I want to create a dialog box that consists of one column of field titles and another column of fields. I want to be able to specify the fields to only allow specific types of data. Using swing, what is the most idiomatic way of creating a reusable class for accomplishing this?
A shown in Validating Input, you can use an InputVerifier to restrict input; a complete example is examined here. In the particular case of columnar data, a JTable can choose the editor based on the underlying model's data type—the value returned by getColumnClass(). You can let the editor validate user-entered text in your implementation of stopCellEditing(), illustrated here. In either case, you can add a panel containing the input component(s) to a dialog, as outlined here.
Related
I'm writing Java game right now, I have a problem that I have a List which type is Ranking, with the fields name and score, and I would like to add that fields to the JLabel. Method setText() unfortunately doesn't fix. What should I do?
with the fields name and score
A JLabel is not designed to display multiple lines of text.
You can format the text using HTML.
Or I would suggest a better approach is to use a JTable, which is designed to display data in a row/column format.
Read the section from the Swing tutorial on How to Use Tables for more information and working examples.
I have a List which type is Ranking
You may also want to check out Row Table Model for an example of a custom TableModel show how you can display your Ranking object in a table.
I'm in a position, where I have to populate a JComboBox with names from my users (5 users). When the user clicks the name in the JComboBox I want to retrieve the UserID of the user, not their actual name due some of them may be the same, and make a SQL query with their UserID as WHERE filter.
I have the all the users informations temporary stored in an Object, retrieved by a MySQL database.
How can I code a way to put more informations in the JComboBox, but only show the actual name to the user?
I hope this make sense, elsewhere feel free to ask questions.
Thanks in advance,
Jesper.
Create a User object that contains the name and user id with appropriate getters (and setters if required). Add these to the combo box. Use a ListCellRenderer to define how the User object is actually renderer.
See How to use comboboxes for more details
Check out Combo Box With Custom Renderer. It explains that you need to follow two steps to implement a proper solution:
use a custom renderer
use a custom KeySelectionManager so you don't break default combo box functionality when using a custom renderer
Is there any way in iText to format a TextField's input? I want to have a TextField accept a phone number "(###)###-####", but I don't want the user to have to format it when they enter it. Pdf supports masks on form fields, is there any way to do this in iText?
My current solution is to create the pdf in Acrobat, then populate known fields through iText. But that isn't ideal for this deployment. Ideally I'll have iText generate the entire form.
Thanks for all assistance in advance.
You can add JavaScript to your form that changes the content of fields. See for instance the Calculator example for a fun PDF that acts as a Calculator (obviously this app only works in a PDF viewer that supports JavaScript).
When you create a text field, you need to add an additional action with the setAdditionalActions() method. You can choose between different events: K for keystroke (e.g. useful if you want to change every character to uppercase when somebody fills out a form), Bl for blurred (useful to process the content of a field as soon as the focus is lost), etc.
You can write your own document-level JavaScript to format the fields. See calculator.js for the JavaScript used in the Calculator example. Or you can use one of the many AF methods that are predefined Adobe Reader, such as AFNumber_Format (I don't find an overview of the available methods right now).
I've been trying to freshen up on my Java knowledge and I've been building a small GUI program and I've been running into a bit of a problem.
Basically, I have a JList which I'm currently populating with strings from an object from one of my classes which implement AbstractListModel which we can call my ItemList class. It contains an ArrayList of objects of the type Item which implements Serializable.
But, what I'd like to do is rather than populate my JList with a bunch of strings I'd like to populate it with some kind of string + JTextField combination so I can see one property of each Item object while also being able to update another property by changing the JTextField.
Now, what I'm looking for is the simplest possible way of doing this, and I am assuming there is a (relatively) simple way to do this since it's such a common thing to want to do in a GUI application (although I wouldn't put it past Java and Swing to make it convoluted and complicated).
So, what is the correct way of doing this?
No need to ever use String objects. Instead:
Put Item objects in the JList.
Add a ListCellRenderer to the list, to show the Item object the most user friendly way.
When the user selects an item, show the details in a different place (I'm thinking a panel with 2 columns of labels and text fields, and two rows - one for each attribute, and perhaps a button to Save)
The edit controls would best be encapsulated in a panel that can then hidden when not required, & put in a variety of places, e.g.
Below the list
In the main part of the GUI
displayed in a JOptionPane or a (modal or not) JDialog
Here is an example of placing the 'view/edit panel' (the file details) below the selection component (the table).
I have a question about GUI design, specifically with Java Swing and creating clean separation between presentation and model.
It's a bit difficult to describe, but essentially we have lots of reference data in our system (i.e. that would correspond to lookup tables in the DB). We want people to be able to edit them all from one screen.
So, in an ideal world what we'd like is a combo box in the top-left corner with a list of 'types' of reference data (so each corresponding to one table in the DB).
Then, when selected, a list of the data is populated below, also a filter (or search box). When one of these items is selected, the panel to the right is activated which will allow the actual data to be edited.
Now, here's the problem: each type of data we need to edit is different, so it has different fields etc. We could go with a generic solution but I'm not really a fan of them - there are lots of different validation rules for each etc, even for different clients, and it would be a nightmare to manage.
We're using the Presentation Model pattern to achieve some degree of separation between GUI code and the model but I can't think of a clean way of doing this which doesn't somehow blur the line of responsibilities a bit.
What are the ways you have solved problems like this?
[Note: apologies for the long question, hope it's understandable, I can re-phrase if necessary]
You could use the Factory Pattern to create a UI widget for the element that you are selecting. You could also use it to create a validation rule object depending on the type. This would give you some of the flexibility you desire.
So you can have something like:
IWidget widget = UIFactory.createFor(myObject.getType())
That can be invoked on the selection event to create the right widget to edit the selected element.
The IWidget could have methods such as:
validateData()
refreshData()
setDataElement(IDataElement element)
That would allow you to treat all UI widgets generically, but still have a special UI widget for each element type. I am assuming that the elements that you are selecting from the table all implement some IDataElement interface that contains the getType() method.
I used this solution tied together with the Eclipse Extension mechanism to plug-in new UI elements into my "base" solution, to have an extensible core and a high level of reuse. You could achieve something similar by injecting types and widgets into your factory, either manually or with Spring.
If you dont want to go down the generic path, you could have your model hold a mapping of combobox item -> panel name for use with a CardLayout. You could then create custom panels for the editing each of the reference data types. When the combo box selection is changed, you can save the current state in your model, request the panel name of the current selection, prepare your next panel for display and then have your CardLayout show it.