To fix the error shown by NetBeans, click on the light bulb to the left of the code line and allow it to import javafx.application.Platform. After a quick click on the Save All button, we're good to go from the NetBeans side. Now to go back to Scene Builder to wrap things up.
And Back to Scene Builder
In order for our buttons to tie to our new methods, we need to connect them to the names we gave those methods in our SampleController class. First, we'll select the top Button (clickmeButton) in the Hierarchy panel. Next we turn our attention to the Properties panel on the right. At the bottom of the right side is a collapsed section labeled "Code: Button". Clicking that line opens the Code properties window so we can update the OnAction property. Notice it still points to the method formerly known as handleButtonAction. Click the dropdown, select handleClickmeButtonAction, tab out of the field, and we're done with that button.
We repeat some of the same steps with the other (Exit) button, although since we already have the Code properties panel open, selecting the button takes us directly there. Choosing handleExitButtonAction from its OnAction dropdown and tabbing out of the field concludes our work with Exit. But there is one more thing, purely cosmetic though it may be...
Since we added quite a lot of text to our label (see the handleClickmeButton method in the SampleController class), we may want to change the default behavior of our display label. Labels default to using an ellipsis when the length of text to display exceeds the space available, but we want to see the text in its entirety! Clicking the "Wrap" checkbox in the label's Properties panel fixes that up nicely and concludes our work in Scene Builder. Click File, Save, and then back to NetBeans for our maiden voyage!
And Now Back to NetBeans for the Big Finale!
Right-clicking the project in the Projects window to the left and clicking Run provides these satisfying results:
Clicking the "Click Me" button displays the following:
And clicking the Exit button closes the application.
Start to finish, you just developed a JavaFX application using Scene Builder in less time than it takes to drink a cup of coffee...while learning your way around in the process. Fast, fun, and productive: THAT is JavaFX.
All the best,
P.S. - There isn't much to the code, but I'll post it to GitHub if anyone wants it. Just let me know.
P.P.S. - If there is any interest in a video, please let me know that as well by commenting below. No promises, but if enough people ask and I can find some free time...