kylin17

1. For paddingStart, Severity: Errors.
   because we also have paddingLeft, so for old platform, the paddingStart is ignored; so api < 17, the lint tool 
   will show error about paddingStart, and we do not currently support RTL, and paddingStart work the same way as 
   paddingLeft, so i think it really about the NewApi. Because the lint tool just check whether paddingStart is 
   compatible with api < 17, and I check that when api == 16, it works fine and does not crash. I have checked all
   the lint error list, i do not find other lint checks might solve this. So I think just add 
   tools:ignore="NewApi" will be fine. 
   
2. the warnings in build.gradle showing that some of the tools are using the old version, do i need change 
   these to newest, or just suppress lint to ignore NewerVersionAvailable.

kylin17

import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;

public abstract class EndlessRecyclerOnScrollListener extends RecyclerView.OnScrollListener {
    public static String TAG = EndlessRecyclerOnScrollListener.class.getSimpleName();

    private int previousTotal = 0; // The total number of items in the dataset after the last load
    private boolean loading = true; // True if we are still waiting for the last set of data to load.
    private int visibleThreshold = 5; // The minimum amount of items to have below your current scroll position before loading more.
    int firstVisibleItem, visibleItemCount, totalItemCount;