JbuttonsをコンボボックスでJavaのswitch文の中で使う方法

Question

これは私の初めての投稿です。親切であり、何か提案を修正することを忘れないでください！

シェイプを描画するプログラムを作成しようとしています。一度に1つの選択、円、正方形、または三角形のみを表示するプログラムが必要です。 "Draw a .."オプションをクリックすると、対応するシェイプのみが高さまたは半径で側面に表示されます。形状は固定サイズですが、ラベルはユーザーの入力内容を反映する必要があります。

しかし、switch文を使用して切り替えます。私のスイッチはすべてを一度に表示しています！どうすれば修正できますか？ここで

は私のコードです：

import java.awt.event.ActionEvent; 
import java.awt.Graphics; 
import java.awt.Color; 
import javax.swing.JButton; 
import javax.swing.JLabel; 
import javax.swing.JPanel; 
import javax.swing.JTextField; 
import java.awt.event.ActionListener; 
import javax.swing.JComboBox; 

public class MainPanel extends JPanel implements ActionListener{ 


      JTextField num1; 
      JTextField num2; 
      JTextField num3; 
      JTextField num4; 
      JLabel equals; 
      JTextField answer; 
      JLabel labelTxt; 
      JComboBox shapeList; 
      JButton drawAThing; 
      JLabel radiusLabel; 
      JLabel base; 
      JLabel lengthLabel; 
      JLabel height; 
      JButton drawACircle; 
      JButton drawASquare; 
      JButton drawATriangle; 

    MainPanel(){ 

     String [] shapes = {"circle", "square", "triangle"}; 
     shapeList = new JComboBox(shapes); 
     shapeList.setSelectedIndex(2); 
     shapeList.addActionListener(this); 
     add(shapeList); 


    } 

      @Override 
    public void actionPerformed(ActionEvent e) { 
     Object o = e.getSource(); 
     Object a = e.getSource(); 

     if (o == shapeList){ 
      JComboBox cb = (JComboBox)e.getSource(); 
      String msg = (String)cb.getSelectedItem(); 


      switch(msg){ 
      case "circle": 
       radiusLabel = new JLabel(); 
       radiusLabel.setText("Radius: "); 
       add(radiusLabel); 

       num1 = new JTextField(12); 
       add(num1); 


       drawACircle = new JButton("Draw a circle "); 
       drawACircle.addActionListener(this); 
       add(drawACircle); 

       if (a == drawACircle){ 

        drawACircleThing(); 
        remove(drawACircle); 

        this.revalidate(); 
        this.repaint(); 
        } 



       break; 

      case "square": 
        lengthLabel = new JLabel(); 
        lengthLabel.setText("Side Length: "); 
        add(lengthLabel); 

        num2 = new JTextField(12); 
        add(num2); 


        drawASquare = new JButton("Draw a square "); 
        drawASquare.addActionListener(this); 
        add(drawASquare); 

        if (a == drawASquare){ 

        drawASquareThing(); 
        remove(drawASquare); 

        this.revalidate(); 
        this.repaint(); 
        } 

       break; 

      case "triangle": 
        base = new JLabel(); 
        base.setText("Base: "); 
        add(base); 

        num3 = new JTextField(12); 
        add(num3); 

        height = new JLabel(); 
        base.setText("height: "); 
        add(height); 

        num4 = new JTextField(12); 
        add(num4); 


        drawATriangle = new JButton("Draw a triangle "); 
        drawATriangle.addActionListener(this); 
        add(drawATriangle); 

        if (a == drawATriangle){ 

         drawATriangleThing(); 

        remove(drawATriangle); 

        this.revalidate(); 
        this.repaint(); 

        } 

        break; 


       default: 
        break; 

     } 
    } 
    } 

      @Override 
public void paintComponent(Graphics g) 
{ 
    g.setColor(Color.BLUE); 
    g.fillRect(50, 50, 200, 200); 
    g.fillOval(100,100,200,200); 

} 
private void drawASquareThing() 
{ 
    Graphics g = getGraphics(); 
    g.setColor(Color.green); 
    g.fillRect(150,100,330,200);  
    g.drawString("My square", 50, 10); 

} 
private void drawATriangleThing() 
{ 
    Graphics g = getGraphics(); 
    g.setColor(Color.yellow); 
    g.fillRect(150,100,330,200);  
     g.drawString("My Triangle", 50, 10); 

} 

public void drawACircleThing() 
{ 
    Graphics g = getGraphics(); 
    g.setColor(Color.ORANGE); 

    int [] xPoints = {50, 50, 100}; 
    int [] yPoints = {50, 100, 100}; 

    g.drawPolygon(xPoints, yPoints, 3); 
    g.fillPolygon(yPoints, xPoints, 3); 

} 


} 

私の新しいコード：

import java.awt.event.ActionEvent; 
import java.awt.Graphics; 
import java.awt.Color; 
import javax.swing.JButton; 
import javax.swing.JLabel; 
import javax.swing.JPanel; 
import javax.swing.JTextField; 
import java.awt.event.ActionListener; 
import javax.swing.JComboBox; 

public class MainPanel extends JPanel implements ActionListener{ 


      JTextField num1; 
      JTextField num2; 
      JTextField num3; 
      JTextField num4; 

      JTextField answer; 
      JLabel labelTxt; 
      JComboBox shapeList; 
      JButton drawAThing; 
      JLabel radiusLabel; 
      JLabel base; 
      JLabel lengthLabel; 
      JLabel height; 
      JButton drawACircle; 
      JButton drawASquare; 
      JButton drawATriangle; 

    MainPanel(){ 

     String [] shapes = {"circle", "square", "triangle"}; 
     shapeList = new JComboBox(shapes); 
     shapeList.setSelectedIndex(2); 
     shapeList.addActionListener(this); 
     add(shapeList); 

    setVisible(true); 


    } 

      @Override 
    public void actionPerformed(ActionEvent e) { 
     Object o = e.getSource(); 
     Object a = e.getSource(); 

     if (o == shapeList){ 
      JComboBox cb = (JComboBox)e.getSource(); 
      String message = (String)cb.getSelectedItem(); 


      switch(message){ 
      case "circle": 

       radiusLabel = new JLabel(); 
       radiusLabel.setText("Radius: "); 
       add(radiusLabel); 

       num1 = new JTextField(12); 
       add(num1); 
       int radiusSize = Integer.parseInt(num1.getText()); 
       this.revalidate(); 
       drawACircle = new JButton("Draw a circle "); 
       drawACircle.addActionListener(this); 
       add(drawACircle); 

       if (a == drawACircle){ 

        drawACircleThing(radiusSize); 

        } 

        this.repaint(); 

       break; 

      case "square": 

        lengthLabel = new JLabel(); 
        lengthLabel.setText("Side Length: "); 
        add(lengthLabel); 

        num2 = new JTextField(12); 
        add(num2); 
        int lengthSize = Integer.parseInt(num2.getText()); 
        this.revalidate(); 
        drawASquare = new JButton("Draw a square "); 
        drawASquare.addActionListener(this); 
        add(drawASquare); 


        if (a == drawASquare){ 

        drawASquareThing(lengthSize); 


        } 

        this.repaint(); 

       break; 

      case "triangle": 

        base = new JLabel(); 
        base.setText("Base: "); 
        add(base); 


        num3 = new JTextField(12); 
        add(num3); 
        int baseSize = Integer.parseInt(num3.getText()); 

        height = new JLabel(); 
        base.setText("height: "); 
        add(height); 

        num4 = new JTextField(12); 
        add(num4); 
        int heightSize = Integer.parseInt(num4.getText()); 
        this.revalidate(); 
        drawATriangle = new JButton("Draw a triangle "); 
        drawATriangle.addActionListener(this); 
        add(drawATriangle); 

        if (a == drawATriangle){ 

         drawATriangleThing(baseSize, heightSize); 

        } 

        this.repaint(); 

        break; 

       default: 
        break; 

     } 
    } 
} 

@Override 
public void paintComponent(Graphics g) //The last thing that is called and passed by java run time environment of Graphics g. It let’s us draw on the screen. 
{ 
g.setColor(Color.BLUE); // NEED an import. Don’t need to know all the colors. 
g.fillRect(50, 50, 200, 200); 
g.fillOval(100,100,200,200); 

} 
private void drawASquareThing(int lengthSize) 
{ 
    Graphics g = getGraphics(); 
     g.setColor(Color.PINK); 
     g.drawRect(lengthSize, 45, 25, 35); 
     g.drawString("My Square", 30, 23);   
} 
private void drawATriangleThing(int baseSize, int heightSize) 
{ 

    Graphics g = getGraphics(); 
    g.setColor(Color.GREEN); 
    g.fillRect(60,79,809,400); 
     g.drawRect(baseSize, baseSize, heightSize, heightSize); 
     g.drawString("My Triangle", baseSize, heightSize); 

} 

public void drawACircleThing(int radiusSize) 
{ 
    Graphics g = getGraphics(); 
    g.setColor(Color.ORANGE); 

    int [] xPoints = {50, 50, 100}; 
    int [] yPoints = {50, 100, 100}; 

    g.drawPolygon(xPoints, yPoints, radiusSize); 
    g.fillPolygon(yPoints, xPoints, 3); 

} 


} 

Answer 1

カスタムペイントを行う上で、よりスイングのチュートリアルを行う必要があります。しかし、基本的には、paintComponentメソッドですべてを行うべきであり、他のメソッドでは、paintComponentで使用される変数/パラメータを設定する必要があります。たとえば、（あなたのコードを使用して）それと

  @Override 
public void paintComponent(Graphics g) 
{ 
    g.setColor(Color.BLUE); 
    if (fillSquareFlag) g.fillRect(50, 50, 200, 200); 
    if (fillCircleFlag) g.fillOval(100,100,200,200); 

} 

、あなたが

public void actionPerformed(ActionEvent ae) { 
    fillSquareFlag = !fillSquareFlag; 
    repaint(); 
}