我是一个Java爱好者
分类： Java
2009-07-20 15:50:19
● JFileChooser类专门用来实现文件存取对话框
例:选择一图片添加到JLabel上。
package filechooser;
import java.awt.BorderLayout;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.filechooser.FileNameExtensionFilter;;
publicclass TestJFileChooser extends JFrame
{
privatestaticfinallongserialVersionUID = 1L;
JButton bt=new JButton("选择");
JLabel lb=new JLabel();
JPanel pl=new JPanel();
public TestJFileChooser()
{
pl.setLayout(new BorderLayout());
pl.add(bt,"North");
pl.add(lb,"Center");
this.getContentPane().add(pl);
this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
bt.addActionListener(new ActionListener()
{
publicvoid actionPerformed(ActionEvent e)
{
JFileChooser jchooser=new JFileChooser();
FileNameExtensionFilter filter=new FileNameExtensionFilter
("JPG & GIF Images", "jpg", "gif");
jchooser.setFileFilter(filter);
int returnValue=jchooser.showOpenDialog(TestJFileChooser.this);
if(returnValue==JFileChooser.APPROVE_OPTION)
{
System.out.println("You chose to open this file: " +
jchooser.getSelectedFile().getName());
String strPath=jchooser.getSelectedFile().getAbsolutePath();
ImageIcon icon=new ImageIcon(strPath);
lb.setIcon(icon);
}
}
});
}
publicstaticvoid main(String[] args)
{
// TODO Auto-generated method stub
TestJFileChooser mainJFrame=new TestJFileChooser();
mainJFrame.setTitle("TestJFileChooser");
mainJFrame.setSize(400,400);
mainJFrame.setVisible(true);
}
}
计算器界面的程序实例
要求：
● 单击任何按钮，按钮上面的数字或符号按从左到右的顺序显示在文本框中
● 文本框中的文字是右对齐显示
package calc;
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class TestCalc extends JFrame implements ActionListener,KeyListener
{
private static final long serialVersionUID = 1L;
JTextField tf=new JTextField(20);
JButton bt1,bt2,bt3,bt4,bt5,bt6,bt7,bt8,bt9,bt10,bt11,bt12,
bt13,bt14,bt15,bt16,bt17,bt18,bt19,bt20;
//按钮旗标
int flag=0;
//键盘旗标
int flagk=0;
double x=0;
double y=0;
double result=0;
String str="";
public TestCalc()
{
super("计算器");
this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
tf.setHorizontalAlignment(JTextField.RIGHT);
tf.setText("0");
tf.setEditable(false);
Container c=this.getContentPane();
JPanel pl=new JPanel();
JPanel pltf=new JPanel();
//this.setBackground(Color.LIGHT_GRAY);
bt1=new JButton("1");
bt1.setForeground(Color.RED);
bt1.setFont(new Font("",Font.BOLD,20));
bt1.addActionListener(this);
bt2=new JButton("2");
bt2.setForeground(Color.RED);
bt2.setFont(new Font("",Font.BOLD,20));
bt2.addActionListener(this);
bt3=new JButton("3");
bt3.setForeground(Color.RED);
bt3.setFont(new Font("",Font.BOLD,20));
bt3.addActionListener(this);
bt11=new JButton("+");
bt11.setForeground(Color.RED);
bt11.setFont(new Font("",Font.BOLD,20));
bt11.addActionListener(this);
bt4=new JButton("4");
bt4.setForeground(Color.RED);
bt4.setFont(new Font("",Font.BOLD,20));
bt4.addActionListener(this);
bt5=new JButton("5");
bt5.setForeground(Color.RED);
bt5.setFont(new Font("",Font.BOLD,20));
bt5.addActionListener(this);
bt6=new JButton("6");
bt6.setForeground(Color.RED);
bt6.setFont(new Font("",Font.BOLD,20));
bt6.addActionListener(this);
bt12=new JButton("-");
bt12.setForeground(Color.RED);
bt12.setFont(new Font("",Font.BOLD,20));
bt12.addActionListener(this);
bt7=new JButton("7");
bt7.setForeground(Color.RED);
bt7.setFont(new Font("",Font.BOLD,20));
bt7.addActionListener(this);
bt8=new JButton("8");
bt8.setForeground(Color.RED);
bt8.setFont(new Font("",Font.BOLD,20));
bt8.addActionListener(this);
bt9=new JButton("9");
bt9.setForeground(Color.RED);
bt9.setFont(new Font("",Font.BOLD,20));
bt9.addActionListener(this);
bt13=new JButton("*");
bt13.setForeground(Color.RED);
bt13.setFont(new Font("",Font.BOLD,20));
bt13.addActionListener(this);
bt10=new JButton("0");
bt10.setForeground(Color.RED);
bt10.setFont(new Font("",Font.BOLD,20));
bt10.addActionListener(this);
bt14=new JButton(".");
bt14.setForeground(Color.RED);
bt14.setFont(new Font("",Font.BOLD,20));
bt14.addActionListener(this);
bt15=new JButton("/");
bt15.setForeground(Color.RED);
bt15.setFont(new Font("",Font.BOLD,20));
bt15.addActionListener(this);
bt16=new JButton("=");
bt16.setForeground(Color.RED);
bt16.setFont(new Font("",Font.BOLD,20));
bt16.addActionListener(this);
bt17=new JButton("清空");
bt17.setForeground(Color.BLUE);
bt17.addActionListener(this);
bt18=new JButton("Backspace");
bt18.setForeground(Color.BLUE);
bt18.addActionListener(this);
bt19=new JButton("");
bt20=new JButton("");
pltf.add(tf);
pl.add(bt19);
pl.add(bt17);
pl.add(bt20);
pl.add(bt18);
pl.add(bt1);
pl.add(bt2);
pl.add(bt3);
pl.add(bt11);
pl.add(bt4);
pl.add(bt5);
pl.add(bt6);
pl.add(bt12);
pl.add(bt7);
pl.add(bt8);
pl.add(bt9);
pl.add(bt13);
pl.add(bt10);
pl.add(bt14);
pl.add(bt15);
pl.add(bt16);
GridLayout gltf=new GridLayout(1,1,10,5);
GridLayout gl=new GridLayout(5,4,10,20);
pltf.setLayout(gltf);
pl.setLayout(gl);
tf.setFocusable(true);
c.add(pltf,BorderLayout.NORTH);
c.add(pl,BorderLayout.CENTER);
tf.addKeyListener(this);
}
public static void main(String[] args)
{
// TODO Auto-generated method stub
TestCalc mainFrame=new TestCalc();
//mainFrame.setTitle("计算器界面的实现");
mainFrame.setSize(300,300);
mainFrame.setLocation(100,100);
mainFrame.setVisible(true);
mainFrame.setResizable(false);
}
public void actionPerformed(ActionEvent e)
{
//数字键1
if(e.getSource()==bt1)
{
if(tf.getText().trim().indexOf('=')==-1)
{
if(tf.getText().equals("0"))
{
tf.setText(e.getActionCommand().trim());
//tf.setFocusable(true);
}
else
{
tf.setText(tf.getText().trim()+e.getActionCommand().trim());
//tf.setFocusable(true);
}
}
}
//数字键2
else if(e.getSource()==bt2)
{
if(tf.getText().trim().indexOf('=')==-1)
{
if(tf.getText().equals("0"))
{
tf.setText(e.getActionCommand().trim());
}
else
{
tf.setText(tf.getText().trim()+e.getActionCommand().trim());
}
}
}
//数字键3
else if(e.getSource()==bt3)
{
if(tf.getText().trim().indexOf('=')==-1)
{
if(tf.getText().equals("0"))
{
tf.setText(e.getActionCommand().trim());
}
else
{
tf.setText(tf.getText().trim()+e.getActionCommand().trim());
}
}
}
//数字键4
else if(e.getSource()==bt4)
{
if(tf.getText().trim().indexOf('=')==-1)
{
if(tf.getText().equals("0"))
{
tf.setText(e.getActionCommand().trim());
}
else
{
tf.setText(tf.getText().trim()+e.getActionCommand().trim());
}
}
}
//数字键5
else if(e.getSource()==bt5)
{
if(tf.getText().trim().indexOf('=')==-1)
{
if(tf.getText().equals("0"))
{
tf.setText(e.getActionCommand().trim());
}
else
{
tf.setText(tf.getText().trim()+e.getActionCommand().trim());
}
}
}
//数字键6
else if(e.getSource()==bt6)
{
if(tf.getText().trim().indexOf('=')==-1)
{
if(tf.getText().equals("0"))
{
tf.setText(e.getActionCommand().trim());
}
else
{
tf.setText(tf.getText().trim()+e.getActionCommand().trim());
}
}
}
//数字键7
else if(e.getSource()==bt7)
{
if(tf.getText().trim().indexOf('=')==-1)
{
if(tf.getText().equals("0"))
{
tf.setText(e.getActionCommand().trim());
}
else
{
tf.setText(tf.getText().trim()+e.getActionCommand().trim());
}
}
}
//数字键8
else if(e.getSource()==bt8)
{
if(tf.getText().trim().indexOf('=')==-1)
{
if(tf.getText().equals("0"))
{
tf.setText(e.getActionCommand().trim());
}
else
{
tf.setText(tf.getText().trim()+e.getActionCommand().trim());
}
}
}
//数字键9
else if(e.getSource()==bt9)
{
if(tf.getText().trim().indexOf('=')==-1)
{
if(tf.getText().equals("0"))
{
tf.setText(e.getActionCommand().trim());
}
else
{
tf.setText(tf.getText().trim()+e.getActionCommand().trim());
}
}
}
//数字键0
else if(e.getSource()==bt10)
{
if(tf.getText().trim().indexOf('=')==-1)
{
if(tf.getText().equals("0"))
{}
else
{
tf.setText(tf.getText().trim()+e.getActionCommand().trim());
}
}
}
//数字键.
else if(e.getSource()==bt14)
{
int dianStart=tf.getText().trim().indexOf('.');
int dianEnd=tf.getText().trim().lastIndexOf('.');
if(dianEnd-dianStart>4)
{
tf.setText(tf.getText().trim());
}
else
{
if(tf.getText().length()<0)
{
tf.setText("0"+e.getActionCommand().trim());
}
else
{
tf.setText(tf.getText().trim()+e.getActionCommand().trim());
}
}
}
//数字键+
else if(e.getSource()==bt11)
{
if(flag==2||flag==3||flag==4)
{}
else
{
flag=1;
if(tf.getText().trim().indexOf('+')==-1)
{
x=Double.valueOf(tf.getText().trim());
tf.setText(tf.getText().trim()+"+");
y=0d;
}
else
{
tf.setText(tf.getText().trim());
}
}
}
//数字键-
else if(e.getSource()==bt12)
{
if(flag==1||flag==3||flag==4)
{}
else
{
flag=2;
if(tf.getText().trim().indexOf('-')==-1)
{
x=Double.valueOf(tf.getText().trim());
tf.setText(tf.getText().trim()+"-");
y=0d;
}
else
{
tf.setText(tf.getText().trim());
}
}
}
//数字键*
else if(e.getSource()==bt13)
{
if(flag==1||flag==2||flag==4)
{}
else
{
flag=3;
if(tf.getText().trim().indexOf('*')==-1)
{
x=Double.valueOf(tf.getText().trim());
tf.setText(tf.getText().trim()+"*");
y=0d;
}
else
{
tf.setText(tf.getText().trim());
}
}
}
