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关于JLabel的setText在监听器中不刷新

发布时间： 2012-12-16 12:02:32 作者： rapoo

关于JLabel的setText在监听器中不刷新问题
我在事件监听中修改一个JLabel里的文字，但是原来的字体没有清除，后面的文字又叠加上去，如果不在监听中修改就正常，求助要怎么解决，是什么的原因？
[最优解释]
被遮盖的内容是什么？
那个没看清.
更改的JLabel1你setText(""）;
看原来的内容是否在。
另外下次上传代码的时候带上Java格式，
如下面的

java代码

最后，建议一下楼主多加注释
[其他解释]
你用的是什么事件，事件里面是怎么写的。
关键部分的代码也要给出来啊
[其他解释]
你应该把代码放出来大家才能帮你找到错误
[其他解释]
对，把代码贴出来 大家共同看下
[其他解释]
估计你实例化了两个JLabel对象。
还是发代码吧。要么谁也不能判断出错误原因。
[其他解释]
xuexuexixi xuexi
[其他解释]
class test{
public static void main(String[] args)throws Exception{
MyFrame f = new MyFrame();
f.setSize(500,300);
f.setVisible(true);
}//main
}

class MyFrame extends JFrame {
public MyFrame()throws Exception{
MainPanel mainPanel = new MainPanel();
setLayout(new BorderLayout());
add(mainPanel,"Center");
setDefaultCloseOperation(EXIT_ON_CLOSE);
}
}


class MainPanel extends JPanel{
// Declare a label for displaying message
private JLabel jLabel1 = new JLabel("Display the border type",JLabel.CENTER);

//A check box for seleting a border with or without a title
private JCheckBox jchkTitled;

// Radio buttons for border styles
private JRadioButton jrbLoweredBevel , jrbRaisedBevel , jrbEtched ,
jrbLine , jrbMatte , jrbEmpty;

// Radio buttons for titled border options
private JRadioButton jrbAboveBottom , jrbBottom , jrbBelowBottom , jrbAboveTop ,
jrbTop , jrbBelowTop , jrbLeft , jrbCenter , jrbRight;

// TitledBorder for the label -------------------???????
private TitledBorder jLabel1Border;

/** Constructor **/
public MainPanel(){
// Create a JLabel instance and set colors
jLabel1.setBackground(Color.red);
jLabel1.setBorder(jLabel1Border);

//11111111111111111111111111111111111
// Place title position radio buttons
JPanel jpPosition = new JPanel();
jpPosition.setLayout(new GridLayout(3,2));
jpPosition.add(jrbAboveBottom = new JRadioButton("ABOVE_BOTTOM"));
jpPosition.add(jrbAboveTop = new JRadioButton("ABOVE_TOP"));
jpPosition.add(jrbBottom = new JRadioButton("BOTTOM"));
jpPosition.add(jrbTop = new JRadioButton("TOP"));
jpPosition.add(jrbBelowBottom = new JRadioButton("BELOW_BOTTOM"));
jpPosition.add(jrbBelowTop = new JRadioButton("BELOW_TOP"));


jpPosition.setBorder(new TitledBorder("Position"));

// Place title justification radio buttons
JPanel jpJustification = new JPanel();
jpJustification.setLayout(new GridLayout(3,1));
jpJustification.add(jrbLeft = new JRadioButton("LEFT"));
jpJustification.add(jrbCenter = new JRadioButton("CENTER"));
jpJustification.add(jrbRight = new JRadioButton("RIGHT"));
jpJustification.setBorder(new TitledBorder("Justification"));

// Creat panel jpTitleOptions to how jpPosition and jpJustification
JPanel jpTitleOptions = new JPanel();
jpTitleOptions.setLayout(new BorderLayout());
jpTitleOptions.add(jpPosition,BorderLayout.CENTER);
jpTitleOptions.add(jpJustification,BorderLayout.EAST);

// Create Panel jpTitle to hold a check box and title position radio
// buttons, and title justification radio buttons
JPanel jpTitle = new JPanel();
jpTitle.setBorder(new TitledBorder("Border Title"));
jpTitle.setLayout(new BorderLayout());
jpTitle.add(jchkTitled = new JCheckBox("Titled"),BorderLayout.NORTH);
jpTitle.add(jpTitleOptions , BorderLayout.CENTER);

// Group radio buttons for title position
ButtonGroup btgTitlePosition = new ButtonGroup();
btgTitlePosition.add(jrbAboveBottom);
btgTitlePosition.add(jrbAboveTop);
btgTitlePosition.add(jrbBottom);
btgTitlePosition.add(jrbTop);
btgTitlePosition.add(jrbBelowBottom);
btgTitlePosition.add(jrbBelowTop);

// Group radio buttons for title justification
ButtonGroup btgTitleJustification = new ButtonGroup();
btgTitleJustification.add(jrbLeft);
btgTitleJustification.add(jrbCenter);
btgTitleJustification.add(jrbRight);


//22222222222222222222222222222
// Create Panel jpBorderStyle to hold border style radio buttons
JPanel jpBorderStyle = new JPanel();
jpBorderStyle.setBorder(new TitledBorder("Border Style"));
jpBorderStyle.setLayout(new GridLayout(6,1));
jpBorderStyle.add(jrbLoweredBevel = new JRadioButton("Lowered Bevel"));
jpBorderStyle.add(jrbRaisedBevel = new JRadioButton("Raised Bevel"));
jpBorderStyle.add(jrbEtched = new JRadioButton("Etched"));
jpBorderStyle.add(jrbLine = new JRadioButton("Line"));
jpBorderStyle.add(jrbMatte = new JRadioButton("Matte"));
jpBorderStyle.add(jrbEmpty = new JRadioButton("Empty"));

//Group radio buttons for border styles
ButtonGroup btgBorderStyle = new ButtonGroup();
btgBorderStyle.add(jrbLoweredBevel);
btgBorderStyle.add(jrbRaisedBevel);
btgBorderStyle.add(jrbEtched);
btgBorderStyle.add(jrbLine);
btgBorderStyle.add(jrbMatte);
btgBorderStyle.add(jrbEmpty);

// Create Panel jpAllChoices to place jpTitle and jpBorderStyle
JPanel jpAllChoies = new JPanel();
jpAllChoies.setLayout(new BorderLayout());
jpAllChoies.add(jpTitle , "Center");
jpAllChoies.add(jpBorderStyle, "East");

// Place panels in the frame
setLayout(new BorderLayout());
add(jLabel1,"Center");
add(jpAllChoies,"South");




// Register listeners
ActionListener listener = new MyEventListener();
jchkTitled.addActionListener(listener);

jrbAboveBottom.addActionListener(listener);
jrbAboveTop.addActionListener(listener);
jrbBottom.addActionListener(listener);
jrbTop.addActionListener(listener);
jrbBelowBottom.addActionListener(listener);
jrbBelowTop.addActionListener(listener);

jrbLeft.addActionListener(listener);
jrbCenter.addActionListener(listener);
jrbRight.addActionListener(listener);

jrbLoweredBevel.addActionListener(listener);
jrbRaisedBevel.addActionListener(listener);
jrbEtched.addActionListener(listener);
jrbLine.addActionListener(listener);
jrbMatte.addActionListener(listener);
jrbEmpty.addActionListener(listener);

}

private class MyEventListener implements ActionListener {

/* Handle ActionEvents on check box and radio buttons */
public void actionPerformed(ActionEvent e){
Border border = new EmptyBorder(2,2,2,2);

if(jrbLoweredBevel.isSelected()){
border = new BevelBorder(BevelBorder.LOWERED);
jLabel1.setText("Lowered Bevel Style");
}
else if(jrbRaisedBevel.isSelected()){
border = new BevelBorder(BevelBorder.RAISED);
jLabel1.setText("Raised Bevel Style");
}
else if(jrbEtched.isSelected()){
border = new EtchedBorder();
jLabel1.setText("Etched Style");
}
else if(jrbLine.isSelected()){
border = new LineBorder(Color.black,5);
jLabel1.setText("Line Style");
}
else if(jrbMatte.isSelected()){
}
else if(jrbEmpty.isSelected()){
border = new EmptyBorder(2,2,2,2);
jLabel1.setText("Empty Style");
}

if(jchkTitled.isSelected()){
//Get the title position and justification
int titlePosition = TitledBorder.DEFAULT_POSITION;
int titleJustification = TitledBorder.DEFAULT_JUSTIFICATION;

if(jrbAboveBottom.isSelected())
titlePosition = TitledBorder.ABOVE_BOTTOM;
else if(jrbBottom.isSelected())
titlePosition = TitledBorder.BOTTOM;
else if(jrbBelowBottom.isSelected())
titlePosition = TitledBorder.BELOW_BOTTOM;
else if(jrbAboveTop.isSelected())
titlePosition = TitledBorder.ABOVE_TOP;
else if(jrbTop.isSelected())
titlePosition = TitledBorder.TOP;
else if(jrbBelowTop.isSelected())
titlePosition = TitledBorder.BELOW_TOP;

if(jrbLeft.isSelected())
titleJustification = TitledBorder.LEFT;
else if(jrbCenter.isSelected())
titleJustification = TitledBorder.CENTER;
else if(jrbRight.isSelected())
titleJustification = TitledBorder.RIGHT;

jLabel1Border = new TitledBorder("A Title");
jLabel1Border.setBorder(border);
jLabel1Border.setTitlePosition(titlePosition);
jLabel1Border.setTitleJustification(titleJustification);
jLabel1.setBorder(jLabel1Border);
}
else{
jLabel1.setBorder(border);
}

}
}
}

[其他解释]

运行就是这样！

------其他解决方案-------------------- 



class test{
public static void main(String[] args)throws Exception{
MyFrame f = new MyFrame();
f.setSize(500,300);
f.setVisible(true);
}//main
}
         
class MyFrame extends JFrame {
public MyFrame()throws Exception{
  MainPanel mainPanel = new MainPanel();
  setLayout(new BorderLayout());
  add(mainPanel,"Center");
setDefaultCloseOperation(EXIT_ON_CLOSE);
}
}


class MainPanel extends JPanel{
// Declare a label for displaying message
private JLabel jLabel1 = new JLabel("Display the border type",JLabel.CENTER);

//A check box for seleting a border with or without a title
private JCheckBox jchkTitled;

// Radio buttons for border styles
private JRadioButton  jrbLoweredBevel , jrbRaisedBevel , jrbEtched , 
jrbLine , jrbMatte , jrbEmpty;

// Radio buttons for titled border options 
private JRadioButton  jrbAboveBottom , jrbBottom , jrbBelowBottom , jrbAboveTop ,
jrbTop , jrbBelowTop , jrbLeft , jrbCenter , jrbRight;

// TitledBorder for the label                  
private TitledBorder  jLabel1Border;

/** Constructor **/
public MainPanel(){
// Create a JLabel instance and set colors
jLabel1.setBackground(Color.red);
jLabel1.setBorder(jLabel1Border);

//11111111111111111111111111111111111
// Place title position radio buttons
JPanel jpPosition = new JPanel();
jpPosition.setLayout(new GridLayout(3,2));
jpPosition.add(jrbAboveBottom = new JRadioButton("ABOVE_BOTTOM"));
jpPosition.add(jrbAboveTop = new JRadioButton("ABOVE_TOP"));
jpPosition.add(jrbBottom = new JRadioButton("BOTTOM"));
jpPosition.add(jrbTop = new JRadioButton("TOP"));
jpPosition.add(jrbBelowBottom = new JRadioButton("BELOW_BOTTOM"));
jpPosition.add(jrbBelowTop = new JRadioButton("BELOW_TOP"));
jpPosition.setBorder(new TitledBorder("Position"));

// Place title justification radio buttons
JPanel jpJustification = new JPanel();
jpJustification.setLayout(new GridLayout(3,1));
jpJustification.add(jrbLeft = new JRadioButton("LEFT"));
jpJustification.add(jrbCenter = new JRadioButton("CENTER"));
jpJustification.add(jrbRight = new JRadioButton("RIGHT"));
jpJustification.setBorder(new TitledBorder("Justification"));

// Creat panel jpTitleOptions to how jpPosition and jpJustification
JPanel jpTitleOptions = new JPanel();
jpTitleOptions.setLayout(new BorderLayout());
jpTitleOptions.add(jpPosition,BorderLayout.CENTER);
jpTitleOptions.add(jpJustification,BorderLayout.EAST);

// Create Panel jpTitle to hold a check box and title position radio 
 
// buttons, and title justification radio buttons
JPanel jpTitle = new JPanel();
jpTitle.setBorder(new TitledBorder("Border Title"));
jpTitle.setLayout(new BorderLayout());
jpTitle.add(jchkTitled = new JCheckBox("Titled"),BorderLayout.NORTH);
jpTitle.add(jpTitleOptions , BorderLayout.CENTER);

// Group radio buttons for title position
ButtonGroup btgTitlePosition = new ButtonGroup();
btgTitlePosition.add(jrbAboveBottom);
btgTitlePosition.add(jrbAboveTop);
btgTitlePosition.add(jrbBottom);
btgTitlePosition.add(jrbTop);
btgTitlePosition.add(jrbBelowBottom);
btgTitlePosition.add(jrbBelowTop);

// Group radio buttons for title justification
ButtonGroup btgTitleJustification = new ButtonGroup();
btgTitleJustification.add(jrbLeft);
btgTitleJustification.add(jrbCenter);
btgTitleJustification.add(jrbRight);


//22222222222222222222222222222
// Create Panel jpBorderStyle to hold border style radio buttons
JPanel jpBorderStyle = new JPanel();
jpBorderStyle.setBorder(new TitledBorder("Border Style"));
jpBorderStyle.setLayout(new GridLayout(6,1));
jpBorderStyle.add(jrbLoweredBevel = new JRadioButton("Lowered Bevel"));
jpBorderStyle.add(jrbRaisedBevel = new JRadioButton("Raised Bevel"));
jpBorderStyle.add(jrbEtched = new JRadioButton("Etched"));
jpBorderStyle.add(jrbLine = new JRadioButton("Line"));
jpBorderStyle.add(jrbMatte = new JRadioButton("Matte"));
jpBorderStyle.add(jrbEmpty = new JRadioButton("Empty"));

//Group radio buttons for border styles
ButtonGroup btgBorderStyle = new ButtonGroup();
btgBorderStyle.add(jrbLoweredBevel);
btgBorderStyle.add(jrbRaisedBevel);
btgBorderStyle.add(jrbEtched);
btgBorderStyle.add(jrbLine);
btgBorderStyle.add(jrbMatte);
btgBorderStyle.add(jrbEmpty);

// Create Panel jpAllChoices to place jpTitle and jpBorderStyle
JPanel jpAllChoies = new JPanel();
jpAllChoies.setLayout(new BorderLayout());
jpAllChoies.add(jpTitle , "Center");
jpAllChoies.add(jpBorderStyle, "East");

// Place panels in the frame
setLayout(new BorderLayout());
add(jLabel1,"Center");
add(jpAllChoies,"South");


// Register listeners 
ActionListener listener = new MyEventListener();
jchkTitled.addActionListener(listener);

jrbAboveBottom.addActionListener(listener);
jrbAboveTop.addActionListener(listener);
jrbBottom.addActionListener(listener);
jrbTop.addActionListener(listener);
jrbBelowBottom.addActionListener(listener);
jrbBelowTop.addActionListener(listener);

jrbLeft.addActionListener(listener);
jrbCenter.addActionListener(listener);
jrbRight.addActionListener(listener);

jrbLoweredBevel.addActionListener(listener);
jrbRaisedBevel.addActionListener(listener);
jrbEtched.addActionListener(listener);
jrbLine.addActionListener(listener);
jrbMatte.addActionListener(listener);
jrbEmpty.addActionListener(listener);

}

private class MyEventListener implements ActionListener {

/* Handle ActionEvents on check box and radio buttons */ 
 
public void actionPerformed(ActionEvent e){
Border border = new EmptyBorder(2,2,2,2);

if(jrbLoweredBevel.isSelected()){
border = new BevelBorder(BevelBorder.LOWERED);
jLabel1.setText("Lowered Bevel Style");
}
else if(jrbRaisedBevel.isSelected()){
border = new BevelBorder(BevelBorder.RAISED);
jLabel1.setText("Raised Bevel Style");
}
else if(jrbEtched.isSelected()){
border = new EtchedBorder();
jLabel1.setText("Etched Style");
}
else if(jrbLine.isSelected()){
border = new LineBorder(Color.black,5);
jLabel1.setText("Line Style");
}
else if(jrbMatte.isSelected()){
}
else if(jrbEmpty.isSelected()){
border = new EmptyBorder(2,2,2,2);
jLabel1.setText("Empty Style");
}

if(jchkTitled.isSelected()){
//Get the title position and justification
int titlePosition = TitledBorder.DEFAULT_POSITION;
int titleJustification = TitledBorder.DEFAULT_JUSTIFICATION;

if(jrbAboveBottom.isSelected())
titlePosition = TitledBorder.ABOVE_BOTTOM;
else if(jrbBottom.isSelected())
titlePosition = TitledBorder.BOTTOM;
else if(jrbBelowBottom.isSelected())
titlePosition = TitledBorder.BELOW_BOTTOM;
else if(jrbAboveTop.isSelected())
titlePosition = TitledBorder.ABOVE_TOP;
else if(jrbTop.isSelected())
titlePosition = TitledBorder.TOP;
else if(jrbBelowTop.isSelected())
titlePosition = TitledBorder.BELOW_TOP;

if(jrbLeft.isSelected())
titleJustification = TitledBorder.LEFT;
else if(jrbCenter.isSelected())
titleJustification = TitledBorder.CENTER;
else if(jrbRight.isSelected())
titleJustification = TitledBorder.RIGHT;

jLabel1Border = new TitledBorder("A Title");
jLabel1Border.setBorder(border);
jLabel1Border.setTitlePosition(titlePosition);
jLabel1Border.setTitleJustification(titleJustification);
jLabel1.setBorder(jLabel1Border);
}
else{
jLabel1.setBorder(border);
}

}
}

}

[其他解释]

setText(""）;改了后点Button就成这样了
我点的Lowered Bevel 后遮盖的内容就是 Lowered Bevel
引用:
被遮盖的内容是什么？
那个没看清.
更改的JLabel1你setText(""）;
看原来的内容是否在。
另外下次上传代码的时候带上Java格式，
如下面的Java code?1java代码
最后，建议一下楼主多加注释



[其他解释]
奇怪，我把它精简为2个按钮，他就不会出现错误了，看来可能是代码出现问题，我再找找。
[其他解释]
好吧，我还想还是没理解。
这样吧。你原来预计的结果是应该出现什么？
实际输出的结果是什么。
发行来，不要发图片，发显示的内容。
除了这个JAreaText覆盖，其他的没问题吧？
[其他解释]
该回复于2012-11-24 17:17:30被管理员删除
[其他解释]
不知道为啥，复制到另外的文档从新编译又可以了

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