java.awt.TextField#setEchoChar ( )源码实例Demo

public LoginRequester(Frame parent, String title, String user_label, String password_label, 
	String posText_, String negText) {
  
  super(parent, title, true);
  setLayout(new GridBagLayout());
  posText = posText_;
  
  add(new Label(user_label), Awt.constraints(false, GridBagConstraints.HORIZONTAL));
  u_text = new TextField(30);
  try{u_text.setText(System.getProperty("user.name",""));}
  catch(Exception e) {}
  add(u_text, Awt.constraints(true, GridBagConstraints.HORIZONTAL));
  
  add(new Label(password_label), Awt.constraints(false, GridBagConstraints.HORIZONTAL));
  p_text = new TextField(30);
  p_text.setEchoChar('*');
  add(p_text, Awt.constraints(true, GridBagConstraints.HORIZONTAL));
  
  Button pos = new Button(posText);
  add(pos, Awt.constraints(false, 10, 4, GridBagConstraints.HORIZONTAL));
  pos.addActionListener(this);
  
  Button neg = new Button(negText);
  add(neg, Awt.constraints(true, 10, 4, GridBagConstraints.HORIZONTAL));
  neg.addActionListener(this);
  
  pack();
}
 

public LoginGUI(){
	// set title
	super("EventHandling basics");
	txtF1 = new TextField();
	passF = new TextField();
	label1 = new Label();
	label2 = new Label();
	panelLogin = new Panel();
	buttonExit = new Button("close");
	buttonLogin = new Button("login");

	// explictely setting layout. default is Flow itself
	setLayout(new FlowLayout());


	// create a label for username
	label1.setAlignment(Label.CENTER);
	label1.setText("Username");
	add(label1); // add the label to the Frame

	// set initial width of the the TextFields
	txtF1.setColumns(20);
	passF.setColumns(20);

	// changing echoing of characters typed in password field into *
	passF.setEchoChar('*');

	add(txtF1);

	// create a label for password
	label2.setAlignment(Label.CENTER);
	label2.setText("Password");
	add(label2);

	add(passF);

	// create an exit button
	add(buttonExit);

	// login button
	panelLogin.add(buttonLogin);
	add(panelLogin);

	// create an listener object.
	theHandler handler = new theHandler();

	// add action listeners for both the buttons
	buttonExit.addActionListener(handler);
	buttonLogin.addActionListener(handler);
}