如何在JPanel上布局这些组件？

Question

我制作了一个小型的GUI应用程序，该应用程序现在仅具有表示层。 它构造了基本的GUI（但尚未添加逻辑）。 我在布局控件/组件（例如文本字段和按钮）时遇到麻烦。

这是代码：

Main.java

public class Main {

    public static void main(String[] args) {
    // Make a new Client (TempConverter application)
    Client client = new Client();
    }

}

Client.java

import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JTextField;

public class Client extends JFrame{

    private JPanel panel;
    private JTextField inputTextBox;
    private JTextField outputTextBox;
    private JButton convertButton;

    public Client(){
        panel = new JPanel();
        inputTextBox = new JTextField(6);
        outputTextBox = new JTextField(6);
        convertButton = new JButton("Convert!");
        ConstructGUI();
    }

    private void ConstructGUI(){
        this.setTitle("Temerature Converter");
        this.setSize(300, 400);
        PanelLayout();
        this.setVisible(true);
        this.setDefaultCloseOperation(EXIT_ON_CLOSE);
    }

    private void PanelLayout(){
        this.add(panel);
        panel.add(inputTextBox);
        panel.add(outputTextBox);
        panel.add(convertButton);
    }

}

组件都彼此相邻出现，这不是我期望的那样，但是无论我尝试哪种布局（除非我做错了），它都不会改变。

我是否必须重写某些内容？

Answer 1

您可以使用BoxLayout将它们堆叠在一起。

private void PanelLayout(){
    this.add(panel);

    //next three lines aligning the components horizontally
    inputTextBox.setAlignmentX(Component.CENTER_ALIGNMENT);
    outputTextBox.setAlignmentX(Component.CENTER_ALIGNMENT);
    convertButton.setAlignmentX(Component.CENTER_ALIGNMENT);
    //aligning horizontally end. If you don't want the align them horizontally just remove these three lines.

    panel.setLayout(new BoxLayout(panel, BoxLayout.Y_AXIS));
    panel.add(Box.createVerticalGlue());//remove this line if you don't want to center them vertically
    panel.add(inputTextBox);
    panel.add(outputTextBox);
    panel.add(convertButton);
    panel.add(Box.createVerticalGlue());//remove this line if you don't want to center them vertically
}

Answer 2

您可以根据需要实现的方式使用GridBagLayout或GridLayout 。

public class Client extends JFrame {

    private JPanel panel;
    private JTextField inputTextBox;
    private JTextField outputTextBox;
    private JButton convertButton;

    public Client() {
        panel = new JPanel(new GridBagLayout());
        inputTextBox = new JTextField(6);
        outputTextBox = new JTextField(6);
        convertButton = new JButton("Convert!");
        ConstructGUI();
    }

    private void ConstructGUI() {
        this.setTitle("Temerature Converter");
        PanelLayout();
    }

    private void PanelLayout() {
        GridBagConstraints gbc = new GridBagConstraints();
        gbc.gridwidth = GridBagConstraints.REMAINDER;
        this.add(panel);
        panel.add(inputTextBox, gbc);
        panel.add(outputTextBox, gbc);
        panel.add(convertButton, gbc);
    }

}

有关更多详细信息，请参见在容器中布置组件 。

我也劝阻您不要直接从JFrame进行扩展，而是从JPanel进行扩展，这将使您的代码脱钩并提供更好的可重用性。