Java Swing JTextfield 调整大小(高度)

Question

我在将程序中的 JTextfield 设置为适当大小时遇到​​了一些问题，我正在尝试使用文本“Price must be a real value”修改文本字段。这就是我希望它看起来像的样子:

这是我现在的样子:

我的代码如下:

package test1;

import java.awt.Container;
import java.awt.FlowLayout;
import javax.swing.*;

public class Test1{

    //Should components be final? Should they be defined outside of the class?
    private final JTextArea outputArea = new JTextArea();
    private final JTextField errorReportField = new JTextField();

    private final JPanel inputPanel = new JPanel();

    private final JLabel nameLabel = new JLabel("Item Name");
    private final JLabel numberLabel = new JLabel("Number of units (or Volume in L)");
    private final JLabel priceLabel = new JLabel("Price per unit (or L) in pence");

    private final JTextField nameField = new JTextField(10);
    private final JTextField numberField = new JTextField(10);
    private final JTextField priceField = new JTextField(10);

    private final JButton addVolumeButton = new JButton("Add by Volume");
    private final JButton addNumberButton = new JButton("Add by number of units");         

    public Test1() {
        JFrame frame = new JFrame("Fuel station shop");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        outputArea.setEditable(false);
        outputArea.setRows(30);
        JScrollPane scrollPanel = new JScrollPane(outputArea);
        scrollPanel.setVerticalScrollBarPolicy(ScrollPaneConstants.VERTICAL_SCROLLBAR_ALWAYS);
        errorReportField.setEditable(false);

        //Better way of adding multiple components to panel?
        inputPanel.setLayout(new FlowLayout());
        inputPanel.add(nameLabel);
        inputPanel.add(nameField);
        inputPanel.add(numberLabel);
        inputPanel.add(numberField);
        inputPanel.add(priceLabel);
        inputPanel.add(priceField);
        inputPanel.add(addVolumeButton);
        inputPanel.add(addNumberButton);

        Container contentPane = frame.getContentPane();
        //Why is it adding components from bottom to top?
        contentPane.setLayout(new BoxLayout(contentPane, BoxLayout.Y_AXIS));
        contentPane.add(scrollPanel);
        contentPane.add(errorReportField);
        contentPane.add(inputPanel);

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

    public static void main(String[] args) {
        Test1 test = new Test1();
    }

}

所以基本上我想增加文本字段的高度，同时保持文本居中，以及将背景更改为白色同时保持其不可编辑。

Answer 1

使用 BorderLayout 而不是 BoxLayout。

将文本区域放在 BorderLayout.CENTER 中，并使用 GridLayout(0, 1) 将文本字段和底部面板包裹在另一个面板中。将该面板添加到 BorderLayout.PAGE_END。文本字段将与底部面板的大小相同

放在一边

• Swing 应用程序应该在事件调度线程上运行/启动。参见 Initial Threads
• 有关布局管理器的一般信息，请参阅 Layout Components Withing a Container
• 也不确定为什么您的字段和文本不可编辑。

---

重构

import java.awt.BorderLayout;
import java.awt.Container;
import java.awt.FlowLayout;
import java.awt.GridLayout;
import javax.swing.*;

public class Test1{

    //Should components be final? Should they be defined outside of the class?
    private final JTextArea outputArea = new JTextArea();
    private final JTextField errorReportField = new JTextField();

    private final JPanel inputPanel = new JPanel();

    private final JLabel nameLabel = new JLabel("Item Name");
    private final JLabel numberLabel = new JLabel("Number of units (or Volume in L)");
    private final JLabel priceLabel = new JLabel("Price per unit (or L) in pence");

    private final JTextField nameField = new JTextField(10);
    private final JTextField numberField = new JTextField(10);
    private final JTextField priceField = new JTextField(10);

    private final JButton addVolumeButton = new JButton("Add by Volume");
    private final JButton addNumberButton = new JButton("Add by number of units");         

    public Test1() {
        JFrame frame = new JFrame("Fuel station shop");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        //outputArea.setEditable(false);
        outputArea.setRows(30);
        JScrollPane scrollPanel = new JScrollPane(outputArea);
        scrollPanel.setVerticalScrollBarPolicy(ScrollPaneConstants.VERTICAL_SCROLLBAR_ALWAYS);
        //errorReportField.setEditable(false);

        //Better way of adding multiple components to panel?
        inputPanel.setLayout(new FlowLayout());
        inputPanel.add(nameLabel);
        inputPanel.add(nameField);
        inputPanel.add(numberLabel);
        inputPanel.add(numberField);
        inputPanel.add(priceLabel);
        inputPanel.add(priceField);
        inputPanel.add(addVolumeButton);
        inputPanel.add(addNumberButton);

        Container contentPane = frame.getContentPane();
        //Why is it adding components from bottom to top?
        contentPane.setLayout(new BorderLayout());
        contentPane.add(scrollPanel);
        JPanel wrapper = new JPanel(new GridLayout(0, 1));
        wrapper.add(errorReportField);
        wrapper.add(inputPanel);
        contentPane.add(wrapper, BorderLayout.PAGE_END);

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

    public static void main(String[] args) {
        SwingUtilities.invokeLater(new Runnable(){
            public void run() {
                Test1 test = new Test1();
            }
        });  
    }
}

---

注意

如果您希望字段稍微大一点(在高度方面)，您可以向 inputPanel 添加一个空边框，从而使字段也扩展。但这意味着 inputPanel 也会更大一些(可能需要也可能不需要)。但无论哪种方式，对于 GridLayout，字段和 inputPanel 的大小都将相同。

inputPanel.setBorder(BorderFactory.createEmptyBorder(5, 5, 5, 5));

另一种选择是给 wrapper 面板一个 BorderLayout 并将字段添加到中心，给它一个 EmptyBorder 来扩展它的尺寸。

contentPane.setLayout(new BorderLayout());
contentPane.add(scrollPanel);
JPanel wrapper = new JPanel(new BorderLayout());
wrapper.add(errorReportField);
wrapper.add(inputPanel, BorderLayout.PAGE_END);

Border border = errorReportField.getBorder();
CompoundBorder compound = BorderFactory.createCompoundBorder(
        border,BorderFactory.createEmptyBorder(10, 10, 10, 10));
errorReportField.setBorder(compound);

contentPane.add(wrapper, BorderLayout.PAGE_END);

这将在字段左侧留出少量空白(这可能是理想的，也可能不是理想的)。如果您不想要它，只需更改空边框的值即可。

createEmptyBorder(top, left, bottom, right)