I did not put any undefined variables in the view but it appear some Unknow tags,so I wonder what is Unknown there?
<View> <View style={styles.row}> <Text>{rowData.user.name}· {rowData.createdDate}</Text> <Text>{rowData.title}</Text> </View> <View style={styles.separator} /> </View>
in chrome I seen between the View and Text there is a Unknown.
I wonder if this is due to text nodes in your code, specifically white space like tabs and newlines. Please see this issue from the react dev tools:
https://github.com/facebook/react-devtools/issues/44
There are several such issues on the devtools tracker, sometimes related to a lack of displayName on components but I don't see how that applies here.
Suggest opening an issue on the React Native Github tracker as I doubt this is expected. Someone on the RN team might be able to give us a better explanation.
Did you define Text and View?
At the top of your file you should have something like this,
ES6
var { View, Text, } = React; ES5
var View = React.View; var Text = React.Text; 
