Jframe执行时大小不正确，为什么？

Question

我正在做一个游戏，但是每当我运行第二个jFrame时，我都必须调整它的大小才能获得第二个jFrame的正确大小，有人知道为什么吗？

这是第一个jFrame类中的方法，它将打开第二个类：

  private void playButtonMouseClicked(java.awt.event.MouseEvent evt) {                                        
        if (playerOneNameText.getText().equals(""))
        {
        }

        if (playerTwoNameText.getText().equals(""))
        {
        }
        else{
        pOneName = playerOneNameText.getText();
        pTwoName = playerTwoNameText.getText();

        ChessBoardUI class1 = new ChessBoardUI(); // Creating object of Class1
        class1.setVisible(true);

        this.setVisible(false);
        }
    }

这是第二个jFrame类，我必须重新调整它的大小才能正确显示山雀：

package chess;

public class ChessBoardUI extends javax.swing.JFrame {

    public ChessBoardUI() {
        initComponents();
    }

    /**
     * This method is called from within the constructor to initialize the form.
     * WARNING: Do NOT modify this code. The content of this method is always
     * regenerated by the Form Editor.
     */
    @SuppressWarnings("unchecked")
    // <editor-fold defaultstate="collapsed" desc="Generated Code">
    private void initComponents() {

        jLabel2 = new javax.swing.JLabel();
        jLabel3 = new javax.swing.JLabel();
        jLabel1 = new javax.swing.JLabel();
        jLabel4 = new javax.swing.JLabel();
        blackTeamName = new javax.swing.JLabel();
        whiteTeamName = new javax.swing.JLabel();

        setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);
        getContentPane().setLayout(null);
        getContentPane().add(jLabel2);
        jLabel2.setBounds(21, 49, 0, 0);

        jLabel3.setIcon(new javax.swing.ImageIcon(getClass().getResource("/chess/board.jpg"))); // NOI18N
        getContentPane().add(jLabel3);
        jLabel3.setBounds(0, 30, 400, 400);

        jLabel1.setText("Black:");
        getContentPane().add(jLabel1);
        jLabel1.setBounds(400, 100, 34, 16);

        jLabel4.setText("White:");
        getContentPane().add(jLabel4);
        jLabel4.setBounds(400, 150, 38, 16);

        blackTeamName.setText("jLabel5");
        getContentPane().add(blackTeamName);
        blackTeamName.setBounds(400, 120, 41, 16);

        whiteTeamName.setText("jLabel5");
        getContentPane().add(whiteTeamName);
        whiteTeamName.setBounds(400, 170, 41, 16);

        pack();
    }// </editor-fold>

    /**
     * @param args the command line arguments
     */
    public static void main(String args[]) {
        /* Set the Nimbus look and feel */
        //<editor-fold defaultstate="collapsed" desc=" Look and feel setting code (optional) ">
        /* If Nimbus (introduced in Java SE 6) is not available, stay with the default look and feel.
         * For details see http://download.oracle.com/javase/tutorial/uiswing/lookandfeel/plaf.html 
         */
        try {
            for (javax.swing.UIManager.LookAndFeelInfo info : javax.swing.UIManager.getInstalledLookAndFeels()) {
                if ("Nimbus".equals(info.getName())) {
                    javax.swing.UIManager.setLookAndFeel(info.getClassName());
                    break;
                }
            }
        } catch (ClassNotFoundException ex) {
            java.util.logging.Logger.getLogger(ChessBoardUI.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        } catch (InstantiationException ex) {
            java.util.logging.Logger.getLogger(ChessBoardUI.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        } catch (IllegalAccessException ex) {
            java.util.logging.Logger.getLogger(ChessBoardUI.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        } catch (javax.swing.UnsupportedLookAndFeelException ex) {
            java.util.logging.Logger.getLogger(ChessBoardUI.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        }
        //</editor-fold>

        /* Create and display the form */
        java.awt.EventQueue.invokeLater(new Runnable() {
            public void run() {
                new ChessBoardUI().setVisible(true);
            }
        });
    }
    // Variables declaration - do not modify
    private javax.swing.JLabel blackTeamName;
    private javax.swing.JLabel jLabel1;
    private javax.swing.JLabel jLabel2;
    private javax.swing.JLabel jLabel3;
    private javax.swing.JLabel jLabel4;
    private javax.swing.JLabel whiteTeamName;
    // End of variables declaration
}

Answer 1

我读得很快，正在寻找一种特定的方法。

该方法是：

pack();

JFrame中的此方法可能非常有用，但也很难处理，您需要非常了解如何设置每个组件的正确大小。同样，使用“空”布局可以使所有工作正常进行。

我的建议是忘记使用

setLayout(null)

因为根据我的经验，它几乎没有比其他布局更好的结果。

我能告诉你的最好的事情是使用BoxLayout。使用此布局，您可以精确设置每个组件的位置和大小。窍门还在于您可以使用刚性区域和胶水。

您的代码可以是：

// This is a BoxLayout with top to bottom orientation, the trick is to nest many JPanel
// with BoxLayout in both the direction to have all working
// What I want to achieve is:
//
//     1. Having a main box top to bottom where I will put:
//           - Top margin (a rigid area with dimension (0,MARGIN)
//           - Main JPanel with BoxLayout and LINE_AXIS (left to right) orientation
//           - Bottom margin (a rigid area like top margin)
//
//     2. In the main panel I will put:
//           - Left Margin (a rigid area with dimensions (MARGIN,0)
//           - A JPanel (leftPanel) Boxed top to bottom containing the things on the left that actually are jLabel3 and jLabel2
//           - A little separator between the two panel, a rigid area (10,0) i.e.
//           - A JPanel (rightPanel) Boxed top to bottom containing the remaining 4 JLabels
//           - Right Margin (as left)
//
//     3. In rightPanel JPanel (BoxLayout.PAGE_AXIS, top to bottom) I will have:
//           - a rigid area space to match the position that I want
//           - the first label
//           - a rigid area.. etc so on
//     
//     For each JLabel I must set all:
//           - setPreferredSize(dimension)
//           - setMinimumSize(dimension)
//           - setMaximumSize(dimension)
//
//     Then, if you specify also the JFrame is better, but you can try to pack().
//     BoxLayout take care of sizes, not exceeding maximum and not making it smaller than minimum. Yust try it and you will love it.

getContentPane().setLayout(new BoxLayout(getContentPane(), BoxLayout.PAGE_AXIS);

JPanel main = new JPanel();
main.setLayout(new BoxLayout(main, BoxLayout.LINE_AXIS));

this.add(Box.createRigidArea(new Dimension(0,20))); // VERTICAL SPACE (top margin)
this.add(main);
this.add(Box.createRigidArea(new Dimension(0,20))); // VERTICAL SPACE (bottom margin)

JPanel rightPanel = new JPanel();
rightPanel.setLayout( new BoxLayout(rightPanel, BoxLayout.PAGE_AXIS));
JPanel leftPanel = new JPanel();
leftPanel.setLayout( new BoxLayout(leftPanel, BoxLayout.PAGE_AXIS));

main.add(Box.createRigidArea(new Dimension(20,0))); // HORIZONTAL SPACE (left margin)
main.add(leftPanel);
main.add(Box.createRigidArea(new Dimension(10,0))); // HORIZONTAL SPACE (between the two)
main.add(rightPanel);
main.add(Box.createRigidArea(new Dimension(20,0))); // HORIZONTAL SPACE (right margin)

// now you should have understood how it works, just try to fill the right and left panel with your labels. Remember to set preferredm, maximum and minimum sizes.

我希望这对您有用。编辑，我想念一些“）”