I've got a JTextField, and I'd like the system to do some processing on what the user typed whenever the user leaves the text field. The ActionListener that you can add to just the JTextField only fires when the user presses enter, however.
I'd like the processing routine to run whenever the user leaves the text box by any means - tabs, clicks out of it, presses enter, etc. (The processing in question is to save the text the user typed to the appropriate data object, nothing fancy.)
My google-fu has failed on this one: I'm confident that it's possible, I just can't see how.
Add a FocusListener.
It's worth noting that this is a relatively low-level listener. On JComboBox it wont work unless you find the text field (and perhaps button) that the particular PL&F inserts. Swing is a bit odd that way (amongst many other ways).
Although for my money, non-cosmetic changes that happen when focus leaves a field give poor user experience. Much better to do any relevant changes on every change with a listener on the text field's document.
If you want to edit the text as it is typed then you should use an DocumentFilter.
If you want to validate the text as a complete entity then you can use an InputVerifier.
Related
I am creating a simple form for a class and I want the user to be able to press enter after filling out one JTextField. It moves on to the next available JTextField (not all of them are editable at a given time), similar to using tab.
When it gets to the last editable JTextField it should submit the form. Is that possible or is tab and the usual enter function (as a submit my only option)?
I'll post the code if necessary, but if you can answer the question without it, that'd be great too.
Like Durandal mentioned, there are multiple ways to go about it.
You could use JTextField's addActionListener method, addAction method, addKeyListener method, etc... They're all fairly similar - you're telling the text field to do something when something happens. (Although exactly how you do it differs by method)
Regardless, each time the action will need to know which text field is next in line. Then you can call JTextField#requestFocus() to transfer input focus to it.
You can also do this with setFocusTraversalKeys and setNextFocusableComponent
I am creating a log in form in Java. I have already completed the entire structure of the program, as well, I have designed it's purpose and perfected it's functionality. However, now I am focusing on styling the program. I'm proud of it as it is and it's fine if I don't add this feature, however I really would like to and cannot discover how.
In summary, when a username is typed into the login form, I have a void that runs after the JTextField loses focus. This void searches for possible invalid characters such as spaces. I can successfully change the color of the border on my JTextField, and other attributes I wish to change, however I also would like to have a small dialogue box to hover over the JTextField to say what specifically is wrong with what was typed. (e.g. "Your username cannot contain spaces!").
Ideally, it would be a rectangle that could simply be filled with text, and only appear when the username is deemed incorrect, and be able to disappear when it is fixed ( I can handle the appearance and disappearance most likely, I just need help with creating this box thing ).
Is there any such thing as like a "JHoverBox" or something that I could add to my JTextField?
Well, you can have, as Gene said, a label that's normally empty near the text field, but you can have it coloured like the background colour. This will make the user not able to see it, and when you detect something wrong, you can change the colour and add the text. Simple!
I have a text box in which the user enters a unique number. After he enters a number and press tab or enter. I want to write query to search record matching to that unique number. The number is an integer. It will be passport no, pan card no or etc. If it is available in database, I want to display all information of that user.
I don't want to do that on button click.
I was looking for some TextChanged event but I found that the alternative in Java is the methods in document listener. But I am not getting how to use that. Also in Netbeans in the design view it does not show me any event on text changed. How to use Documentlistener to my JFrame/how to fix this?
Here you can find a tutorial on DocumentListeners and example code as well.
This is for an assignment so responses should not contain the code written for me.
I have written a program that is essentially an auto-complete program. It takes a word and returns the best matches.
I am trying to write a front end for it in swing(which I have no experience in) and want my front end to do the following: I want the input box to constantly be reading for user input, feeding that value to the other program, and returning the matches immediately in a drop down box, as, say, Google does. I can't seem to find any information on how to do this, all the intro tutorials use a submit button.
Can anyone explain to me how this would be done, or point me to a resource that could explain it? Again, please don't write the code for me, I don't want to unwittingly cheat on my assignment.
If you are using a JTextField, you could register a document listener on it.
If your input box is a JTextField, you can add a DocumentListener (this is a good tutorial) to capture character entries.
I think that no one from answerers ..., I'm only about Don't reinvent the wheel
1) use JTable with one (or two if is about Dictionary) Column and with basic implmentation for Sorting and Filtering (example with filtering from JTextField is in the Tutorial), JTable could be most complex from JComponents and there is everything (quite easilly) possible
2) use AutoComplete JComboBox / JTextField
3) use SwingX Decorator with JXList or JXTable
4) if you needed redirect output to the separate window then use JDialog / JWindow for popup window
One approach could be:
Attach a handler to detect a key press on the text box.
Grab the text from the box, and construct a "lookup" event which is runnable and submit this to some form of service which will dispatch it at some point in the future (hint: ExecutorService, Future)
Save this handle, and if the key press event happens again, cancel the previous and submit a new one.
When the event executes in the future and returns the result, popup a panel which displays the list of items.
I'm working on a form and I'd like to have a drop-down box where you select a person. It brings up their stored information in the text-fields below, but as soon as you edit one of the text-fields it disables the drop-down box until you save or cancel the changes. The purpose of this is to prevent the user from editing something, thinking it's saved, and then changing to a different person and losing their changes.
Add a DocumentListener to all your text fields. Whenever any data is changed you disable the combo box. When the data is saved you enable the combo box.
See How to Write a DocumentListener for more information and examples.
A better approach might be to popup a JDialog with the data to be changed.
Dynamically disabling combo boxes doesn't seem like a common practice. Perhaps instead you could indicate to the user when something is saved, and if the user attempts to switch people after info has been inputted, you could notify them and ask if they want to continue and lose the data. Is it not possible that some users will enter data, try to use a disabled combo box, and not knowing why it is disabled, they will think you program is broken?