如何创建动态列表视图并设置Textview的可见性

Question

I'm new to Android development. I successfully created a demo project with a dynamic listview but now my problem is that I have two textviews in my list_row xml file.

Textview2 is default hide(Visibility=Gone).

Now I set the visibility of that textview visible only in fifth position in listview. I wrote code for that but the textview shows up randomly, not just in the fifth position. I have 100 records in the listview.

What am I doing wrong?

EDIT :

public View getView(int position, View convertView, ViewGroup parent) 
{
    // TODO Auto-generated method stub
    ViewHolder holder;

    if (convertView == null) 
    {
        convertView = mLayoutInflater.inflate(R.layout.list_row, null);
        holder = new ViewHolder();
        holder.text1 = (TextView) convertView.findViewById(R.id.mytext);
        holder.text2 = (TextView) convertView.findViewById(R.id.invisibletext);
        convertView.setTag(holder);
        if (position == 5) 
            holder.text2.setVisibility(View.VISIBLE);
        else
            holder.text2.setVisibility(View.GONE);
    } 
    else 
    {
        holder = (ViewHolder) convertView.getTag();
    }

    return convertView;
}

static class ViewHolder 
{
    TextView text1;
    TextView text2;
}

Answer 1

the issue is that convertViews in the Adapter are recycled.

I'm assuming you're testing for position in the getView() function in your adapter. Modify your code so that it does the following:

if (position == 4)
    convertView.setVisibility(View.INVISIBLE);
else 
    convertView.setVisibility(View.VISIBLE);

this will force the convertView to reappear after being set to visible in the 5th position

Edit: the if else condition is in the wrong place

 public View getView(int position, View convertView, ViewGroup parent) {
    // TODO Auto-generated method stub
    ViewHolder holder;

    if (convertView == null) {
        convertView = mLayoutInflater.inflate(R.layout.list_row, null);

        holder = new ViewHolder();

        holder.text1 = (TextView) convertView.findViewById(R.id.mytext);

        holder.text2 = (TextView) convertView

        .findViewById(R.id.invisibletext);

        convertView.setTag(holder);


    } else {

        holder = (ViewHolder) convertView.getTag();

    }

    if (position == 5) {
        holder.text2.setVisibility(View.INVISIBLE);
    } else {
        holder.text2.setVisibility(View.VISIBLE);
    }

    return convertView;

}

}

static class ViewHolder {
TextView text1;

TextView text2;

}

Answer 2

if your convertView is not null then if-else condtion not fire, So when convertView is null then its fire so it works randomly.

Update your code as per below...

   public View getView(int position, View convertView, ViewGroup parent) {
        // TODO Auto-generated method stub
        ViewHolder holder;

        if (convertView == null) {
            convertView = mLayoutInflater.inflate(R.layout.list_row, null);

            holder = new ViewHolder();

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


      holder.text1 = (TextView) convertView.findViewById(R.id.mytext);
      holder.text2 = (TextView) convertView.findViewById(R.id.invisibletext);

      if (position == 5) {
                holder.text2.setVisibility(View.VISIBLE);

            } else {
                holder.text2.setVisibility(View.GONE);
            }

        return convertView;

    }

}