    else
        ;
    blinked = false;
}

修改

所以经过一些混合我改变了程序......没有一个答案有效(或者我做了一些错误的idk ......)

新代码现在是:

public static void nextSymbol() {   
    ImageIcon nextIcon = null;
    nextIcon = new ImageIcon("res/image/next.gif");
    vnGame.nextSymbolIcon.setIcon(nextIcon);
    boolean next = false;
    Continue = 0;

    do {
        vnGame.contentPane.requestFocus();
        switch(Continue) {
            case 1:{
                next = true;
                break;
            }
            default:break;
        }
    }while(!next);
    SysPrint("Continue!");nl();
}

继续更改方法在这里(另一个类):

public void keyPressed(KeyEvent e) {
    if (e.getKeyChar() == 's') {
        VONGINE.SysPrint("S");
        VONGINE.Continue = 1;
    }
} 

最后是新问题......我怎么称呼......

keyPressed(KeyEvent e)

...在do循环期间?

1 个答案:

答案 0 :(得分:4)

首先,您不需要使用while (true)循环。这是一个Swing GUI,你冒险在Swing事件线程上循环,冻结你的GUI。相反,你需要以不同的方式思考,以事件驱动的方式思考,因为大多数GUI都是如此,包括Swing的工作方式。

做点什么"眨眼"在JLabel中,使用Swing Timer代替while循环,并在Timer的ActionListener中显示并显示">" JLabel中的角色。

要在按下Enter键时停止此操作,请使用键绑定(不是KeyListener)。或者,如果JTextField具有焦点,则添加到JTextField的ActionListener将起作用。


例如,考虑尝试这些方面:

import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.event.ActionEvent;
import java.awt.event.KeyEvent;
import java.net.MalformedURLException;
import java.net.URL;

import javax.swing.*;

@SuppressWarnings("serial")
public class SwappingLabel extends JPanel {
   public static final String IMG_PATH = "http://www.guitarchordsmagic.com/images/arrow.gif";
   private static final int PREF_W = 400;
   private static final int PREF_H = PREF_W;
   private JLabel nextSymbolIcon = new JLabel("", SwingConstants.CENTER);
   private Icon nextIcon;

   public SwappingLabel() throws MalformedURLException {
      // Create our ImageIcon from online (or local) source
      nextIcon = getOnlineIcon(IMG_PATH);

      // add icon to JLabel
      nextSymbolIcon.setIcon(nextIcon);

      // set up key binding to recognize enter key press
      setupKeyBinding();

      // add the JLabel to the bottom of the GUI
      setBackground(Color.white);
      JPanel southPanel = new JPanel();
      southPanel.setOpaque(false);
      southPanel.add(nextSymbolIcon);
      setLayout(new BorderLayout());
      add(southPanel, BorderLayout.PAGE_END);
   }

   private Icon getOnlineIcon(String path) throws MalformedURLException {
      URL imgUrl = new URL(path);
      return new ImageIcon(imgUrl);
   }

   private void setupKeyBinding() {
      int condition = WHEN_IN_FOCUSED_WINDOW;
      InputMap inputMap = getInputMap(condition);
      ActionMap actionMap = getActionMap();
      KeyStroke enterKey = KeyStroke.getKeyStroke(KeyEvent.VK_ENTER, 0);

      // the action that will be called when enter is pressed
      Action action = new EnterAction();

      // bind the key press to the component to the action
      inputMap.put(enterKey, enterKey.toString());
      actionMap.put(enterKey.toString(), action);
   }

   @Override
   public Dimension getPreferredSize() {
      if (isPreferredSizeSet()) {
         return super.getPreferredSize();
      }
      return new Dimension(PREF_W, PREF_H);
   }

   private class EnterAction extends AbstractAction {
      @Override
      public void actionPerformed(ActionEvent e) {
         nextSymbolIcon.setIcon(null);
      }
   }

   private static void createAndShowGui() {
      JFrame frame = new JFrame("Blinking Label");
      frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
      try {
         frame.getContentPane().add(new SwappingLabel());
      } catch (MalformedURLException e) {
         e.printStackTrace();
         System.exit(-1);
      }
      frame.pack();
      frame.setLocationRelativeTo(null);
      frame.setVisible(true);
   }

   public static void main(String[] args) {
      SwingUtilities.invokeLater(new Runnable() {
         public void run() {
            createAndShowGui();
         }
      });
   }
}

请注意,此处没有while或do-while循环,没有不必要的静态方法或字段,并且所有调用都在Swing事件线程上完成。