如何让动画在移动时移动其双腿？

有可能许多问题的答案。我能想到的最好的基本是设计某种“循环”。

甲周期的时间在其动画可以运行公知的周期。在这个例子中，它是1秒。

然后，您需要提供一系列的通知的变化周期随着时间的推移，这使得他们能够做出相应的变化Animatable对象。您也可以忽略那些不需要循环的元素的循环。

的目的是提供一个单一动画引擎可以负责一气呵成更新整个状态，而不是试图用多个线程/定时器这可能会降低系统的性能。

import java.awt.BorderLayout; 
import java.awt.Color; 
import java.awt.Container; 
import java.awt.Dimension; 
import java.awt.EventQueue; 
import java.awt.Graphics; 
import java.awt.Graphics2D; 
import java.awt.GridBagLayout; 
import java.awt.event.ActionEvent; 
import java.awt.event.ActionListener; 
import java.text.NumberFormat; 
import java.util.ArrayList; 
import java.util.List; 
import javax.swing.JFrame; 
import javax.swing.JPanel; 
import javax.swing.Timer; 
import javax.swing.UIManager; 
import javax.swing.UnsupportedLookAndFeelException; 
public class TestAnimation06 { 
    public static void main(String[] args) { 
     new TestAnimation06(); 
    } 
    public TestAnimation06() { 
     EventQueue.invokeLater(new Runnable() { 
      @Override 
      public void run() { 
       try { 
        UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName()); 
       } catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) { 
       } 
       JFrame frame = new JFrame("Testing"); 
       frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); 
       frame.setLayout(new BorderLayout()); 
       frame.add(new TestPane()); 
       frame.pack(); 
       frame.setLocationRelativeTo(null); 
       frame.setVisible(true); 
      } 
     }); 
    } 
    public interface Animatable { 
     public void update(float progress); 
    } 
    public class AnimationEngine { 
     private List<Animatable> animations; 
     private int cycleTime = 1000; 
     private long startTime = -1; 
     public AnimationEngine() { 
      animations = new ArrayList<>(25); 
      Timer timer = new Timer(40, new ActionListener() { 
       @Override 
       public void actionPerformed(ActionEvent e) { 
        if (startTime < 0) { 
         startTime = System.currentTimeMillis(); 
        } 
        long duration = System.currentTimeMillis() - startTime; 
        float progress = (float)duration/(float)cycleTime; 
        if (duration >= cycleTime) { 
         progress = 1f; 
         startTime = System.currentTimeMillis(); 
        } 
        for (Animatable animatable : animations) { 
         animatable.update(progress); 
        } 
       } 
      }); 
      timer.setRepeats(true); 
      timer.setCoalesce(true); 
      timer.start(); 
     } 
     public void add(Animatable animatable) { 
      animations.add(animatable); 
     } 
    } 
    public class TestPane extends JPanel { 
     private AnimationEngine engine; 
     public TestPane() { 
      setLayout(null); 
      engine = new AnimationEngine(); 
      Legs legs = new Legs(); 
      Walker walker = new Walker(legs); 
      engine.add(legs); 
      engine.add(walker); 
      walker.setSize(walker.getPreferredSize()); 
      add(walker); 
     } 
     @Override 
     public Dimension getPreferredSize() { 
      return new Dimension(200, 200); 
     } 
     @Override 
     protected void paintComponent(Graphics g) { 
      super.paintComponent(g); 
      Graphics2D g2d = (Graphics2D) g.create(); 
      g2d.dispose(); 
     } 
    } 
    public class Walker extends JPanel implements Animatable { 
     private int speed = 2; 
     public Walker(Legs legs) { 
      setLayout(new GridBagLayout()); 
      add(legs); 
     } 
     @Override 
     public void update(float progress) { 
      Container parent = getParent(); 
      int width = parent.getWidth(); 
      int xPos = getX() + speed; 
      if (xPos <= 0) { 
       speed *= -1; 
       xPos = 0; 
      } else if (xPos + getWidth() >= width) { 
       speed *= -1; 
       xPos = width - getWidth(); 
      } 
      System.out.println(xPos); 
      setLocation(xPos, (parent.getHeight() - getHeight())/2); 
      repaint(); 
     } 
    } 
    public class Legs extends JPanel implements Animatable { 
     private float frameProgress; 
     public Legs() { 
      setOpaque(false); 
     } 
     @Override 
     public Dimension getPreferredSize() { 
      return new Dimension(25, 50); 
     } 
     @Override 
     public void update(float progress) { 
      frameProgress = progress; 
      repaint(); 
     } 
     @Override 
     protected void paintComponent(Graphics g) { 
      super.paintComponent(g); 
      int width = getWidth(); 
      int height = getHeight(); 
      g.setColor(Color.BLACK); 
      g.drawLine(width/2, 0, (int)(width * frameProgress), height); 
      g.drawLine(width/2, 0, width - (int)(width * frameProgress), height); 
     } 
    } 
}