android performance issue

my android application works well but it's performance(speed) is slow. In my logcat i saw frequent garbage collection operation like

11-02 15:07:20.647: DEBUG/dalvikvm(12571): G开发者_如何学CC freed 295 objects / 38448 bytes in 93ms

Is this the reason for low performance?? How can i improve my applications performance??? anybody please help

If you use the emulator don't worry - it is slow by itself. GC is not responcible for this i think, 93 ms is time you won't even notice. So try your application at the real phone and if there are preformance issues - use the profiler.

Your application performance in terms of user interface and memory is quite related.

In this case 93ms means that your device could be dropping about 6 frames in the ideal scenario. If the GC is executed often this could be a problem.

The Android ART/Dalvik virtual machine is a version of the Java Virtual Machine where the Garbage Collector implementation is based on generations. This means that your application process has a heap associated separated by different generations where the GC is going to act once a generation is full. You can think of these generations as buckets or arrays of memory.

Once a generation is full the Android virtual machine will start the garbage collector process. As the Android virtual machine can not collect and fragment your application heap while the app process is running the garbage collector event will stop all the threads in your app while the garbage collector is working. That's why your application can be dropping frames if the app garbage collector is invoked so repeatedly.

Here you have an example:

Last week I discovered my app was leaking memory. I discovered this because after 20 minutes using my app I noticed the UI was performing really slow. Closing/opening an activity or scrolling a RecyclerView was really slow. After monitoring some of my users in production using http://flowup.io/ I found this:

The frame time was really really high and the frames per second really really low. You can see that some frames needed about 2 seconds to render :S.

Trying to figure it out what was causing this bad frame time/fps I discovered I had a memory issue as you can see here:

Even when the average memory consumption was close to the 15MB at the same time the app was dropping frames.

That's how I discovered the UI issue. I had a memory leak in my app causing a lot of garbage collector events and that's was causing the bad UI performance because the Android VM had to stop my app to collect memory every single frame.

Looking at the code I had a leak inside a custom view because I was not unregistering a listener registered into a Android Choreographer instance. After releasing the fix, everything became normal :)

If your app is dropping frames due to a memory issue you should review two common errors:

• Review if your app is allocating objects inside a method invoked multiple times per second. An example could be creating new instances of an object inside a onDraw custom view method.
• Review if your app is registering an instance into the Android SDK but not releasing it. Registering a listener into a bus event could also be possible leak.

Disclaimer: The tool I've been using to monitor my app is under development. I have access to this tool because I'm one of the developers :) If you want access to this tool we will release a beta version soon! You can join in our web site: http://flowup.io/.

If you want to use different tools you can use: traveview, dmtracedump, systrace or the Andorid performance monitor integrated into Android Studio. But remember that this tools will monitor your connected device and not the rest of your user devices or Android OS installations.