Performance issues in Main thread even with AsyncTasks

Question

My Main thread seems to be pretty bad with performance. Transitioning between activities results in significant delays. I have pushed all of Web/Bitmap/File work into AsyncTasks and yet this is still happening. I have been doing my head in trying to figure out what is causing the slow-downs.

My question is - If the Main thread uses a class (say ImageDownloader) that creates its own little AsyncTasks (say ImageDownloadTask), will Main wait for ImageDownloader to finish it's AsyncTasks (hence delays?)

I would love to post code, but it's a very large project. If there is anything specific I should look for, please let me know and I'll be sure to share.

Answer 1

If you haven't already done so, I recommend you enable strict mode and look for activity on the main thread that way.

Answer 2

Check your onCreates and onResumes for anything that might run for more than an instant. This includes network calls, database calls, loops that may have a lot of iterations, and even reading from locally stored files (SharedPreferences read from an xml). Also try to benchmark how long your onCreate executes the setContentView method -- I believe nested LinearLayouts cause significant performance hits especially in complex UI structures. Acquiring a location with the LocationProvider, when not done properly, will also cause severe performance issues.

You may think you are fine with passing off long-running threads on an asynctask, but you also need to check that prior to starting these tasks, the data you need to start them may take a while to acquire.