java - ActionListener 阻止程序运行？

Question

好的，我有两个问题。

1. 在添加 help.addActionListener(this) 之前，我的程序 UI 已经正常工作了进入我的程序。我在静态方法方面遇到了一些问题，因为 Eclipse 想要其中的某个 main 方法，而 ActionListener不喜欢使用静态方法。 (当时我正在 public static void main(String args[]) 中进行方法调用。)一旦我将方法调用移至构造函数或单独的方法，程序将不会执行代码中的任何内容。

 JFrame screen; 
 JButton start, submit, help;
 JPanel UI,userWhite, passWhite;
 JLabel usrTxt, passTxt;
 JTextArea usrInput, passInput;

static String[] strings = new String[2]; //See getInformation() method
HELP runner = new HELP();

public UserInterface()
{
    run(); 
}

public void run()
{
    uiSetup();
    displaySetup();
    inputSetup();
}

public static void main(String args[])
{
    // Had to make every method static if I did the method call in here
    // which was fine until it came time to use "help.addActionListener(this)".
    // When I did use this method in a static context, I kept getting an error. 
}


public void uiSetup()
{
    // This method sets up the initial interface which all other
    // elements within this program will be built off of

    screen = new JFrame("Bing Rewards Bot v.Development 1.0");
    screen.setVisible(true);
    screen.setSize(800, 600);
    screen.setResizable(false);
    screen.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    screen.getContentPane().setLayout(new BorderLayout());

    UI = new JPanel();
    UI.setVisible(true);
    UI.setLayout(null);
    UI.setBackground(Color.CYAN);
    screen.add(UI);
                                        // Buttons must me initialized here. If done in another method,
                                        // it can sometimes block JPanels from appearing. Fixed: 12/27/15
    start = new JButton("Start Bot");
    start.setVisible(true);
    start.setFocusable(false);
    start.setBounds(300,300,200,75);
    UI.add(start);

    submit = new JButton("Submit");
    submit.setVisible(true);
    submit.setFocusable(false);
    submit.setBounds(75,170,100,50);
    UI.add(submit);

    help = new JButton("HELP");
    help.setVisible(true);
    help.setFocusable(false);
    help.setBounds(355,500,100,50);
    help.setActionCommand("helpClicked");
    help.addActionListener(this);
    UI.add(help); 
}


public void displaySetup()
{
    // This method sets up the interface text

    usrTxt = new JLabel("Bing/Microsoft Account Username");
    usrTxt.setFont(new Font("Monospaced", Font.BOLD, 16));
    usrTxt.setForeground(Color.BLACK);
    usrTxt.setBounds(0,0,310,20); // Adjusts Absolute Size
    usrTxt.setLocation(25,50); // Sets Location
    UI.add(usrTxt);

    passTxt = new JLabel("Password");
    passTxt.setFont(new Font("Monospaced", Font.BOLD, 16));
    passTxt.setForeground(Color.BLACK);
    passTxt.setBounds(0,0,310,20);
    passTxt.setLocation(25,100);
    UI.add(passTxt);
}

public void inputSetup()
{
    // This method handles the User name and Password field setup

    //----- Adds White Space In JTextAreas ----------------------------
    userWhite = new JPanel();
    userWhite.setVisible(true);
    userWhite.setBackground(Color.WHITE);
    userWhite.setLocation(25,70);
    userWhite.setSize(200,25);
    UI.add(userWhite);

    passWhite = new JPanel();
    passWhite.setVisible(true);
    passWhite.setBackground(Color.WHITE);
    passWhite.setLocation(25,120);
    passWhite.setSize(200,25);
    UI.add(passWhite);

    //----------- JTextAreas ------------------------------------------
    usrInput = new JTextArea();
    usrInput.setBounds(0,0,200,18);
    usrInput.setLocation(25,75);
    usrInput.setBackground(Color.WHITE);
    usrInput.setForeground(Color.BLACK);
    UI.add(usrInput);

    passInput = new JTextArea();
    passInput.setBounds(0,0,200,18);
    passInput.setLocation(25,125);
    passInput.setBackground(Color.WHITE);
    passInput.setForeground(Color.BLACK);
    UI.add(passInput);
}

public void getInformation()
{
    // This method gets the information from the
    // JTextAreas in the inputSetup method and
    // stores it into an array called "strings"
    // ("strings" is initialized in the class)

    strings[0] = usrInput.getText();
    strings[1] = passInput.getText();
}

public void actionPerformed(ActionEvent e){
    if (e.getActionCommand().equals("helpClicked")) 
    {
        UI.setVisible(false);
        runner.helpSetup(screen);

    }
} 

}

当单击按钮时，计划是 JPanel “用户界面”:UI.setVisible(false) ，然后创建一个 Object到了不同的类(class)，那里会有不同的JPanel至setVisible(true) ，然后将其添加到 JFrame “屏幕”。如何在让按钮正常工作的同时执行方法调用？

有谁知道有关获取用户输入的信息然后将其发送到网站，然后从网站获取数据以在 java 程序中显示它的教程吗？我环顾过这里和其他地方，但它要么满足了我正在寻找的大部分内容，要么还不够。

Answer 1

您的 main 方法应该用于创建和设置运行代码的主要对象，这里是您的 UserInterface 对象。由于您的 main 方法为空，因此您的程序会运行，但不会显示任何内容，因为 JVM 从未被告知创建或显示任何 GUI。因此，对于您来说，您需要创建 UserInterface，然后调用其 uiSetup 方法，以便它显示 GUI:

public static void main(String args[]) {
    UserInterface userInterface = new UserInterface();
    userInterface.uiSetup();
}

或类似的东西。

要交换 View ，请使用 CardLayout (请检查教程的链接)，这是专门为更改 View 而构建的布局。

其他问题:

• 避免空布局和setBounds(...)。虽然这似乎是创建 GUI 的最简单方法，但事实并非如此，如果您需要更改组件或向 GUI 添加新组件(这种情况经常发生)，那么这将成为维护的噩梦。请改用布局管理器。

例如，您的代码可能类似于:

import java.awt.CardLayout;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.event.ActionEvent;
import javax.swing.*;

public class MyUserInterface extends JPanel {
    public static final String MAIN = "main";
    public static final String HELP = "help";
    private MainPanel mainPanel = new MainPanel(this);
    private HelpPanel helpPanel = new HelpPanel();

    private CardLayout cardLayout = new CardLayout();

    public MyUserInterface() {
        setLayout(cardLayout);
        add(mainPanel, MAIN);
        add(helpPanel, HELP);

    }

    public void showview(String key) {
        cardLayout.show(this, key);
    }

    private static void createAndShowGui() {
        JFrame frame = new JFrame("MyUserInterface");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.getContentPane().add(new MyUserInterface());
        frame.pack();
        frame.setLocationRelativeTo(null);
        frame.setVisible(true);
    }

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

class HelpPanel extends JPanel {
    public HelpPanel() {
        add(new JLabel("Help", SwingConstants.CENTER));
        setBorder(BorderFactory.createTitledBorder("Help Panel"));
    }
}

class MainPanel extends JPanel {
    private static final Color BG = Color.CYAN;
    private static final int PREF_W = 800;
    private static final int PREF_H = 600;
    private MyUserInterface myUserInterface;

    public MainPanel(MyUserInterface myUserInterface) {
        setBackground(BG);
        setBorder(BorderFactory.createTitledBorder("Main Panel"));
        this.myUserInterface = myUserInterface;
        add(new JButton(new HelpAction("Help")));
    }

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

    private class HelpAction extends AbstractAction {
        public HelpAction(String name) {
            super(name);
        }

        @Override
        public void actionPerformed(ActionEvent e) {
            myUserInterface.showview(MyUserInterface.HELP);
        }
    }
}