ListView first Item overlaid

My ListView displays in first Item something else as the rest of the ListView

The Problem is, that it replaces the first item instead of taking a own position.

Example how it has to be:

A (diferent to the others)

B

B

B

How it is:

A (B Overlaid by A)

B

B

As you can see, one B is missing because it is overlaid by A.

Here is the Code. I wrote my own CustomAdapter:

@Override
public int getCount() {
    if (taskItems.size() + 1 >= 0)
        return taskItems.size();
    return 0;
}

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

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

public static class ViewHolder {
    public TextView taskTitleTextView;
    public TextView taskObjectTextView;
    public TextView taskLocationTextView;
    public ImageView taskImageImageView;

}

public static class ViewHolderProjects {
    public TextView projectTitelTextView;
    public TextView projectInfoTextView;
    public TextView projectDeadline;
    public ImageView projectImageImageView;
}

@Override
public View getView(int position, View convertView, ViewGroup parent) {
    View vi = convertView;
    ViewHolderProjects holderProjects;
    if (position == 0) {
        if (convertView == null) {
            vi = inflater.inflate(R.layout.list_item_projects, null);
            holderProjects = new ViewHolderProjects();

            holderProjects.projectTitelTextView = (TextView) vi.findViewById(R.id.projectTitle);
            holderProjects.projectInfoTextView = (TextView) vi.findViewById(R.id.projectInfo);
            holderProjects.projectImageImageView = (ImageView) vi.findViewById(R.id.projectImage);
            holderProjects.projectDeadline = (TextView) vi.findViewById(R.id.projectdeadline);

            vi.setTag(holderProjects);
        } else {
            holderProjects = (ViewHolderProjects) vi.getTag();
        }
        if (projectMap.size() <= 0) {
            holderProjects.projectInfoTextView.setText("Keine Infos");
            holderProjects.projectTitelTextView.setText("Kein Titel");
        } else {
            if (projectMap.get(position).containsKey("project_company_image")) {
                if (projectMap.get(position).get("project_company_image").getBytes().length == 0) {
                    holderProjects.projectTitelTextView.setText(jobMap.get(position).get("job_subject"));
                    holderProjects.projectDeadline.setText(jobMap.get(position).get("job_deadline"));
                    return vi;
                }
                Bitmap bm = Bitmap.createBitmap(base64EncodeDecode.decodeBase64(projectMap.get(position).get("project_company_image")));
                holderProjects.projectTitelTextView.setText(jobMap.get(position).get("job_subject"));
                holderProjects.projectDeadline.setText(jobMap.get(position).get("job_deadline"));
                holderProjects.projectImageImageView.setImageBitmap(bm);
            }
        }
    } else {

        ViewHolder holder;
        if (convertView == null) {
            vi = inflater.inflate(R.layout.list_item_tasks, null);

            holder = new ViewHolder();
            holder.taskTitleTextView = (TextView) vi.findViewById(R.id.taskTitle);
            holder.taskObjectTextView = (TextView) vi.findViewById(R.id.taskObject);
            holder.taskLocationTextView = (TextView) vi.findViewById(R.id.taskLocation);
            holder.taskImageImageView = (ImageView) vi.findViewById(R.id.taskImage);

            vi.setTag(holder);
        } else {
            holder = (ViewHolder) vi.getTag();
        }

        if (taskItems.size() <= 0) {
            holder.taskTitleTextView.setText("Kein Titel");
            holder.taskObjectTextView.setText("Kein Objekt");
            holder.taskLocationTextView.setText("Kein Standort");
        } else {
            if (taskItems.get(position).containsKey("object_image")) {
                if (taskItems.get(position).get("object_image").getBytes().length == 0) {
                    holder.taskTitleTextView.setText(taskItems.get(position).get("task_headline"));
                    holder.taskObjectTextView.setText(taskItems.get(position).get("object_name"));
                    holder.taskLocationTextView.setText(taskItems.get(position).get("object_location"));

                    return vi;
                }
            }
            Bitmap bm = Bitmap.createBitmap(base64EncodeDecode.decodeBase64(taskItems.get(position).get("object_image")));
            holder.taskTitleTextView.setText(taskItems.get(position).get("task_headline"));
            holder.taskObjectTextView.setText(taskItems.get(position).get("object_name"));
            holder.taskLocationTextView.setText(taskItems.get(position).get("object_location"));
            holder.taskImageImageView.setImageBitmap(bm);
        }
    }
    return vi;

}