Warning shows when i use Hash Map In android(Use new SparseArray<String>)

Question

I am new to developing in android. In my android app I'm using HashMap, but I'm getting a warning:

**"Use new SparseArray<String>(...) instead for better performance"** 

What does this mean, and how can I use SparseArray<String> instead?

Answer 1

Use new SparseArray<String>(...) instead for better performance

You are getting this warning because of reason described here.

SparseArrays map integers to Objects. Unlike a normal array of Objects, there can be gaps in the indices. It is intended to be more efficient than using a HashMap to map Integers to Objects.

Now

how i use SparseArray ?

You can do it by below ways:

1. HashMap way:

   Map<Integer, Bitmap> _bitmapCache = new HashMap<Integer, Bitmap>(); private void fillBitmapCache() {      _bitmapCache.put(R.drawable.icon, BitmapFactory.decodeResource(getResources(), R.drawable.icon));      _bitmapCache.put(R.drawable.abstrakt, BitmapFactory.decodeResource(getResources(), R.drawable.abstrakt));      _bitmapCache.put(R.drawable.wallpaper, BitmapFactory.decodeResource(getResources(), R.drawable.wallpaper));      _bitmapCache.put(R.drawable.scissors, BitmapFactory.decodeResource(getResources(),   }  Bitmap bm = _bitmapCache.get(R.drawable.icon); 

2. SparseArray way:

   SparseArray<Bitmap> _bitmapCache = new SparseArray<Bitmap>(); private void fillBitmapCache() {      _bitmapCache.put(R.drawable.icon, BitmapFactory.decodeResource(getResources(), R.drawable.icon));      _bitmapCache.put(R.drawable.abstrakt, BitmapFactory.decodeResource(getResources(), R.drawable.abstrakt));      _bitmapCache.put(R.drawable.wallpaper, BitmapFactory.decodeResource(getResources(), R.drawable.wallpaper));      _bitmapCache.put(R.drawable.scissors, BitmapFactory.decodeResource(getResources(),   }  Bitmap bm = _bitmapCache.get(R.drawable.icon); 

Hope it Will Help.