Develop Reference

Is there an way to remove a JTextFiled if a certain item in JComboBox is selected in java?

I have a registration panel where if student, instructor, and course administrator can register so if student is selected it should show something like this when Student is selected:
and should show like this if other two are selected like this when any of other two are selected:
I tried using if condition on the selected item in where I have added those text fields but it seems it only works at the beginning of the program when I run it on the basis of what is pre-selected and does not change when I select other items in JComboBox. Is there a solution to this?

You can achieve this in different ways. One of such ways is to use Action Listeners. A JComboBox object generates an action event when a selection is made (see Handling Events on a Combo Box).
In your case, you need to trigger an event based on the selection made in a combo box. This action should change the visibility of components in your panel, which are simply changing the visible attribute from true to false (or vice versa) depending on the selection made.

Disabling JavaFX ComboBox input

How do I disable input on my editable Combobox? (Well, actually JFoenix JFXCombobox but it's basically the same apart from it's appearance)
setEditable(false) would disable keyboard input on the Combobox but the list would still appear
setDisabled(true) would disable whole Combobox but I want user to be able to focus Combobox so he can copy it's contents if necessery.
Why do I want it like that? In my forms user must first click edit button to be able to change stuff.

Basically, the method ComboBox.setEditable adds/removes an Editor to the ComboBox which can be retrieved via ComboBox.getEditor()
To keep the TextField (to copy from) but disable user-input, simply set the editable flag on the underlying TextField:
private ComboBox<String> myComboBox;
[...]
myComboBox.setEditable(true);
myComboBox.getEditor().setEditable(false);
EDIT:
As #jewelsea said in a comment below, you can hide the list as soon as the user requests to open it:
myComboBox.setOnShown(event -> comboBox.hide());
I think it would be "cleaner" to disable the button which opens the dropdown but unfortunately I have not yet found a way to do that.

How to make the textfield remember history of words typed in GXT

Do we have an option to make the GXT textfield remember the history of the words that have been given as an input. So when i click the textfield next time, it should list all the searches below the textbox. Thanks in advance!

You can use an editable combobox. In order to look like text field and hide the arrow image in combobox, you can use setHideTrigger(false). So, you can have a combo box that functions like a text box. Also, you can add all the search terms in a store. That is it. You are done.

JavaFX Table Menu Button list shows text but not graphic

I am working on an application that uses a TableView and has a Table Menu Button to add or remove columns from the list.
Since I wanted my column headers to have tooltips, I had no choice but to create a label and use it in the following manner in :
// Some code here
TableColumn col;
// some code here
col.setGraphic(header_title);
The problem with this is that when the program runs, the table menu button shows a list of empty text:
On the other hand when I do:
// Some code here
TableColumn col;
// some code here
col.setText(rs.getString("column_title"));
col.setGraphic(header_title);
I can see the text on the column menu, but the actual titles are appended to the graphic:
I have tried to look for a way to perform a setContentDisplay(GRAPHIC_ONLY), but this does not seem to exist for TableColumn, and I am not sure how to access the header node in order to set this setting.
Any help would be greatly appreciated.

Just forget about the inbuilt table menu button. It's absolutely minimal and not worth mentioning. If you e. g. want to click away 10 columns you have to click on the button, hide the column, click on the button, hide the column, etc. In other words: It closes as soon as you press a menu item.
You can't even extend it with e. g. a hide all and a show all button. And it's buggy: When the last column gets hidden, the menu button vanishes as well, so you have to restart your application if you want to see anything in your table again.
Just create your own table menu. There are 2 examples on this gist:
example which uses a lookup, i. e. works without reflection
example which uses reflection
Then you can adapt whatever header you want and whatever menu items you want.

Make a state change in one jcombobox enable a different jcombobox

I have 7 jcomboboxes, say:
customerInfo1
customerInfo2
customerInfo3
customerInfo4
customerInfo5
customerInfo6
customerInfo7
All but the first one are set to setEnabled(false) and have setSelectedItem("Please Select a Customer from the dropdown menu"). I am having the hardest time figuring out how I would go about listening for a state change on customerInfo1 which would then make customerInfo2 setEnabled(true). And, once customerInfo2 is enabled have a state change event trigger the same thing for customerInfo3, and so on. Basically I don't want a given customerInfo jcombobox to be enabled until something other than what was initially set is selected in the preceding one. Your clear and specific help is much appreciated.

you can add a focus listener on the combo boxes such that if a combo has lost focus then you can check about the condition and take your action accordingly!!!
eg
if we have a combo box then we would add a focus listener on it and check the condition whether the check box is checked or not then add the required combobox.
JComboBox jb1;
jb1.addFocusListener(this);
this is to be done in main and the following code in other method in the same class
public void focusLost(FocusEvent fe)
{
//your code for enabling or disabling the combo box
}
this should do the required thing
Regards
ChArAnJiT

You need to call a JavaScript method on change event of the first combo box.
Say if you change the state of the first combo box, this JavaScript method will be called and it will change the state of other combo boxes as u wish.
Same thing have to be done for all the other combo boxes.