无法访问的语句，menuItem.setActionView(R.layout.theme_switch);

Question

1. 第一节

包 com.gmsofficial.GmSOfficial;

 import android.content.Intent;
 import android.content.SharedPreferences;
 import android.os.Bundle;
 import android.view.MenuItem;
 import android.widget.CompoundButton;
 import android.widget.Switch;

 import androidx.annotation.NonNull;
 import androidx.appcompat.app.ActionBarDrawerToggle;
 import androidx.appcompat.app.AppCompatActivity;
 import androidx.appcompat.app.AppCompatDelegate;
 import androidx.appcompat.widget.Toolbar;
 import androidx.drawerlayout.widget.DrawerLayout;

1. 第二节

导入 com.google.android.material.navigation.NavigationView；

 public class NavigationDrawer extends AppCompatActivity {


 DrawerLayout drawerLayout;
 ActionBarDrawerToggle actionBarDrawerToggle;
 NavigationView navigationView;

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

    if (loadState() == true){
        AppCompatDelegate.setDefaultNightMode(AppCompatDelegate.MODE_NIGHT_YES);
        setTheme(R.style.darkTheme);
    } else {
        AppCompatDelegate.setDefaultNightMode(AppCompatDelegate.MODE_NIGHT_NO);
        setTheme(R.style.Theme_AppCompat);
    }

    setUpToolbar();
    navigationView = (NavigationView) findViewById(R.id.navigation_menu);
    navigationView.setNavigationItemSelectedListener(new NavigationView.OnNavigationItemSelectedListener() {
      

     

3.第三节

    @Override
        public boolean onNavigationItemSelected(@NonNull MenuItem menuItem) {
            switch (menuItem.getItemId())
            {
                case R.id.nav_home:

                    Intent intent = new Intent(NavigationDrawer.this, NavigationDrawer.class);
                    startActivity(intent);
                    break;

                case R.id.nav_Website:

                    intent = new Intent(NavigationDrawer.this, Websitewebview.class);
                    startActivity(intent);
                    break;

                case R.id.nav_Mobiles:

                    intent = new Intent(NavigationDrawer.this, Mobileswebview.class);
                    startActivity(intent);
                    break;

             

4. 第四节

               case R.id.nav_TechNews:
   
                   intent = new Intent(NavigationDrawer.this, TechNewswebview.class);
                   startActivity(intent);
                   break;
   
               case R.id.nav_Gadgets:
   
                   intent = new Intent(NavigationDrawer.this, Gadgetswebview.class);
                   startActivity(intent);
                   break;
   
               case R.id.nav_CustomROM:
   
                   intent = new Intent(NavigationDrawer.this, CustomRomwebview.class);
                   startActivity(intent);
                   break;
   
                   menuItem.setActionView(R.layout.theme_switch);
                   final Switch themeswitch = (Switch) menuItem.getActionView().findViewById(R.id.action_switch);
                   if (loadState() == true){
                       themeswitch.setChecked(true);
           }
   

5. 无法访问的错误部分

                       themeswitch.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
                       @Override
                       public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
                           if (isChecked) {
                               AppCompatDelegate.setDefaultNightMode(AppCompatDelegate.MODE_NIGHT_YES);
                               saveState(true);
                               recreate();
                           } else {
                               AppCompatDelegate.setDefaultNightMode(AppCompatDelegate.MODE_NIGHT_NO);
                               saveState(false);
                           }
                       }
                   });
                   break;
   
               case R.id.nav_AboutUs:
   
                   intent = new Intent(NavigationDrawer.this, AboutUS.class);
                   startActivity(intent);
                   break;
   

6. 第六节 //粘贴您的隐私政策链接

   // case R.id.nav_Policy:{ // // Intent browserIntent = new Intent(Intent.ACTION_VIEW , Uri.parse("")); // startActivity(browserIntent); // // } // 休息; 案例 R.id.nav_share:{

        Intent sharingIntent = new Intent(android.content.Intent.ACTION_SEND);
        sharingIntent.setType("text/plain");
        String shareBody =  "http://play.google.com/store/apps/detail?id=" + getPackageName();
        String shareSub = "Try now";
        sharingIntent.putExtra(android.content.Intent.EXTRA_SUBJECT, shareSub);
        sharingIntent.putExtra(android.content.Intent.EXTRA_TEXT, shareBody);
        startActivity(Intent.createChooser(sharingIntent, "Share using"));
   
             }
               break;
           }
           return false;
       }
   });
   

   }

7. 第七节

   public void setUpToolbar() {
   drawerLayout = findViewById(R.id.drawerLayout);
   Toolbar toolbar = findViewById(R.id.toolbar);
   setSupportActionBar(toolbar);
   actionBarDrawerToggle = new ActionBarDrawerToggle(this, drawerLayout, toolbar, R.string.app_name, R.string.app_name);
   drawerLayout.addDrawerListener(actionBarDrawerToggle);
   actionBarDrawerToggle.getDrawerArrowDrawable().setColor(getResources().getColor(R.color.purple));
   actionBarDrawerToggle.syncState();
   

   }

   private void saveState(Boolean state){
   SharedPreferences sharedPreferences = getSharedPreferences("GmS Official", MODE_PRIVATE);
   SharedPreferences.Editor editor = sharedPreferences.edit();
   editor.putBoolean("NightMode", state);
   editor.apply();
   

   }

    private Boolean loadState(){
   SharedPreferences sharedPreferences = getSharedPreferences("GmS Official", MODE_PRIVATE);
   Boolean state = sharedPreferences.getBoolean("NightMode", false);
   return state;
   

   } }

Answer 1

break;
menuItem.setActionView(R.layout.theme_switch);

我猜你不知道break 做了什么？这两行紧挨着，你的编译器/编辑器正指向它。 break 将完全跳出switch 语句，menuItem... 行无法运行，这就是编译器告诉你的原因：“这不可能是正确的；我不会帮你挖这个坟墓更进一步。”。