Summary of problems when coding

Git commit problems

1. Warning:(142, 62) Suspicious call to ‘HashMap.get’
2. android git commit Warning:(3, 1) Default File template
3. Not annotated parameter overrides @NonNull parameter

It's an annotation, but the correct name is NonNull:protected void onSaveInstanceState(@NonNull Bundle outState)(And also)import android.support.annotation.NoNNull;The purpose is to allow the compiler to warn when certain assumptions are being violated (such as a parameter of a method that should always have a value, as in this particular case, although there are others). From the Support Annotations documentation:The @NonNull annotation can be used to indicate that a given parameter can not be null.If a local variable is known to be null (for example because some earlier code checked whether it was null), and you pass that as a parameter to a method where that parameter is marked as @NonNull, the IDE will warn you that you have a potential crash.They are tools for static analysis. Runtime behavior is not altered at all.In this case, the particular warning is that the original method you're overriding (in Activity) has a @NonNull annotation on the outState parameter, but you did not include it in the overriding method. Just adding it should fix the issue, i.e.@Overrideprotected void onSaveInstanceState(@NonNull Bundle outState) {    super.onSaveInstanceState(outState);}

4.BitmapDrawable() method deprecated

popupMessage.setBackgroundDrawable(null) will clear the background.

5.catch branch identical to ‘FileNotFoundException’ branch

You can collapse exception branches if they're identical, and with the multi-catch syntax, you'll wind up with one catch statement that does the same thing as your three:

RecyclerView Problem

1. When data changes, the view not change (Because Picasso cache)