JPanelで長方形を描く

debugcn 投稿 Dev

サティッシュ：

JPanelに長方形を描きたい。以下のコードで描画できます。

public class DrawingColor extends JFrame
{
    public static void main(String[] args) 
    {
        DrawingColor d = new DrawingColor();
    }

    public DrawingColor()
    {
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        getContentPane().add(new MyComponent());
        setSize(400,400);
        setVisible(true);
    }

    public class MyComponent extends JComponent
    {
        @Override
        public void paint(Graphics g)
        {
            int height = 200;
            int width = 120;
            g.setColor(Color.red);
            g.drawRect(10, 10, height, width);
            g.setColor(Color.gray);
            g.fillRect(11, 11, height, width);
            g.setColor(Color.red);
            g.drawOval(250, 20, height, width);
            g.setColor(Color.magenta);
            g.fillOval(249, 19, height, width);
        }
    }
}

しかしgetContentPane（）。add（new MyComponent（））; このステートメントの代わりに、フレームにベースパネルを1つ追加する必要があります。ベースパネルにMyComponentパネルを追加します。

  JPanel basePanel = new JPanel();
  basePanel = new MyComponent();
  getContentPane().add(basePanel);

このようにすると、長方形が表示されなくなります。何か案が？また、実行時に長方形のサイズを変更する必要があります。出来ますか？

Shaik Md：

実行時にサイズを動的に変化させて正方形と円を描画しようとしました...それが役立つ場合は、完全なコードを添付してください。

import java.awt.Color;
import java.awt.Container;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
import java.awt.geom.Ellipse2D;
import java.awt.geom.Rectangle2D;
import javax.swing.*;
import java.*;
import java.awt.Canvas;
import javax.swing.event.ChangeEvent;
import javax.swing.event.ChangeListener;                    

class DisplayCanvas extends Canvas
{
    static boolean clip = false;
    static boolean clipfurther = false;
    static boolean  isReset = false, isSlider = false;
    int w, h;
    static int wi = 300, hi = 300;
    public DisplayCanvas()
    {
        //setSize(300, 300);
    setBounds(20, 40, 300, 300);
    setBackground(Color.white);
    }
    public void paint(Graphics g)
    {
        Graphics2D g2=(Graphics2D) g;
    w = getSize().width;
    h = getSize().height;

    if(clip)
    {
        // Ellipse2D e = new Ellipse2D.Float(w/4.0f,h/4.0f,w/2.0f,h/2.0f);
        Rectangle2D r = null;
        if(isSlider)
        {
            r = new Rectangle2D.Float((w)/(4.0f), (h)/(4.0f), wi/2.0f, hi/2.0f);
        //     isSlider=false;
        }
        else
        r = new Rectangle2D.Float(w/4.0f, h/4.0f, wi/2.0f, hi/2.0f);
            //g2.setClip(e);

        System.out.println("Width : "+ wi +" Height : "+ hi);
        g2.setClip(r);
        System.out.println(g2.getClipBounds());

        if(shape.selectedcolor == "red")
        {
            g2.setColor(Color.red);
        }
        else if(shape.selectedcolor == "blue")
        {
            g2.setColor(Color.BLUE);
        }
        else if(shape.selectedcolor == "yellow")
        {
            g2.setColor(Color.yellow);
        }

        //g2.setColor(Color.RED);
        g2.fillRect(0, 0, w, h);
        }
    else if(clipfurther)
    {
        //Rectangle r = new Rectangle(w/4, h/4, w/4, h/4);
        Ellipse2D r = new Ellipse2D.Float(w/4.0f, h/4.0f, wi/2.0f, hi/2.0f);
        g2.clip(r);
        //g2.setColor(Color.green);
        //g2.setColor(Color.getColor(shape.selectedcolor));

        if(shape.selectedcolor == "red")
        {
            g2.setColor(Color.red);
        }
        else if(shape.selectedcolor == "blue")
        {
        g2.setColor(Color.BLUE);
        }
        else if(shape.selectedcolor == "yellow")
        {
        g2.setColor(Color.yellow);
        }

        g2.fillRect(0, 0, w, h);
        }
    }   
}

class RadioListener implements ActionListener
{
    public void actionPerformed(ActionEvent e)
    {
        if(e.getSource() == shape.circle)
        {
        shape.selectedcolor = shape.selectedcolor_reset;
        System.out.println("Inside circle "+            shape.selectedcolor_reset);
        System.out.println("2222222222");
        DisplayCanvas.clip = true;
        DisplayCanvas.clipfurther = false;
        shape.canvas.repaint();
    }
    if (e.getSource() == shape.square)
    {
        shape.selectedcolor = shape.selectedcolor_reset;
        System.out.println("333333333333333");
        DisplayCanvas.clip = false;
        DisplayCanvas.clipfurther = true;
        shape.canvas.repaint();
    }                  
    }
}

class shape extends JFrame implements ActionListener
{
    static String fname;
    static JPanel panel, draw;
    static Container contentpane, draw_pane;
    static JFrame frame;
    static JLayeredPane layer, draw_layer;
    static JTextField user;
    static JButton reset, cancel;

    static JLabel file1, file2;
    static JTextField text1;
    static JRadioButton circle, square;
    static JInternalFrame iframe, errmessage;
    static JComboBox colors;
    static JEditorPane sqc;
    static JScrollPane scroller;
    static JSlider slider;
    String colors_array[]={"...", "red", "blue", "yellow"};
    static DisplayCanvas canvas;
    static String selectedcolor, selectedcolor_reset;

    shape()
    {
        canvas=new DisplayCanvas();

    panel= new JPanel();
    panel.setBounds(20,20,250,140);
    //panel.setLayout(new FlowLayout(10, 10, 10));
    panel.setLayout(null);
    contentpane = getContentPane();
    contentpane.add(canvas);
    //draw_pane=getContentPane();

    layer = new JLayeredPane();
    layer.setBounds(50,245,300,205);
    layer.setForeground(Color.blue);

    draw_layer = new JLayeredPane();
    draw_layer.setBounds(200, 200, 80, 30);
    draw_layer.setForeground(Color.BLACK);

    draw = new JPanel();
    draw.setBounds(20, 20, 250, 300);
    draw.setLayout(null);

    reset = new JButton("RESET");
    reset.setBounds(360, 60, 100, 25);

    circle = new JRadioButton("Square");
    circle.setBounds(400, 100, 100, 40);
    circle.setActionCommand("encryption");

    square = new JRadioButton("Circle");
    square.setBounds(330,100, 60, 40);
    square.setActionCommand("decryption");

    colors = new JComboBox(colors_array);
    colors.setBounds(405, 140, 80, 30);
    colors.setVisible(true);

    file1 = new JLabel(" Select Color :");
    file1.setBounds(320, 130, 150, 50);
    //defining the Button Group for the Radio Buttons

    ButtonGroup group = new ButtonGroup();
    group.add(circle);
    group.add(square);

    cancel = new JButton("Exit");
    cancel.setBounds(365, 250, 85, 25);

    file2 = new JLabel("SIZE :");
    file2.setBounds(336, 180, 150, 50);
    setslider(0, 100, 100, 25, 5);
    slider.setBounds(386, 190, 100, 50);

        slider.setVisible(true);

    panel.add(file2);
    panel.add(layer);
        panel.add(circle);
    panel.add(square);
    panel.add(colors);
    panel.add(slider);
    panel.add(file1);
    panel.add(reset);
    panel.add(cancel);
    //panel.add(new CircleDraw());

    //draw.add(draw_layer);
    // draw_pane.add(draw);
    contentpane.add(panel);
    //   contentpane.add(draw);
    //  contentpane.add(scroller);
    RadioListener radio = new RadioListener();
    circle.addActionListener(radio);
    square.addActionListener(radio);
    reset.addActionListener(this);
    cancel.addActionListener(this);

    colors.addActionListener(new ActionListener()
    {
        public void actionPerformed(ActionEvent ae)
        {                           
            JComboBox cb = (JComboBox)ae.getSource();
        selectedcolor = (String)cb.getSelectedItem();
        System.out.println(selectedcolor);
        selectedcolor_reset = selectedcolor;
        System.out.println("SELECTED "+ cb.getSelectedIndex());
        canvas.repaint();
        }
        });

    addWindowListener(new WindowAdapter()
    {
        public void windowClosing(WindowEvent e)
        {
            System.exit(0);
        }
    });
    }

    public void actionPerformed(ActionEvent e) 
    {
        if(e.getSource()== cancel)
    {
        System.exit(0);
    }
    if (e.getSource() == reset)
    {
        System.out.println("111111111");
        DisplayCanvas.clip = true;
        DisplayCanvas.clipfurther = false;
        DisplayCanvas.isReset = true;
        shape.selectedcolor = "...";
        System.out.println(" PREVIOUS " + selectedcolor_reset);
        DisplayCanvas.hi = DisplayCanvas.wi = 300;
        canvas.repaint();
    }
    }
    public class SliderListener implements ChangeListener 
    {
        public SliderListener() 
        {
    }
    public void stateChanged(ChangeEvent e) 
        {
        JSlider slider = (JSlider)e.getSource();
        System.out.println(slider.getValue());
        DisplayCanvas.wi = slider.getValue() * 3;
        DisplayCanvas.hi = DisplayCanvas.wi;
        DisplayCanvas.isSlider = true;
        canvas.repaint();
    }
    }
    public void setslider(int min,int max,int init,int mjrtk,int mintk)
    {
        slider = new JSlider(JSlider.HORIZONTAL, min, max, init);
    slider.setPaintTicks(true);
    slider.setMajorTickSpacing(mjrtk);
    slider.setMinorTickSpacing(mintk);
    slider.setPaintLabels(true);
    slider.addChangeListener((ChangeListener) new SliderListener());
    }
}

public class display 
{
    static JFrame frame;
    /**
      * @param args the command line arguments
      */
    public static void main(String[] args) 
    {
        // TODO code application logic here
    frame=new shape();

    frame.setBounds(380, 200, 500, 400);
    frame.setTitle("SHAPE AND COLOR");
    frame.setVisible(true);

    }
}

この記事はインターネットから収集されたものであり、転載の際にはソースを示してください。

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