Question

我已在导航抽屉中成功实施cardview and recycleview。现在的问题是，当我点击我的第一张卡片视图时，我会点击我的第一张片段，然后按返回，我的卡片视图不再出现在我的列表标签（第一张片段）中。查看cardviews列表的唯一选项是再次滑动到我的导航抽屉，然后单击第一个片段以查看cardviews。

这是我的代码的 RecyclerViewAdapter.class

package com.example.guitarista.citem.Exhibitor;

import android.content.Context;
import android.content.Intent;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.RecyclerView;
import android.support.v7.widget.CardView;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ImageView;
import android.widget.TextView;

import com.example.guitarista.citem.Gallery_SpringForward.GalleryFragment;
import com.example.guitarista.citem.Gallery_activity.GalleryActivity;
import com.example.guitarista.citem.R;
import java.util.List;



/**
 * Created by smdojt on 1/24/2017.
 */

public class TabInt_RV_Adapter extends RecyclerView.Adapter<TabInt_RV_Adapter.ItemViewHolder> {

    public static class ItemViewHolder extends RecyclerView.ViewHolder {
        static CardView cv;
        TextView itemName;
        TextView itemCathegory;
        ImageView itemPhoto;

        ItemViewHolder(View itemView) {
            super(itemView);
            cv = (CardView)itemView.findViewById(R.id.cv);
            itemName = (TextView) itemView.findViewById(R.id.item_name);
            itemCathegory = (TextView) itemView.findViewById(R.id.item_cathegory);
            itemPhoto = (ImageView) itemView.findViewById(R.id.item_photo);
        }
    }

    List<Exhibitors_Int> items;
    Context context;
    TabInt_RV_Adapter(List<Exhibitors_Int> items, Context context) {
        this.context = context;
        this.items = items;
    }


    @Override
    public void onAttachedToRecyclerView(RecyclerView recyclerView) {
        super.onAttachedToRecyclerView(recyclerView);
    }

    @Override
    public ItemViewHolder onCreateViewHolder(ViewGroup viewGroup, int i) {
        View v = LayoutInflater.from(viewGroup.getContext()).inflate(R.layout.fragment_exhibitor_tabint_item, viewGroup, false);
        ItemViewHolder ivh = new ItemViewHolder(v);
        return ivh;
    }

    @Override
    public void onBindViewHolder(ItemViewHolder itemViewHolder, final int i) {
        itemViewHolder.cv.setOnClickListener(null);
        itemViewHolder.itemName.setText(items.get(i).name);
        itemViewHolder.itemCathegory.setText(items.get(i).cathegory);
        itemViewHolder.itemPhoto.setImageResource(items.get(i).photoId);

        ItemViewHolder.cv.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                if (i == 1) {
                    //Toast.makeText(context, "Index position is 1", Toast.LENGTH_SHORT).show();
                    Intent intent = new Intent (context, GalleryActivity.class);
                    context.startActivity(intent);
                }
                else if (i == 2) {
                    //Toast.makeText(context, "Index position is 2 ", Toast.LENGTH_SHORT).show();
                    AppCompatActivity activity = (AppCompatActivity) v.getContext();
                    GalleryFragment gf = new GalleryFragment();
                    activity.getSupportFragmentManager().beginTransaction().replace(R.id.fragment_container, gf).addToBackStack(null).commit();
                }

            }
        });
    }

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


}

请注意，在我的onClick上，有两个版本的图库。第一个是原始活动，第二个是片段实现。

因此，当我点击第一个，然后再按下时，将显示cardviews。现在问题是什么？当我点击图库的活动版本时，我无法在导航抽屉中滑动。

在哪里，当我点击实施片段的第二个cardview时，导航抽屉滑动在图库内部工作，但是当我按下时，卡片视图列表不会显示。

即使我将这些代码行放入片段：

GalleryFragment fr = new GalleryFragment();
                     Bundle args = new Bundle();
                     fr.setArguments(args);
                     FragmentManager fm = getFragmentManager();
                     FragmentTransaction fragmentTransaction = fm.beginTransaction();
                     fragmentTransaction.replace(R.id.fragment_container, fr);
                     fragmentTransaction.addToBackStack(null);
                     fragmentTransaction.commit();

我甚至在 getFragmentManager（）;

中出错

还有其他方法可以解决这个问题吗？

CARDVIEWS代码

package com.example.guitarista.citem.Exhibitor;

import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;

import com.example.guitarista.citem.R;

import java.util.ArrayList;
import java.util.List;

/**
 * A simple {@link Fragment} subclass.
 */
public class TabInternationalFragment extends Fragment {

    private List<Exhibitors_Int> items;
    private RecyclerView rv;

    public TabInternationalFragment() {
        // Required empty public constructor
    }
    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        // Inflate the layout for this fragment
        View v = inflater.inflate(R.layout.fragment_exhibitor_tab_international, container, false);

        rv=(RecyclerView)v.findViewById(R.id.rv);
        LinearLayoutManager llm = new LinearLayoutManager(getActivity());
        rv.setLayoutManager(llm);
        //GridLayoutManager glm = new GridLayoutManager(getActivity(), 4);
        //rv.setLayoutManager(glm);
        rv.setHasFixedSize(true);

        initializeData();
        initializeAdapter();
        return v;
    }

    private void initializeData() {
        items = new ArrayList<>();
        items.add(new Exhibitors_Int("A. GARCIA CRAFTS", "FURNITURE", R.drawable.image1));
        items.add(new Exhibitors_Int("BALEX BOXES", "HOLIDAY DECORATION", R.drawable.image2));
        items.add(new Exhibitors_Int("CAGAYAN DE ORO HANDMADE PAPER", "HOME DECOR/HOUSEWARE", R.drawable.image3));
    }

    private void initializeAdapter(){
        TabInt_RV_Adapter adapter = new TabInt_RV_Adapter(items, getContext());
        rv.setAdapter(adapter);

    }

}

Answer 1

如果您希望按下后退按钮后保持第一个活动，则应在AndroidManifest.xml中定义第一个活动的启动模式。还要为您的第二个活动定义父活动，以便Android知道当您按下后退按钮时它应该导航回哪个活动。

    <activity
        android:name=".activity.HomeActivity"
        android:label="@string/app_name"
        android:launchMode="singleTop" />
    <activity
        android:name=".activity.GalleryActivity"
        android:label="@string/app_name"
        android:parentActivityName=".activity.HomeActivity"
        tools:ignore="UnusedAttribute">
        <meta-data
            android:name="android.support.PARENT_ACTIVITY"
            android:value=".activity.HomeActivity" />
    </activity>

如果活动堆栈中已有实例，则singleTop启动模式将确保不会创建该活动的新实例。因此，按下后退按钮后，您的卡片仍会在第一个活动中显示。

后退后卡片视图未显示

1 个答案: