Add an event for button

Question

I have jbutton1 which has a text "Connect" when the user clicks the jbutton1 the application runs and the text of jbutton1 changes from "Connect" to "Disconnect". Now again when the user clicks jbutton1 and the text is "Disconnect" so the application should close.

The code i have given here does not checks anything it automatically closes the application which i don't want. I want to check the text of the button if it is connect i should do a different process and if it is disconnect it shouls close my application when the button is clicked.

  private void jButton1ActionPerformed(java.awt.event.ActionEvent evt) {                                         
  if(jComboBox2.getSelectedItem()==null)
  {
  System.out.println("Select one name");

  }
 else
 {
try {

    Runtime r = Runtime.getRuntime();

    p = Runtime.getRuntime().exec("C:\\Program Files");


    AS a4sObj = new AS(new String[]{jComboBox2.getSelectedItem().toString()});  

} catch (IOException ex) {
    Logger.getLogger(serialportselection.class.getName()).log(Level.SEVERE, null, ex);
} 

 jButton1.setText("Disconnect");  //This sets connect button to disconnect

 if(jButton1.getText()== "Disconnect")  // I wanted to change this line of code
 {
     System.exit(0);
}

[How do I compare strings in Java?](http://stackoverflow.com/questions/513832/how-do-i-compare-strings-in-java) — MadProgrammer, Mar 17 '16 at 07:24

score 1 · Answer 1 · edited May 23 '17 at 12:07

1

This is wrong if(jButton1.getText()== "Disconnect") , take a look at this great answer to check the reason and learn how to compare Strings in java

You should do:

if("Disconnect".equalsIgnoreCase(jButton1.getText()))

instead

edited May 23 '17 at 12:07

Community

1
1

answered Mar 17 '16 at 04:36

ΦXocę 웃 Пepeúpa ツ

47,427
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in this case, `==` actually works as expected, since the string literals are internalized. – Erich Kitzmueller Mar 17 '16 at 06:52
1

@ammoQ But it's a bad habit to get into – MadProgrammer Mar 17 '16 at 07:24
in this case the PO just had luck, but the intention there was comparing content and not ref. as @MadProgrammer comments, it is a bad habit that can break down apps, and can bring bugs hards to find.... – ΦXocę 웃 Пepeúpa ツ Mar 17 '16 at 07:34
MadProgrammer: I agree. Anyway, I don't like the idea of testing the program's internal state by checking the text on a button, so replacing `==` with `equals` still doesn't make it a good program. – Erich Kitzmueller Mar 17 '16 at 09:58
@Xoce웃Пepeúpa I just pointed that out since your answer doesn't solve the problem at hand. – Erich Kitzmueller Mar 17 '16 at 09:59

score 1 · Accepted Answer · answered Mar 17 '16 at 06:54

1

Just move setText to the end:

 if(jButton1.getText()== "Disconnect")  // I wanted to change this line of code
 {
     System.exit(0);
}

jButton1.setText("Disconnect");  //This sets connect button to disconnect

answered Mar 17 '16 at 06:54

Erich Kitzmueller

36,381
5
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Thx fr ur answer it works fine. But now the folder I have given n runtime opens again once I click disconnect – Sruthi Acg Mar 17 '16 at 07:51
@SruthiAcg: move the `if` block to the top of the event handler – Erich Kitzmueller Mar 17 '16 at 09:55

Add an event for button

2 Answers2