Question

我有这个应用程序，但是，当我调整窗口大小，内部元素JTextArea时，它不会随窗口调整大小。为什么呢？

import java.awt.*;
import java.awt.event.*;

import javax.swing.*;

public class ExampleGUI {

private JTextArea text_area;
private JScrollPane scroll_bar;

private JFrame frame;
private JPanel panel;

public ExampleGUI(){

    frame = new JFrame("Example GUI");
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

    text_area = new JTextArea();
    scroll_bar = new JScrollPane(text_area);

    panel = new JPanel();
    panel.add(scroll_bar);

    frame.add(panel);

    frame.pack();
    frame.setVisible(true);
}

public static void main(String[] args) {

    SwingUtilities.invokeLater(new Runnable(){public void run(){new ExampleGUI();}});
}
}

Answer 1

您需要将GridBagConstraint x和y权重（weightx和weighty - GridBagConstraint构造函数中的第5和第6个参数）设置为0.0以外的正值。你应该阅读关于GridBagLayout的教程，如果你打算使用它，因为它相当复杂。有些人已经成功地嵌套了更简单的布局或使用第三方布局，例如MigLayout。

Answer 2

您的框架布局是FlowLayout。这不会调整孩子的大小。来自the docs：

流布局允许每个组件采用其自然（首选）大小。

最好使用BorderLayout并将窗格放在CENTER中。

替换它：

frame.setLayout(new FlowLayout());
frame.add(pane);

用这个：

frame.setLayout(new BorderLayout());
frame.add(pane, BorderLayout.CENTER);

另外，正如Hovercraft指出的那样，如果你需要在窗格调整大小时调整单个组件的大小，那么你需要在GridBagConstraints中有非零权重。

Answer 3

这考虑到了Hovercraft Full Of Eels＆amp; amp; Ted Hopp还有其他一些调整。

import java.awt.*;
import java.awt.event.*;

import javax.swing.*;

import java.util.Collection;

public class AziendaGUI implements ActionListener {

private JButton view_list;
private JButton save_list;
private JTextArea text_area;
private JScrollPane scrollpane;
private JPanel pane;

private JFrame frame;
private GridBagLayout grid;

public AziendaGUI() {

    frame = new JFrame("Immobiliari s.p.a");
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

    frame.setLayout(new BorderLayout());

    view_list = new JButton("View Property");
    view_list.setActionCommand("view_list");
    view_list.addActionListener(this);

    save_list = new JButton("Save List");
    save_list.setActionCommand("save_list");
    save_list.addActionListener(this);

    text_area = new JTextArea(10,22);
    text_area.setEditable(false);
    scrollpane = new JScrollPane(text_area);

    grid = new GridBagLayout();
    pane = new JPanel();
    pane.setLayout(grid);

    /* Set Constraints view_list button */
    grid.setConstraints(view_list, new GridBagConstraints(0,0,1,1,0.0,0.0,GridBagConstraints.WEST,GridBagConstraints.NONE,new Insets(5,5,5,5),0,0));
    pane.add(view_list);

    /* Set Constraints save_list button */
    grid.setConstraints(save_list,new GridBagConstraints(1,0,1,1,0.1,0.1,GridBagConstraints.EAST,GridBagConstraints.NONE,new Insets(5,5,5,5),0,0));
    pane.add(save_list);

    frame.add(scrollpane);

    frame.add(pane, BorderLayout.NORTH);

    frame.pack();
    frame.setVisible(true);
}

private void store(){

    String file_name = JOptionPane.showInputDialog("Inserisci il nome del file");

}

@Override
public void actionPerformed(ActionEvent e){

    String s = e.getActionCommand();

    if(s.equals("view_list")){
    }
    if(s.equals("save_list")){

        store();
    }
}


public static void main(String[] args) {

    SwingUtilities.invokeLater(new Runnable(){@Override
                                              public void run(){new AziendaGUI();}});
}
}

该应用程序不会调整其组件的大小

3 个答案: