public static String nullStrToEmpty(Object str) {

        return (str == null
                ? ""
                : (str instanceof String ? (String) str : str.toString()));
    }
null Object to empty string
<p/>
<pre>
nullStrToEmpty(null) = &quot;&quot;;
nullStrToEmpty(&quot;&quot;) = &quot;&quot;;
nullStrToEmpty(&quot;aa&quot;) = &quot;aa&quot;;
</pre>

@param str str
@return String
app/src/main/java/coder/prettygirls/util/StringUtil.java