java使用OnOptions ItemSelected显示/隐藏搜索视图

Question

我想使我的Searchview仅在从抽屉中打开产品选项时可见，为此，我尝试使用OnOptions ItemSelected方法来侦听正在使用的选项。 问题是每次我试图从OnOptions ItemSelected获取我的SearchView id时，我总是得到一个NullPointerException

我知道如何使用以下方法在OnCreateOptions菜单中隐藏SearchView：

menu.findItem(R.id.action_search).setVisible(false);

这是我的OnCreateOptions菜单的源代码：

@Override
public boolean onCreateOptionsMenu(Menu menu) {
    // Inflate the menu; this adds items to the action bar if it is present.
    getMenuInflater().inflate(R.menu.main, menu);

    View lay = findViewById(R.id.nav_header);
    //id in this line is found
    menu.findItem(R.id.action_search).setVisible(false);

    sharedpreferences = getSharedPreferences(Login.my_shared_preferences, Context.MODE_PRIVATE);
    session = sharedpreferences.getBoolean(session_status, false);
    id = sharedpreferences.getString(TAG_ID, null);
    username = sharedpreferences.getString(TAG_USERNAME, null);
    name = sharedpreferences.getString(TAG_NAME, null);

    txt_id = lay.findViewById(R.id.txt_id_admin);
    txt_username = lay.findViewById(R.id.txt_textView);
    txt_name = lay.findViewById(R.id.txt_name_admin);
    imb = lay.findViewById(R.id.btn_exit);

    txt_id.setText("ID : " + id);
    txt_name.setText("Nama : " + name);
    txt_username.setText("Status : " + username);

    imb.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            SharedPreferences.Editor editor = sharedpreferences.edit();
            editor.clear();
            editor.commit();

            intent = new Intent(getApplicationContext(), Login.class);
            finish();
            startActivity(intent);
        }
    });
    return true;

但是我不能在onOptionsItemSelected方法中做同样的事情，因为它使用的参数是MenuItem，而不是Menu

这是我对OnOptions ItemSelected方法的最新尝试：

@Override
public boolean onOptionsItemSelected(MenuItem item) {
    NavigationView navigationView = findViewById(R.id.nav_view);
    Menu menu = navigationView.getMenu();
    //id in this line is null
    MenuItem item_search = menu.findItem(R.id.action_search);
    Log.d(TAG, "Response : " + item_search);
    SearchView searchView = (SearchView) item_search.getActionView();

    if (item.getItemId() == R.id.nav_produk) {
        searchView.setVisibility(View.VISIBLE);
        return true;
    } else {
        Log.d(TAG, "Response : " + searchView);
        searchView.setVisibility(View.INVISIBLE);
        return super.onOptionsItemSelected(item);
    }
}

这是我的res/menu/main。xml文件：

<?xml version="1.0" encoding="utf-8"?>
<menu xmlns:安卓="http://schemas.安卓.com/apk/res/安卓"
xmlns:app="http://schemas.安卓.com/apk/res-auto">
<item
    安卓:id="@+id/action_settings"
    安卓:visible="false"
    安卓:orderInCategory="100"
    安卓:title="@string/action_settings"
    app:showAsAction="never"/>
<item
    安卓:id="@+id/action_search"
    安卓:visible="true"
    安卓:orderInCategory="100"
    安卓:icon="@安卓:drawable/ic_menu_search"
    安卓:title="@string/search"
    app:actionViewClass="安卓.widget.SearchView"
    app:showAsAction="ifRoom|collapseActionView"/>

Answer 1

我已经找到答案了！显然，我根本不需要选择选项项

我在抽屉布局上使用的是NavController，因此创建侦听器的更简单方法是在创建选项菜单中使用onDestinationChanged方法

结果是：

    @Override
    public boolean onCreateOptionsMenu(final Menu menu) {
    // Inflate the menu; this adds items to the action bar if it is present.
    getMenuInflater().inflate(R.menu.main, menu);

    View lay = findViewById(R.id.nav_header);
    menu.findItem(R.id.action_search).setVisible(false);

    sharedpreferences = getSharedPreferences(Login.my_shared_preferences, Context.MODE_PRIVATE);
    session = sharedpreferences.getBoolean(session_status, false);
    id = sharedpreferences.getString(TAG_ID, null);
    username = sharedpreferences.getString(TAG_USERNAME, null);
    name = sharedpreferences.getString(TAG_NAME, null);

    txt_id = lay.findViewById(R.id.txt_id_admin);
    txt_username = lay.findViewById(R.id.txt_textView);
    txt_name = lay.findViewById(R.id.txt_name_admin);
    imb = lay.findViewById(R.id.btn_exit);

    txt_id.setText("ID : " + id);
    txt_name.setText("Nama : " + name);
    txt_username.setText("Status : " + username);

    imb.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            SharedPreferences.Editor editor = sharedpreferences.edit();
            editor.clear();
            editor.commit();

            intent = new Intent(getApplicationContext(), Login.class);
            finish();
            startActivity(intent);
        }
    });
    
    //Only show SearchView when produk is open
    NavController navController = Navigation.findNavController(this, R.id.nav_host_fragment);
    navController.addOnDestinationChangedListener(new NavController.OnDestinationChangedListener() {
        @Override
        public void onDestinationChanged(@NonNull NavController controller, @NonNull NavDestination destination, @Nullable Bundle arguments) {
            if (destination.getId() == R.id.nav_produk) {
                menu.findItem(R.id.action_search).setVisible(true);
            } else {
                menu.findItem(R.id.action_search).setVisible(false);
            }
        }
    });
    
    return true;
}