選擇導航選單項時不會替換上一個片段-有解無憂

我有一個導航抽屜活動，它根據從前一個活動作為主頁片段傳遞的一些資料顯示餐館串列。單擊其中一張餐廳卡片，會創建另一個片段，顯示餐廳的詳細資訊。所有這些片段都將導航抽屜活動作為它們的父活動。當我在導航項上選擇主頁片段選單時，片段不會替換前一個片段，而是將自身疊加在前一個片段上。我將添加一些圖片來解釋這個場景。

這是我的導航抽屜 - 選擇導航選單項時不會替換上一個片段

這是包含餐廳串列的家庭片段 -

選擇導航選單項時不會替換上一個片段

這是點擊一家餐廳時顯示餐廳詳細資訊的片段 -

選擇導航選單項時不會替換上一個片段

當我從餐廳詳細資訊螢屏按下導航抽屜上的主頁專案時，會發生這種情況 -

選擇導航選單項時不會替換上一個片段

這是相關的代碼- MainActivity2.class

package com.example.wfdmockapp;

import android.content.Intent;
import android.graphics.Color;
import android.os.Bundle;
import android.view.MenuItem;
import android.view.View;
import android.view.Menu;

import com.example.wfdmockapp.ui.home.HomeFragment;
import com.google.android.material.snackbar.Snackbar;
import com.google.android.material.navigation.NavigationView;

import androidx.annotation.NonNull;
import androidx.core.view.GravityCompat;
import androidx.navigation.NavController;
import androidx.navigation.Navigation;
import androidx.navigation.ui.AppBarConfiguration;
import androidx.navigation.ui.NavigationUI;
import androidx.drawerlayout.widget.DrawerLayout;
import androidx.appcompat.app.AppCompatActivity;


import com.example.wfdmockapp.databinding.ActivityMain2Binding;

public class MainActivity2 extends AppCompatActivity{

    private static final String TAG = "MainActivity2";

    private String cityId = null;
    private String townId = null;

    private DrawerLayout drawer;

    private AppBarConfiguration mAppBarConfiguration;
    private ActivityMain2Binding binding;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        binding = ActivityMain2Binding.inflate(getLayoutInflater());
        setContentView(binding.getRoot());

        setSupportActionBar(binding.appBarMain.toolbar);
        binding.appBarMain.fab.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                Snackbar.make(view, "Replace with your own action", Snackbar.LENGTH_LONG)
                        .setAction("Action", null).show();
            }
        });

        drawer = binding.drawerLayout;
        NavigationView navigationView = binding.navView;
        // Passing each menu ID as a set of Ids because each
        // menu should be considered as top level destinations.
        mAppBarConfiguration = new AppBarConfiguration.Builder(
                R.id.nav_home)
                .setOpenableLayout(drawer)
                .build();
        NavController navController = Navigation.findNavController(this, R.id.nav_host_fragment_content_main);
        NavigationUI.setupActionBarWithNavController(this, navController, mAppBarConfiguration);
        NavigationUI.setupWithNavController(navigationView, navController);

        Intent getRestaurantIntent = getIntent();
        cityId = getRestaurantIntent.getStringExtra("cityId");
        townId = getRestaurantIntent.getStringExtra("townId");

        Bundle bundle = new Bundle();
        bundle.putString("cityId",cityId);
        bundle.putString("townId",townId);
        System.out.println(cityId " " townId);

        if (savedInstanceState == null) {
            getSupportFragmentManager().beginTransaction()
                    .setReorderingAllowed(true)
                    .replace(R.id.nav_host_fragment_content_main, HomeFragment.class, bundle)
                    .commit();

        }
    }

    @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_activity2, menu);
        return true;
    }

    @Override
    public boolean onSupportNavigateUp() {
        NavController navController = Navigation.findNavController(this, R.id.nav_host_fragment_content_main);
        return NavigationUI.navigateUp(navController, mAppBarConfiguration)
                || super.onSupportNavigateUp();
    }
}```

HomeFragment.Java

public class HomeFragment extends Fragment {

    private static final String TAG = "HomeFragment";

    private RequestQueue mRequestQueue;

    private String cityId = null;
    private String townId = null;
    private String ShopListUrl= Global.base_url "v1/get-shop-list";

    private ArrayList<Shop> shops = new ArrayList<>();

    private RecyclerView recyclerView;
    private ShopRecyclerViewAdapter adapter;

    private GifImageView loadingAnimation;

    @Override

    public View onCreateView(@NonNull LayoutInflater inflater,
                             ViewGroup container, Bundle savedInstanceState) {
        Bundle bundle = this.getArguments();
        if(bundle!=null){
            cityId = bundle.getString("cityId");
            townId = bundle.getString("townId");
            System.out.println(cityId " " townId);
        }

        return inflater.inflate(R.layout.fragment_home, container, false);
    }

    @Override
    public void onViewCreated(@NonNull View view, @Nullable Bundle savedInstanceState) {
        super.onViewCreated(view, savedInstanceState);

        mRequestQueue = Volley.newRequestQueue(getContext());

        loadingAnimation = view.findViewById(R.id.loading_animation);

        initRecyclerView(view);
        getShopList();
    }

    public void getShopList(){
        Log.d(TAG,"Creating Shop Object");
        JSONObject shopInfoObject = new JSONObject();

        try {
            shopInfoObject.put("city",cityId);
            shopInfoObject.put("town",townId);
            shopInfoObject.put("shop_type",null);
            shopInfoObject.put("api_token","a4e426652ed46154d67c8af897e77022");
        } catch (JSONException e) {
            e.printStackTrace();
        }

        Log.d(TAG,"JSON Shop Object created,collecting response for Request");
        JsonObjectRequest ShopListRequest = new JsonObjectRequest(Request.Method.POST, ShopListUrl, shopInfoObject, new Response.Listener<JSONObject>() {
            @Override
            public void onResponse(JSONObject response) {
                try {

                    Log.d(TAG,"Getting response");
                    JSONArray shopList = response.getJSONArray("shopList");

                    for(int i=0;i<shopList.length();i  ){
                        JSONObject jsonObject = shopList.getJSONObject(i);

                        Shop shop = new Shop();
                        shop.setShopId(jsonObject.getString("shopId"));
                        shop.setName(jsonObject.getString("title"));
                        shop.setTypeName(jsonObject.getString("typeName"));
                        shop.setLogo(Global.base_imageUrl jsonObject.getString("logo"));
                        shop.setSpecialOffer(jsonObject.getString("special_offer_text"));
                        shop.setDeliveredBy(jsonObject.getInt("deliveredBy"));
                        shop.setMixMatch(jsonObject.getInt("mixAndMatch"));
                        shop.setDeliveryFee(jsonObject.getString("delivery_fee"));
                        shop.setMinimumOrder(jsonObject.getString("minOrder"));
                        shop.setPaymentModeText(jsonObject.getString("paymentModeText"));
                        shop.setShopStatus(jsonObject.getString("currentStatus"));
                        shops.add(shop);
                    }

                    adapter.notifyDataSetChanged();
                    Log.d(TAG,"Shop data fetched");

                    loadingAnimation.setVisibility(View.GONE);

                } catch (JSONException e) {
                    e.printStackTrace();
                }
            }
        }, new Response.ErrorListener() {
            @Override
            public void onErrorResponse(VolleyError error) {
                if (error instanceof TimeoutError) {
                    Global.displayToast("Timeout! Please Try Again",getContext());
                }
            }
        });
        ShopListRequest.setRetryPolicy(new DefaultRetryPolicy(
                6000,
                DefaultRetryPolicy.DEFAULT_MAX_RETRIES,
                DefaultRetryPolicy.DEFAULT_BACKOFF_MULT));
        mRequestQueue.add(ShopListRequest);
    }

    public void initRecyclerView(View view){
        recyclerView = view.findViewById(R.id.recycler_view);
        adapter = new ShopRecyclerViewAdapter(shops,getContext(),this);
        recyclerView.setAdapter(adapter);
        recyclerView.setLayoutManager(new LinearLayoutManager(getContext()));
    }
}```

RestaurantDetailsFragment.Java

package com.example.wfdmockapp;

import android.graphics.drawable.Drawable;
import android.os.Bundle;

import androidx.annotation.NonNull;
import androidx.annotation.Nullable;
import androidx.fragment.app.Fragment;
import androidx.recyclerview.widget.LinearLayoutManager;
import androidx.recyclerview.widget.RecyclerView;

import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.LinearLayout;
import android.widget.TextView;

import com.android.volley.DefaultRetryPolicy;
import com.android.volley.Request;
import com.android.volley.RequestQueue;
import com.android.volley.Response;
import com.android.volley.TimeoutError;
import com.android.volley.VolleyError;
import com.android.volley.toolbox.JsonObjectRequest;
import com.android.volley.toolbox.Volley;
import com.bumptech.glide.Glide;
import com.example.wfdmockapp.models.Restaurant;

import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;

import java.util.ArrayList;

import de.hdodenhof.circleimageview.CircleImageView;
import pl.droidsonroids.gif.GifImageView;

public class RestaurantDetailsFragment extends Fragment {

    private static final String TAG = "RestaurantDetails";

    private RequestQueue mRequestQueue;

    private Restaurant restaurant = new Restaurant();
    private String getShopDetailsUrl = Global.base_url "v1/get-shop-details";
    private String shopId;
    private ArrayList<String> FoodTypeList;

    //UI Components
    private TextView name;
    private TextView typeName;
    private TextView shopMessage;
    private TextView minOrder;
    private TextView paymentModeText;
    private RecyclerView foodTypeListRecyclerView;
    private FoodTypeRecyclerViewAdapter adapter;
    private TextView deliveryText;
    private TextView deliveryFee;
    private TextView deliveryTime;
    private TextView shopStatus;
    private CircleImageView shopLogo;
    private LinearLayout shopDetailsView;
    private GifImageView loadingAnimation;


    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        shopId = getArguments().getString("shopId");
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        // Inflate the layout for this fragment
        return inflater.inflate(R.layout.fragment_restaurant_details, container, false);
    }

    @Override
    public void onViewCreated(@NonNull View view, @Nullable Bundle savedInstanceState) {
        super.onViewCreated(view, savedInstanceState);

        loadingAnimation = view.findViewById(R.id.shop_details_loading_animation);
        shopDetailsView = view.findViewById(R.id.shop_view);
        shopDetailsView.setVisibility(View.GONE);

        FoodTypeList = restaurant.getFoodTypeList();
        mRequestQueue = Volley.newRequestQueue(getContext());

        initRecyclerView(view);
        initUIComponents(view);
        showRestaurantDetails(view);
    }

    public void showRestaurantDetails(View view){
        JSONObject ShopInfoObject = new JSONObject();

        try {
            ShopInfoObject.put("api_token","cadbc10d3aa13257cd7c69bb3d434d00");
            ShopInfoObject.put("shopId",shopId);

        } catch (JSONException e) {
            e.printStackTrace();
        }


        JsonObjectRequest getShopDetailsRequest = new JsonObjectRequest(Request.Method.POST, getShopDetailsUrl, ShopInfoObject, new Response.Listener<JSONObject>() {
            @Override
            public void onResponse(JSONObject response) {
                try {
                    JSONArray shopDetails = response.getJSONArray("shop");

                    String deliveryTextResponse = response.getString("deliveryText");
                    restaurant.setDeliveryText(deliveryTextResponse);

                    for(int i=0;i<shopDetails.length();i  ){
                        JSONObject shopJsonObject = shopDetails.getJSONObject(i);

                        restaurant.setName(shopJsonObject.getString("title"));

                        restaurant.setTypeName(shopJsonObject.getString("typeName"));

                        restaurant.setShop_message(shopJsonObject.getString("shop_message"));

                        String ImageUrl = Global.base_imageUrl shopJsonObject.getString("logo");
                        restaurant.setLogo(ImageUrl);

                        restaurant.setMinOrder(shopJsonObject.getString("minOrder"));

                        restaurant.setStatus(shopJsonObject.getString("currentStatus"));

                        JSONArray foodTypeListJSONArray = shopJsonObject.getJSONArray("foodTypeList");
                        for(int j=0;j<foodTypeListJSONArray.length();j  ){
                            JSONObject foodTypeListJSONObject = foodTypeListJSONArray.getJSONObject(j);

                            Log.d(TAG,foodTypeListJSONObject.getString("foodTypeName"));
                            restaurant.addFoodListItems(foodTypeListJSONObject.getString("foodTypeName"));
                        }

                        adapter.notifyDataSetChanged();

                        restaurant.setDelivery_fee(shopJsonObject.getString("delivery_fee"));

                        JSONObject deliveryHours = shopJsonObject.getJSONObject("deliveryHours");
                        String openingHours = deliveryHours.getString("openingHour");
                        String closingHours = deliveryHours.getString("closingHour");
                        restaurant.setDeliveryTime("Delivery: " openingHours " - " closingHours);

                        restaurant.setPaymentModeText(shopJsonObject.getString("paymentModeText"));

                        setUIComponentValues(restaurant,view);

                        loadingAnimation.setVisibility(View.GONE);
                        shopDetailsView.setVisibility(View.VISIBLE);
                    }

                } catch (JSONException e) {
                    e.printStackTrace();
                }

            }
        }, new Response.ErrorListener() {
            @Override
            public void onErrorResponse(VolleyError error) {
                if (error instanceof TimeoutError) {
                    Global.displayToast("Timeout error!Please try again",getContext());
                }
            }
        });
        getShopDetailsRequest.setRetryPolicy(new DefaultRetryPolicy(
                5000,
                DefaultRetryPolicy.DEFAULT_MAX_RETRIES,
                DefaultRetryPolicy.DEFAULT_BACKOFF_MULT));
        mRequestQueue.add(getShopDetailsRequest);
    }

    public void initUIComponents(View view){
        name = view.findViewById(R.id.shopName);
        typeName = view.findViewById(R.id.shopTypename);
        shopMessage = view.findViewById(R.id.shop_message);
        minOrder = view.findViewById(R.id.min_order);
        paymentModeText = view.findViewById(R.id.payment_Method);
        deliveryFee = view.findViewById(R.id.min_delivery_fee);
        deliveryText = view.findViewById(R.id.delivery_time_today);
        deliveryTime = view.findViewById(R.id.shop_delivery_time);
        shopLogo = view.findViewById(R.id.shopLogo);
        shopStatus = view.findViewById(R.id.status);
    }

    public void setUIComponentValues(Restaurant restaurant,View view){
        Glide.with(getContext()).load(restaurant.getLogo()).into(shopLogo);
        name.setText(restaurant.getName());
        typeName.setText(restaurant.getTypeName());

        String message = restaurant.getShop_message();
        System.out.println(message);
        if(message.equals("")||message.equals("null")){
            Log.d(TAG,"No shop message,hiding field");
            LinearLayout shopMsgField = view.findViewById(R.id.shop_message_field);
            shopMsgField.setVisibility(View.GONE);
        }else{
            shopMessage.setText(message);
        }


        minOrder.setText("\u20ac " restaurant.getMinOrder() " MIN ");
        paymentModeText.setText(restaurant.getPaymentModeText());
        deliveryFee.setText("Delivery \u20ac " restaurant.getDelivery_fee());

        String text = restaurant.getDeliveryText();
        if(text.equals("null")||text.equals("")){
            deliveryText.setVisibility(View.GONE);
        }else{
            deliveryText.setText(text);
        }

        deliveryTime.setText(restaurant.getDeliveryTime());
        Global.setCurrentStatusText(restaurant.getStatus(),shopStatus);

    }

    public void initRecyclerView(View view){
        foodTypeListRecyclerView = view.findViewById(R.id.FoodTypeRecyclerView);
        adapter = new FoodTypeRecyclerViewAdapter(FoodTypeList,getContext());
        foodTypeListRecyclerView.setAdapter(adapter);
        foodTypeListRecyclerView.setLayoutManager(new LinearLayoutManager(getContext()));
    }
}```

ShopRecyclerViewAdapter.java

package com.example.wfdmockapp;

import android.content.Context;
import android.content.Intent;
import android.os.Bundle;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ImageView;
import android.widget.RelativeLayout;
import android.widget.TextView;

import androidx.annotation.NonNull;
import androidx.fragment.app.Fragment;
import androidx.fragment.app.FragmentManager;
import androidx.fragment.app.FragmentTransaction;
import androidx.recyclerview.widget.RecyclerView;

import com.bumptech.glide.Glide;
import com.example.wfdmockapp.models.Shop;

import java.io.FileNotFoundException;
import java.util.ArrayList;

public class ShopRecyclerViewAdapter extends RecyclerView.Adapter<ShopRecyclerViewAdapter.ViewHolder> {

    private static final String TAG="ShopRecyclerViewAdapter";

    private ArrayList<Shop> shops;
    private Context  mContext;
    private Fragment fragment;

    public ShopRecyclerViewAdapter(ArrayList<Shop> shops,Context mContext,Fragment fragment) {
        this.shops = shops;
        this.mContext = mContext;
        this.fragment = fragment;
    }

    @NonNull
    @Override
    public ViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
        Log.d(TAG,"Reached onCreate");
        View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.shoplistitem,parent,false);
        ViewHolder holder = new ViewHolder(view);
        return holder;
    }

    @Override
    public void onBindViewHolder(@NonNull ViewHolder holder, int position) {
        Log.d(TAG,"Reached onBind");
        try{
            Glide.with(mContext).load(shops.get(position).getLogo()).into(holder.shopLogo);
        }catch (Exception e){
            Glide.with(mContext).load(R.drawable.shop_logo_base).into(holder.shopLogo);
        }

        holder.deliveryFee.setText("Delivery \u20ac " shops.get(position).getDeliveryFee());
        holder.minOrder.setText("\u20ac " shops.get(position).getMinimumOrder() " MIN ");
        holder.paymentMethod.setText(shops.get(position).getPaymentModeText());

        String status = shops.get(position).getShopStatus();
        Global.setCurrentStatusText(status,holder.shopStatus);

        holder.shopName.setText(shops.get(position).getName());
        holder.shopTypeName.setText(shops.get(position).getTypeName());

        String offerText = shops.get(position).getSpecialOffer();
        if(!(offerText==null)){
            holder.shopOffer.setText(offerText);
        }else{
            holder.offerSection.setVisibility(View.GONE);
        }

        int deliveredBy = shops.get(position).getDeliveredBy();
        makeViewInvisible(holder.delivery_layout,deliveredBy);

        int mixAndMatch = shops.get(position).getMixMatch();
        makeViewInvisible(holder.mixMatchLayout,mixAndMatch);


        holder.parent_layout.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                Bundle bundle = new Bundle();
                bundle.putString("shopId",shops.get(position).getShopId());

                FragmentManager fm = fragment.getActivity().getSupportFragmentManager();
                FragmentTransaction fragmentTrans = fm.beginTransaction();
                fragmentTrans.replace(R.id.nav_host_fragment_content_main,RestaurantDetailsFragment.class,bundle);
                fragmentTrans.setReorderingAllowed(true);
                fragmentTrans.addToBackStack(null);
                fragmentTrans.commit();
            }
        });
    }

    @Override
    public int getItemCount() {
        return shops.size();
    }

    public class ViewHolder extends RecyclerView.ViewHolder {
            ImageView shopLogo;
            TextView shopName;
            TextView shopTypeName;
            TextView shopOffer;
            TextView minOrder;
            TextView deliveryFee;
            TextView paymentMethod;
            TextView shopStatus;
            RelativeLayout offerSection;
            RelativeLayout parent_layout;
            RelativeLayout delivery_layout;
            RelativeLayout mixMatchLayout;

        public ViewHolder(@NonNull View itemView) {
            super(itemView);
            shopLogo = itemView.findViewById(R.id.shop_logo);
            shopName = itemView.findViewById(R.id.shop_title);
            shopTypeName = itemView.findViewById(R.id.shop_typename);
            shopOffer = itemView.findViewById(R.id.offer_text);
            offerSection = itemView.findViewById(R.id.offer_section);
            minOrder = itemView.findViewById(R.id.shop_min_order);
            deliveryFee = itemView.findViewById(R.id.deliver_fee);
            shopStatus = itemView.findViewById(R.id.status);
            paymentMethod = itemView.findViewById(R.id.shop_payment);
            parent_layout = itemView.findViewById(R.id.parent_layout);
            delivery_layout = itemView.findViewById(R.id.delivered_by);
            mixMatchLayout = itemView.findViewById(R.id.mix_and_match);
        }
    }


    public void makeViewInvisible(View view,int flag){
        if(flag==1){
            view.setVisibility(View.GONE);
        }
    }

}```

uj5u.com熱心網友回復：

您需要在 onBackPressed 上彈出片段，因此函式需要從 MainActivity 執行。

主要活動

public void popFragment() {
    if (getSupportFragmentManager() == null)
        return;
    getSupportFragmentManager().popBackStack();
}


@Override
public void onBackPressed() {
    if (getSupportFragmentManager().getBackStackEntryCount() > 1) {
        popFragment();
    }
}

uj5u.com熱心網友回復：

原來，問題出在 ShopRecyclerViewAdapter.java 檔案中。

在行中

FragmentManager fm = fragment.getActivity().getSupportFragmentManager

fragment.getActivity使背景關系為空。從視圖中獲取背景關系反而解決了這個問題。

我用以下內容替換了上面的行：

FragmentManager fm = ((FragmentActivity) view.getContext()).getSupportFragmentManager()

以下是解決方案的參考：

從回收器配接器替換片段

轉載請註明出處，本文鏈接：https://www.uj5u.com/yidong/324318.html

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