drawjpanel.java

来自「32个java程序源代码」· Java 代码 · 共 54 行

// Exercise 27.12: DrawJPanel.java
// Creates a JPanel that allows a user to create shapes on.
import java.awt.*;
import java.util.ArrayList;
import java.util.Iterator;
import javax.swing.*;

public class DrawJPanel extends JPanel
{
   // ArrayList for storing all of the shapes
   private ArrayList shapeArrayList = new ArrayList();

   // paint all the shapes
   public void paintComponent( Graphics g )
   {
      super.paintComponent( g );

      MyShape nextShape;
      Iterator shapesIterator = shapeArrayList.iterator();

      // iterate through all of the shapes
      while ( shapesIterator.hasNext() )
      {
         // draw each shape
         nextShape = ( MyShape ) shapesIterator.next();
         nextShape.draw( g );
      }
   
   } // end method paintComponent

   // clear the ArrayList
   public void clear()
   {
      shapeArrayList.clear();
      repaint();

   } // end method clear

} // end class DrawJPanel
   
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