How do I colorize the text in a JFrame Title bar

Question

I have an application controlling hardware that has a JDialog displayed when the user wants 'backdoor' access to the hardware. That JDialog is filled with buttons and features and I don't want to increase its size, especially vertically. I do want to add a warning text so some new users will be warned not to play with the buttons, as doing the wrong thing can damage the hardware. Adding a dialog that the user has to dismiss is not an option.

There is space in the header I would like to use so I updated it to this: This is cool, but I would like to emphasize it by coloring the warning text red like this: I have tried using HTML tags which works in a JLabel, but the setTitle() method doesn't recognize them and just puts them into the header.

I though of using an icon, so I created a long rectangle with red text and called the setIconImage(): The icon is there but resized to fit a square. (Look at the upper left. I laughed, then sighed)

The only solution I could find searching the web is to create my own LookAndFeel, which I didn't want to get into, as it seems excessive for just a red text.

Is there a way to manipulate the text in a Title similar to what you can do to a JLabel?

In the past I have though about using that header space for often used controls but couldn't figure out how. For example, Microsoft Excel now has a Save icon and a Search Text Box up there on a spreadsheet. (Does Javafx have this feature?)

Answer 1

When an application displays a window, it tells the operating system: “I want to display a window with these contents, and with this title.”

The operating system then creates the title bar and its window management controls (close, minimize, maximize, and the window management menu). It is not just Java applications that work this way; programs written in any language also must create windows this way.

Since it is the operating system, not Java, that paints the title bar, there is no way to make it display colors.

Even a custom look-and-feel wouldn’t allow you to do it, for the same reason: Java doesn’t paint the title bar.

One option is creating an undecorated Frame: a Frame which tells the operating system, “I have a title but I don’t want the system to show it at all.”

Of course, that will mean having no title bar, and no window management controls. So you’ll have to draw them yourself. This isn’t as easy as it sounds, because your window will look weird and different unless you closely follow the system’s settings, including the current theme, font sizes, and HiDPI scaling. You will have to draw (and scale) the application icon. You will have to properly render the title text even when there isn’t enough horizonal room for it. And just adding minimize, maximize, and close buttons isn’t enough; you will need to emulate the behavior when the user clicks on the icon; when the user right-clicks, middle-clicks, or double-clicks on the title bar; when the user drags the window; and when the user drags the window near the edge of the screen.

Considering all the work needed to emulate a proper title bar, I would opt for adding a red banner at the top of a regular Frame instead.

You also asked: “Microsoft Excel now has a Save icon and a Search Text Box up there on a spreadsheet. (Does Javafx have this feature?)” The answer is that it does in theory: JavaFX lets you specify a stage style which is StageStyle.UNIFIED. This is supposed to give you a “unified title bar”—meaning, the title bar isn’t a separate area above the window content, but rather the window scene overlaps the title bar.

However, I can’t get it to work in Windows 10 or 11, and Platform.isSupported(ConditionalFeature.UNIFIED_WINDOW) returns false in Linux/Gnome. The setting is ignored in both. I have no way to test it in OSX.

So even with JavaFX, I would opt for a red banner across the very top of the window’s content area. Title bars have not been customizable (beyond disallowing minimize/maximize controls) for almost as long as GUI applications have existed.