java - 在运行时设置 JLabel 文本

Question

我是 Java 的新手(大约 2 周)，我正在尝试设置 JLabel 的文本。唯一的问题是我正在另一个类中进行计算，我不知道如何引用我已经创建的 Jlabel。这是有问题的两个类。

package fightsim;

import javax.swing.JPanel;
import net.miginfocom.swing.MigLayout;
import javax.swing.JLabel;
import javax.swing.JButton;
import java.awt.event.ActionListener;
import java.awt.event.ActionEvent;

public class FightSimPane extends JPanel {
FightManager FightManager = new FightManager();
/**
 * Create the panel.
 */
public FightSimPane() {
    setLayout(new MigLayout("", "[][][][][][][][][][]", "[][][][]"));

    JLabel lblChampionleft = new JLabel("ChampionLeft");
    add(lblChampionleft, "cell 1 3");

    JButton btnGo = new JButton("Go");
    btnGo.addActionListener(new ActionListener() {
        public void actionPerformed(ActionEvent arg0) {

            FightManager.startFight();
            FightManager.runTheFight();

        }
    });
    add(btnGo, "cell 5 3");

    JLabel lblChampionright = new JLabel("ChampionRight");
    add(lblChampionright, "cell 9 3");

}


public void setLeftChampionLabel(String s){
    //not able to reference Jlabel lblChampionLeft here???
    System.out.println("Setting Left Champion text to"+s);

}

public void setRightChampionLabel(String s){
    //not able to reference Jlabel lblChampionRight here???
    System.out.println("Setting Right Champion text to"+s);
}


}

以及试图设置标签的类。

package fightsim;

public class FightManager {

Champion LeftChamp = new Champion();
Champion RightChamp = new Champion();

public FightManager() {

}

Thread LeftChampThread = new Thread(LeftChamp);
Thread RightChampThread = new Thread(RightChamp);

;

public void startFight() {

    LeftChamp.setHealth(200);
    RightChamp.setHealth(300);
    LeftChamp.setATKsp(1000);
    RightChamp.setATKsp(1000);
    LeftChamp.setAD(20);
    RightChamp.setAD(20);

}

public void runTheFight() {
    System.out.println("Starting Threads");
    LeftChampThread.start();
    RightChampThread.start();

    while ((LeftChamp.getHealth() > 0) && (RightChamp.getHealth() > 0)) {

        if (RightChamp.isReadyToAttack()) {
            LeftChamp.setHealth(LeftChamp.getHealth() -     RightChamp.getAD());
            RightChamp.setNotReady();
            System.out.println("Setting Left Champion test to"
                    + Integer.toString(LeftChamp.getHealth()));

            // This is where I'd like to update the left Jlabel in
            // FightSimPane

        }
        if (LeftChamp.isReadyToAttack()) {
            RightChamp
                    .setHealth(RightChamp.getHealth() - LeftChamp.getAD());
            LeftChamp.setNotReady();
            System.out.println("Setting Right Champion test to"
                    + Integer.toString(RightChamp.getHealth()));

            // This is where I'd like to update the right Jlabel in
            // FightSimPane
        }

    }

}
}

那么，问题是……如何让我的 FightManager 类访问和更改我的 FightSimPane 类/Gui 中的 JLabel。在此先感谢，如果这是一个愚蠢的问题，我们深表歉意。我对编程非常陌生，我仍在努力接受这一切。话虽如此，任何其他建议都会很棒。谢谢!

Answer 1

传递引用以便类可以相互通信，不仅如此，还可以与其他类型的类的正确 Activity 实例通信。例如，您可以为 FlightManager 提供一个 FlightSimPane 字段:

class FightManager {

   private FightSimPane fightSimPane;

   // and fill it in the constructor:
   public FightManager(FightSimPane fightSimPane) {
      this.fightSimPane = fightSimPane;
   }

然后您将处理实际可视化的 FightSimPane GUI 对象。

请注意，您必须注意传递正确的实例:

public class FightSimPane extends JPanel {
   FightManager FightManager = new FightManager(this);

然后可以在FightManager类中调用FightSimPane的公共(public)方法:

public void runTheFight() {
  System.out.println("Starting Threads");
  LeftChampThread.start();
  RightChampThread.start();

  while ((LeftChamp.getHealth() > 0) && (RightChamp.getHealth() > 0)) {

     if (RightChamp.isReadyToAttack()) {
        LeftChamp.setHealth(LeftChamp.getHealth() - RightChamp.getAD());
        RightChamp.setNotReady();
        System.out.println("Setting Left Champion test to"
              + Integer.toString(LeftChamp.getHealth()));

        // !!!  **** added this *************
        fightSimPane.setRightChampionLabel("Setting Left Champion test to"
              + Integer.toString(LeftChamp.getHealth()));

     }

编辑 1
我在这里看到另一个潜在的严重且无关的问题:

  while ((LeftChamp.getHealth() > 0) && (RightChamp.getHealth() > 0)) {

     //.........

  }

这段代码似乎是在主 Swing 线程、EDT 上调用的，它的本质(while (true))表明它很有可能锁定 EDT，从而使您的 Swing GUI 的图形处理和更新以及所有用户互动戛然而止。您可能需要为此使用 Swing 计时器或后台线程，以便让 EDT 自由执行其必要的工作。