Add data to ArrayList android

Question

In logcat I am getting a null pointer exception for this code sample. I am trying to add the e.g oneObject.has(TAG_TITLE) inside an Arraylist but when I print currentPost.getid() for example i am getting this nullpointer excepttion. Can someone help me please.

// getting JSON string from URL

JSONArray jArray = jParser.getJSONFromUrl(url);
ArrayList<Post> PostList = new ArrayList<Post>();
Post currentPost = new Post();

// looping through All element
for(int i = 0; i < jArray.length(); i++){
    try{
        JSONObject  oneObject = jArray.getJSONObject(i);
        // Storing each json item in variable
        if(oneObject.has(TAG_ID)){
            id = oneObject.getString(TAG_ID);
            currentPost.setId(id);
        }
        else{
            id="";
        }
        if(oneObject.has(TAG_TITLE)){
            title = oneObject.getString(TAG_TITLE);
            currentPost.setTitle(title);
        }
        else{
            title ="";
        }
        if(oneObject.has(TAG_CONTENT)){
            content = oneObject.getString(TAG_CONTENT);
            currentPost.setContent(content);
        }
        else{
            content ="";
        }
        System.out.println("postlist: "+currentPost.getId());
        PostList.add(currentPost);
        currentPost = new Post();   

Answer 1

In your code

// Storing each json item in variable

                    if(oneObject.has(TAG_ID)){

                        id = oneObject.getString(TAG_ID);

                        currentPost.setId(id);
                    }
                    else{

                        id="";
                    }

You have missed to set the Id for current oneObject.has(TAG_ID) returns false.

Best way to avoid this would be to return empty string from all your getters if the parameter is not being set.

EDIT:

Add make the change that is in bold.

// Storing each json item in variable

                    if(oneObject.has(TAG_ID)){

                        id = oneObject.getString(TAG_ID);

                        currentPost.setId(id);
                    }
                    else{

                        id=""; 
                        **currentPost.setId(id);**
                    }

Answer 2

you also need to set currentPost object fields values to default value if key name not exist in Json String as :

           // your code here...
            if(oneObject.has(TAG_ID)){

                id = oneObject.getString(TAG_ID);

                currentPost.setId(id);
            }
            else{

                id="DEFAULT_VALUE";
                currentPost.setId(id);  //<<<< set default value here
            }
           // your code here...