Java JPanel与JTextArea保持一致

Question

我正在用JPanel测试一些东西。当我向它内部的JTextArea添加随机文本时，它不断增加JPanel的大小，直到达到边缘。

如何保持JPanel内部的文本不被拉伸？

public class Game 
{ 
TitleScreenHandler tsHandler = new TitleScreenHandler(); 
ChoiceHandler choiceHandler = new ChoiceHandler(); 
ComponentHandler compHandler = new ComponentHandler();  

GridBagConstraints gbc = new GridBagConstraints(); 
Border whiteline = BorderFactory.createLineBorder(Color.WHITE); 

JFrame window; 
Container con; 
JPanel titlePanel , startPanel, mainTextPanel, choiceButtonPanel, playerPanel; 
JLabel titleLabel, hpLabel, hpLabelNumber, weaponLabel, weaponLabelName; 

public static JButton startButton, choice1,choice2,choice3,choice4,choice5,choice6,choice7,choice8; 

public static JTextArea mainTextArea; 

Font titleFont = new Font("Times New Roman", Font.PLAIN, 100); 
Font normalFont = new Font("Times New Roman", Font.PLAIN, 30); 

public static String playerName; 
public static String weapon,position; 

public static int playerHP; 
public static int weaponDamage; 

public static void main(String[] args) 
{ 
    new Game(); 

} 

public Game() 
{ 
    window = new JFrame(); 
    window.setSize(1440,900); 
    window.setTitle("W: " + window.getWidth() + " H: " + window.getHeight()); 
    window.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); 
    window.getContentPane().setBackground(Color.black); 
    window.setLayout(new GridBagLayout()); 

    con = window.getContentPane(); 

    //Panels are used to make sections in the window (Background) 
    //Labels are used to write in the sections/panels (Foreground) 
    //Buttons can be pressed inside Panels 

    //To make a text you need to design a panel, design its size/color, 
    //Design its text the same way, then add it to the panel 

    titlePanel = new JPanel(); 
    titlePanel.setBounds(100, 100, 1080 , 150); 
    titlePanel.setBackground(Color.black);  

    titleLabel = new JLabel("Adventure"); 
    titleLabel.setForeground(Color.white); 
    titleLabel.setFont(titleFont); 

    startPanel = new JPanel(); 
    startPanel.setBounds(540, 600, 200, 100); 
    startPanel.setBackground(Color.black); 

    startButton = new JButton("START"); 
    startButton.setBackground(Color.black); 
    startButton.setForeground(Color.white); 
    startButton.setFont(normalFont); 
    startButton.addActionListener(tsHandler); 

    window.addComponentListener(compHandler); 

    titlePanel.add(titleLabel); 
    startPanel.add(startButton); 

    con.add(titlePanel, gbc); 

    gbc.gridx = 0; 
    gbc.gridy = 2; 

    con.add(startPanel, gbc); 

    window.setVisible(true); 
} 

public void createGameScreen() 
{ 
    titlePanel.setVisible(false); 
    startButton.setVisible(false); 

    mainTextPanel = new JPanel(); 
    //mainTextPanel.setBounds(100, 100, 1080, 250); 
    mainTextPanel.setBackground(Color.black); 
    mainTextPanel.setBorder(whiteline); 

    mainTextArea = new JTextArea("This is the main text area"); 
    mainTextArea.setBounds(100,100,1080,250); 
    mainTextArea.setBackground(Color.black); 
    mainTextArea.setForeground(Color.white); 
    mainTextArea.setLayout(new GridLayout()); 
    mainTextArea.setFont(normalFont); 
    mainTextArea.setLineWrap(true); 
    mainTextArea.setWrapStyleWord(true); 

    playerPanel = new JPanel(); 
    playerPanel.setBounds(100, 100, 1080, 50); 
    playerPanel.setBackground(Color.blue); 
    playerPanel.setLayout(new GridLayout(1,4)); 

    choiceButtonPanel = new JPanel(); 
    choiceButtonPanel.setBounds(500, 350, 300, 250); 
    choiceButtonPanel.setLayout(new GridLayout(2,4, 50, 50)); 
    choiceButtonPanel.setBackground(Color.red); 

    choice1 = new JButton("Choice 1"); 
    choice1.setBackground(Color.black); 
    choice1.setForeground(Color.white); 
    choice1.setFont(normalFont); 
    choice1.setFocusPainted(false); 
    choice1.addActionListener(choiceHandler); 
    choice1.setActionCommand("c1"); 

    choiceButtonPanel.add(choice1); 

    choice2 = new JButton("Choice 2"); 
    choice2.setBackground(Color.black); 
    choice2.setForeground(Color.white); 
    choice2.setFont(normalFont); 
    choice2.setFocusPainted(false); 
    choice2.addActionListener(choiceHandler); 
    choice2.setActionCommand("c2"); 

    choiceButtonPanel.add(choice2); 

    choice3 = new JButton("Choice 3"); 
    choice3.setBackground(Color.black); 
    choice3.setForeground(Color.white); 
    choice3.setFont(normalFont); 
    choice3.setFocusPainted(false); 
    choice3.addActionListener(choiceHandler); 
    choice3.setActionCommand("c3"); 

    choiceButtonPanel.add(choice3); 

    choice4 = new JButton("Choice 4"); 
    choice4.setBackground(Color.black); 
    choice4.setForeground(Color.white); 
    choice4.setFont(normalFont); 
    choice4.setFocusPainted(false); 
    choice4.addActionListener(choiceHandler); 
    choice4.setActionCommand("c4"); 

    choiceButtonPanel.add(choice4); 

    choice5 = new JButton("Choice 5"); 
    choice5.setBackground(Color.black); 
    choice5.setForeground(Color.white); 
    choice5.setFont(normalFont); 
    choice5.setFocusPainted(false); 
    choice5.addActionListener(choiceHandler); 
    choice5.setActionCommand("c5"); 

    choiceButtonPanel.add(choice5); 

    choice6 = new JButton("Choice 6"); 
    choice6.setBackground(Color.black); 
    choice6.setForeground(Color.white); 
    choice6.setFont(normalFont); 
    choice6.setFocusPainted(false); 
    choice6.addActionListener(choiceHandler); 
    choice6.setActionCommand("c6"); 

    choiceButtonPanel.add(choice6); 

    choice7 = new JButton("Choice 7"); 
    choice7.setBackground(Color.black); 
    choice7.setForeground(Color.white); 
    choice7.setFont(normalFont); 
    choice7.setFocusPainted(false); 
    choice7.addActionListener(choiceHandler); 
    choice7.setActionCommand("c7"); 

    choiceButtonPanel.add(choice7); 

    choice8 = new JButton("Choice 8"); 
    choice8.setBackground(Color.black); 
    choice8.setForeground(Color.white); 
    choice8.setFont(normalFont); 
    choice8.setFocusPainted(false); 
    choice8.addActionListener(choiceHandler); 
    choice8.setActionCommand("c8"); 

    choiceButtonPanel.add(choice8); 

    gbc.anchor = GridBagConstraints.PAGE_END; 
    gbc.fill = GridBagConstraints.BOTH; 

    gbc.gridx = 0; 
    gbc.gridy = 0; 

    con.add(playerPanel,gbc); 

    gbc.fill = GridBagConstraints.HORIZONTAL; 
    //gbc.ipadx = 750; 
    gbc.ipady = 1000; 
    gbc.gridwidth = 2; 
    gbc.gridx = 1; 
    gbc.gridy = 0; 
    con.add(mainTextPanel,gbc); 

    gbc.fill = GridBagConstraints.NONE; 
    gbc.ipadx = 0; 
    gbc.ipady = 0; 
    gbc.gridx = 1; 
    gbc.gridy = 5; 
    con.add(choiceButtonPanel,gbc); 

    hpLabel = new JLabel("HP: "); 
    hpLabel.setFont(normalFont); 
    hpLabel.setForeground(Color.white); 

    hpLabelNumber = new JLabel(); 
    hpLabelNumber.setFont(normalFont); 
    hpLabelNumber.setForeground(Color.white); 

    weaponLabel = new JLabel("Weapon: "); 
    weaponLabel.setFont(normalFont); 
    weaponLabel.setForeground(Color.white); 

    weaponLabelName = new JLabel(); 
    weaponLabelName.setFont(normalFont); 
    weaponLabelName.setForeground(Color.white); 

    playerPanel.add(hpLabel); 
    playerPanel.add(hpLabelNumber); 
    playerPanel.add(weaponLabel); 
    playerPanel.add(weaponLabelName); 
    mainTextPanel.add(mainTextArea, BorderLayout.PAGE_START); 

    playerSetup(); 

} 


public void playerSetup() 
{ 
    playerHP = 15; 
    weapon = "Fists"; 
    weaponLabelName.setText(weapon); 
    hpLabelNumber.setText("" + playerHP); 

    ForestEvents.townGate(); 
} 

/*public void townGate() 
{ 
    position = "towngate"; 

    mainTextArea.setText("You are at the gates of the town. A guard is standing in front of you. What do you do?"); 
    choice1.setText("Talk to the Guard"); 
    choice2.setText("Attack the Guard"); 
    choice3.setText("Leave"); 
    choice4.setText(""); 
}*/ 

public void talkGuard() 
{ 
    position = "talkguard"; 

    mainTextArea.setText("Guard: Hello Stranger. I have never seen you before. I'm sorry but I cannot let you enter."); 

    choice1.setText("Go Back"); 
    choice2.setText(""); 
    choice3.setText(""); 
    choice4.setText(""); 

} 

public void attackGuard() 
{ 
    position = "attackguard"; 

    mainTextArea.setText("Guard: HOW DARE YOU!\nThe guard fought back and hit you hard.\n(You received 3 damage)"); 
    playerHP -= 3; 
    hpLabelNumber.setText("" + playerHP); 

    choice1.setText("Go Back"); 
    choice2.setText(""); 
    choice3.setText(""); 
    choice4.setText(""); 

} 

public void crossRoad() 
{ 
    position = "crossroads"; 

    mainTextArea.setText("You are at the crossroad.\n Go south to go back to the town."); 

    choice1.setText("Go North"); 
    choice2.setText("Go East"); 
    choice3.setText("Go South"); 
    choice4.setText("Go West"); 

} 

public class ComponentHandler implements ComponentListener 
{ 
    public void componentResized(ComponentEvent e) 
    { 
     Component c = (Component)e.getSource(); 
     window.setTitle("W: " + c.getWidth() + " H: " + c.getHeight()); 


    } 

    @Override 
    public void componentHidden(ComponentEvent e) 
    { 
     // TODO Auto-generated method stub 

    } 

    @Override 
    public void componentMoved(ComponentEvent e) 
    { 

    } 

    @Override 
    public void componentShown(ComponentEvent e) 
    { 

    } 
} 

public class TitleScreenHandler implements ActionListener 
{ 
    public void actionPerformed(ActionEvent event) 
    { 
     createGameScreen(); 
    } 
} 

public class ChoiceHandler implements ActionListener 
{ 
    public void actionPerformed(ActionEvent event) 
    { 
     String yourChoice = event.getActionCommand(); 

     switch (position) 
     { 
      case "towngate": 
       switch(yourChoice) 
       { 
       case "c1": 
        talkGuard(); 
        break; 
       case "c2": 
        attackGuard(); 
        break; 
       case "c3": 
        crossRoad(); 
        break; 
       case "c4": 
        break; 
       } 
       break; 

      case "talkguard": 
       switch(yourChoice) 
       { 
       case "c1": 
        ForestEvents.townGate(); 
        break; 
       } 
       break; 

      case "attackguard": 
       switch(yourChoice) 
       { 
       case "c1": 
        ForestEvents.townGate(); 
        break; 
       } 
       break; 

      case "crossroad": 
       switch(yourChoice) 
       { 
       case"c1": 
        break; 
       case"c2": 
        break; 
       case"c3": 
        ForestEvents.townGate(); 
        break; 
       case"c4": 
        break; 
       } 
       break; 


     } 

    } 

} 

} 

编辑：添加的代码的其余部分，将加入到textarea的滚动面板和滚动面板到现在的JPanel显示面板将文字心不是。

import javax.swing.JTextArea; 

public class ForestEvents 
{ 
String pos; 
int hp; 

public ForestEvents() 
{ 
    pos = Game.position; 
    hp = Game.playerHP; 
} 

public static void townGate() 
{ 
    Game.position = "towngate"; 

    Game.mainTextArea.setText("You are at the gates of the town. A guard is standing in front of you. What do you do? \na\nas\n\n\n\n\\n" 
      + "\n\n\n\1\n1\n\n\n\n\n\\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n1\n1\n2\n2\n3\n4\n6"); 
    Game.choice1.setText("Talk to the Guard"); 
    Game.choice2.setText("Attack the Guard"); 
    Game.choice3.setText("Leave"); 
    Game.choice4.setText(""); 
} 





} 

Answer 1

你会希望得到您的JTextArea为JScrollPane，如阿迪尔在评论（+1）说，然后用GridBagLayout控制它。无需设置组件边界，首选大小等。如果您要使用GridBagLayout，则必须了解weights如何与fill和anchor配合使用。另外，在以下变化gbc.fillHORIZONTAL代码VERTICAL和交换weights我用于添加scroll到window（所以它应该是weightx = 0，y = 1），或改变填充到BOTH和使双方的权重等于1（在这种情况下，你可以注释掉这个空的JLabel我在最后添加）。观察并学习。

在你的代码中，你没有设置权重。所以，正如你可能猜到的，一切都有重量相同的。 mainTextArea被添加，而gbc.fill是HORIZONTAL，没有权重，不在里面JScrollPane - 这就是为什么它延伸。并小心使用ipad。

SSCCE（代码中的注释）

public class DontStretchMyTextArea { 

    public static void main(String[] args) { 
     JFrame window = new JFrame(); 
     window.setSize(1440, 900); 
     window.setTitle("W: " + window.getWidth() + " H: " + window.getHeight()); 
     window.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE); 

     window.setLayout(new GridBagLayout()); 

     GridBagConstraints gbc = new GridBagConstraints(); 

     gbc.fill = GridBagConstraints.HORIZONTAL; 
     gbc.anchor = GridBagConstraints.NORTH; 
     gbc.insets = new Insets(10, 10, 10, 10); 

     JTextArea mainTextArea = new JTextArea("This is the main text area" , 10 , 30); //here you can set how many rows/columns you want, 
                          //but anyway GridBagLayout will recalculate size of component 
                          //based on gbc.fill, weights and surrounding components 
     //mainTextArea.setLayout(new GridLayout()); 
     mainTextArea.setLineWrap(true); 
     mainTextArea.setWrapStyleWord(true); 

     JScrollPane scroll = new JScrollPane(mainTextArea); 
     scroll.setVerticalScrollBarPolicy(JScrollPane.VERTICAL_SCROLLBAR_ALWAYS); 

      JPanel panel = new JPanel(); 
      panel.setLayout(new GridBagLayout()); 
      GridBagConstraints panelGBC = new GridBagConstraints(); 

      panelGBC.weightx = 1;     //I want to fill whole panel with JTextArea 
      panelGBC.weighty = 1;     //so both weights =1 
      panelGBC.fill = GridBagConstraints.BOTH; //and fill is set to BOTH 

      panel.add(scroll, panelGBC); 
      panel.setBackground(Color.gray);//this shouldn't be visible 


     gbc.weightx = 1; 
     gbc.weighty = 0; 
     window.add(panel, gbc); 

     gbc.weightx = 1; 
     gbc.weighty = 1; 
     gbc.gridx++; 
     window.add(new JLabel(), gbc); //GridBagLayout always needs component with both weights =1 

     SwingUtilities.invokeLater(() -> { //we get our frame on EDT 
      window.pack(); 
      window.setVisible(true); 
     }); 
    } 
} 

How to use GridBagLayout

您也可以直接添加到scrollwindow。 panel仅用于说明目的。