java - 如何从底部导航 fragment 移动到其他 fragment

Question

我在其中声明底部应用栏的类的代码是:

import androidx.appcompat.app.AppCompatActivity;
import androidx.appcompat.widget.Toolbar;
import androidx.fragment.app.Fragment;
import androidx.fragment.app.FragmentManager;
import androidx.fragment.app.FragmentTransaction;

import android.content.Intent;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.Toast;

import com.google.android.material.bottomappbar.BottomAppBar;
import com.google.android.material.bottomsheet.BottomSheetDialogFragment;
import com.google.android.material.floatingactionbutton.FloatingActionButton;

public class NavigActivity extends AppCompatActivity {

    private BottomAppBar mbottomAppBar;
    private FloatingActionButton fab;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_navig);
        mbottomAppBar = findViewById(R.id.bottom_app_bar);
        setSupportActionBar(mbottomAppBar);
        fab= findViewById(R.id.fab);
        fab.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Fragment fragment = new AddNewProductFragment();
                FragmentManager fragmentManager = getSupportFragmentManager();
                FragmentTransaction ft = fragmentManager.beginTransaction();
                ft.addToBackStack(null);
                ft.replace(R.id.content_frame, fragment);
                ft.commit();
            }
        });

       mbottomAppBar.setOnMenuItemClickListener(new Toolbar.OnMenuItemClickListener() {
           @Override
           public boolean onMenuItemClick(MenuItem item) {
               Fragment fragment = null;
              switch (item.getItemId())
              {
                  case R.id.home:
                        fragment = new HomeFragment();
                      break;
                  case R.id.notification:
                        fragment = new NotificationFragment();
                      break;
                  case R.id.my_invoices:
                      fragment = new InvoiceFragment();
                      break;
              }
              if(fragment != null)
              {
                  FragmentManager fragmentManager = getSupportFragmentManager();
                  FragmentTransaction ft = fragmentManager.beginTransaction();
                  ft.replace(R.id.content_frame, fragment);
                  ft.commit();
              }
              return false;
           }
       });
        mbottomAppBar.setNavigationOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                //open bottom sheet
                BottomSheetDialogFragment bottomSheetDialogFragment = BottomSheetNavigationFragment.newInstance();
                bottomSheetDialogFragment.show(getSupportFragmentManager(), "Bottom Sheet Dialog Fragment");
            }
        });

    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        super.onCreateOptionsMenu(menu);
        getMenuInflater().inflate(R.menu.menu,menu);
        return true;
    }
}

Bottom Sheet 导航 fragment 的代码是:

import android.annotation.SuppressLint;
import android.app.Activity;
import android.app.Dialog;
import android.content.Intent;
import android.os.Bundle;
import android.view.MenuItem;
import android.view.View;
import android.widget.ImageView;
import android.widget.Toast;

import androidx.annotation.NonNull;
import androidx.coordinatorlayout.widget.CoordinatorLayout;
import androidx.fragment.app.Fragment;
import androidx.fragment.app.FragmentManager;
import androidx.fragment.app.FragmentTransaction;

import com.google.android.material.bottomsheet.BottomSheetBehavior;
import com.google.android.material.bottomsheet.BottomSheetDialogFragment;
import com.google.android.material.navigation.NavigationView;

public class BottomSheetNavigationFragment extends BottomSheetDialogFragment {
    public static BottomSheetNavigationFragment newInstance() {

        Bundle args = new Bundle();

        BottomSheetNavigationFragment fragment = new BottomSheetNavigationFragment();
        fragment.setArguments(args);
        return fragment;
    }
    //Bottom Sheet Callback
    private BottomSheetBehavior.BottomSheetCallback mBottomSheetBehaviorCallback = new BottomSheetBehavior.BottomSheetCallback() {

        @Override
        public void onStateChanged(@NonNull View bottomSheet, int newState) {
            if (newState == BottomSheetBehavior.STATE_HIDDEN) {
                dismiss();
            }

        }

        @Override
        public void onSlide(@NonNull View bottomSheet, float slideOffset) {
            //check the slide offset and change the visibility of close button
            if (slideOffset > 0.5) {
                closeButton.setVisibility(View.VISIBLE);
            } else {
                closeButton.setVisibility(View.GONE);
            }
        }
    };

    private ImageView closeButton;

    @SuppressLint("RestrictedApi")
    @Override
    public void setupDialog(Dialog dialog, int style) {
        super.setupDialog(dialog, style);
        //Get the content View
        View contentView = View.inflate(getContext(), R.layout.bottom_navigation_drawer, null);
        dialog.setContentView(contentView);

        NavigationView navigationView = contentView.findViewById(R.id.navigation_view);

        //implement navigation menu item click event
        navigationView.setNavigationItemSelectedListener(new NavigationView.OnNavigationItemSelectedListener() {
            @Override
            public boolean onNavigationItemSelected(@NonNull MenuItem item) {
                F
                Fragment fragment;
                switch (item.getItemId()) {
                    case R.id.user_details:

                        break;
                    case R.id.settings:

                        break;
                    case R.id.help:

                        break;
                    case R.id.logout:
                        MainActivity obj = new MainActivity();
                        obj.logout();
                        startActivity( new Intent(getActivity(), MainActivity.class));
                        break;
                }

                return false;
            }
        });
        closeButton = contentView.findViewById(R.id.close_image_view);
        closeButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                //dismiss bottom sheet
                dismiss();
            }
        });

        //Set the coordinator layout behavior
        CoordinatorLayout.LayoutParams params = (CoordinatorLayout.LayoutParams) ((View) contentView.getParent()).getLayoutParams();
        CoordinatorLayout.Behavior behavior = params.getBehavior();

        //Set callback
        if (behavior instanceof BottomSheetBehavior) {
            ((BottomSheetBehavior) behavior).setBottomSheetCallback(mBottomSheetBehaviorCallback);
        }
    }
}

我无法理解如何将屏幕从这个 fragment 移动到其他 fragment - 因为 getSupportFragmentManager() 在此不可用。当我尝试生成 Intent 时，它会抛出错误。

如有任何建议或帮助，我们将不胜感激。谢谢!

Answer 1

您可以使用可变 Activity 。在附件 fragment 时声明它，如下所示:

 private AppCompatActivity activity;

    @Override
     public void onAttach(@NonNull Context context) {
    super.onAttach(context);
    if (context instanceof AppCompatActivity) {
        activity = (AppCompatActivity) context;
    }
  }

及之后

/.../

activity.getSupportFragmentManager /...some logic.../