Search code examples
androidlistviewandroid-listviewandroid-filterable

Bypassing the bug in filtering that does not update ListView Android


Here is the code, I used a custom adapter, and applied the Filter method, now the ListView does not update when the backspace key is entered, on when one switches back from an item activity. I read it is a bug in filter, but how do I bypass it, I know of apps that have achieved this kind of setup I want.

public class IndexPageActivity extends Activity implements OnItemClickListener{ 
    ListView listView;
    EditText editTextB;
    PagesAdapter adapter1;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_main);
        listView = (ListView) findViewById(R.id.pageList);
        editTextB = (EditText) findViewById(R.id.searchB);
        adapter1 = new PagesAdapter(this);
        listView.setAdapter(adapter1);
        adapter1.notifyDataSetChanged();
        listView.setOnItemClickListener(this);

        editTextB.addTextChangedListener(new TextWatcher() {
            @Override
            public void onTextChanged(CharSequence cs, int arg1, int arg2, int arg3) {
                IndexPageActivity.this.adapter1.getFilter().filter(cs.toString());
                adapter1.notifyDataSetChanged();
            }

            @Override
            public void beforeTextChanged(CharSequence arg0, int arg1,
                        int arg2, int arg3) { }

            @Override
            public void afterTextChanged(Editable arg0) { }
        });
    }

    @Override
    public void onItemClick(AdapterView<?> arg0, View v, int position, long arg3) {
        Intent i;
        String name = adapter1.getItem(position);
        Log.d("id", name);

        if (name.equals("Item1"))
        {
            i = new Intent(this, anActivity.class);
            startActivity(i);
        }
        else if (name.equals("Item2"))
        {
            i = new Intent(this, anActivity2.class);
            startActivity(i);
        }
    }
}

class SingleRow {
    String pagedata;
    SingleRow(String pagedata){
        this.pagedata=pagedata;
    }
}
class PagesAdapter extends BaseAdapter implements Filterable{
    ArrayList<String> pagelist;
    List<String> arrayList;
    Context context;
    String [] pagedatas;

    PagesAdapter(Context c){
        context=c;
        pagelist = new ArrayList<String>();
        Resources res = c.getResources();
        pagedatas = res.getStringArray(R.array.pages_data);
        for (int i=0;i<463;i++){
            pagelist.add(pagedatas[i]);
        }
    }
    @Override
    public int getCount() {
        return pagelist.size();
    }

    @Override
    public String getItem(int i) {
        return pagelist.get(i);
    }

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

    @Override
    public View getView(int i, View view, ViewGroup viewG) {
        LayoutInflater inflater=(LayoutInflater)             context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        View row=inflater.inflate(R.layout.single_row,viewG,false);
        TextView pagetitle = (TextView) row.findViewById(R.id.textViewRow);

        String temp=pagelist.get(i);

        pagetitle.setText(temp);
        return row;
    }

    public class filter_here extends Filter{
        @Override
        protected FilterResults performFiltering(CharSequence constraint) {
            FilterResults Result = new FilterResults();
            // if constraint is empty return the original names
            if(constraint.length() == 0 ){
                Result.values = pagelist;
                Result.count = pagelist.size();
                return Result;
            }

            ArrayList<String> Filtered_Names = new ArrayList<String>();
            String filterString = constraint.toString().toLowerCase();
            String filterableString;

            for(int i = 0; i<pagelist.size(); i++){
                filterableString = pagelist.get(i);
                if(filterableString.toLowerCase().contains(filterString)){
                    Filtered_Names.add(filterableString);
                }
            }
            Result.values = Filtered_Names;
            Result.count = Filtered_Names.size();

            return Result;
        }

        @Override
        protected void publishResults(CharSequence constraint,FilterResults results) {
            pagelist = (ArrayList<String>) results.values;
            notifyDataSetChanged();
        }
    }

    @Override
    public Filter getFilter() {
        return new filter_here();
    }
}

Solution

  • Finally found the bug of the backspace, you had some error in the filter function, that am returning an ArrayList, instead of the List that holds the variable the code should the final code is:

    public class IndexPageActivity extends Activity implements OnItemClickListener{ 
    ListView listView;
    EditText editTextB;
    PagesAdapter adapter1;
    
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        // TODO Auto-generated method stub
        super.onCreate(savedInstanceState);
         setContentView(R.layout.activity_main);
            listView = (ListView) findViewById(R.id.pageList);
            editTextB = (EditText) findViewById(R.id.searchB);
            adapter1 = new PagesAdapter(this);
            listView.setAdapter(adapter1);
            adapter1.notifyDataSetChanged();
            listView.setOnItemClickListener(this);
    
            editTextB.addTextChangedListener(new TextWatcher() {
    
                @Override
                public void onTextChanged(CharSequence cs, int arg1, int arg2,
                        int arg3) {
                    // When user changed the Text
                    IndexPageActivity.this.adapter1.getFilter().filter(cs.toString());
                    adapter1.notifyDataSetChanged();
                }
    
                @Override
                public void beforeTextChanged(CharSequence arg0, int arg1,
                        int arg2, int arg3) {
                    // TODO Auto-generated method stub
    
                }
    
                @Override
                public void afterTextChanged(Editable arg0) {
                    // TODO Auto-generated method stub
                }
            });
    }
    
    
    @Override
    public void onItemClick(AdapterView<?> arg0, View v, int position, long arg3) {
    // TODO Auto-generated method stub
    Intent i;
    String name = adapter1.getItem(position);
            Log.d("id", name);
    if (name.equals("Item1"))
    {
        i = new Intent(this, anActivity.class);
        startActivity(i);
    }
    else if (name.equals("Item2"))
    {
        i = new Intent(this, anActivity2.class);
        startActivity(i);
    }
    }
    }
    
    
    class SingleRow {
    String pagedata;
    SingleRow(String pagedata){
        this.pagedata=pagedata;
    }
    }
    class PagesAdapter extends BaseAdapter implements Filterable{
    ArrayList<String> pagelist;
    List<String> arrayList;
    Context context;
    String [] pagedatas;
    
    PagesAdapter(Context c){
    context=c;
    pagelist = new ArrayList<String>();
    Resources res = c.getResources();
    pagedatas = res.getStringArray(R.array.pages_data);
    
    for (int i=0;i<463;i++){
        pagelist.add(pagedatas[i]);
    }
    arrayList = pagelist;
    }
    @Override
    public int getCount() {
    // TODO Auto-generated method stub
    return arrayList.size();
    }
    
    @Override
    public void notifyDataSetChanged() {
    super.notifyDataSetChanged();
    }
    
    @Override
    public String getItem(int i) {
    // TODO Auto-generated method stub
    return arrayList.get(i);
    }
    
    @Override
    public long getItemId(int i) {
    // TODO Auto-generated method stub
    return i;
    }
    
    
    @Override
    public View getView(int i, View view, ViewGroup viewG) {
    // TODO Auto-generated method stub
    LayoutInflater inflater=(LayoutInflater)                 context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
    View row=inflater.inflate(R.layout.single_row,viewG,false);
    TextView pagetitle = (TextView) row.findViewById(R.id.textViewRow);
    
    String temp=arrayList.get(i);
    
    pagetitle.setText(temp);
    return row;
    }
    
    @Override
    public Filter getFilter() {
    // TODO Auto-generated method stub
    Filter filter = new Filter() {
        @SuppressWarnings("unchecked")
        @Override
        protected void publishResults(CharSequence constraint, FilterResults results) {
    
            arrayList = (List<String>) results.values;
            notifyDataSetChanged();
        }
    
        @Override
        protected FilterResults performFiltering(CharSequence constraint) {
    
         FilterResults results = new FilterResults();
            ArrayList<String> FilteredArrayNames = new ArrayList<String>();
    
            if (pagelist == null)    {
                pagelist = new ArrayList<String>(arrayList);
            }
            if (constraint == null || constraint.length() == 0) {
                results.count = pagelist.size();
                results.values = pagelist;
            } else {
                constraint = constraint.toString().toLowerCase();
                for (int i = 0; i < pagelist.size(); i++) {
                    String dataNames = pagelist.get(i);
                    if (dataNames.toLowerCase().startsWith(constraint.toString()))  {
                        FilteredArrayNames.add(dataNames);
                    }
                }
    
                results.count = FilteredArrayNames.size();
                System.out.println(results.count);
    
                results.values = FilteredArrayNames;
                Log.e("VALUES", results.values.toString());
            }
    
            return results;
    }
    };
    return filter;
    }
    }