Annotate the parameter in TextUtils#isEmpty() as @Nullable

package android.text;

import android.annotation.Nullable;

import android.content.res.Resources;

import android.os.Parcel;

import android.os.Parcelable;

     * @param str the string to be examined

     * @return true if str is null or zero length

     */

    public static boolean isEmpty(CharSequence str) {

    public static boolean isEmpty(@Nullable CharSequence str) {

        if (str == null || str.length() == 0)

            return true;

        else