When you want to improve an Android application performance, you need to do profiling. Welcome MAT!
What is MAT?
It’s a Java heap analyzer tool introduced by Eclipse that helps you find memory leaks.
First you need to extract a hprof file from the Android device. When running the device select the Dump HPROF file option as shown here
Convert the .hprof file from the Dalvik format to the J2SE HPROF format. You can do this using the hprof-conv tool provided in the Android SDK.
hprof-conv dump.hprof converted-dump.hprof
Import the converted hprof file into MAT, and start anaylzing