sumarray.java

来自「32个java程序源代码」· Java 代码 · 共 110 行

// Tutorial 16: SumArray.java
// Sum the values in an array and display it.
import javax.swing.*;
import java.awt.event.*;
import java.awt.*;

public class SumArray extends JFrame
{
   // JLabel and JTextField for number of array elements
   private JLabel totalJLabel;
   private JTextField totalJTextField;
   
   // JButton to sum the array
   private JButton sumArrayJButton;

   // no-argument constructor
   public SumArray()
   {
      createUserInterface();
   }

   // create and position GUI components; register event handlers
   private void createUserInterface()
   {
      // get content pane for attaching GUI components
      Container contentPane = getContentPane();
      
      // enable explicit positioning of GUI components
      contentPane.setLayout( null );

	  // set up totalJLabel
      totalJLabel = new JLabel();
      totalJLabel.setBounds( 10, 16, 135, 23 );
      totalJLabel.setText( "Total of array elements:" );
      contentPane.add( totalJLabel );

      // set up totalJTextField
      totalJTextField = new JTextField();
      totalJTextField.setBounds( 152, 16, 24, 23 );
      totalJTextField.setEditable( false );
      totalJTextField.setHorizontalAlignment( JLabel.RIGHT );
      contentPane.add( totalJTextField );
      
      // set up sumArrayJButton
      sumArrayJButton = new JButton();
      sumArrayJButton.setBounds( 50, 56, 100, 23 );
      sumArrayJButton.setText( "Sum Array" );
      contentPane.add( sumArrayJButton );
      sumArrayJButton.addActionListener(
      
         new ActionListener() // anonymous inner class
         {
            // event handler called when sumArrayJButton is pressed
            public void actionPerformed( ActionEvent event )
            {
               sumArrayJButtonActionPerformed( event );
            }
            
         } // end anonymous inner class
      
      ); // end call to addActionListener
      
      // set properties of application's window
      setTitle( "Sum Array" ); // set title bar string
      setSize( 200, 120 );     // set window size
      setVisible( true );      // display window

   } // end method createUserInterface

   // method called to determine sum of array
   private void sumArrayJButtonActionPerformed( ActionEvent event )
   {
      // declare and initialize array
      int[] array = { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 };
      int total = 0;
      
      // sum the array
      for ( int index = 0; index < array.length; index++ )
      {
         total += array[ index ];
      }
      
      totalJTextField.setText( String.valueOf( total ) );
      
   } // end method sumArrayJButtonActionPerformed
   
   // main method
   public static void main( String args[] )
   {
      SumArray application = new SumArray();
      application.setDefaultCloseOperation( JFrame.EXIT_ON_CLOSE );
   
   } // end method main

} // end class SumArray

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