雖然循環移動形狀從一個點到另一個點

Question

Java仍然年輕，目前試圖找出如何通過繪圖區域移動一個形狀。我希望形狀在整條線上移動，但最終會排成一排。任何幫助將非常感激。謝謝。

int x = 10; 

while (x < 100) 
{ 
    repaint(); 
    g.setColor(Color.BLACK); 
    g.fillRect(x, x, 10, 10); 
    repaint(); 
    x += 1; 
} 

Answer 1

下面是一個在圖形面板上移動圖像的GUI。

首先，我們創建腿和旅途的模型類。這些類跟蹤我們想要在屏幕上移動的矩形。我們給旅程的每一段提供一個名稱和一個延遲。

接下來，我們從JPanel創建一個繪圖面板。我們將繪圖面板放置在JFrame中。這是觀點。

最後，我們創建一個Runnable，獲取旅行腿並在繪圖面板上繪製矩形。這是控制器。

查看繪圖面板的paintComponent方法，我們看到方法代碼除了繪畫之外什麼都不做。要繪製的內容的控制代碼位於Runnable中。

下面是完整的可運行代碼。

package com.ggl.testing; 

import java.awt.Color; 
import java.awt.Dimension; 
import java.awt.Font; 
import java.awt.Graphics; 
import java.awt.Rectangle; 
import java.awt.event.WindowAdapter; 
import java.awt.event.WindowEvent; 
import java.awt.font.FontRenderContext; 
import java.awt.geom.Rectangle2D; 
import java.util.ArrayList; 
import java.util.List; 

import javax.swing.JFrame; 
import javax.swing.JPanel; 
import javax.swing.SwingUtilities; 

public class ImageMove implements Runnable { 

    private JFrame frame; 

    private JourneyRunnable journeyRunnable; 

    public static void main(String[] args) { 
     SwingUtilities.invokeLater(new ImageMove()); 
    } 

    @Override 
    public void run() { 
     frame = new JFrame("Image Move"); 
     frame.setDefaultCloseOperation(JFrame.DO_NOTHING_ON_CLOSE); 
     frame.addWindowListener(new WindowAdapter() { 
      @Override 
      public void windowClosing(WindowEvent event) { 
       exitProcedure(); 
      } 
     }); 

     DrawingPanel drawingPanel = new DrawingPanel(); 
     frame.add(drawingPanel); 

     frame.pack(); 
     frame.setLocationByPlatform(true); 
     frame.setVisible(true); 

     journeyRunnable = new JourneyRunnable(drawingPanel, new Journey()); 
     new Thread(journeyRunnable).start(); 
    } 

    public void exitProcedure() { 
     journeyRunnable.setRunning(false); 
     frame.dispose(); 
     System.exit(0); 
    } 

    public class DrawingPanel extends JPanel { 

     private static final long serialVersionUID = -8498462824787395933L; 

     private int xPos, yPos, width, height; 

     private Leg leg; 

     public DrawingPanel() { 
      this.width = 100; 
      this.height = 50; 
      this.xPos = 0; 
      this.yPos = (200 - height)/2; 
      this.setPreferredSize(new Dimension(600, 200)); 
     } 

     public void setLeg(Leg leg) { 
      this.leg = leg; 
      this.xPos += 10; 
      repaint(); 
     } 

     @Override 
     protected void paintComponent(Graphics g) { 
      super.paintComponent(g); 

      g.setColor(Color.WHITE); 
      g.fillRect(0, 0, getWidth(), getHeight()); 

      g.setColor(Color.ORANGE); 
      g.fillRect(xPos, yPos, width, height); 

      if (leg != null) { 
       g.setColor(Color.BLACK); 
       centerString(g, new Rectangle(xPos, yPos, width, height), 
         leg.getName(), g.getFont()); 
      } 
     } 

     /** 
     * This method centers a <code>String</code> in a bounding 
     * <code>Rectangle</code>. 
     * 
     * @param g 
     *   - The <code>Graphics</code> instance. 
     * @param r 
     *   - The bounding <code>Rectangle</code>. 
     * @param s 
     *   - The <code>String</code> to center in the bounding 
     *   rectangle. 
     * @param font 
     *   - The display font of the <code>String</code> 
     * 
     * @see java.awt.Graphics 
     * @see java.awt.Rectangle 
     * @see java.lang.String 
     */ 
     private void centerString(Graphics g, Rectangle r, String s, Font font) { 
      FontRenderContext frc = new FontRenderContext(null, true, true); 

      Rectangle2D r2D = font.getStringBounds(s, frc); 
      int rWidth = (int) Math.round(r2D.getWidth()); 
      int rHeight = (int) Math.round(r2D.getHeight()); 
      int rX = (int) Math.round(r2D.getX()); 
      int rY = (int) Math.round(r2D.getY()); 

      int a = (r.width/2) - (rWidth/2) - rX; 
      int b = (r.height/2) - (rHeight/2) - rY; 

      g.setFont(font); 
      g.drawString(s, r.x + a, r.y + b); 
     } 
    } 

    public class JourneyRunnable implements Runnable { 

     private boolean running; 

     private DrawingPanel drawingPanel; 

     private Journey journey; 

     public JourneyRunnable(DrawingPanel drawingPanel, Journey journey) { 
      this.drawingPanel = drawingPanel; 
      this.journey = journey; 
      this.running = true; 
     } 

     @Override 
     public void run() { 
      while (running) { 
       Leg leg = journey.getLeg(); 
       setLeg(leg); 
       sleep(leg); 
      } 
     } 

     private void setLeg(final Leg leg) { 
      SwingUtilities.invokeLater(new Runnable() { 
       @Override 
       public void run() { 
        drawingPanel.setLeg(leg); 
       } 
      }); 
     } 

     private void sleep(Leg leg) { 
      try { 
       Thread.sleep(leg.getDelay()); 
      } catch (InterruptedException e) { 

      } 
     } 

     public void setRunning(boolean running) { 
      this.running = running; 
     } 

    } 

    public class Journey { 

     private int index; 
     private List<Leg> legs; 

     public Journey() { 
      this.legs = new ArrayList<>(); 

      this.legs.add(new Leg("Name 1", 2000L)); 
      this.legs.add(new Leg("Name 2", 1000L)); 
      this.legs.add(new Leg("Name 3", 2000L)); 
      this.legs.add(new Leg("Name 4", 1000L)); 
      this.legs.add(new Leg("Name 5", 2000L)); 
      this.legs.add(new Leg("Name 6", 1000L)); 
      this.legs.add(new Leg("Name 7", 2000L)); 
      this.legs.add(new Leg("Name 8", 1000L)); 
      this.legs.add(new Leg("Name 9", 2000L)); 
      this.legs.add(new Leg("Name 10", 1000L)); 

      this.index = 0; 
     } 

     public Leg getLeg() { 
      Leg leg = legs.get(index); 
      index = ++index % legs.size(); 
      return leg; 
     } 
    } 

    public class Leg { 
     private final String name; 
     private final long delay; 

     public Leg(String name, long delay) { 
      this.name = name; 
      this.delay = delay; 
     } 

     public String getName() { 
      return name; 
     } 

     public long getDelay() { 
      return delay; 
     } 

    } 

}