Question

I have an application which has (mostly) images in its layouts. As I understand, Android is supposed to free the memory when the activity is not needed anymore. Thus, I am not releasing this Drawables used by my app’s layouts when the Activity goes onPause() manually. I understand Android should do this.

Then, I use this code to check the memory status:

{
    ActivityManager activityManager = (ActivityManager) context.getSystemService(Context.ACTIVITY_SERVICE);
    android.app.ActivityManager.MemoryInfo memoryInfo = new ActivityManager.MemoryInfo();
    activityManager.getMemoryInfo(memoryInfo);

    Log.i("MEMCHECK", " memoryInfo.availMem " + memoryInfo.availMem + "\n" );
    Log.i("MEMCHECK", " memoryInfo.lowMemory " + memoryInfo.lowMemory + "\n" );
    Log.i("MEMCHECK", " memoryInfo.threshold " + memoryInfo.threshold + "\n" );

    android.os.Debug.MemoryInfo[] memoryInfoArray = activityManager.getProcessMemoryInfo(pids);
    for(android.os.Debug.MemoryInfo pidMemoryInfo: memoryInfoArray) {
        Log.i("MEMCHECK", " pidMemoryInfo.getTotalPrivateDirty(): " + pidMemoryInfo.getTotalPrivateDirty() + "\n");
        Log.i("MEMCHECK", " pidMemoryInfo.getTotalPss(): " + pidMemoryInfo.getTotalPss() + "\n");
        Log.i("MEMCHECK", " pidMemoryInfo.getTotalSharedDirty(): " + pidMemoryInfo.getTotalSharedDirty() + "\n");
}

On every created activity, the memory footprint grows (the heap – getTotalPrivateDirty() ). I don’t wanna do this since every ‘kb’ of memory in my app is really important.

Also, when this callback is processed:

Camera.PictureCallback mPictureCallback = new Camera.PictureCallback() {
    public void onPictureTaken(byte[] imageData, Camera c) {

    }
}

Empty, just like that. The heap grows from 10MB to 20MB. 100%. Is this normal? How to avoid?

Answer 1

For images and Callbacks you need to free memory manually, instead being dependent on garbage collector.
Also you need to take care of context of the views. whereas possible assign context at lowest level, like if a view is to be used only in an activity, assign it activity context, if a listener/callback should be used only in view, assign view context to it.

And also you can unbind xml drawables manually.