ListView Item changing color issue. Multiple items change down the view

Question

lv.setOnItemClickListener(new AdapterView.OnItemClickListener() {
        @Override
        public void onItemClick(AdapterView<?> adapterView, View view, int position, long   l) {

            if (selectedCourses.contains(courseNames.get(position))){
                selectedCourses.remove(selectedCourses.lastIndexOf(courseNames.get(position)));
                Toast.makeText(getApplicationContext(),
                      courseNames.get(position) + " removed", Toast.LENGTH_LONG)
                      .show();

                row = view;
                row.setBackgroundResource(R.drawable.charback);

                System.out.println(selectedCourses);
            }

            else{
                selectedCourses.add(courseNames.get(position));
                Toast.makeText(getApplicationContext(),
                        courseNames.get(position) +" added", Toast.LENGTH_LONG)
                          .show();

                row = view;
                row.setBackgroundResource(R.drawable.white);

                myarrayAdapter.notifyDataSetChanged();
                System.out.println(selectedCourses);

            }

The selected item turns white, but also about 12 items late another random item turns white just as it comes into view? Can someone please help me??

Answer 1

Try this:

lv.setOnItemClickListener(new AdapterView.OnItemClickListener() {
    @Override
    public void onItemClick(AdapterView<?> adapterView, View view, int position, long   l) {

        if (selectedCourses.contains(courseNames.get(position))){
            selectedCourses.remove(selectedCourses.lastIndexOf(courseNames.get(position)));
            Toast.makeText(getApplicationContext(),
                  courseNames.get(position) + " removed", Toast.LENGTH_LONG)
                  .show();

            row = view;
            row.setBackgroundResource(R.drawable.charback);

            System.out.println(selectedCourses);
        }

        else{
            selectedCourses.add(courseNames.get(position));
            Toast.makeText(getApplicationContext(),
                    courseNames.get(position) +" added", Toast.LENGTH_LONG)
                      .show();

            row = view;
            row.setBackgroundResource(R.drawable.white);

            System.out.println(selectedCourses);

        }

I removed myarrayAdapter.notifyDataSetChanged(); line....

Answer 2

What will be happening is that your getView method in your adapter is not recycling/reusing the convertView that is supplied.

If the convertView is not null, that means it is a view that is being reused . That means you should explicitly set the background resource to the default, unless the item is selected. The reason you're seeing the white background re-used is because you're not resetting the background to the default.

Something like:

if (convertView != null) {
   if (selectedCourses.contains(courseNames.get(position))){
       convertView.setBackgroundResource(R.drawable.white);
   } else {
       convertView.setBackgroundResource(R.drawable.charback);
   }
}

Answer 3

You can use Holder class for this :

In your adapter class create another static class that holds your components: see below code

static class MyHolder {

        TextView mTextView;
        RelativeLayout lv;
        ImageView imgInvite;
        RelativeLayout rel_bckground;
    }

After that use it in your getView method :

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

           View row = convertView;
            holder = null;

          if (row == null) {

         // initialize your components
         holder = new MyHolder();
         holder.mImageView = (ImageView) row.findViewById(R.id.someID);

        }else{

         holder = (MyHolder) row.getTag();
             }
    }