SparseArrayAdapter for Spinner and Listview

SparseArrayAdapter.java

import android.content.Context;
import android.content.res.Resources;
import android.support.annotation.IdRes;
import android.support.annotation.LayoutRes;
import android.support.annotation.NonNull;
import android.util.Log;
import android.util.SparseArray;
import android.view.ContextThemeWrapper;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.TextView;
import android.widget.ThemedSpinnerAdapter;

/*
* @author PlexusSquare Software Solutions Pvt Ltd
* */

public class SparseArrayAdapter<E> extends BaseAdapter implements ThemedSpinnerAdapter {
    private Context mContext;
    private final LayoutInflater mInflater;
    /**
     * Contains the list of objects that represent the data of this ArrayAdapter.
     * The content of this list is referred to as "the array" in the documentation.
     */
    private SparseArray<E> mObjects;

    /**
     * The resource indicating what views to inflate to display the content of this
     * array adapter.
     */
    private int mResource;

    /**
     * The resource indicating what views to inflate to display the content of this
     * array adapter in a drop down widget.
     */
    private int mDropDownResource;

    /**
     * Layout inflater used for {@link #getDropDownView(int, View, ViewGroup)}.
     */
    private LayoutInflater mDropDownInflater;

    /**
     * If the inflated resource is not a TextView, {@link #mFieldId} is used to find
     * a TextView inside the inflated views hierarchy. This field must contain the
     * identifier that matches the one defined in the resource file.
     */
    private int mFieldId = 0;

    /*// A copy of the original mObjects array, initialized from and then used instead as soon as
    // the mFilter ArrayFilter is used. mObjects will then only contain the filtered values.
    private SparseArray<E> mOriginalValues;
    private ArrayFilter mFilter;*/

    /**
     * Constructor
     *
     * @param context  The current context.
     * @param resource The resource ID for a layout file containing a TextView to use when
     *                 instantiating views.
     * @param objects  The objects to represent in the ListView.
     */
    public SparseArrayAdapter(Context context, @LayoutRes int resource, @NonNull SparseArray<E> objects) {
        this(context, resource, 0, objects);
    }

    /**
     * Constructor
     *
     * @param context            The current context.
     * @param resource           The resource ID for a layout file containing a layout to use when
     *                           instantiating views.
     * @param textViewResourceId The id of the TextView within the layout resource to be populated
     * @param objects            The objects to represent in the ListView.
     */
    public SparseArrayAdapter(Context context, @LayoutRes int resource, @IdRes int textViewResourceId,
                              @NonNull SparseArray<E> objects) {
        mContext = context;
        mInflater = LayoutInflater.from(context);
        mResource = mDropDownResource = resource;
        mObjects = objects;
        mFieldId = textViewResourceId;
    }

    /**
     * {@inheritDoc}
     */
    public View getView(int position, View convertView, ViewGroup parent) {
        return createViewFromResource(mInflater, position, convertView, parent, mResource);
    }

    private View createViewFromResource(LayoutInflater inflater, int position, View convertView,
                                        ViewGroup parent, int resource) {
        View view;
        TextView text;

        if (convertView == null) {
            view = inflater.inflate(resource, parent, false);
        } else {
            view = convertView;
        }

        try {
            if (mFieldId == 0) {
                //  If no custom field is assigned, assume the whole resource is a TextView
                text = (TextView) view;

            } else {
                //  Otherwise, find the TextView field within the layout
                text = (TextView) view.findViewById(mFieldId);
            }
        } catch (ClassCastException e) {
            Log.e("SparseArrayAdapter", "You must supply a resource ID for a TextView");
            throw new IllegalStateException(
                    "SparseArrayAdapter requires the resource ID to be a TextView", e);
        }

        E item = getItem(position);

        if (item instanceof CharSequence) {
            text.setText((CharSequence) item);
        } else {
            text.setText(item.toString());
        }

        return view;
    }

    /**
     * {@inheritDoc}
     */
    /*public Filter getFilter() {
        if (mFilter == null) {
            mFilter = new ArrayFilter();
        }
        return mFilter;
    }*/
    public void setData(SparseArray<E> data) {
        mObjects = data;
    }

    @Override
    public int getCount() {
        return mObjects.size();
    }

    @Override
    public E getItem(int position) {
        return mObjects.valueAt(position);
    }

    @Override
    public long getItemId(int position) {
        return mObjects.keyAt(position);
    }

    /**
     * <p>Sets the layout resource to create the drop down views.</p>
     *
     * @param resource the layout resource defining the drop down views
     * @see #getDropDownView(int, android.view.View, android.view.ViewGroup)
     */
    public void setDropDownViewResource(@LayoutRes int resource) {
        this.mDropDownResource = resource;
    }

    /**
     * Sets the {@link Resources.Theme} against which drop-down views are
     * inflated.
     * <p/>
     * By default, drop-down views are inflated against the theme of the
     * {@link Context} passed to the adapter's constructor.
     *
     * @param theme the theme against which to inflate drop-down views or
     *              {@code null} to use the theme from the adapter's context
     * @see #getDropDownView(int, View, ViewGroup)
     */
    @Override
    public void setDropDownViewTheme(Resources.Theme theme) {
        if (theme == null) {
            mDropDownInflater = null;
        } else if (theme == mInflater.getContext().getTheme()) {
            mDropDownInflater = mInflater;
        } else {
            final Context context = new ContextThemeWrapper(mContext, theme);
            mDropDownInflater = LayoutInflater.from(context);
        }
    }

    @Override
    public Resources.Theme getDropDownViewTheme() {
        return mDropDownInflater == null ? null : mDropDownInflater.getContext().getTheme();
    }

    @Override
    public View getDropDownView(int position, View convertView, ViewGroup parent) {
        final LayoutInflater inflater = mDropDownInflater == null ? mInflater : mDropDownInflater;
        return createViewFromResource(inflater, position, convertView, parent, mDropDownResource);
    }
}