Swing: what to do when a JTree update takes too long and freezes other GUI elements?
- by java.is.for.desktop
Hello, everyone!
I know that GUI code in Java Swing must be put inside
SwingUtilities.invokeAndWait or SwingUtilities.invokeLater.
This way threading works fine.
Sadly, in my situation, the GUI update it that thing which takes much longer than background thread(s). More specific: I update a JTree with about just 400 entries, nesting depth is maximum 4, so should be nothing scary, right? But it takes sometimes one second! I need to ensure that the user is able to type in a JTextPane without delays. Well, guess what, the slow JTree updates do cause delays for JTextPane during input. It refreshes only as soon as the tree gets updated.
I am using Netbeans and know empirically that a Java app can update lots of information without freezing the rest of the UI.
How can it be done?
NOTE 1: All those DefaultMutableTreeNodes are prepared outside the invokeAndWait.
NOTE 2: When I replace invokeAndWait with invokeLater the tree doesn't get updated.
NOTE 3: Fond out that recursive tree expansion takes far the most time.
NOTE 4: I'm using custom tree cell renderer, will try without and report.
NOTE 4a: My tree cell renderer uses a map to cache and reuse created JTextComponents, depending on tree node (as a key).
CLUE 1: Wow! Without setting custom cell renderer it's 10 times faster. I think, I'll need few good tutorials on writing custom tree cell renderers.
