Java GUI - JFrame 问题

Question

只是想知道为什么最后一个 JTextArea 没有被添加/显示。我明白了:

http://gyazo.com/19f571409541d3a5d8b53cf816e82b1a

来自这段代码:

public static void initGUI() {

    JFrame frame = new JFrame();
    frame.setTitle("Sudoku");
    frame.setLocation(500, 0);
    frame.setDefaultCloseOperation(EXIT_ON_CLOSE);

    //Initiate faces
    for( int j = 0; j < 9; j++) {
        for( int i = 0; i < 9; i++) {
            field[i][j] = new JTextArea();
            field[i][j].setFont(font);
            field[i][j].setBorder(BorderFactory.createLineBorder(Color.BLACK));
            field[i][j].setVisible(true);
            field[i][j].setBounds(i*100, j*100, 100, 100);
            field[i][j].setText(i+" "+j);
            frame.add(field[i][j]);
        }
    }
    frame.setSize(1000,1000);
    frame.setVisible(true);
}

有什么帮助吗？提前致谢

Answer 1

JFrame 的默认布局管理器是 BorderLayout。 BorderLayout 只允许单个组件占用它管理的任何可用空间。

相反，尝试将布局管理器更改为 GridLayout

例如 frame.setLayout(new GridLayout(9, 9)); 可能会有帮助

您不应该使用 setBounds，因为它对布局管理器控制下的组件没有影响。相反，您应该使用 JTextArea 的 cols 和 rows 构造函数来提供有关您希望如何调整文本区域大小的详细信息

使用 GridLayout 示例更新

每个 JTextArea 都将获得等量的可用空间，因此当您调整窗口大小时，字段的大小也会改变...

import java.awt.Color;
import java.awt.EventQueue;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import java.awt.GridLayout;
import javax.swing.BorderFactory;
import javax.swing.JFrame;
import static javax.swing.JFrame.EXIT_ON_CLOSE;
import javax.swing.JTextArea;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;

public class TestLayout101 {

    public static void main(String[] args) {
        new TestLayout101();
    }

    public TestLayout101() {
        EventQueue.invokeLater(new Runnable() {
            @Override
            public void run() {
                try {
                    UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
                } catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
                    ex.printStackTrace();
                }

                JFrame frame = new JFrame();
                frame.setTitle("Sudoku");
                frame.setLocation(500, 0);
                frame.setDefaultCloseOperation(EXIT_ON_CLOSE);
                frame.setLayout(new GridLayout(9, 9));

                JTextArea[][] field = new JTextArea[9][9];

                //Initiate faces
                for (int j = 0; j < 9; j++) {
                    for (int i = 0; i < 9; i++) {
                        field[i][j] = new JTextArea(1, 3);
                        field[i][j].setBorder(BorderFactory.createLineBorder(Color.BLACK));
                        field[i][j].setText(i + " " + j);
                        frame.add(field[i][j]);
                    }
                }
                frame.pack();
                frame.setVisible(true);
            }
        });
    }

}

更新了 GridBagLayout 示例

如果有足够的可用空间，这将为每个 JTextArea 提供其首选大小。

这意味着当您调整窗口大小时，字段的大小不会改变，除非没有足够的可用空间来满足首选或最小大小...

import java.awt.Color;
import java.awt.EventQueue;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import java.awt.GridLayout;
import javax.swing.BorderFactory;
import javax.swing.JFrame;
import static javax.swing.JFrame.EXIT_ON_CLOSE;
import javax.swing.JTextArea;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;

public class TestLayout101 {

    public static void main(String[] args) {
        new TestLayout101();
    }

    public TestLayout101() {
        EventQueue.invokeLater(new Runnable() {
            @Override
            public void run() {
                try {
                    UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
                } catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
                    ex.printStackTrace();
                }

                JFrame frame = new JFrame();
                frame.setTitle("Sudoku");
                frame.setLocation(500, 0);
                frame.setDefaultCloseOperation(EXIT_ON_CLOSE);
                frame.setLayout(new GridBagLayout());

                JTextArea[][] field = new JTextArea[9][9];

                //Initiate faces
                GridBagConstraints gbc = new GridBagConstraints();
                for (int j = 0; j < 9; j++) {
                    gbc.gridy = j;
                    for (int i = 0; i < 9; i++) {
                        gbc.gridx = i;
                        field[i][j] = new JTextArea(1, 3);
                        field[i][j].setBorder(BorderFactory.createLineBorder(Color.BLACK));
                        field[i][j].setText(i + " " + j);
                        frame.add(field[i][j], gbc);
                    }
                }
                frame.pack();
                frame.setVisible(true);
            }
        });
    }
}