i dont know why but a week ago when i am debugging my app in android studio, the app in device is very slow, but if a generate the APK or use the play (Not debug) option works fine..
Anyone have idea why? I think i didnt any change in sdk or in the app to do it this..
When ART is enabled, the device cannot ensure the compiled code matches the bytecode instructions. It therefore cannot step through instructions and therefore lines.
This forces the device to fallback to a very slow interpreter, which possibly doesn't even JIT-compile.
For faster debugging, switch back to Dalvik.
来源：https://stackoverflow.com/questions/23300953/when-debugging-in-device-with-art-enabled-android-app-is-slow