為什么我的按鈕占用了整個JFrame？

Question

我的代碼之前正在運行，但現在一個JButton占用了整個JFrame，任何幫助都將受到贊賞！

我正在使用名為fl的FlowLayout和一個名為Ken的類

我有十個按鈕（oneButton，twoButton，ThreeButton等。）

我的代碼：

import java.awt.ComponentOrientation;
import java.awt.Dimension;
import java.awt.FlowLayout;


import javax.swing.JButton;
import javax.swing.JFrame;



public class Ken {

public static void frame(){
    JFrame frame = new JFrame("Pow");
    frame.setSize(500, 600);
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    frame.setVisible(true);
    frame.setResizable(false);
    FlowLayout fl = new FlowLayout(0, 50, 40);


    JButton oneButton = new JButton("         1         ");
    oneButton.setPreferredSize(new Dimension(100, 90));
    frame.add(oneButton);
    JButton twoButton = new JButton("         2         ");
    twoButton.setPreferredSize(new Dimension(100, 90));
    frame.add(twoButton);
    JButton threeButton = new JButton("         3         ");
    threeButton.setPreferredSize(new Dimension(100, 90));
    frame.add(threeButton);
    JButton fourButton = new JButton("         4         ");
    fourButton.setPreferredSize(new Dimension(100, 90));
    frame.add(fourButton);
    JButton fiveButton = new JButton("         5         ");
    fiveButton.setPreferredSize(new Dimension(100, 90));
    frame.add(fiveButton);
    JButton sixButton = new JButton("          6         ");
    sixButton.setPreferredSize(new Dimension(100, 90));
    frame.add(sixButton);
    JButton sevenButton = new JButton("         7         ");
    sevenButton.setPreferredSize(new Dimension(100, 90));
    frame.add(sevenButton);
    JButton eightButton = new JButton("         8         ");
    eightButton.setPreferredSize(new Dimension(100, 90));
    frame.add(eightButton);
    JButton nineButton = new JButton("         9         ");
    nineButton.setPreferredSize(new Dimension(100, 90));
    frame.add(nineButton);
    JButton zeroButton = new JButton("                                                                       
                                  0                               ");
    zeroButton.setPreferredSize(new Dimension(400, 90));
    frame.add(zeroButton);
    frame.setComponentOrientation(
            ComponentOrientation.LEFT_TO_RIGHT);
}



public static void main(String[] args){
    frame();
}
}

我可以嘗試一下嗎？

Answer 1

我正在使用一個名為fl的FlowLayout ...

實際上你並沒有使用FlowLayout，因為你從不在容器上調用setLayout(...) 。 相反，您的Frame的contentPane正在使用contentPanes的默認布局BorderLayout，這將導致以默認方式添加的最后一個組件填充容器的BorderLayout.CENTER位置。

因此，一種解決方案是使用布局：

FlowLayout fl = new FlowLayout(0, 50, 40);    
frame.getContentPane().setLayout(fl);

但話說回來，你可能最好不要設置組件的首選大小，而是使用嵌套容器的組合，每個容器都使用自己的布局，以實現令人愉悅和復雜的GUI，這將更容易維護和擴展。

或者，您可以使用更復雜的布局，例如GridBagLayout。 例如：

import java.awt.Component;
import java.awt.Font;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import java.awt.Insets;

import javax.swing.*;

public class Ken2 {
   private static final String[][] NUMBERS = {
      {"1", "2", "3"},
      {"4", "5", "6"},
      {"7", "8", "9"},
      {"0"}
   };
   private static final float BUTTON_FONT_PTS = 45f;
   private static final int INSETS = 20;
   private static final Insets BUTTON_INSETS = new Insets(INSETS, INSETS, 
           INSETS, INSETS);
   private static final int IPAD = 20;
   private JPanel mainPanel = new JPanel();

   public Ken2() {
      mainPanel.setLayout(new GridBagLayout());
      for (int row = 0; row < NUMBERS.length; row++) {
         addRowToPanel(row, NUMBERS[row]);
      }
   }

   private void addRowToPanel(int row, String[] numbersRow) {
      int columns = numbersRow.length;
      for (int col = 0; col < numbersRow.length; col++) {
         addNumberButton(row, col, columns, numbersRow[col]);
      }
   }

   private void addNumberButton(int row, int col, int columns, 
           String numberText) {
      JButton button = new JButton(numberText);
      button.setFont(button.getFont().deriveFont(Font.BOLD, BUTTON_FONT_PTS));
      GridBagConstraints gbc = new GridBagConstraints();
      gbc.gridx = col;
      gbc.gridy = row;
      gbc.gridheight = 1;
      gbc.gridwidth = 3 / columns;
      gbc.weightx = 1.0;
      gbc.weighty = 1.0;
      gbc.anchor = GridBagConstraints.CENTER;
      gbc.fill = GridBagConstraints.BOTH;
      gbc.insets = BUTTON_INSETS;
      gbc.ipadx = IPAD;
      gbc.ipady = IPAD;

      mainPanel.add(button, gbc);
   }

   private static void createAndShowGui() {
      Ken2 ken = new Ken2();

      JFrame frame = new JFrame("Ken2");
      frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
      frame.getContentPane().add(ken.getMainPanel());
      frame.pack();
      frame.setLocationByPlatform(true);
      frame.setVisible(true);
   }

   private Component getMainPanel() {
      return mainPanel;
   }

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

Answer 2

在void frame()方法上調用setLayout(fl) 。