how to add separators in a listview at specific positions?

Question

I have a ListView with custom Adapter . I have to add at position 2,6,9 separators. How to do that? Here is my code

    class MyIndexerAdapter<T> extends ArrayAdapter<T> implements SectionIndexer {

    ArrayList<String> myElements;
    HashMap<String, Integer> alphaIndexer;
    private static final int TYPE_ITEM = 0;
    private static final int TYPE_SEPARATOR = 1;
    private static final int TYPE_MAX_COUNT = TYPE_SEPARATOR + 1;
    TreeSet mSeparatorsSet = new TreeSet();
    String[] sections;
    LayoutInflater mInflater;

    public MyIndexerAdapter(Context context, int textViewResourceId,
                    List<T> objects) {


            super(context, textViewResourceId, objects);
            mInflater=(LayoutInflater)getSystemService(Context.LAYOUT_INFLATER_SERVICE);
            myElements = (ArrayList<String>) objects;
            // here is the tricky stuff
            alphaIndexer = new HashMap<String, Integer>();
            // in this hashmap we will store here the positions for
            // the sections

            int size = elements.size();
            for (int i = size - 1; i >= 0; i--) {
                    String element = elements.get(i);
                    alphaIndexer.put(element.substring(0, 1), i);
            //We store the first letter of the word, and its index.
            //The Hashmap will replace the value for identical keys are putted in
            }

            // now we have an hashmap containing for each first-letter
            // sections(key), the index(value) in where this sections begins

            // we have now to build the sections(letters to be displayed)
            // array .it must contains the keys, and must (I do so...) be
            // ordered alphabetically

            Set<String> keys = alphaIndexer.keySet(); // set of letters ...sets
            // cannot be sorted...

            Iterator<String> it = keys.iterator();
            ArrayList<String> keyList = new ArrayList<String>(); // list can be
            // sorted

            while (it.hasNext()) {
                    String key = it.next();
                    keyList.add(key);
            }

            Collections.sort(keyList);

            sections = new String[keyList.size()]; // simple conversion to an
            // array of object
            keyList.toArray(sections);

            // ooOO00K !

    }

 public int getItemViewType(int position)
 {
     return  mSeparatorsSet.contains(position) ? TYPE_SEPARATOR : TYPE_ITEM;
 }

 public int getViewTypeCount()
 {
     return TYPE_MAX_COUNT;
 }

    public int getPositionForSection(int section) {
            // Log.v("getPositionForSection", ""+section);
            String letter = sections[section];

            return alphaIndexer.get(letter);
    }

    public int getSectionForPosition(int position) {

            // you will notice it will be never called (right?)
            Log.v("getSectionForPosition", "called");
            getSections();
            return 0;
    }

    public Object[] getSections() {

            return sections; // to string will be called each object, to display
            // the letter
    }
    public void onListItemClick(ListView parent,View v, int position, long id)
    {

    Toast.makeText(getContext(), "you have selected" + elements.get(position), Toast.LENGTH_SHORT).show();
    }
    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        ViewHolder holder = null;
        int type = getItemViewType(position);
        System.out.println("getView " + position + " " + convertView + " type = " + type);
        if (convertView == null) {
            holder = new ViewHolder();
            switch (type) {
                case TYPE_ITEM:
                    convertView = mInflater.inflate(R.layout.main, null);
                    holder.textView = (TextView)convertView.findViewById(R.id.text);
                    //break;
                case TYPE_SEPARATOR:
                    convertView = mInflater.inflate(R.layout.item1, null);
                    holder.textView = (TextView)convertView.findViewById(R.id.textSeparator);
                    break;
            }
            convertView.setTag(holder);
        } else {
            holder = (ViewHolder)convertView.getTag();
        }
        holder.textView.setText(elements.get(position));
        return convertView;
    }

}


}

Answer 1

In your getView() of MyIndexerAdapter, use the position argument to check whether it is 2.6.9 and then add the separator in code

if(position==2 || position==6||position==9){
//code for adding separators to the convertview
}

Try the below completed code, it was running for me : This code also shows how to use adapter methods like getItemViewType(), getViewTypeCount(), getView() when needed to display different types of views at different positions. It also shows how to implement a SectionIndexer and its methods.

I added some random data at position 2,6,9 where you wanted the separators. This made things easier.

 public class FastScrollActivity extends Activity {
    ListView myListView;
    ArrayList<String> elements;

    @Override
    public void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.main);

            // elements
            String s = "QWERTZUIOPASDFGHJKLYXCVBNM";
            Random r = new Random();
            elements = new ArrayList<String>();
            for (int i = 0; i < 300; i++) {

                    elements.add(s.substring(r.nextInt(s.length())));

            }
            Collections.sort(elements); // Must be sorted!

            //for 2,6,9 Adding some random data--use an array of positions if you want to :
            elements.add(2,"Don't care");
            elements.add(6,"Don't care");
            elements.add(9,"Don't care");
            // listview
            myListView = (ListView) findViewById(R.id.myListView);
            myListView.setFastScrollEnabled(true);
myListView.setOnItemClickListener(new OnItemClickListener() {

    @Override
    public void onItemClick(AdapterView<?> arg0, View arg1, int arg2, long arg3) {
        Toast.makeText(FastScrollActivity.this, "clicked pos = "+arg2, Toast.LENGTH_SHORT).show();

    }

});

            //myListView.
            MyIndexerAdapter<String> adapter = new MyIndexerAdapter<String>(
                            this, R.layout.simple_layout,
                            elements);
            myListView.setAdapter(adapter);

  //          if (myListView.getFirstVisiblePosition() > adapter.getItemId( adapter.getCount()) || myListView.getLastVisiblePosition() <= adapter.getCount()) {
   //               myListView.smoothScrollToPosition( adapter.getCount());}

    }
    class MyIndexerAdapter<T> extends ArrayAdapter<String> implements SectionIndexer {

        ArrayList<String> myElements;
        HashMap<String, Integer> alphaIndexer;
        private static final int TYPE_ITEM = 0;
        private static final int TYPE_SEPARATOR = 1;
        private static final int TYPE_MAX_COUNT = TYPE_SEPARATOR + 1;
        TreeSet<String> mSeparatorsSet = new TreeSet<String>();
        String[] sections;
        LayoutInflater mInflater;
        int MytextViewResourceId;
        public MyIndexerAdapter(Context context, int textViewResourceId,
                        ArrayList<String> objects) {


                super(context, textViewResourceId, objects);
                mInflater=(LayoutInflater)getSystemService(Context.LAYOUT_INFLATER_SERVICE);
                myElements =  objects;
                // here is the tricky stuff
                alphaIndexer = new HashMap<String, Integer>();
                // in this hashmap we will store here the positions for
                // the sections
                //Adding positions in the separator set
                mSeparatorsSet.add("2");
                mSeparatorsSet.add("6");
                mSeparatorsSet.add("9");
                int size = elements.size();
                for (int i = size - 1; i >= 0; i--) {
                        String element = elements.get(i);
                        alphaIndexer.put(element.substring(0, 1), i);
                //We store the first letter of the word, and its index.
                //The Hashmap will replace the value for identical keys are putted in
                }

                // now we have an hashmap containing for each first-letter
                // sections(key), the index(value) in where this sections begins

                // we have now to build the sections(letters to be displayed)
                // array .it must contains the keys, and must (I do so...) be
                // ordered alphabetically

                Set<String> keys = alphaIndexer.keySet(); // set of letters ...sets
                // cannot be sorted...

                Iterator<String> it = keys.iterator();
                ArrayList<String> keyList = new ArrayList<String>(); // list can be
                // sorted

                while (it.hasNext()) {
                        String key = it.next();
                        keyList.add(key);
                }

                Collections.sort(keyList);

                sections = new String[keyList.size()]; // simple conversion to an
                // array of object
                keyList.toArray(sections);

                // ooOO00K !

        }

     public int getItemViewType(int position)
     {
         return  mSeparatorsSet.contains(position+"") ? TYPE_SEPARATOR : TYPE_ITEM;
     }

     public int getViewTypeCount()
     {
         return TYPE_MAX_COUNT;
     }

        public int getPositionForSection(int section) {
                // Log.v("getPositionForSection", ""+section);
                String letter = sections[section];

                return alphaIndexer.get(letter);
        }

        public int getSectionForPosition(int position) {

                // you will notice it will be never called (right?)
                Log.v("getSectionForPosition", "called");
                getSections();
                return 0;
        }

        public Object[] getSections() {

                return sections; // to string will be called each object, to display
                // the letter
        }
       public void onListItemClick(ListView parent,View v, int position, long id)
        {

        Toast.makeText(getContext(), "you have selected" + elements.get(position), Toast.LENGTH_SHORT).show();
        }
        @Override
        public View getView(int position, View convertView, ViewGroup parent) {
            ViewHolder holder = null;
            int type = getItemViewType(position);
            System.out.println("getView " + position + " " + convertView + " type = " + type);
            if (convertView == null) {
                holder = new ViewHolder();
                convertView = mInflater.inflate(R.layout.simple_layout, null);
                holder.textView = (TextView)convertView.findViewById(R.id.textView1);
                holder.textView.setBackgroundColor(android.R.attr.colorBackground);
                switch (type) {

                        //break;
                    case TYPE_SEPARATOR:
                        /*convertView = mInflater.inflate(R.layout.item1, null);
                        holder.textView = (TextView)convertView.findViewById(R.id.textSeparator);
                        */
                        holder.textView .setOnClickListener(null);
                        holder.textView .setOnLongClickListener(null);
                        holder.textView .setLongClickable(false);
                       holder.textView.setFocusable(false);
                      holder.textView.setTextColor(Color.WHITE);
                       holder.textView.setBackgroundColor(Color.RED); 
                       break;
                }
                convertView.setTag(holder);
            } else {
                holder = (ViewHolder)convertView.getTag();
            }
            if(type==TYPE_ITEM)
                            holder.textView.setText(elements.get(position));
                //holder.textView.setMinHeight(android.R.attr.listPreferredItemHeight);
                //holder.textView.setTextAppearance(getContext(), android.R.attr.textAppearanceLarge);
                return convertView;
        }

    }

   /* public void quickScroll(View v) {
        String alphabet = (String)v.getTag();
        int index = 0;
        //find the index of the separator row view
        list.setSelectionFromTop(index, 0);
    }*/


    public static class ViewHolder {
        public TextView textView;
    }


}

the xml I used is :

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical" >

<TextView 
    android:id="@+id/textView1"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:textAppearance="?android:attr/textAppearanceLarge"
    android:gravity="center_vertical"
    android:paddingLeft="6dip"
    android:minHeight="?android:attr/listPreferredItemHeight"
/>
</RelativeLayout>