Why does my App start incredibly slow (10s+) at first run, showing only white screen on android 5.0?

Question

I have a freshly created app (built in android studio 2.0), having a few activities.

When I test it on my Android 4.3 (note 2) device it starts nicely and fast after

Answer 1

This is because of InstantRun feature, it only occurs with debug-builds.

If you want to stop using InstantRun go to Settings>Build,Execution,Development>InstantRun and then uncheck all and apply.