为什么在顶部栏中的搜索在 android studio 中不起作用？

Question

I made an app with listView and I want to use search in top bar but it doesn't work. In this program, I get the data from the firebase.

These are the codes below:

This is MainActivity code:

public class MainActivity extends AppCompatActivity implements LoaderManager.LoaderCallbacks<Cursor> {

    private static final int List_APP_LOADER = 0;

    ArrayList<Informatin> listItem;
    ListView listView;
    listAdapter adapter;

    DatabaseReference reference;

    ArrayList<Informatin> mInformation;

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

        listItem = new ArrayList<>();
        listView = findViewById(R.id.list);

        LoaderManager.getInstance(this).initLoader(LIST_APP_LOADER, null, this);

        mInformation = new ArrayList<>();

        adapter = new listAdapter(this, mInformation);
        listView.setAdapter(adapter);
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        super.onCreateOptionsMenu(menu);
        getMenuInflater().inflate(R.menu.menu_main_screen, menu);

        MenuItem searchItem = menu.findItem(R.id.search_item);
        SearchView searchView = (SearchView) searchItem.getActionView();

        searchView.setOnQueryTextListener(new SearchView.OnQueryTextListener() {
            @Override
            public boolean onQueryTextSubmit(String query) {
                return false;
            }

            @Override
            public boolean onQueryTextChange(String newText) {
                listView.getFilter().filter(newText);
                return true;
            }
        });
        return true;
    }

}

This is listAdapter code

public class listAdapter extends ArrayAdapter<Informatin> implements Filterable {

    List<Informatin> arrayList;

    Context context;
    public listAdapter(Context context, ArrayList<Informatin> informatins) {
        super(context, 0, informatins);
        this.context=context;
        arrayList = informatins;

    }

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

        View listItemView = convertView;
        if (listItemView == null) {
            listItemView = LayoutInflater.from(getContext()).inflate(
                    R.layout.list_item, parent, false);
        }

        Informatin currentList = getItem(position);

        TextView nameTextView = listItemView.findViewById(R.id.name);
        TextView descriptionTextView = listItemView.findViewById(R.id.description);
        TextView ageTextView = listItemView.findViewById(R.id.age);
        ImageView imageView = listItemView.findViewById(R.id.image);

        String firstName = currentList.getFirstName();
        String lastName = currentList.getLastName();

        String name = firstName + " " + lastName;

        nameTextView.setText(name);
        descriptionTextView.setText(currentList.getDescription());

        ageTextView.setText(currentList.getAge());

        return listItemView;
    }

    List<Informatin> informatins;
    public Filter getFilter() {
        return new Filter() {

            @Override
            protected FilterResults performFiltering(CharSequence constraint) {
                final FilterResults oReturn = new FilterResults();
                final ArrayList<Informatin> results = new ArrayList<>();
                if (informatins == null)
                    informatins = arrayList;
                if (constraint != null) {
                    if (informatins != null && informatins.size() > 0) {
                        for (final Informatin g : informatins) {
                            if (g.getFirstName().toLowerCase()
                                    .contains(constraint.toString()))
                                results.add(g);
                        }
                    }
                    oReturn.values = results;
                }
                return oReturn;
            }

            @SuppressWarnings("unchecked")
            @Override
            protected void publishResults(CharSequence constraint,
                                          FilterResults results) {
                arrayList = (ArrayList<Informatin>) results.values;
                notifyDataSetChanged();
            }
        };
    }
}

this is the picture of the problem

this is a screenshot for the problem from the device

Answer 1

Add this to your listadapter code:

    ArrayList<Informatin> informatins;
    public Filter getFilter() {
    return new Filter() {

        @Override
        protected FilterResults performFiltering(CharSequence constraint) {
            final FilterResults oReturn = new FilterResults();
            final ArrayList<Informatin> results = new ArrayList<Informatin>();
            if (informatins == null)
                informatins = employeeArrayList;
            if (constraint != null) {
                if (informatins != null && informatins.size() > 0) {
                    for (final Information g : informatins) {
                        if (g.getName().toLowerCase()
                                .contains(constraint.toString()))
                            results.add(g);
                    }
                }
                oReturn.values = results;
            }
            return oReturn;
        }

        @SuppressWarnings("unchecked")
        @Override
        protected void publishResults(CharSequence constraint,
                                      FilterResults results) {
            arraylist = (ArrayList<Informatin>) results.values;
            notifyDataSetChanged();
        }
    };
}

Add this in your onquerytextchaged:

       yourlistView.getFilter().filter(newText)

Answer 2

In my opinion you don't need the Filterable interface at all with the implementation you are doing here. To fix the problem in your code you can do the following

public class listAdapter extends ArrayAdapter<Informatin> {


public listAdapter(Context context, List<Informatin> informatins) {
    super(context, 0, informatins);
}

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

    View listItemView = convertView;
    if (listItemView == null) {
        listItemView = LayoutInflater.from(getContext()).inflate(
                R.layout.list_item, parent, false);
    }

    Informatin currentList = getItem(position);

    TextView nameTextView = listItemView.findViewById(R.id.name);
    TextView descriptionTextView = listItemView.findViewById(R.id.description);
    TextView ageTextView = listItemView.findViewById(R.id.age);
    ImageView imageView = listItemView.findViewById(R.id.image);

    String firstName = currentList.getFirstName();
    String lastName = currentList.getLastName();

    String name = firstName + " " + lastName;

    nameTextView.setText(name);
    descriptionTextView.setText(currentList.getDescription());

    ageTextView.setText(currentList.getAge());

    return listItemView;
}

Search code

searchView.setOnQueryTextListener(new SearchView.OnQueryTextListener() {
        @Override
        public boolean onQueryTextSubmit(String query) {
            return false;
        }

        @Override
        public boolean onQueryTextChange(String newText) {
            newText = newText.toLowerCase();
            ArrayList<Informatin> newList = new ArrayList<>();
            for (Informatin informatin : listItem) {
                String firstName = informatin.getFirstName().toLowerCase();
                if (firstName.contains(newText)) {
                    newList.add(informatin);
                }
            }
            adapter.clear();
            adapter.addAll(newList);
            adapter.notifyDataSetChanged();
            return true;
        }
    });
    return true;
}