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Thread: JCombobox help

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    Default JCombobox help

    Can somebody help me...............

    I actually dont know how to explain this but here it goes........

    I created a program which is a shipment calculator. There is part there were I have a Combobox which you can choose what type of Service you want to have.

    Now the thing that I need help on is how do you this:
    when you select a certain item in a combobox I the delivery time and price will appear on one of my textfields.
    example: I selected express service after selecting it 24hrs willl apear in my textbox and if I slect Critical 5 hrs will appear in my text box.

    I dont know which method to use I tried getItemAt but it wont work on a If statement.

    here is my code for that portion
     servi.setBounds(10,340,199,20);
            add(servi);
            servi.addItemListener(new ItemListener(){
           	public void itemStateChanged(ItemEvent event){
          	if(event.getStateChange()==ItemEvent.SELECTED){
     
     
     	}
     
           	}
           }
           	);
    Last edited by helloworld922; August 9th, 2010 at 09:10 AM. Reason: added my code


  2. #2
    Super Moderator Norm's Avatar
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    Default Re: JCombobox help

    it wont work on a If statement
    Can you explain? Do you get errors? Please copy and paste full text of the error message here.

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    sman36 (August 11th, 2010)

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    Default Re: JCombobox help

    to make my explanation easiser I just want to translate this into a java code:

    if I select item 1 from my drop down list 24 hrs will appear in my textfield.

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    Default Re: JCombobox help

    pseudo code:
    if(selected item is #1) {
    set textfield to 24 hrs
    }

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    sman36 (August 11th, 2010)

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    Default Re: JCombobox help

    ^^ yup thats what I mean but whats the real code for that?? what API should I use I'm very confused

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    Default Re: JCombobox help

    Look at the doc for the JComboBox: what method will tell you which item was selected
    and for the textfield: what method will set its value.

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    sman36 (August 11th, 2010)

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    Default Re: JCombobox help

    I know that getItemAt and setSelectedIndex will tell which item was selected but it wont work on if statements and I already know what method to use that will set the value of textfield its .setText

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    Default Re: JCombobox help

    What doc are you reading for the JComboBox class? Did you see any methods with names starting with get?

    it wont work on if statements
    Can you explain what "won't work"?

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    sman36 (August 11th, 2010)

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    Default Re: JCombobox help

    Is it just me, or is this redundant:
    public void itemStateChanged(ItemEvent event){
            if(event.getStateChange()==ItemEvent.SELECTED){

    Why would you have to check to see if ItemEvent.SELECTED if that will only fire in the itemStateChanged event and you cant deselect an item in a JComboBox (or can you?). What if instead of doing that search, you instead just called a reference to your JComboBox asking for the selected item?

    What's wrong with this:
    public void itemStateChanged(ItemEvent event)
    {
    	int selected = JComboBox.getSelectedIndex();
    	if(selected==1) // or if you want the first item: if(selected==0)
    	{
    		JTextField.setText("24 hrs");
    	}
    }

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    sman36 (August 11th, 2010)

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    Default Re: JCombobox help

    I got it !!!! thanks to everyone who posted

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    Default Re: JCombobox help

    Quote Originally Posted by aussiemcgr View Post
    Why would you have to check to see if ItemEvent.SELECTED if that will only fire in the itemStateChanged event and you cant deselect an item in a JComboBox (or can you?).
    When you make a selection, the previously selected item gets deselected.

    What if instead of doing that search, you instead just called a reference to your JComboBox asking for the selected item?
    Then that code is liable to be executed twice.

    db

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