Delete selected row in listview in android

Question

I have a listview with custom row having a textview and a clickable image for deleting the row. Listview gets the data from sqlite database. I have successfully loaded the data from the database into the listview. What I want is to delete that row from the database when delete button is pressed. I know this requires binding onclick event handler to the delete button and getting the object or sqlite data bound with the row. How can I get the sqlite data bound with the row on which the user clicked the delete button? Here is my adapter to the listview

public class CommentAdapter extends ArrayAdapter<Comment> {

// private objects
private List<Comment> mListComment;
private LayoutInflater mInflater;

public CommentAdapter(Context c,int textViewResourceId, List<Comment> list) {
    super(c, textViewResourceId, list);
    mListComment = list;
    // create layout inflater
    mInflater = LayoutInflater.from(c);
}

@Override
public int getCount() {
    return mListComment.size();
}

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

@Override
public View getView(int position, View convertView, ViewGroup parent) {
    // get view reference
    View view = convertView;
    // if null
    if(view == null) {
        // inflate new layout
        view = mInflater.inflate(R.layout.comment_row, null);
        // create a holder
        ViewHolder holder = new ViewHolder();
        // find controls
        holder.txtComment = (TextView)view.findViewById(R.id.txtComment);
        holder.btnDelete = (ImageView)view.findViewById(R.id.btnDelete);
        // set data structure to view
        view.setTag(holder);
    }

    Comment cmt = mListComment.get(position);
    // if not null
    if(cmt != null) {
        // query data structure
        ViewHolder holder = (ViewHolder)view.getTag();
        // set data to display
        holder.txtComment.setText(cmt.getComment());
        holder.btnDelete.setClickable(true);
        holder.btnDelete.setImageResource(android.R.drawable.ic_delete);

    }

    // return view
    return view;
}

/*
 * @class ViewHolder
 * to hold data structure on view with comment info
 */
static class ViewHolder {
    private TextView txtComment;
    private ImageView btnDelete;

}
}

Here is my CommentsDataSource class

public class CommentsDataSource {
private SQLiteDatabase database;
private DatabaseHelper dbHelper;
private String[] allColumns = { DatabaseHelper.COLUMN_ID, DatabaseHelper.COLUMN_COMMENT };

public CommentsDataSource(Context context) {
    dbHelper = new DatabaseHelper(context);
}

public void open() throws SQLException {
    database = dbHelper.getWritableDatabase();
}

public void close() {
    dbHelper.close();
}

public Comment createComment(String comment) {
    //insert into databasae
    return newComment;
}

private Comment cursorToComment(Cursor cursor) {
    //convert cursor to comment
    return comment;
}

public void deleteComment(Comment comment) {
    //delete row from datbase
}


public List<Comment> getAllComments() {
    //get all rows
    return comments;
}

}

Answer 1

Mobify your getView method as below:

@Override
public View getView(int position, View convertView, ViewGroup parent) {
    // get view reference
    View view = convertView;
    // if null
    if(view == null) {
        // inflate new layout
        view = mInflater.inflate(R.layout.comment_row, null);
        // create a holder
        ViewHolder holder = new ViewHolder();
        // find controls
        holder.txtComment = (TextView)view.findViewById(R.id.txtComment);
        holder.btnDelete = (ImageView)view.findViewById(R.id.btnDelete);
        // set data structure to view
        view.setTag(holder);
    }

    final Comment cmt = mListComment.get(position);
    // if not null
    if(cmt != null) {
        // query data structure
        ViewHolder holder = (ViewHolder)view.getTag();
        // set data to display
        holder.txtComment.setText(cmt.getComment());
        holder.btnDelete.setClickable(true);
        holder.btnDelete.setImageResource(android.R.drawable.ic_delete);
        holder.btnDelete.setOnClickListener(new View.OnClickListener(){
               public void onClick(View view)
               {
                     commentsDataSource.deleteComment(cmt);
                     //Requery DB to get Updated results
                     notifyDataSetChanged();
               }
        })

    }

    // return view
    return view;
}