swing - Java-读取复选框是否被选中

Question

我的程序编译并运行，但这是我的问题。我为每个项目设置了一个复选框，但我只需要它来汇总已检查的项目而不是所有项目。相反，它汇总所有项目，无论它们是否被选中。

import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JCheckBox;
import javax.swing.JPanel;
import javax.swing.JTextField;
import java.awt.GridLayout;
import java.text.*;

public class StudentShopping extends JFrame
{
    public static void main(String[] args) {

        JFrame frame = new JFrame();

        frame.setSize(550, 400); //Sets size of the window
        frame.setTitle("Student Shopping");//Adds title to the GUI
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        JCheckBox ClothingCheckBox = new JCheckBox();
        JLabel Clothinglbl = new JLabel("Clothing");
        final JTextField ClothingField = new JTextField(3);
        ClothingField.setText("0");

        JCheckBox BooksCheckBox = new JCheckBox(); 
        JLabel Bookslbl = new JLabel("Books");
        final JTextField BooksField = new JTextField(3);
        BooksField.setText("0");

        JCheckBox SuppliesCheckBox = new JCheckBox();
        JLabel Supplieslbl = new JLabel("Supplies");
        final JTextField SuppliesField = new JTextField(3);
        SuppliesField.setText("0");

        JCheckBox MealPlanCheckBox = new JCheckBox();
        JLabel MealPlanlbl = new JLabel("MealPlan");
        final JTextField MealPlanField = new JTextField(3);
        MealPlanField.setText("0");

        JCheckBox InternetAccessCheckBox = new JCheckBox();
        JLabel InternetAccesslbl = new JLabel("InternetAccess");
        final JTextField InternetAccessField = new JTextField(3);
        InternetAccessField.setText("0");

        final JTextField TotalField = new JTextField(10);
        TotalField.setText("0");


        JLabel ButtonLabel = new JLabel("Press Button for Total");      
        JButton button  = new JButton("Calculate Total");


        JPanel panel = new JPanel();

        panel.setLayout(new GridLayout(6,3));
        panel.add(ClothingCheckBox);
        panel.add(Clothinglbl);
        panel.add(ClothingField);
        panel.add(BooksCheckBox);
        panel.add(Bookslbl);
        panel.add(BooksField);
        panel.add(SuppliesCheckBox);    
        panel.add(Supplieslbl);
        panel.add(SuppliesField);
        panel.add(MealPlanCheckBox);
        panel.add(MealPlanlbl);
        panel.add(MealPlanField);
        panel.add(InternetAccessCheckBox);
        panel.add(InternetAccesslbl);
        panel.add(InternetAccessField);
        panel.add(ButtonLabel);
        panel.add(button);
        panel.add(TotalField);
        frame.add(panel);

        class CalculateListener implements ActionListener {


            public void actionPerformed(ActionEvent event) {

            double Clothing = Double.parseDouble(ClothingField.getText());
            double Books = Double.parseDouble(BooksField.getText()) ;
            double Supplies = Double.parseDouble(SuppliesField.getText());
            double MealPlan = Double.parseDouble(MealPlanField.getText());
            double InternetAccess = Double.parseDouble(InternetAccessField.getText());
            double Total = (Clothing+Books+Supplies+MealPlan+InternetAccess)*100

        DecimalFormat df = new DecimalFormat("$#.00");//creates decimal in currency format
        TotalField.setText(df.format(Total)); //
            }
        }

        ActionListener listener = new CalculateListener();
        button.addActionListener(listener);                     

        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setVisible(true);


        }
 }

Answer 1

因为您从不检查复选框的选中状态。应该是这样的:

double total = 0;
if(ClothingCheckBox.isSelected() && !ClothingField.getText().isEmpty()) {
    total += Double.parseDouble(ClothingField.getText());
}
if(BooksCheckBox.isSelected() && !BooksField.getText().isEmpty()) {
    total += Double.parseDouble(BooksField.getText());
}
if(SuppliesCheckBox.isSelected() && !SuppliesField.getText().isEmpty()){
    total += Double.parseDouble(SuppliesField.getText());
}
if(MealPlanCheckBox.isSelected() && !MealPlanField.getText().isEmpty()){
    total += Double.parseDouble(MealPlanField.getText());
}
if(InternetAccessCheckBox.isSelected() && !InternetAccessField.getText().isEmpty()){            
     total += Double.parseDouble(InternetAccessField.getText());
}
total = total * 100;
DecimalFormat df = new DecimalFormat("$#.00");
TotalField.setText(df.format(total));

---

我想建议你的事情:

1. 学习 java coding convention并使用它们。
2. 您还应该在将文本字段中的空白值解析为 double 之前检查它们。请注意，这也不能确保文本字段中的值可解析为 Double。
3. 您似乎只想在 textField 中包含数值。对于不使用 JTextField，请使用 JFormattedTextField .