将KeyListener添加到JLabel [英] add KeyListener to JLabel
本文介绍了将KeyListener添加到JLabel的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！
问题描述
我想让一个类从JLabel扩展并实现KeyListener，但是KeyListener不起作用.
现在，MouseListener可以工作，但KeyListner不能工作，但是为什么呢?
另一个问题是，将JFrame的布局设置为null时，它不显示(图像汽车或汽车对象).
public class car extends JLabel implements KeyListener,MouseListener{
private ImageIcon imgico;//to set Image icon of car
public car(int car_num,boolean line1,Dimension position){
//car_num variable check which of Image of car load
//if line1 is true .line 1 else car load in line 2
super();
this.imgico = this.car_load(car_num, line1);
super.setIcon(this.imgico);
super.setVisible(true);
super.setSize(this.imgico.getIconWidth(),this.imgico.getIconHeight());
super.setLocation(position.width, position.height);
this.addKeyListener(this);
this.addMouseListener(this);
}
private ImageIcon car_load(int car_num,boolean line1){
//load image icon of car
if (car_num == 1 && line1 == true)
return (new ImageIcon("Images/cars/01a.PNG"));
else if (car_num == 1 && line1 == false)
return (new ImageIcon("Images/cars/01b.PNG"));
else if (car_num == 2 && line1 == true)
return (new ImageIcon("Images/cars/02a.PNG"));
else if (car_num == 2 && line1 == false)
return (new ImageIcon("Images/cars/02b.PNG"));
else if (car_num == 3 && line1 == true)
return (new ImageIcon("Images/cars/03a.PNG"));
else if (car_num == 3 && line1 == false)
return (new ImageIcon("Images/cars/03b.PNG"));
else if (car_num == 4 && line1 == true)
return (new ImageIcon("Images/cars/04a.PNG"));
else if (car_num == 4 && line1 == false)
return (new ImageIcon("Images/cars/04b.PNG"));
else if (car_num == 5 && line1 == true)
return (new ImageIcon("Images/cars/05a.PNG"));
else if (car_num == 5 && line1 == false)
return (new ImageIcon("Images/cars/05b.PNG"));
else if (car_num == 6 && line1 == true)
return (new ImageIcon("Images/cars/06a.PNG"));
else
return (new ImageIcon("Images/cars/06b.PNG"));
// by deafult its 06b
}
@Override
public void keyPressed(KeyEvent arg0) {
// TODO Auto-generated method stub
System.out.println(arg0.getKeyCode());
}
@Override
public void keyReleased(KeyEvent arg0) {
// TODO Auto-generated method stub
}
@Override
public void keyTyped(KeyEvent arg0) {
// TODO Auto-generated method stub
System.out.println(arg0.getKeyCode());
}
@Override
public void mouseClicked(MouseEvent arg0) {
if (arg0.getSource() == this)
System.out.println("Hi");
}
@Override
public void mouseEntered(MouseEvent arg0) {
// TODO Auto-generated method stub
}
@Override
public void mouseExited(MouseEvent arg0) {
// TODO Auto-generated method stub
}
@Override
public void mousePressed(MouseEvent arg0) {
// TODO Auto-generated method stub
}
@Override
public void mouseReleased(MouseEvent arg0) {
// TODO Auto-generated method stub
}
}
主要:
JFrame x = new JFrame();
x.setSize(500,500);
x.setVisible(true);
Dimension v = new Dimension(5,5);
car t =new car(1,true,v);
x.setLayout(null);
x.add(t);
解决方案
我认为JLabel不能获得焦点，因此KeyEvent永远不会被解雇.有关更多详细信息，请参见此文档. >
I want to make a class extend from JLabel and implement KeyListener, but KeyListener doesn't work.
Now MouseListener works but KeyListner doesn't work, but why?
Another problem is when setting the layout of JFrame to null, it doesn't show (images car or car object).
public class car extends JLabel implements KeyListener,MouseListener{
private ImageIcon imgico;//to set Image icon of car
public car(int car_num,boolean line1,Dimension position){
//car_num variable check which of Image of car load
//if line1 is true .line 1 else car load in line 2
super();
this.imgico = this.car_load(car_num, line1);
super.setIcon(this.imgico);
super.setVisible(true);
super.setSize(this.imgico.getIconWidth(),this.imgico.getIconHeight());
super.setLocation(position.width, position.height);
this.addKeyListener(this);
this.addMouseListener(this);
}
private ImageIcon car_load(int car_num,boolean line1){
//load image icon of car
if (car_num == 1 && line1 == true)
return (new ImageIcon("Images/cars/01a.PNG"));
else if (car_num == 1 && line1 == false)
return (new ImageIcon("Images/cars/01b.PNG"));
else if (car_num == 2 && line1 == true)
return (new ImageIcon("Images/cars/02a.PNG"));
else if (car_num == 2 && line1 == false)
return (new ImageIcon("Images/cars/02b.PNG"));
else if (car_num == 3 && line1 == true)
return (new ImageIcon("Images/cars/03a.PNG"));
else if (car_num == 3 && line1 == false)
return (new ImageIcon("Images/cars/03b.PNG"));
else if (car_num == 4 && line1 == true)
return (new ImageIcon("Images/cars/04a.PNG"));
else if (car_num == 4 && line1 == false)
return (new ImageIcon("Images/cars/04b.PNG"));
else if (car_num == 5 && line1 == true)
return (new ImageIcon("Images/cars/05a.PNG"));
else if (car_num == 5 && line1 == false)
return (new ImageIcon("Images/cars/05b.PNG"));
else if (car_num == 6 && line1 == true)
return (new ImageIcon("Images/cars/06a.PNG"));
else
return (new ImageIcon("Images/cars/06b.PNG"));
// by deafult its 06b
}
@Override
public void keyPressed(KeyEvent arg0) {
// TODO Auto-generated method stub
System.out.println(arg0.getKeyCode());
}
@Override
public void keyReleased(KeyEvent arg0) {
// TODO Auto-generated method stub
}
@Override
public void keyTyped(KeyEvent arg0) {
// TODO Auto-generated method stub
System.out.println(arg0.getKeyCode());
}
@Override
public void mouseClicked(MouseEvent arg0) {
if (arg0.getSource() == this)
System.out.println("Hi");
}
@Override
public void mouseEntered(MouseEvent arg0) {
// TODO Auto-generated method stub
}
@Override
public void mouseExited(MouseEvent arg0) {
// TODO Auto-generated method stub
}
@Override
public void mousePressed(MouseEvent arg0) {
// TODO Auto-generated method stub
}
@Override
public void mouseReleased(MouseEvent arg0) {
// TODO Auto-generated method stub
}
}
In main:
JFrame x = new JFrame();
x.setSize(500,500);
x.setVisible(true);
Dimension v = new Dimension(5,5);
car t =new car(1,true,v);
x.setLayout(null);
x.add(t);
解决方案
I don't think JLabel can gain focus, thus a KeyEvent would never be fired. See this documentation for further details.
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