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このページのコンテンツ一覧（５個位までにしてください。上が最新で下が最古です）

宿題スレPart60 >>4-5への回答　図形描画 †

JDK6.0で作成。

   // FigureCanvasDemo.java
   import java.awt.Dimension;
   
   import javax.swing.JFrame;
   
   public class FigureCanvasDemo {
       public static void main(String[] args) {
           JFrame frame = new JFrame("FigureCanvas");
           FigureCanvas canvas = new FigureCanvas();
           canvas.setPreferredSize( new Dimension(300, 300) );
           frame.getContentPane().add(canvas);
           frame.pack();
           frame.setLocationByPlatform(true);
           frame.setVisible(true);
       
           JFrame frame2 = new JFrame("FigureCanvas2");
           FigureCanvas2 canvas2 = new FigureCanvas2();
           canvas2.setPreferredSize( new Dimension(300, 300) );
           frame2.getContentPane().add(canvas2);
           frame2.pack();
           frame2.setLocationByPlatform(true);
           frame2.setVisible(true);
       }
   }

   // FigureCanvas.java
   import java.awt.Graphics;
   import java.awt.event.MouseEvent;
   import java.awt.event.MouseListener;
   import java.awt.event.MouseMotionListener;
   
   import javax.swing.JComponent;
   
   public class FigureCanvas extends JComponent implements MouseListener, MouseMotionListener {
       protected int shapeLeftUpX, shapeLeftUpY;
       protected int mouseDownX, mouseDownY;
       protected int shapeWidth, shapeHeight;
       
       public static int STATE_MOUSE_RELEASED= 0;
       public static int STATE_MOUSE_PRESSED = 1;
       public static int STATE_MOUSE_DRAGGED = 2;
       protected int state = STATE_MOUSE_RELEASED;
       
       public FigureCanvas() {
           addMouseListener(this);
           addMouseMotionListener(this);
       }
       
       public void paintComponent(Graphics g) {
           g.drawRect(shapeLeftUpX, shapeLeftUpY, shapeWidth, shapeHeight);
           if( state == STATE_MOUSE_DRAGGED ) {
               g.drawOval(shapeLeftUpX, shapeLeftUpY, shapeWidth, shapeHeight);
           } else if( state == STATE_MOUSE_RELEASED ) {
               g.fillOval(shapeLeftUpX, shapeLeftUpY, shapeWidth, shapeHeight);
           }
       }
       
       public void mouseClicked(MouseEvent e) {}
       public void mouseEntered(MouseEvent e) {}
       public void mouseExited(MouseEvent e) {}
   
       public void mousePressed(MouseEvent e) {
           shapeLeftUpX = e.getX();
           shapeLeftUpY = e.getY();
           mouseDownX = e.getX();
           mouseDownY = e.getY();
           state = STATE_MOUSE_PRESSED;
       }
   
       public void mouseReleased(MouseEvent e) {
           if( state == STATE_MOUSE_DRAGGED ) {
               state = STATE_MOUSE_RELEASED;
               repaint();
           }
       }
   
       public void mouseDragged(MouseEvent e) {
           shapeWidth = e.getX() - shapeLeftUpX;
           shapeHeight = e.getY() - shapeLeftUpY;
           state = STATE_MOUSE_DRAGGED;
           repaint();
       }
   
       public void mouseMoved(MouseEvent e) {}
   
   }

   // FigureCanvas2.java
   import java.awt.event.MouseEvent;
   
   public class FigureCanvas2 extends FigureCanvas {
       public void mouseDragged(MouseEvent e) {
           shapeWidth = Math.abs(e.getX() - mouseDownX);
           shapeHeight = Math.abs(e.getY() - mouseDownY);
           shapeLeftUpX = (e.getX() < mouseDownX) ? e.getX() : mouseDownX;
           shapeLeftUpY = (e.getY() < mouseDownY) ? e.getY() : mouseDownY;
           state = STATE_MOUSE_DRAGGED;
           repaint();
       }
   }

Stateパターンを適用してみた.

  // FigureCanvasDemo.java
  import java.awt.Dimension;
  
  import javax.swing.JFrame;
  
  public class FigureCanvasDemo {
      public static void main(String[] args) {
          JFrame frame = new JFrame("FigureCanvas");
          FigureCanvas canvas = new FigureCanvas();
          canvas.setPreferredSize( new Dimension(300, 300) );
          frame.getContentPane().add(canvas);
          frame.pack();
          frame.setLocationByPlatform(true);
          frame.setVisible(true);
      
          JFrame frame2 = new JFrame("FigureCanvas2");
          FigureCanvas2 canvas2 = new FigureCanvas2();
          canvas2.setPreferredSize( new Dimension(300, 300) );
          frame2.getContentPane().add(canvas2);
          frame2.pack();
          frame2.setLocationByPlatform(true);
          frame2.setVisible(true);
      }
  }

  // FigureCanvas.java
  import java.awt.Graphics;
  import java.awt.event.MouseEvent;
  import java.awt.event.MouseListener;
  import java.awt.event.MouseMotionListener;
  
  import javax.swing.JComponent;
  
  public class FigureCanvas extends JComponent implements MouseListener, MouseMotionListener {
      protected int shapeLeftUpX, shapeLeftUpY;
      protected int mouseDownX, mouseDownY;
      protected int shapeWidth, shapeHeight;
      
      protected MouseState currentState;
      
      public static final MouseState RELEASED = new MouseReleased();
      public static final MouseState PRESSED  = new MousePressed();
      public static final MouseState DRAGGED  = new MouseDragged();
      
             
      public FigureCanvas() {
          addMouseListener(this);
          addMouseMotionListener(this);
          currentState = FigureCanvas.RELEASED;
      }
      
      public void paintComponent(Graphics g) {
          // draw a rectangle
          g.drawRect(shapeLeftUpX, shapeLeftUpY, shapeWidth, shapeHeight);
          // draw an oval
          currentState.drawOval(g, this);
      }
      
      public void mouseClicked(MouseEvent e) {}
      public void mouseEntered(MouseEvent e) {}
      public void mouseExited(MouseEvent e) {}
  
      public void mousePressed(MouseEvent e) {
          shapeLeftUpX = e.getX();
          shapeLeftUpY = e.getY();
          mouseDownX = e.getX();
          mouseDownY = e.getY();
          currentState = PRESSED;
      }
  
      public void mouseReleased(MouseEvent e) {
          if( currentState == DRAGGED ) {
              currentState = RELEASED;
              repaint();
          }
      }
  
      public void mouseDragged(MouseEvent e) {
          shapeWidth = e.getX() - shapeLeftUpX;
          shapeHeight = e.getY() - shapeLeftUpY;
          currentState = DRAGGED;
          repaint();
      }
  
      public void mouseMoved(MouseEvent e) {}
  
  }

  // FigureCanvas2.java
  import java.awt.event.MouseEvent;
  
  public class FigureCanvas2 extends FigureCanvas {
      public void mouseDragged(MouseEvent e) {
          shapeWidth = Math.abs(e.getX() - mouseDownX);
          shapeHeight = Math.abs(e.getY() - mouseDownY);
          shapeLeftUpX = (e.getX() < mouseDownX) ? e.getX() : mouseDownX;
          shapeLeftUpY = (e.getY() < mouseDownY) ? e.getY() : mouseDownY;
          currentState = DRAGGED;
          repaint();
      }
  }

   // MouseState.java
   import java.awt.Graphics;
   
   public interface MouseState {
       void drawOval(Graphics g, FigureCanvas canvas);
   }

   // MouseReleased.java
   import java.awt.Graphics;
   
   public class MouseReleased implements MouseState {
       public void drawOval(Graphics g, FigureCanvas c) {
           g.fillOval(c.shapeLeftUpX, c.shapeLeftUpY, c.shapeWidth, c.shapeHeight);
       }
   }

   // MousePressed.java
   import java.awt.Graphics;
   
   public class MousePressed implements MouseState {
       public void drawOval(Graphics g, FigureCanvas c) {
           // do nothing.
       }
   }

   // MouseDragged.java
   import java.awt.Graphics;
   
   public class MouseDragged implements MouseState {
       public void drawOval(Graphics g, FigureCanvas c) {
           g.drawOval(c.shapeLeftUpX, c.shapeLeftUpY, c.shapeWidth, c.shapeHeight);
       }
   }

宿題スレPart59 >>653への回答　素数カウント †

JDK6.0で作成。

	// PrimeDemo.java
	public class PrimeDemo {
		public static void main(String[] args) {
			PrimeFrame frame = new PrimeFrame("Primes");
			frame.setSize(300, 200);
			frame.setDefaultCloseOperation(PrimeFrame.EXIT_ON_CLOSE);
			frame.setVisible(true);
		}
	}

	// PrimeFrame.java
	import java.awt.BorderLayout;
	import java.awt.FlowLayout;
	import java.awt.GridLayout;
	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.JOptionPane;
	import javax.swing.JPanel;
	import javax.swing.JTextField;
	
	public class PrimeFrame extends JFrame implements ActionListener {
	
		JTextField inputField;
		JButton executeButton, clearButton;
		JLabel resultLabel1, resultLabel2;
	
		public PrimeFrame(String s) {
			super(s);
			inputField = new JTextField("input an integer");
			inputField.selectAll();
			executeButton = new JButton("execute");
			executeButton.addActionListener(this);
			clearButton = new JButton("clear");
			clearButton.addActionListener(this);
			resultLabel1 = new JLabel();
			resultLabel2 = new JLabel();
			JPanel p1 = new JPanel( new BorderLayout() );
			JPanel p2 = new JPanel( new FlowLayout() );
			JPanel p3 = new JPanel( new GridLayout(3, 1) );
			p1.add( inputField, BorderLayout.CENTER );
			p2.add( executeButton );
			p2.add( clearButton );
			p1.add( p2, BorderLayout.EAST );
			p3.add( p1 );
			p3.add( resultLabel1 );
			p3.add( resultLabel2 );
			getContentPane().add(p3);
		}
	
		public void actionPerformed(ActionEvent e) {
			if( e.getSource() == executeButton ) {
				String errorMessage = null;
				int number = 0;
				try {
					number = Integer.parseInt(inputField.getText());
					if( number < 2 || number > 1000 ) errorMessage = "You must input an integer from 2 to 1000.";
				} catch( NumberFormatException nfe ) {
					errorMessage = "You must input an integer from 2 to 1000.";
				}
				if( errorMessage != null ) {
					JOptionPane.showMessageDialog(this, errorMessage, null, JOptionPane.ERROR_MESSAGE);
				} else {
					int count = 0, sum = 0;
	
					for( int i=2; i<=number; i++ ) {
						// judge whether the number i is prime
						boolean isPrime = true;
						for( int j=2; j<(Math.sqrt(i)+1); j++ ) {
							if( i == 2 ) {
								isPrime = true;
								break;
							}
							if( i%j == 0 ) {
								isPrime = false;
								break;
							}
						}
						if( isPrime ) {
							count++;
							sum += i;
						}
					}
					resultLabel1.setText("the numbers of primes from 1 to " + number + " is: " + count);
					resultLabel2.setText("the sum is: " + sum );
				}
			} else if( e.getSource() == clearButton ) {
				inputField.setText("");
				resultLabel1.setText("");
				resultLabel2.setText("");
			}
		}
	}

宿題スレPart59 >>627への回答　3択クイズ †

JDK6.0で作成。

	// QuizDemo.java
	public class QuizDemo {
		public static void main(String[] args) {
			QuizFrame frame = new QuizFrame("三択クイズ");
			frame.setSize(500, 300);
			frame.setVisible(true);
			frame.startQuestion();
		}
	}

	// QuizFrame.java
	import java.awt.BorderLayout;
	import java.awt.Button;
	import java.awt.Frame;
	import java.awt.GridLayout;
	import java.awt.Label;
	import java.awt.Panel;
	import java.awt.event.ActionEvent;
	import java.awt.event.ActionListener;
	import java.util.ArrayList;
	import java.util.Collections;
	
	public class QuizFrame extends Frame implements ActionListener, Runnable {
	
		ArrayList<Question> questions;
		Question nowQuestion;
		Label countLabel, timeLabel, questionLabel, statusLabel;
		Button[] buttons;
		Button result;
		Thread currentThread;
		int count, correct;
		long erapsed;
		String message = "";
	
		public QuizFrame(String s) {
			super(s);
			createQuestions();
			createComponents();
		}
	
		private void createQuestions() {
			questions = new ArrayList<Question>();
			questions.add( new Question( "日本の首都は?", "東京", new String[]{ "東京", "大阪", "名古屋", } ) );
			questions.add( new Question( "インドの首都は?", "ニューデリー", new String[]{ "ニューデリー", "カルカッタ", "ムンバイ", } ) );
			questions.add( new Question( "英雄ポロネーズの作者は?", "ショパン", new String[]{ "ショパン", "リスト", "ベートーベン", } ) );
			questions.add( new Question( "2007年箱根駅伝の総合優勝大学は?", "順大", new String[]{ "順大", "日大", "山学", } ) );
			questions.add( new Question( "2006年オールザッツ漫才優勝コンビは?", "とろサーモン", new String[]{ "とろサーモン", "ジャルジャル", "ギャロップ", } ) );
			Collections.shuffle(questions);
		}
	
		private void createComponents() {
			Panel p1 = new Panel(new GridLayout(1, 2));
			Panel p2 = new Panel(new GridLayout(3, 1));
			Panel p3 = new Panel(new GridLayout(1, 3));
			countLabel = new Label();
			timeLabel = new Label();
			p1.add( countLabel );
			p1.add( timeLabel );
			questionLabel = new Label();
			buttons = new Button[3];
			for( int i=0; i<buttons.length; i++ ) {
				buttons[i] = new Button();
				buttons[i].addActionListener(this);
				p3.add( buttons[i] );
			}
			statusLabel = new Label();
			result = new Button("結果");
			result.setEnabled(false);
			p2.add( p3 );
			p2.add( statusLabel );
			p2.add( result );
			this.setLayout( new BorderLayout() );
			add( p1, BorderLayout.NORTH );
			add( questionLabel, BorderLayout.CENTER );
			add( p2, BorderLayout.SOUTH );
		}
	
		long start;
	
		public void startQuestion() {
			for( count=0; count<questions.size(); count++ ) {
				currentThread = new Thread(this);
				currentThread.start();
				start = System.currentTimeMillis();
				synchronized (this) {
					try {
						wait(2000);
					} catch (InterruptedException e) {
	
						e.printStackTrace();
					}
				}
			}
			for( int i=0; i<buttons.length; i++ ) {
				buttons[i].removeActionListener(this);
			}
			result.setEnabled(true);
			result.addActionListener( new ActionListener() {
				public void actionPerformed(ActionEvent ae) {
					statusLabel.setText( correct + "問正解 正答率" + (correct*100)/questions.size() + "% 正解した問題の平均所要時間: " + (erapsed*1.0/correct) + "msecs." );
				}
			} );
		}
	
		public void run() {
	
			if(message == null)statusLabel.setText("時間切れ");
			message = null;
			nowQuestion = questions.get(count);
			countLabel.setText("第" + (count+1) + "問");
			questionLabel.setText( nowQuestion.getQuestionBody() );
			for( int j=0; j<nowQuestion.getChoices().length; j++ ) {
				buttons[j].setLabel(nowQuestion.getChoices()[j]);
			}
		}
	
		public void actionPerformed(ActionEvent e) {
			long end = System.currentTimeMillis();
			synchronized(this) {
				notify();
			}
			// correct
			if( ((Button)e.getSource()).getLabel().equals(nowQuestion.getAnswer()) ) {
				message = "正解! 所要時間 " + (end-start) + "msecs.";
				correct++;
				erapsed += (end-start);
			// wrong
			} else {
				message = "残念...";
			}
			statusLabel.setText(message);
		}
	
	}

	// Question.java
	public class Question {
		private String questionBody;
		private String answer;
		private String[] choices;
	
		public Question(String questionBody, String answer, String[] choices) {
			this.questionBody = questionBody;
			this.answer = answer;
			this.choices = choices;
		}
	
		public String getAnswer() {
			return answer;
		}
	
		public String[] getChoices() {
			return choices;
		}
	
		public String getQuestionBody() {
			return questionBody;
		}
	
	
	}

宿題スレPart59 >>418-419 への回答　コンソール電話 †

JDK5.0で作成。

   import java.io.BufferedReader;
   import java.io.IOException;
   import java.io.InputStreamReader;
   
   interface iTelephone {
       void call(String num);
       void talk(String s);
       String listen();
       void hang_up();
   }
   
   class PCMogiTel implements iTelephone {
       /** この電話が使用中か否か */
       private boolean using = false;
   
       public void call(String num) {
           if( using ) {
               System.out.println( "この電話は使用中です..." );
           } else {
               using = true;
               System.out.println( num + "に電話をかけています..." );
           }
       }
   
       public void hang_up() {
           if( using ) {
               System.out.println( "電話を切ります。" );
               using = false;
           }
       }
   
       public String listen() {
           System.out.print( "> " );
           BufferedReader br = new BufferedReader( new InputStreamReader(System.in) );
           String message = null;
           try {
               message = br.readLine();
           } catch (IOException e) {
               e.printStackTrace();
           }
           return message;
       }
   
       public void talk(String s) {
           System.out.println( s );
       }
   }
   
   class TelTest {
       public static void main(String args[]) {
           iTelephone tel = new PCMogiTel();
           tel.call("090-1234-5678");
           tel.call("090-8765-4321");
           tel.talk("もしもし");
           System.out.println(tel.listen());
           tel.talk("お元気ですか?");
           System.out.println(tel.listen());
           tel.talk("そうですか。それではまた。");
           tel.hang_up();
       }
   }

宿題スレPart59 >>394 への回答　六角形描画 †

JDK5.0で作成。

   // HexagonDrawer.java
   public class HexagonDrawer {
       public static void main(String[] args) {
           HexagonDrawerFrame frame = new HexagonDrawerFrame();
           frame.setTitle("Hexagon Drawer");
           frame.setSize(400, 400);
           frame.setVisible( true );
           frame.setDefaultCloseOperation( HexagonDrawerFrame.EXIT_ON_CLOSE );
       }
   }

   // HexagonDrawerFrame.java
   import java.awt.Color;
   import java.awt.Graphics;
   import java.awt.event.MouseEvent;
   import java.awt.event.MouseListener;
   import java.io.BufferedWriter;
   import java.io.File;
   import java.io.FileWriter;
   import java.io.IOException;
   import javax.swing.JFrame;
   
   public class HexagonDrawerFrame extends JFrame implements MouseListener {
       
       private int[] xPoints = new int[6];
       private int[] yPoints = new int[6];
       private int nPoints;
       private File file;
       
       public HexagonDrawerFrame() {
           addMouseListener(this);
       }
       
       public void mouseClicked(MouseEvent e) {
           System.out.println( e.getX() + ":" + e.getY() );
           Graphics g = this.getGraphics();
           g.drawString(e.getX() + ":" + e.getY(), e.getX(), e.getY());
           xPoints[nPoints] = e.getX();
           yPoints[nPoints] = e.getY();
           nPoints++;
           if( nPoints == 6 ) {
               g.setColor(Color.BLUE);
               g.fillPolygon(xPoints, yPoints, nPoints);
               file = new File("coordinate.txt");
               BufferedWriter bw = null;
               try {
                   bw = new BufferedWriter( new FileWriter(file) );
                   StringBuffer buf = new StringBuffer();
                   for( int i=0; i<nPoints; i++ ) {
                       buf.append( xPoints[i] + " " + yPoints[i] + " " );
                   }
                   bw.write(buf.toString());
                   bw.flush();
               } catch (IOException e1) {
                   e1.printStackTrace();
               } finally {
                   if( bw != null ) {
                       try {
                           bw.close();
                       } catch (IOException e1) {
                       }
                   }
               }
           }
       }
       
       public void mouseEntered(MouseEvent e) {}
       public void mouseExited(MouseEvent e) {}
       public void mousePressed(MouseEvent e) {}
       public void mouseReleased(MouseEvent e) {}
   }