How to Filter Listview Using Getfilter() in Baseadapter

How could i filter the listview using baseadapter

MainActivity.java

public class MainActivity extends Activity {

private ListView mListView;
private CustomAdapter mCustomAdapter;
private EditText mEditText;
private ArrayList<Contacts> _Contacts = new ArrayList<Contacts>();

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

    for (int i = 0; i < 100; i++) {
        Contacts contacts = new Contacts();
        contacts.setId(""+i);
        contacts.setName("Name "+i);
        _Contacts.add(contacts);
    }

    mListView = (ListView) findViewById(R.id.listView1);
    mEditText = (EditText) findViewById(R.id.editText1);

    mCustomAdapter = new CustomAdapter(MainActivity.this, _Contacts);
    mListView.setAdapter(mCustomAdapter);

    mEditText.addTextChangedListener(new TextWatcher() {

        @Override
        public void onTextChanged(CharSequence arg0, int arg1, int arg2, int arg3) {
            mCustomAdapter.getFilter().filter(arg0);
        }

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

        @Override
        public void afterTextChanged(Editable arg0) {

        }
    });
}

}

CustomAdapter.java

public class CustomAdapter extends BaseAdapter implements Filterable{

private ArrayList<Contacts> _Contacts;
private Activity context;
private LayoutInflater inflater;
private ValueFilter valueFilter;
private ArrayList<Contacts> mStringFilterList;

public CustomAdapter(Activity context, ArrayList<Contacts> _Contacts) {
    super();
    this.context = context;
    this._Contacts = _Contacts;
    mStringFilterList =  _Contacts;
    this.inflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
     getFilter();
}

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

@Override
public Object getItem(int position) {
    return _Contacts.get(position).getName();
}

@Override
public long getItemId(int position) {
    return 0;
}

public class ViewHolder {
    TextView tname, tplace;
}

@Override
public View getView(int position, View convertView, ViewGroup parent) {
    ViewHolder holder;
    if (convertView == null) {
        holder = new ViewHolder();
        convertView = inflater.inflate(R.layout.activity_main, null);
        holder.tname = (TextView) convertView.findViewById(R.id.textView1);
        holder.tplace = (TextView) convertView.findViewById(R.id.textView2);
        convertView.setTag(holder);
    } else
        holder = (ViewHolder) convertView.getTag();
    holder.tname.setText("" + _Contacts.get(position).getName());
    holder.tplace.setText("" + "" + _Contacts.get(position).getId());
    return convertView;
}

@Override
public Filter getFilter() {
    if(valueFilter==null) {

        valueFilter=new ValueFilter();
    }

    return valueFilter;
}
private class ValueFilter extends Filter {

    //Invoked in a worker thread to filter the data according to the constraint.
    @Override
    protected FilterResults performFiltering(CharSequence constraint) {
        FilterResults results=new FilterResults();
        if(constraint!=null && constraint.length()>0){
            ArrayList<Contacts> filterList=new ArrayList<Contacts>();
            for(int i=0;i<mStringFilterList.size();i++){
                if((mStringFilterList.get(i).getName().toUpperCase())
                        .contains(constraint.toString().toUpperCase())) {
                    Contacts contacts = new Contacts();
                    contacts.setName(mStringFilterList.get(i).getName());
                    contacts.setId(mStringFilterList.get(i).getId());
                    filterList.add(contacts);
                }
            }
            results.count=filterList.size();
            results.values=filterList;
        }else{
            results.count=mStringFilterList.size();
            results.values=mStringFilterList;
        }
        return results;
    }

    //Invoked in the UI thread to publish the filtering results in the user interface.
    @SuppressWarnings("unchecked")
    @Override
    protected void publishResults(CharSequence constraint,
            FilterResults results) {
        _Contacts=(ArrayList<Contacts>) results.values;
        notifyDataSetChanged();
    }
}
}

Contacts.java

public class Contacts {

private String name;
private String id;

public String getName() {
    return name;
}
public void setName(String name) {
    this.name = name;
}
public String getId() {
    return id;
}
public void setId(String id) {
    this.id = id;
}
}

main.xml

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

<EditText
    android:id="@+id/editText1"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:ems="10" >

    <requestFocus />
</EditText>

<ListView
    android:id="@+id/listView1"
    android:layout_width="match_parent"
    android:layout_height="wrap_content" >
</ListView>

activity_main.xml

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginBottom="2dp"
android:layout_marginLeft="1dp"
android:layout_marginRight="1dp"
android:layout_marginTop="2dp"
android:background="@android:color/black"
android:gravity="center_vertical"
android:paddingBottom="2dp"
android:paddingTop="2dp"
tools:context=".MainActivity" >

<TextView
    android:id="@+id/textView1"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_marginLeft="8dp"
    android:text="Large Text"
    android:textAppearance="?android:attr/textAppearanceLarge"
    android:textColor="@android:color/white" />

<TextView
    android:id="@+id/textView2"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_marginLeft="8dp"
    android:text="Small Text"
    android:textAppearance="?android:attr/textAppearanceSmall"
    android:textColor="@android:color/white" />

This is a sample project code. Use this code this will really help you

how to implement getFilter() on a BaseAdapter

Use (if you sure about data and device name are both not null)

if(data.getDeviceName().toLowerCase().startsWith(constraint.toString()))

instead of

   if(data.toLowerCase().startsWith(constraint.toString()))

In addition,
Check this likely question and answer.
Question

Creating getFilter for BaseAdapter for Object titles?

I've Implemented this kind of feature in my application.

A brief explanation.
Implement your own class that extends Filter, like the next class:

private class PlanetFilter extends Filter {
@Override
    protected FilterResults performFiltering(CharSequence constraint) {
        FilterResults results = new FilterResults();
        // We implement here the filter logic
        if (constraint == null || constraint.length() == 0) {
            // No filter implemented we return all the list
            results.values = planetList;
            results.count = planetList.size();
        }
        else {
            // We perform filtering operation
            List<Planet> nPlanetList = new ArrayList<Planet>();

            for (Planet p : planetList) {
                if (p.getName().toUpperCase().startsWith(constraint.toString().toUpperCase()))
                    nPlanetList.add(p);
            }

            results.values = nPlanetList;
            results.count = nPlanetList.size();

        }
        return results;
    }
}

In your base adapter implements Filterable interface and it has to implement getFilter() method:

@Override
public Filter getFilter() {
    if (planetFilter == null)
        planetFilter = new PlanetFilter();

    return planetFilter;
}

And to tie all together, use textWatcher on your edittext, where you enter the text.

editTxt.addTextChangedListener(new TextWatcher() {

    @Override
    public void onTextChanged(CharSequence s, int start, int before, int count) {
        System.out.println("Text ["+s+"]");
        aAdpt.getFilter().filter(s.toString());                           
    }

    @Override
    public void beforeTextChanged(CharSequence s, int start, int count,
            int after) {

    }

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

That code is taken from the next tutorial.

Filtering ListView extending BaseAdapter

Use two arraylist one for original data and other is filtering.

update your adapter constructor .

    private ArrayList<Names> originalData = null;
            private ArrayList<Names> filteredData = null;

            public adapter(Activity c, ArrayList<Names> list) {
                infalter = (LayoutInflater) c
                        .getSystemService(Context.LAYOUT_INFLATER_SERVICE);

                this.filteredData = list;
                this.originalData = list;
                mContext = c;
            }

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

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

On Filter

@Override
public Filter getFilter() {
    if (filter == null) filter = new Filter() {
          @Override
            protected FilterResults performFiltering(CharSequence constraint) {
              String constraintStr = constraint.toString().toLowerCase(Locale.getDefault());
                        FilterResults result = new FilterResults();

                        if (constraintStr != null & constraintStr.length() > 0) {
                           ArrayList<Names> filterItems = new ArrayList<Names>();

                            synchronized (this) {
                                for (ContactInfo item : originalData) {
                                    if (item.name.toLowerCase(Locale.getDefault()).startsWith(constraintStr)) {
                                        filterItems.add(item);
                                    }
                                }
                                result.count = filterItems.size();
                                result.values = filterItems;
                            }
                        } else {
                            synchronized (this) {
                                result.count = originalData.size();
                                result.values = originalData;
                            }
                        }
                        return result;

    }

        @Override
        protected void publishResults(CharSequence constraint, FilterResults results) {

            if (results.values != null) {
                namelist = (List<Names>) results.values;
                notifyDataSetChanged();
            }

        }
    };
    return filter;
}

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