我的目的是一个面板中有一个 JTextField 一个JLabel,当在textfield中输入输入数据时,label中的文本从real-time update自动变为keytyped,听起来简单,是则没那么简单,问题我解决了,可错误发生的具体流程我没搞懂,和朋友没切磋一下,最好吧下面两个类粘贴到IDE中,倪们能解释这其中错误的原因吗?public class Apanel extends Panel{
private JTextField textField=null;
private JLabel label
public Apanel(){
}
initialize(){
this.setLayout(new FlowLayout());
this.add(getTextField());
this.add(getLabel());
}
public JTextField getTextField(){
if(textField == null ){
textField = new JTextField();
textField.addKeyListener(new Handler(this));
}
return textField;
}
public JLabel getLabel(){
label= new JLabel("real-time update");
return label;
}}
===============================================
public class Handler implements KeyListener{
private Apanel apanel;public Handler(Apanel apanel){
this.apanel=apanel;
}
public void keyTyped(final KeyEven e){
Thread t= new Thread(){
public void run(){
apanel.getLabel().setText("keytyped");
}
};
t.start();}
public void keyPressed(){}
public void keyReleased(){}
}
private JTextField textField=null;
private JLabel label
public Apanel(){
}
initialize(){
this.setLayout(new FlowLayout());
this.add(getTextField());
this.add(getLabel());
}
public JTextField getTextField(){
if(textField == null ){
textField = new JTextField();
textField.addKeyListener(new Handler(this));
}
return textField;
}
public JLabel getLabel(){
label= new JLabel("real-time update");
return label;
}}
===============================================
public class Handler implements KeyListener{
private Apanel apanel;public Handler(Apanel apanel){
this.apanel=apanel;
}
public void keyTyped(final KeyEven e){
Thread t= new Thread(){
public void run(){
apanel.getLabel().setText("keytyped");
}
};
t.start();}
public void keyPressed(){}
public void keyReleased(){}
}
public class Apanel extends Panel
{
private JTextField textField=null;
private JLabel label = new JLabel("real-time update");////////////
public Apanel()
{
}
initialize()
{
this.setLayout(new FlowLayout());
this.add(getTextField());
this.add(getLabel());
}
public JTextField getTextField()
{
if(textField == null ){
textField = new JTextField();
textField.addKeyListener(new Handler(this));
}
return textField;
} public JLabel getLabel(){
/////////label= new JLabel("real-time update");
return label;
}
}
public class Handler implements KeyListener{
private Apanel apanel;
public Handler(Apanel apanel){
this.apanel=apanel;
}
public void keyTyped(final KeyEven e){
/* Thread t= new Thread(){
public void run(){
apanel.getLabel().setText("keytyped");
}
};
t.start();
*/
apanel.getLabel().setText("keytyped");
}
public void keyPressed(){}
public void keyReleased(){}
}
jTextField.getDocument().addDocumentListener(new DocumentListener(){
public void changedUpdate(DocumentEvent e) {
label.setText(...);
}
public void insertUpdate(DocumentEvent e) {
label.setText(...);
} public void removeUpdate(DocumentEvent e) {
label.setText(...);
}
});