accountbargraphview.java

java 编程源代码

// AccountBarGraphView.java
// AccountBarGraphView is an AbstractAccountView subclass
// that displays an Account balance as a bar graph.
package com.deitel.advjhtp1.mvc.account;

// Java core packages
import java.awt.*;

// Java extension packages
import javax.swing.*;

public class AccountBarGraphView extends AbstractAccountView {
   
   // AccountBarGraphView constructor
   public AccountBarGraphView( Account account )
   {
      super( account );
   }
    
   // draw Account balance as a bar graph
   public void paintComponent( Graphics g )
   {
      // ensure proper painting sequence
      super.paintComponent( g );

      // get Account balance
      double balance = getAccount().getBalance();

      // calculate integer height for bar graph (graph
      // is 200 pixels wide and represents Account balances 
      // from -$5,000.00to +$5,000.00)
      int barLength = ( int ) ( ( balance / 10000.0 ) * 200 );
      
      // if balance is positive, draw graph in black 
      if ( balance >= 0.0 ) {
         g.setColor( Color.black );
         g.fillRect( 105, 15, barLength, 20 );
      }

      // if balance is negative, draw graph in red 
      else {
         g.setColor( Color.red );
         g.fillRect( 105 + barLength, 15, -barLength, 20 );
      }
      
      // draw vertical and horizontal axes
      g.setColor( Color.black );
      g.drawLine( 5, 25, 205, 25 );
      g.drawLine( 105, 5, 105, 45 );      

      // draw graph labels
      g.setFont( new Font( "SansSerif", Font.PLAIN, 10 ) );
      g.drawString( "-$5,000", 5, 10 ); 
      g.drawString( "$0", 110, 10 );
      g.drawString( "+$5,000", 166, 10 );

   } // end method paintComponent

   // repaint graph when display is updated
   public void updateDisplay() 
   {
      repaint();
   }

   // get AccountBarGraphView's preferred size
   public Dimension getPreferredSize()
   {
      return new Dimension( 210, 50 );
   }

   // get AccountBarGraphView's minimum size
   public Dimension getMinimumSize()
   {
      return getPreferredSize();
   }

   // get AccountBarGraphView's maximum size
   public Dimension getMaximumSize()
   {
      return getPreferredSize();
   }
}

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 * (C) Copyright 2002 by Deitel & Associates, Inc. and         *
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