closes #5 Hide placeholder when focused

Author: alvaromb

FloatingLabel.js

@@ -54,7 +54,7 @@ class FloatingLabel extends Textbox {
           {locals.label}
         </Animated.Text>
 
-      const placeholderString = (self.state.placeholderString !== undefined) ? self.state.placeholderString : locals.label;
+      const placeholderString = (self.state.fieldFocused) ? '' : self.state.placeholderString || locals.label;
       return (
         <TouchableWithoutFeedback onPress={() => {
             if (locals.editable === false) {
@@ -147,6 +147,10 @@ class FloatingLabel extends Textbox {
     ].forEach((name) => locals[name] = this.props.options[name]);
     return locals;
   }
+
+  shouldComponentUpdate (nextProps, nextState) {
+    return true;
+  }
 }
 
 const styles = React.StyleSheet.create({