CODEWITHSUNDEEP
javamultithreadingswingjframeswingworker
A. Wali
A. Wali

Reputation: 454

Using SwingWorker to show a loading animation

My Problem:

I have a long executing task in my application (Needs to fetch data from the web), and I'm trying to display a loading screen with an animation (Just a rotating circle, no progress bar needed) while the task is being executed

What I have done so far:

I created the design for the loading screen in a panel and added it to a JFrame and tried to call instantiate the JFrame before the the code for the long process, and then dispose it after the process is done, like this:

LoadingFrame frame = new LoadingFrame();
//Long Process 
Wiring wiring = new Wiring(node.source); 
wiring.generateScopeForTargetNode();
// close() calls setVisible(false) and then dispose()
frame.close();

However, the frame did not get repainted until the task was done and all I received was a blank box, and in the end it didn't get disposed.

I searched SO for the problem, and found that it has to do with Threads and concurrency (Which I am unfamiliar with) and found suggestions to use JDialog instead of JFrame, so I followed the suggestion. What I ended up with is this:

What I need Help with:

I have tried to search more for the problem and found suggestions that I should use SwingWorker to run one task in a thread and the animation in another if I have understood correctly. However I am unfamiliar with threads and with SwingWorker and need help in creating a simple SwingWorker instance that achieves what I'm trying to do

Upvotes: 2

Views: 1023

Answers (1)

trashgod
trashgod

Reputation: 205855

Use a SwingWorker "to fetch data from the web" in the background. publish() interim results as they arrive. Your implementation of process() can then safely update a view component's model on the event dispatch thread. With even modest granularity, the user will start seeing data instead of an uninformative animation. This complete example updates the TableModel of a listening JTable, but the Document of a listening JTextComponent would work as well.

Upvotes: 1

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