优化发帖模块以及帖子详情模块。 reviewed by redding.

@@ -146,6 +146,7 @@ export default class Posting extends Component {
                     autoFocus={true}
                     autoCapitalize={'none'}
                     autoCorrect={false}
+                    selectionColor={'black'}
                     onFocus={() => {
                         this.setState({
                             showKeyboard: true,
@@ -171,6 +172,7 @@ export default class Posting extends Component {
                         placeholder='用力敲出你想说的...'
                         multiline={true}
                         autoCorrect={false}
+                        selectionColor={'black'}
                         onFocus={() => {
                             this.setState({
                                 showKeyboard: true,

@@ -248,6 +248,7 @@ export default class SubjectPost extends Component {
                                 multiline={true}
                                 autoCapitalize={'none'}
                                 autoCorrect={false}
+                                selectionColor={'black'}
                                 autoFocus={true}
                                 maxLength={1000}
                                 onChangeText={
@@ -292,6 +293,7 @@ export default class SubjectPost extends Component {
                                 placeholder={'回复'+this.someOneToReply+':'}
                                 multiline={true}
                                 autoCapitalize={'none'}
+                                selectionColor={'black'}
                                 autoCorrect={false}
                                 autoFocus={true}
                                 maxLength={1000}

@@ -310,6 +310,8 @@ export function requestPostContent(sid,postsId) {
                 });
         })
         .catch(error => {
+            Actions.pop();
+            Alert.alert('提示','帖子不存在或已被删除！');
             dispatch(contentRequestFailure(sid,error));
         });
     }