android - 如何在Android片段之间发送数据

Question

我在 MainActivity 类中初始化的底部导航视图中有四个片段：

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        BottomNavigationView navView = findViewById(R.id.nav_view);

        AppBarConfiguration appBarConfiguration = new AppBarConfiguration.Builder(
                R.id.navigation_home, R.id.navigation_simulation, R.id.navigation_news, R.id.navigation_settings)
                .build();
        NavController navController = Navigation.findNavController(this, R.id.nav_host_fragment);
        NavigationUI.setupActionBarWithNavController(this, navController, appBarConfiguration);
        NavigationUI.setupWithNavController(navView, navController);
    }

}

我希望能够在设置片段中打开或关闭开关，并且主要在 HomeFragment 和 SimulationFragment 中具有此效果方面，在 HomeFragment 类的 OnCreateView 中我为设置类创建了一个视图，以便可以找到在 HomeFragment 中：

public View onCreateView(@NonNull LayoutInflater inflater,
                             ViewGroup container, Bundle savedInstanceState) {

        Retrofit retrofitClient = RetrofitClient.getInstance();
        service = retrofitClient.create(Service.class);
        settings = inflater.inflate(R.layout.fragment_settings, container, false);
        mapView = inflater.inflate(R.layout.fragment_home, container, false);
        return mapView;
    }

但是，例如，当我从 HomeFragment（作为导航主机片段）转到 SettingsFragment，检查 Switch 然后导航回 HomeFragment 时，状态似乎丢失了，这是我正在尝试的基本思想在 HomeFragment 中执行：

Switch heatmap = settings.findViewById(R.id.displayHeatmap);

            heatmap.setOnCheckedChangeListener((buttonView, isChecked) -> {
                if(isChecked) {
                    addHeatMap();
                }
                else {
                    mMap.clear();
                }
            });

标签： androidandroid-fragmentsandroid-activitysettingsbottomnavigationview