List Adapter does not update after removing

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The situation is as follows:

I have a SeparatedListAdapter and with it I create 3 sections for my listview. Inside the sections, add 3 Adapters and 3 ArrayLists.

The problem is that in each of the list items, there is a remove button. I have programmed the removal within each Adapter separate. It removes, the problem is that it does not update the list. So when I press the button then the app stops because the list is empty, but does not update dynamically. Any idea?

Button btt = (Button)convertView.findViewById(R.id.remover_item);
    btt.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            Datastring.remove(position);
            notifyDataSetChanged();
        }
    });

Follow the code of the 3 simple Adapters.

import java.util.ArrayList;

import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.Button;
import android.widget.TextView;

public class Adapter1 extends BaseAdapter {
    Context ctx;
    LayoutInflater lInflater;

    ArrayList<String> Datastring=new ArrayList<String>();

    public Adapter1(Context context,ArrayList<String> Items) {
        ctx = context;
        Datastring.addAll(Items);
        lInflater = (LayoutInflater) ctx
                .getSystemService(Context.LAYOUT_INFLATER_SERVICE);

    }

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

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

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

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

        if (convertView == null) {
            convertView = (View) lInflater.inflate(R.layout.my_list_item, parent, false);
        }
        TextView text=(TextView)convertView.findViewById(R.id.list_content1);
        text.setText(Datastring.get(position));
        Button btt = (Button)convertView.findViewById(R.id.remover_item);
        btt.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Datastring.remove(position);
                notifyDataSetChanged();
            }
        });

        return convertView;
    }
}

And the code of the Separatedlistadapter:

import java.util.LinkedHashMap;
import java.util.Map;
import android.content.Context; 
import android.view.View;
import android.view.ViewGroup;
import android.widget.Adapter;
import android.widget.ArrayAdapter;
import android.widget.BaseAdapter;

public class SeparatedListAdapter extends BaseAdapter {

public final Map<String,Adapter> sections = new LinkedHashMap<String,Adapter>();
public final ArrayAdapter<String> headers;
public final static int TYPE_SECTION_HEADER = 0;

public SeparatedListAdapter(Context context) {
    headers = new ArrayAdapter<String>(context, R.layout.header); 
}

public void addSection(String section, Adapter adapter) {
    this.headers.add(section);
    this.sections.put(section, adapter);
}

public Object getItem(int position) {
for(Object section : this.sections.keySet()) {
    Adapter adapter = sections.get(section);
    int size = adapter.getCount() + 1;

    // check if position inside this section
    if(position == 0) return section;
    if(position < size) return adapter.getItem(position - 1);

    // otherwise jump into next section
    position -= size;
    }
    return null;
}

public int getCount() {
    int total = 0;
for(Adapter adapter : this.sections.values())
    total += adapter.getCount() + 1;
return total;
}

public int getViewTypeCount() {
    int total = 1;
    for(Adapter adapter : this.sections.values())
        total += adapter.getViewTypeCount();
    return total;
}

public int getItemViewType(int position) {
    int type = 1;
    for(Object section : this.sections.keySet()) {
        Adapter adapter = sections.get(section);
        int size = adapter.getCount() + 1;

    // check if position inside this section
    if(position == 0) return TYPE_SECTION_HEADER;
    if(position < size) return type + adapter.getItemViewType(position - 1);

    // otherwise jump into next section
    position -= size;
    type += adapter.getViewTypeCount();
    }
    return -1;
}

public boolean areAllItemsSelectable() {
    return false;
}

public boolean isEnabled(int position) {
    return (getItemViewType(position) != TYPE_SECTION_HEADER);
}

@Override
public View getView(int position, View convertView, ViewGroup parent) {
    int sectionnum = 0;
    for(Object section : this.sections.keySet()) {
    Adapter adapter = sections.get(section);
    int size = adapter.getCount() + 1;

    // check if position inside this section
    if(position == 0) {
        return headers.getView(sectionnum, convertView, parent); // this is where     your header names will get bind. correctly.
    }
    if(position < size) {
        return adapter.getView(position - 1, convertView, parent);
    }

    // otherwise jump into next section
    position -= size;
    sectionnum++;
}
return null;
}

@Override
public long getItemId(int position) {
return position;
}
  • I think we’re gonna need more code, precisely the code of Adapters.

  • I could test with the notifyDataSetInvalidated? The difference to the notifyDataSetChanged is that in it the number of elements has not changed, only the data of each item.

  • notifyDataSetInvalidated worked. However, only when I give a scroll in the list, when I "move" it. Statically it does not remove.

  • I managed to resolve it. I added Adapter.registerDataSetObserver(new Cascadedatasetobserver()); to the addSection() method in the Big Adapter.

  • Now another question. And to add elements dynamically ? I’m trying for the same concept but I haven’t found a solution yet. Any idea ?

  • @If you have another question create a new question, you can even link this to help understand the problem. By the way if you have the answer to your question I would advise you to create an answer and then accept it.

  • @Lucassoares just noticed that the doubt is over a year old, but feel free to create the answer anyway.

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