java - 尝试在 java 中创建搜索视图时，我得到一个错误列表

Question

我正在研究 cs50x，我正在尝试按照他们给我的步骤创建一个搜索视图。但是，当我尝试打开应用程序时，logcat 会输出以下内容：

2020-05-30 15:15:45.371 20144-20144/edu.harvard.cs50.pokedex E/AndroidRuntime: FATAL EXCEPTION: main
Process: edu.harvard.cs50.pokedex, PID: 20144
java.lang.ClassCastException: androidx.appcompat.widget.SearchView cannot be cast to android.widget.SearchView
at edu.harvard.cs50.pokedex.MainActivity.onCreateOptionsMenu(MainActivity.java:34)

还有很多其他错误，但我已经检查过它们，它们并不重要。关键是课程告诉我使用androidxsearchviw 的版本，main_menu.xml但它说它不兼容。这是我的 main_menu.xml：

    <?xml version="1.0" encoding="utf-8"?>
<menu xmlns:tools="http://schemas.android.com/tools"
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto">

    <item
        android:id="@+id/action_search"
        android:icon="@android:drawable/ic_menu_search"
        android:title="@string/search"
        app:actionViewClass="androidx.appcompat.widget.SearchView"
        app:showAsAction="always" />
</menu>

还有我的适配器（sarch 视图部分）：

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

private class PokemonFilter extends Filter {
    @Override
    protected FilterResults performFiltering(CharSequence constraint) {
        FilterResults results = new FilterResults();
        if (constraint.length() == 0 || constraint == null) {
            results.values = pokemon;
            results.count = pokemon.size();
        }
        else {
            List<Pokemon> filteredPokemon = new ArrayList<>();
            for (Pokemon pokemon : filteredPokemon) {
                if (pokemon.getName().toLowerCase().startsWith(constraint.toString())) {
                    filteredPokemon.add(pokemon);
                }
            }
            results.values = filteredPokemon;
            results.count = filteredPokemon.size();
        }
        return results;
        }

    @Override
    protected void publishResults(CharSequence charSequence, FilterResults results) {
        filtered = (List<Pokemon>) results.values;
        notifyDataSetChanged();
    }
}

主要活动：

public class MainActivity extends AppCompatActivity implements SearchView.OnQueryTextListener {
private RecyclerView recyclerView;
private PokedexAdapter adapter;
private RecyclerView.LayoutManager layoutManager;

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

    recyclerView = findViewById(R.id.recycler_view);
    adapter = new PokedexAdapter(getApplicationContext());
    layoutManager = new LinearLayoutManager(this);

    recyclerView.setAdapter(adapter);
    recyclerView.setLayoutManager(layoutManager);
}

@Override
public boolean onCreateOptionsMenu(Menu menu) {
    getMenuInflater().inflate(R.menu.main_menu, menu);
    MenuItem searchItem = menu.findItem(R.id.action_search);
    androidx.appcompat.widget.SearchView searchView = (androidx.appcompat.widget.SearchView) searchItem.getActionView();
    searchView.setOnQueryTextListener((androidx.appcompat.widget.SearchView.OnQueryTextListener) this);

    return true;
}

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

@Override
public boolean onQueryTextSubmit(String newText) {
    adapter.getFilter().filter(newText);
    return false;
}

}

标签： javaandroid-studiosearchview