标签文本在Java中未更改

Question

Im creating a UI for my project and that involves JLabel (javax.swing) which needs to update the text (of the Label) everytime that task is done.

I use label.setText to change/update the text inside (like the one shown below.) However, most of the time, the label doesnt change the text. I tried to use label.UpdateUI() hoping that it will solve the problem, but it doesnt.

taskLabel.setText(msg);

Any ideas?

if (gatherSamplesValue)
{
      if (SourceACheckBox)
      {
           try 
           { 
                Thread setLabelText1 = new Thread(){
                    public void run(){
                        taskLabel.setText(msg);

                    taskLabel.validate();
                }
             };
             msg = "Task : Gathering URLs from Phish Tank. DateTime: " + Main.getCurrentDate();
             setLabelText1.start();
             SourceA.sourceAMain();
             msg="Done with the task : " + Main.getCurrentDate();
             Thread setLabelText2 = new Thread(){
                public void run(){
                    taskLabel.setText(msg);
                    taskLabel.validate();
                }
             };
             setLabelText2.start();
      } catch (Exception ex) {
            Logger.getLogger(Main.class.getName()).log(Level.SEVERE, null, ex);
      }
 }

 if (SourceBCheckBox)
 {
  .
  .
 }

 if (SourceCCheckBox)
 {
  .
  .
 }

}

Here's the code, imagine that I nee to put the same commmand inside Source A and B. The Thread inside that is not working.

Answer 1

..needs to update the text (of the Label) everytime that task is done.

• you have issue with Concurency in Swing

• all updates to the Swing GUI must be done on EDT, even Whatever.setText() is declared as thread safe, but usage of Thread.sleep(int) from Swing Listener by default freeze Swing GUI and any changes aren't updated on the screen

• hack will be put taskLabel.setText(msg); into invokeLater() , then output to the Swing GUI should be done on EDT

• see and to use SwingWorker as one of proper of ways, where methods process , publish and done notified EDT

Answer 2

After you add the text to JLabel you should add that to the panel like this. label.setText("something"); panel.add(label)