试图将Jcombobox列表添加到Jtextfield区域

Question

我花了很多时间在网上挖掘，似乎找不到直接的答案或方法，可以在我的主面板中添加一个下拉列表，以包含各种文本字段，在这种情况下，我试图在面板，因此可以将颜色用作确定成本的变量。

我到目前为止最接近的是在新窗口中有一个组合盒弹出窗口，但后来无法检索选择。

package paintestimator;
import java.lang.String;
import java.awt.Button;
import java.awt.Choice;
import java.awt.Component;
import java.awt.Frame;
import java.awt.GridLayout;
import java.awt.Label;
import java.awt.PopupMenu;
import javax.swing.JComboBox;
import javax.swing.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JFrame;

 public class PaintEstimator extends JFrame
     {





private JTextField wallHeight = new JTextField(3);
private JTextField wallWidth = new JTextField(3);
private JTextField wallArea = new JTextField(3);
private JTextField gallonsNeeded = new JTextField(3);
private JTextField cansNeeded = new JTextField(3);
private JTextField paintTime = new JTextField(3);
private JTextField sColor = new JTextField(3);
private JTextField matCost = new JTextField(3);
private JTextField laborCost = new JTextField(3);

//Josh
public PaintEstimator()

{

    
    JButton CalcChangeBTN = new JButton("Calculate");
    JButton ClearBTN = new JButton("Clear");
    JButton ChoiceA = new JButton("Paint Color");
    //JComboBox vendorBTN = (new JComboBox());
    
    ChoiceA.addActionListener(new ChoiceAListener());
    CalcChangeBTN.addActionListener(new CalcChangeBTNListener());
    ClearBTN.addActionListener(new ClearBTNListener());
    
    wallHeight.setEditable(true);
    wallWidth.setEditable(true);
    wallArea.setEditable(false);
    gallonsNeeded.setEditable(false);
    paintTime.setEditable(false);
    cansNeeded.setEditable(false);
   sColor.setEditable(true); 
    matCost.setEditable(false);
    laborCost.setEditable(true);



    JPanel mainPanel = new JPanel();
    

    mainPanel.setLayout(new GridLayout(16, 3, 0, 0));

    // need cost of paint array to set equations for material cost
    // need combobox arrays for both color and cost
    // vendor selection combo box sets array field for cost/color
    
    

    mainPanel.add(new JLabel("Please enter wall height in feet"));

    mainPanel.add(wallHeight);

    mainPanel.add(new JLabel("please enter wall width in feet"));

    mainPanel.add(wallWidth);

    //box to show chosen color 
    //mainPanel.add(new JLabel("Color Chosen"));
   // mainPanel.add(sColor);

    mainPanel.add(new JLabel("wall area"));

    mainPanel.add(wallArea);

    mainPanel.add(new JLabel("Gallons Needed"));

    mainPanel.add(gallonsNeeded);

    mainPanel.add(new JLabel("Number of cans Needed"));
    mainPanel.add(cansNeeded);

    mainPanel.add(new JLabel("Time to paint in Hours"));

    mainPanel.add(paintTime);

    mainPanel.add(new JLabel("Cost of Labor"));
    mainPanel.add(laborCost);

    mainPanel.add(new JLabel("Total Cost of Material"));
    mainPanel.add(matCost);

    mainPanel.add( new JLabel("Select a Color"));
    mainPanel.add (ChoiceA);
   // mainPanel.add(sColor);
    
    
   // Select<String> select = new Select<>();
//select.setLabel("Sort by");
//select.setItems("Most recent first", "Rating: high to low",
 // "Rating: low to high", "Price: high to low", "Price: low to high");
//select.setValue("Most recent first");
   // mainPanel.add(select);
    
    mainPanel.add(CalcChangeBTN);

    mainPanel.add(ClearBTN);
    
   // mainPanel.add(ChoiceA);
    
    setContentPane(mainPanel);

    pack();

    setTitle("Paint Estimator Tool");

    setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

    setLocationRelativeTo(null);
}




//Josh
class CalcChangeBTNListener implements ActionListener
{

    public void actionPerformed(ActionEvent e)
    {
        try
        {

            final double paintCvrGal = 320.0;

            final double gallonsPerCan = 1.0;

            double h = Integer.parseInt(wallHeight.getText());

            double w = Integer.parseInt(wallWidth.getText());

            double a = h * w;

            double c = ((a / paintCvrGal) * gallonsPerCan);

            double n = (c / gallonsPerCan);

            double p = (int) ((a * 0.76) / 60);

            double l = Integer.parseInt(laborCost.getText());

            double labCost = l * p;

            // double mc = c * CostofPaint
            wallArea.setText(String.valueOf(a));
            String wallArea = String.valueOf(a);

            gallonsNeeded.setText(String.valueOf(c));
            String gallonsNeeded = Double.toString(c);

            cansNeeded.setText(String.valueOf(n));
            String cansNeeded = Double.toString(n); // still need refine decimal point to #.0 
 (one decimal place)

            paintTime.setText(String.valueOf(p));
            String paintTime = String.valueOf(p);

            laborCost.setText(String.valueOf(labCost));
            String laborCost = Double.toString(labCost);
            
            
            


        } catch (NumberFormatException f)
        {
            wallHeight.requestFocus();
            wallHeight.selectAll();
        }
    }

}

class ClearBTNListener implements ActionListener
{

    public void actionPerformed(ActionEvent e)
    {

// clear text fields and set focus
        cansNeeded.setText("");
        gallonsNeeded.setText("");
        wallArea.setText("");
        wallHeight.setText("");
        wallWidth.setText("");
        paintTime.setText("");
        sColor.setText("");
        laborCost.setText("");
        //set focus
        wallHeight.requestFocus();
    }
}

class ChoiceAListener implements ActionListener
{
public void actionPreformed (ActionEvent e)
{ 
    
   

}
public static void main(String[] args)
{
   


    
    PaintEstimator window = new PaintEstimator();
    window.setVisible(true);
    

}

}

以下是我能够创建的组合框：

public static void main(String[] args)
{
    String[] optionsToChoose =
    {
        "White", "Cream", "Sage", "Light Blue", "Eggshell White"
    };

    JFrame jFrame = new JFrame();

    JComboBox<String> jComboBox = new JComboBox<>(optionsToChoose);
    jComboBox.setBounds(80, 50, 140, 20);

    JButton jButton = new JButton("Done");
    jButton.setBounds(100, 100, 90, 20);

    JLabel jLabel = new JLabel();
    jLabel.setBounds(90, 100, 400, 100);

    jFrame.add(jButton);
    jFrame.add(jComboBox);
    jFrame.add(jLabel);

    jFrame.setLayout(null);
    jFrame.setSize(350, 250);
    jFrame.setVisible(true);

    jButton.addActionListener((ActionEvent e) ->
    {
        String selectedColor = "You selected " + 
jComboBox.getItemAt(jComboBox.getSelectedIndex());
        jLabel.setText(selectedColor);
    });

}

Answer 1

首先阅读如何使用组合盒 请浏览一些示例不会受到伤害

从创建ComboBox的实例字段开始，

public class PaintEstimator extends JFrame {
    //...
    private JComboBox<String> colorChoice = new JComboBox<>();
    //...

...接下来，创建一个comboboxModel以保持要呈现的值并替换choicea带有ComboBox ...

mainPanel.add(new JLabel("Select a Color"));
//mainPanel.add(ChoiceA);
// mainPanel.add(sColor);

String[] optionsToChoose = {
            "White", "Cream", "Sage", "Light Blue", "Eggshell White"
        };
DefaultComboBoxModel<String> model = new DefaultComboBoxModel<>(optionsToChoose);
colorChoice.setModel(model);
mainPanel.add(colorChoice);

然后在您的ActionListener的按钮，获取所选值...

public void actionPerformed(ActionEvent e) {
    try {

        String choosenColor = (String) colorChoice.getSelectedItem();
        System.out.println("choosenColor = " + choosenColor);

可运行的示例...

import java.awt.EventQueue;
import java.awt.GridLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.DefaultComboBoxModel;
import javax.swing.JButton;
import javax.swing.JComboBox;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JTextField;

public class Main {

    public static void main(String[] args) {
        new Main();
    }

    public Main() {
        EventQueue.invokeLater(new Runnable() {
            @Override
            public void run() {
                JFrame frame = new PaintEstimator();
                frame.pack();
                frame.setLocationRelativeTo(null);
                frame.setVisible(true);
            }
        });
    }

    public class PaintEstimator extends JFrame {

        private JTextField wallHeight = new JTextField(3);
        private JTextField wallWidth = new JTextField(3);
        private JTextField wallArea = new JTextField(3);
        private JTextField gallonsNeeded = new JTextField(3);
        private JTextField cansNeeded = new JTextField(3);
        private JTextField paintTime = new JTextField(3);
        private JTextField sColor = new JTextField(3);
        private JTextField matCost = new JTextField(3);
        private JTextField laborCost = new JTextField(3);

        private JComboBox<String> colorChoice = new JComboBox<>();

        public PaintEstimator() {

            JButton CalcChangeBTN = new JButton("Calculate");
            JButton ClearBTN = new JButton("Clear");

            //ChoiceA.addActionListener(new ChoiceAListener());
            CalcChangeBTN.addActionListener(new CalcChangeBTNListener());
            ClearBTN.addActionListener(new ClearBTNListener());

            wallHeight.setEditable(true);
            wallWidth.setEditable(true);
            wallArea.setEditable(false);
            gallonsNeeded.setEditable(false);
            paintTime.setEditable(false);
            cansNeeded.setEditable(false);
            sColor.setEditable(true);
            matCost.setEditable(false);
            laborCost.setEditable(true);

            JPanel mainPanel = new JPanel();

            mainPanel.setLayout(new GridLayout(16, 3, 0, 0));

            // need cost of paint array to set equations for material cost
            // need combobox arrays for both color and cost
            // vendor selection combo box sets array field for cost/color
            mainPanel.add(new JLabel("Please enter wall height in feet"));

            mainPanel.add(wallHeight);

            mainPanel.add(new JLabel("please enter wall width in feet"));

            mainPanel.add(wallWidth);

            mainPanel.add(new JLabel("wall area"));

            mainPanel.add(wallArea);

            mainPanel.add(new JLabel("Gallons Needed"));

            mainPanel.add(gallonsNeeded);

            mainPanel.add(new JLabel("Number of cans Needed"));
            mainPanel.add(cansNeeded);

            mainPanel.add(new JLabel("Time to paint in Hours"));

            mainPanel.add(paintTime);

            mainPanel.add(new JLabel("Cost of Labor"));
            mainPanel.add(laborCost);

            mainPanel.add(new JLabel("Total Cost of Material"));
            mainPanel.add(matCost);

            mainPanel.add(new JLabel("Select a Color"));

            String[] optionsToChoose = {
                "White", "Cream", "Sage", "Light Blue", "Eggshell White"
            };
            DefaultComboBoxModel<String> model = new DefaultComboBoxModel<>(optionsToChoose);
            colorChoice.setModel(model);
            mainPanel.add(colorChoice);
            mainPanel.add(CalcChangeBTN);

            mainPanel.add(ClearBTN);

            setContentPane(mainPanel);

            pack();

            setTitle("Paint Estimator Tool");

            setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

            setLocationRelativeTo(null);
        }

        class CalcChangeBTNListener implements ActionListener {

            public void actionPerformed(ActionEvent e) {
                try {

                    String choosenColor = (String) colorChoice.getSelectedItem();
                    System.out.println("choosenColor = " + choosenColor);

                    final double paintCvrGal = 320.0;
                    final double gallonsPerCan = 1.0;
                    double h = Integer.parseInt(wallHeight.getText());
                    double w = Integer.parseInt(wallWidth.getText());
                    double a = h * w;
                    double c = ((a / paintCvrGal) * gallonsPerCan);
                    double n = (c / gallonsPerCan);
                    double p = (int) ((a * 0.76) / 60);
                    double l = Integer.parseInt(laborCost.getText());
                    double labCost = l * p;

                    // double mc = c * CostofPaint
                    wallArea.setText(String.valueOf(a));
                    String wallArea = String.valueOf(a);

                    gallonsNeeded.setText(String.valueOf(c));
                    String gallonsNeeded = Double.toString(c);

                    cansNeeded.setText(String.valueOf(n));
                    String cansNeeded = Double.toString(n);

                    paintTime.setText(String.valueOf(p));
                    String paintTime = String.valueOf(p);

                    laborCost.setText(String.valueOf(labCost));
                    String laborCost = Double.toString(labCost);

                } catch (NumberFormatException f) {
                    wallHeight.requestFocus();
                    wallHeight.selectAll();
                }
            }

        }

        class ClearBTNListener implements ActionListener {

            public void actionPerformed(ActionEvent e) {
                cansNeeded.setText("");
                gallonsNeeded.setText("");
                wallArea.setText("");
                wallHeight.setText("");
                wallWidth.setText("");
                paintTime.setText("");
                sColor.setText("");
                laborCost.setText("");
                //set focus
                wallHeight.requestFocus();
            }
        }
    }
}