The subnet calculator helps you design networks by taking an IP address and network mask and returning information such as network, broadcast address, and host range.
One of a set of tools we're offering as a way of saying thank you for being a part of the community.
adding new items into JComboBox
Hi,
I have a JComboBox already. And now I would like make this JComboBox bigger, more choices, if some flags are set. How can I do this?
Here is my codes...
String ComboBoxStr[] = { "a1", "a2", "a3", "a4", "a5"};
JComboBox aComboBox = new JComboBox(ComboBoxStr);
Boolean setFlag = false;
if (setFlag == true)
{
// let say if I want to have 5 more choices like this...ComboBoxStr[] = { "a1", "a2", "a3", "a4", "a5", "a6", "a7", "a8", "a9", "a10"};
// so what can I do here???
}
I have a JComboBox already. And now I would like make this JComboBox bigger, more choices, if some flags are set. How can I do this?
Here is my codes...
String ComboBoxStr[] = { "a1", "a2", "a3", "a4", "a5"};
JComboBox aComboBox = new JComboBox(ComboBoxStr);
Boolean setFlag = false;
if (setFlag == true)
{
// let say if I want to have 5 more choices like this...ComboBoxStr[] = { "a1", "a2", "a3", "a4", "a5", "a6", "a7", "a8", "a9", "a10"};
// so what can I do here???
}
Who is Participating?
you can just add the new items. eg.
aComboBox.addItem("a6");
aComboBox.addItem("a7");
aComboBox.addItem("a8");
aComboBox.addItem("a9");
aComboBox.addItem("a10");
aComboBox.addItem("a6");
aComboBox.addItem("a7");
aComboBox.addItem("a8");
aComboBox.addItem("a9");
aComboBox.addItem("a10");
If I do have an ActionListener when I first initialized aComboBox and now I add some new items...will the new items also ahve action listener???
so that means I don't need to add ActionListener to the new items?? Ok...so if I want to remove the new item...I need to use "removeItem"??
How can I know whether the new item I wanna add is existing in a JComboBox so I won't add another one again??
How can I know whether the new item I wanna add is existing in a JComboBox so I won't add another one again??
>> so that means I don't need to add ActionListener to the new items??
The actionlistener listens to actions happening on *the combobox* no matter how many items are in it
>> if I want to remove the new item
To remove you can use
void removeItem(Object anObject)
or
void removeItemAt(int anIndex)
For the first you have to pass the object that is in it
For the first you only need to pass the index
>>How can I know whether the new item I wanna add is existing in a JComboBox so I won't add another one again??
Whenever you add an item to it or remove an item from it, you could also add/remove it from a Set.
Then before adding you could look if it exists in the set. If so, you shouldn't add it anymore.
(The Set is for not having to interrogate each item of the Combobox to check if the item you want to insert is already in)
The actionlistener listens to actions happening on *the combobox* no matter how many items are in it
>> if I want to remove the new item
To remove you can use
void removeItem(Object anObject)
or
void removeItemAt(int anIndex)
For the first you have to pass the object that is in it
For the first you only need to pass the index
>>How can I know whether the new item I wanna add is existing in a JComboBox so I won't add another one again??
Whenever you add an item to it or remove an item from it, you could also add/remove it from a Set.
Then before adding you could look if it exists in the set. If so, you shouldn't add it anymore.
(The Set is for not having to interrogate each item of the Combobox to check if the item you want to insert is already in)
Question has a verified solution.
Are you are experiencing a similar issue? Get a personalized answer when you ask a related question.
Have a better answer? Share it in a comment.
All Courses
From novice to tech pro — start learning today.
-
Course of the Month5 days, left to enrollMonitoring and Operating a Private Cloud with System Center 2012 R2 273 lessons
Set theSet = new HashSet()
1) Adding to the combo box should be like this:
instead of
yourCombo.add("a1");
you should write:
if ( !theSet.contains("a1") ) {
yourCombo.add("a1");
theSet.add("a1")
}
2) Removing
instead of
yourCombo.removeItem("a1")
you should write:
yourCombo.removeItem("a1")
theSet.remove("a1");