CODEWITHSUNDEEP
javaandroidnullpointerexception
drew moore
drew moore

Reputation: 32680

NullPointerException on populating data in BaseAdapter

I'm trying to populate a listview with data passed into the activity via a the intent that created it. The println statement you see confirms that the data is passed in correctly (i.e. the expected content is printed, meaning that the ArrayList referenced in the adapter is properly initialized). However, I keep getting a NullPointerException on the line 

content.setText(Html.fromHtml(cmts.get(position).content));

There must be something wrong in the adapter - maybe in the getItem(), or perhaps my calls to cmts.get(position) isn't doing what I think it is, but at this point I can't figure it out.

public class CommentsView extends Activity {
ArrayList<Comment> cmts;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_comments_view);

    cmts = (ArrayList<Comment>) getIntent().getExtras().getSerializable("clist");

    for (Comment c : cmts) {
        System.out.println("CMTinCV: " + c.content);
    }

    ListView lv = (ListView)findViewById(R.id.commentsList);

    CommentAdapter ca = new CommentAdapter();

    lv.setAdapter(ca);

}   

class CommentAdapter extends BaseAdapter {
    public CommentAdapter(){

    }
@Override
public int getCount() {
    return cmts.size()-1;
}

@Override
public Object getItem(int position) {
    return cmts.get(position);
}

@Override
public long getItemId(int position) {
    return position;
}

@Override
public View getView(int position, View convertView, ViewGroup parent) {

    if (convertView == null) {
        convertView = getLayoutInflater().inflate(R.layout.commentbox, null);

        TextView content = (TextView)findViewById(R.id.commentText);
        TextView author = (TextView)findViewById(R.id.commentAuthor);            
        TextView date = (TextView)findViewById(R.id.commentDate);     

        content.setText(Html.fromHtml(cmts.get(position).content));
        author.setText(cmts.get(position).author.name);
        date.setText(cmts.get(position).date);   
    }

    return convertView;
}

}
}

Upvotes: 1

Views: 370

Answers (4)

hardartcore
hardartcore

Reputation: 17037

Change your Adapter's constructor to this (if it's not an inner class for your activity) :

ArrayList<Comment> cmts;
public CommentAdapter(ArrayList<Comment> mComments){
     this.cmts = mComments;
}

and these lines :

TextView content = (TextView)findViewById(R.id.commentText);
TextView author = (TextView)findViewById(R.id.commentAuthor);            
TextView date = (TextView)findViewById(R.id.commentDate);

should be like :

TextView content = (TextView) convertView.findViewById(R.id.commentText);
TextView author = (TextView) convertView.findViewById(R.id.commentAuthor);            
TextView date = (TextView) convertView.findViewById(R.id.commentDate);

Upvotes: 2

Nani
Nani

Reputation: 11

To create the adapter like this

CommentAdapter ca = new CommentAdapter(cmts);

And CommentAdapter class to create constructor like this

public CommentAdapter(ArrayList<Comment> cmts){
       this.cmts = cmts;
}

And create local variable in CommentAdapter class

 private ArrayList<Comment> cmts;

Upvotes: 0

GrIsHu
GrIsHu

Reputation: 23648

You need to access the textview's in your getview method as below: convertView.findViewById(R.id.commentText); access it like this.

  @Override
   public View getView(int position, View convertView, ViewGroup parent) {
   if (convertView == null) {
    convertView = getLayoutInflater().inflate(R.layout.commentbox, null);

    TextView content = (TextView)convertView.findViewById(R.id.commentText);
    TextView author = (TextView)convertView.findViewById(R.id.commentAuthor);            
    TextView date = (TextView)convertView.findViewById(R.id.commentDate);     

    content.setText(Html.fromHtml(cmts.get(position).content));
    author.setText(cmts.get(position).author.name);
    date.setText(cmts.get(position).date);   
}
  return convertView;
 }

Upvotes: 3

Nermeen
Nermeen

Reputation: 15973

Check if the variable is null or not first:

if(cmts.get(position) != null) {
    content.setText(Html.fromHtml(cmts.get(position).content));
    author.setText(cmts.get(position).author.name);
    date.setText(cmts.get(position).date); 
}

Upvotes: 0

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