java Swing GUI 入门-简易货币计算器

java Swing GUI 入门-简易货币计算器

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• 视频教程地址: https://www.bilibili.com/video/BV1HK4y1L75a

设计布局

• 大部分和上一节: https://xuzhiwei.blog.csdn.net/article/details/111470880 的内容一致,新加入的内容有

1. JcomboBox下拉框
2. JTextField的不可编辑的属性
3. 可以通过调节一个控件的Vertical Align属性以调节一个元素的位置,特别是将其设置为top可以将这个控件调得较高,默认为center

• 大概就这样:

注意一定不要选中Custom Create

• 对于 ComboBox 控件,单击model属性
  

添加事件操作

添加下拉框事件

• 为了使下拉框变化时,JLabel中的值也能相应的变化,向下拉框添加动作监听器.
  

    public CurrencyConverter() {
        comboBox1.addActionListener(new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent e) {
                moneyTypeLabel.setText(" "+comboBox1.getSelectedItem());
            }
        });
    }//end CurrencyConverter()

• 添加main函数,右键添加
  

添加按钮事件

• 思路:点击这个按钮之后将前一个TextField中的值读取出来乘以其和JCombox中国家币种得汇率,得到的结果输出到第二个TextField中.

        convertButton.addActionListener(new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent e) {
                double[] rates = {0.1253, 15.7953, 0.1527};//Eurc,Yen,U.S.dollar
                double selectedRate = rates[comboBox1.getSelectedIndex()];
                double converted = Double.parseDouble(canadianField.getText()) * selectedRate;
                convertedField.setText(" " + converted + " in " + comboBox1.getSelectedItem());
            }
        });

程序演示

• 

完整代码

import javax.swing.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

public class CurrencyConverter {
    private JPanel mainPanel;
    private JPanel topPanel;
    private JPanel bottomPanel;
    private JTextField canadianField;
    private JComboBox comboBox1;
    private JButton convertButton;
    private JTextField convertedField;
    private JLabel moneyTypeLabel;

    public CurrencyConverter() {
        comboBox1.addActionListener(new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent e) {
                moneyTypeLabel.setText(" " + comboBox1.getSelectedItem());
            }
        });
        convertButton.addActionListener(new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent e) {
                double[] rates = {0.1253, 15.7953, 0.1527};//Eurc,Yen,U.S.dollar
                double selectedRate = rates[comboBox1.getSelectedIndex()];
                double converted = Double.parseDouble(canadianField.getText()) * selectedRate;
                convertedField.setText(" " + converted + " in " + comboBox1.getSelectedItem());
            }
        });
    }//end CurrencyConverter()

    public static void main(String[] args) {
        JFrame frame = new JFrame("Currency Converter");
        frame.setContentPane(new CurrencyConverter().mainPanel);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.pack();
        frame.setVisible(true);
    }
}//end class