java on Andrés Álvarez

Custom File Types in Netbeans Platform

Wed, 28 Mar 2018 00:00:00 +0000

If your desktop Java application needs to deal with very particular or special kinds of files, we can make use of Netbeans Platform's custom File Type feature to define a file that our application can recognize, and display visual and editing components to view and edit the file's data.

Moreover, we can also make use of Netbeans Platform's Favorites pane, which displays a tree view of a file system, where we can open the special files we need to work with.

Creating a New Module

For this article, we are going to create a new file type for CSV (Comma Separated Value) files. When we open these files, our application will display a visual representation in the form of an editable JTable.

All this functionaltiy will live in its own Netbeans Platform Module. Meaning that it can be plugged in into different applications in a modular fashion.

We are going to create the module and build it using Maven, since we are also going to be adding some functionalities that depend on external libraries that we can easily include in our project with Maven. But you can also just create the module without Maven as well. To create the module go to New Project > Maven > Netbeans Module

Java JTable Tricks

Wed, 20 Dec 2017 00:00:00 +0000

Java's JTable is a GUI component that has been around for many many years. While a bit difficult to work with, it's almost a mandatory component in an application that displays a lot of data.

In this post I share some nice tricks for working with JTables in Java applications.

Scrolling

A JTable by itself does not provide any scrolling when handling a lot of data. To fix this, we need to place the table inside a JScrollPane component. Additionally, we can place this JScrollPane into a JPanel in our window:

myPanel.add(new JScrollPane(myTable,
    JScrollPane.VERTICAL_SCROLLBAR_AS_NEEDED,
    JScrollPane.HORIZONTAL_SCROLLBAR_AS_NEEDED)
    );

Creating an Upload Progress Dialog in Java

Thu, 16 Nov 2017 00:00:00 +0000

Many Java file upload tutorials teach you how to show the current progress of a file upload using a JProgressBar in the user interface, usually placed in the main JFrame.

However I was trying make this much more visually appealing, like the way WinSCP does it:

This will require the use of another Swing class: JDialog. Basically the flow of the program will be like this:

Main class with main method calls SwingWorker class.
SwingWorker is in charge of doing the actual upload. It will also create an instance of a JDialog to show the current upload progress.
JDialog class will contain the progress bar and other useful upload information.