CODE:
import java.awt.*;
import java.awt.event.*;
import java.awt.event.FocusListener;
import java.util.EventListener;
import java.awt.event.FocusEvent;
import java.awt.event.MouseListener;
import java.awt.event.MouseEvent;class TestFocus extends Frame implements MouseListener
{
Button btn1,btn2,btn3,btn4;
TextField tf1;
TextField tf2;
TestFocus(String title)
{
super(title);
btn1=new Button("Text 1");
btn2=new Button("Text 2");
tf2=new TextField("Text Two");
tf1.setColumns(20);
tf2.setColumns(20);
setLayout(new FlowLayout());
setSize(400,300);
setFont( new Font("Courier",Font.BOLD,25));
add(tf1);
add(tf2);
add(btn1);
add(btn2);
addMouseListener(this);
}
public static void main(String args[])
{
TestFocus tf=new TestFocus("Test Focus");
tf.setVisible(true);
}
public void mouseClicked(MouseEvent e)
{
tf1.setText("X point:"+e.getX());
tf2.setText("Y point:"+e.getY());
} public void mousePressed(MouseEvent e) {
tf1.setText("Mouse Pressed:"+e.getMouseModifiersText(e.getModifiers()));
} public void mouseReleased(MouseEvent e)
{
} public void mouseEntered(MouseEvent e)
{
tf1.setText("Mouse In");
} public void mouseExited(MouseEvent e)
{
tf1.setText("Mouse Out");
}
}编译通过,运行抛出异常,说有引用没有创建实例,帮忙看一下
import java.awt.*;
import java.awt.event.*;
import java.awt.event.FocusListener;
import java.util.EventListener;
import java.awt.event.FocusEvent;
import java.awt.event.MouseListener;
import java.awt.event.MouseEvent;class TestFocus extends Frame implements MouseListener
{
Button btn1,btn2,btn3,btn4;
TextField tf1;
TextField tf2;
TestFocus(String title)
{
super(title);
btn1=new Button("Text 1");
btn2=new Button("Text 2");
tf2=new TextField("Text Two");
tf1.setColumns(20);
tf2.setColumns(20);
setLayout(new FlowLayout());
setSize(400,300);
setFont( new Font("Courier",Font.BOLD,25));
add(tf1);
add(tf2);
add(btn1);
add(btn2);
addMouseListener(this);
}
public static void main(String args[])
{
TestFocus tf=new TestFocus("Test Focus");
tf.setVisible(true);
}
public void mouseClicked(MouseEvent e)
{
tf1.setText("X point:"+e.getX());
tf2.setText("Y point:"+e.getY());
} public void mousePressed(MouseEvent e) {
tf1.setText("Mouse Pressed:"+e.getMouseModifiersText(e.getModifiers()));
} public void mouseReleased(MouseEvent e)
{
} public void mouseEntered(MouseEvent e)
{
tf1.setText("Mouse In");
} public void mouseExited(MouseEvent e)
{
tf1.setText("Mouse Out");
}
}编译通过,运行抛出异常,说有引用没有创建实例,帮忙看一下
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tf1=new TextField("Text One");