为什么顶部栏中的搜索在 android studio 中不起作用？

Question

我用listView 制作了一个应用程序，我想在顶部栏中使用搜索，但它不起作用。 在这个程序中，我从 firebase 获取数据。

这些是下面的代码：

这是MainActivity 代码：

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;
    }

}

这是listAdapter 代码

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

将此添加到您的列表适配器代码中：

    Context context;
     public listAdapter(Context context, List<Informatin> informatins) {
    super();
    this.context=context;
    arraylist=informatins;

}
    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 = arraylist;
            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();
        }
    };
}

在你的 onquerytextchaged 中添加这个：

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

        @Override
        public boolean onQueryTextChange(String newText) {
           adapter.getFilter().filter(newText);//replace adapter with listview name which in your case is listview as informed by you in comment
            return true;
        }
    });
    return true;

修改MainActivity onCreate()代码：

@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);
    listView.setTextFilterEnabled(true)//add this line
}