Fix bug YH-3071. reviewed by redding.

@@ -169,7 +169,6 @@ export default class Posting extends Component {
                     <TextInput
                         style={styles.contentInput}
                         placeholder='用力敲出你想说的...'
-                        maxLength={2000}
                         multiline={true}
                         autoCorrect={false}
                         onFocus={() => {
@@ -178,6 +177,9 @@ export default class Posting extends Component {
                             });
                         }}
                         onChangeText={(text) => {
+                            if(text.length>2000) {
+                                text = text.substring(0,2000);
+                            }
                             this.contentLength = text.length;
                             this.props.contentEdited(text);
                         }}