How To Build WordPress App with React Native Part #10: Save Bookmark Feature

We are going to learn how to bookmark the articles so that we can easily access them in our Bookmark screen later. The process is simple. We are going to save post id to Asyncstorage from the SinglePost screen and then fetch the articles on the bookmark screen. Here, we are going to add the bookmark icon to the SinglePost screen and configure its functionality.

But first, we need to define the state variable called 

already_bookmark

SinglePost.js

 constructor(props) {
        super(props);
        this.state = {
          isloading: true,
          post: [],
          already_bookmark: false,
        };
      }

Then, we need to add the Bookmark icon to the screen. For that, we need to use the code from the following code snippet:

<List.Item
                 title={`Published on ${moment(
                   post[0].date,
                   'YYYYMMDD',
                 ).fromNow()}`}
                 right={props => {
                   if (this.state.already_bookmark == true) {
                     return (
                       <TouchableOpacity
                         onPress={() => this.removeBookMark(post[0].id)}>
                         <FontAwesome name="bookmark" size={30} />
                       </TouchableOpacity>
                     );
                   } else {
                     return (
                       <TouchableOpacity
                         onPress={() => this.saveBookMark(post[0].id)}>
                         <FontAwesome name="bookmark-o" size={30} />
                       </TouchableOpacity>
                     );
                   }
                 }}
               />

Here, we have displayed the bookmark icon template based on the

already_bookmark

TouchableOpacity

FontAwesome

removeBookMark 

saveBookMark

Hence, we will get the following result in the emulator screen:

Next, we need to use the AsyncStorage component from the
@react-native-community/async-storage package. For that, we need to use install the package first. In order to install the package we need to run the command from the following code snippet:

  yarn add @react-native-community/async-storage

We can get the information as well as the installation instruction from the
package documentation.

Now, we need to import this package into our Bookmark.js file as shown in the code snippet below:

 import AsyncStorage from '@react-native-community/async-storage';

Save Bookmark

Here, we are going to implement the saveBookMark function. For that, we need to define the function first as shown in the code snippet below:

  saveBookMark = async post_id => {
        this.setState({already_bookmark: true});
      };

Here, we have taken the parameter as post id with asynchronous execution of the function. Then, we have set the

already_bookmark

Now, we need to save the post id of the bookmarked post to the 

AsyncStorage

  saveBookMark = async post_id => {
             this.setState({already_bookmark: true});
             let bookmark = [];
             bookmark.push(post_id);
             AsyncStorage.setItem('bookmark', JSON.stringify(bookmark));

     };

Here, we have defined a new array called bookmark and pushed the post id value into it. Then, we have made use of the setItem function of the 

AsyncStorage 

Next, we need to prevent the duplicate bookmarks of the same article. For that, we need to use the code from the following code snippet:

  saveBookMark = async post_id => {
        this.setState({already_bookmark: true});
        await AsyncStorage.getItem('bookmark').then(token => {
          const res = JSON.parse(token);
          if (res !== null) {
            let data = res.find(value => value === post_id);
            if (data == null) {
              res.push(post_id);
              AsyncStorage.setItem('bookmark', JSON.stringify(res));
            }
          } else {
            let bookmark = [];
            bookmark.push(post_id);
             AsyncStorage.setItem('bookmark', JSON.stringify(bookmark));
          }
        });
      };

Here, we get the bookmark data and then parse it to an array called res. Then, if we have the bookmark data, we search the post_id for the current post. If the post does not exist in the bookmark, then we can add the bookmark to it and prevent duplicate bookmarks. The third case is for the users who have not made any bookmarks yet. Hence, we can normally apply and save the bookmarks using the saveBookMark function.

Summary

In this chapter, we learned how to implement the UI and functionality of the bookmark button using the 

AsyncStorage

This series intends to show how I build an app to serve content from my WordPress blog by using react-native. Since my blog is talking about react-native, the series and the articles are interconnected. We will learn how to set-up many packages that make our lives comfortable and learn how to deal with WordPress APIs. Here, the most prominent features talked about in the book are the dark theme, offline mode, infinite scroll and many more. You can discover much more in this series. this inspiration to do this tutorial series came from the React Native App Templates from instamobile