Question

我正在尝试从recyclerview适配器打开一个新片段但当我点击该项目时...我的应用程序崩溃

我尝试了一些解决方案，但它们没有用而且我完全是编码和安卓的新手

这是我的适配器类

public class RecyclerViewDataAdapter extends RecyclerView.Adapter<RecyclerViewDataAdapter.ViewHolder> {
private Context context;
public ImageLoader mImageLoader;

//List of superHeroes
List<ListOfData> superHeroes;

public RecyclerViewDataAdapter(List<ListOfData> superHeroes, Context context) {
    super();
    //Getting all the superheroes
    this.superHeroes = superHeroes;
    this.context = context;

}

@Override
public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
    View v = LayoutInflater.from(parent.getContext())
            .inflate(R.layout.recyclerview_row, parent, false);
    ViewHolder viewHolder = new ViewHolder(v);
    return viewHolder;
}


@Override
public void onBindViewHolder(ViewHolder holder, int position) {
    ListOfData superHero = superHeroes.get(position);


    mImageLoader = MyApplication.getInstance().getImageLoader();
    mImageLoader.get(superHero.getImageUrl(), ImageLoader.getImageListener(holder.imageView1, R.mipmap.ic_launcher, android.R.drawable.ic_dialog_alert));
    holder.imageView1.setImageUrl(superHero.getImageUrl(), mImageLoader);
    holder.textViewName1.setText(superHero.getName());
    //holder.textViewName2.setText(superHero.getName());
    //holder.textViewRank.setText(String.valueOf(superHero.getRank()));
    //holder.textViewRealName.setText(superHero.getRealName());
    //holder.textViewCreatedBy.setText(superHero.getCreatedBy());
    //holder.textViewFirstAppearance.setText(superHero.getFirstAppearance());

    //String powers = "";

   /* for(int i = 0; i<superHero.getPowers().size(); i++){
        powers+= superHero.getPowers().get(i);
    }*/

    //holder.textViewPowers.setText(powers);


    holder.imageView1.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            BehindTheLayoutFragment fragment = new BehindTheLayoutFragment();
            FragmentTransaction ft = ((AppCompatActivity)context).getFragmentManager().beginTransaction();
            ft.replace(R.id.behind_the_layout_fragment, fragment);
            ft.addToBackStack(null);
            ft.commit();
            //((AppCompatActivity)context).getFragmentManager().beginTransaction().replace(R.id.behind_the_layout_fragment, fragment).commit();

        }
    });

}

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

class ViewHolder extends RecyclerView.ViewHolder {
    public NetworkImageView imageView1;
    public TextView textViewName1;
    public TextView textViewName2;
    public TextView textViewRank;
    public TextView textViewRealName;
    public TextView textViewCreatedBy;
    public TextView textViewFirstAppearance;
    public TextView textViewPowers;

    public ViewHolder(View itemView) {
        super(itemView);
        imageView1 = (NetworkImageView) itemView.findViewById(R.id.thumbnail);
        textViewName1 = (TextView) itemView.findViewById(R.id.category_title_one);
        /* textViewRank= (TextView) itemView.findViewById(R.id.textViewRank);
        textViewRealName= (TextView) itemView.findViewById(R.id.textViewRealName);
        textViewCreatedBy= (TextView) itemView.findViewById(R.id.textViewCreatedBy);
        textViewFirstAppearance= (TextView) itemView.findViewById(R.id.textViewFirstAppearance);
        textViewPowers= (TextView) itemView.findViewById(R.id.textViewPowers);
        */
    }

}

}

这里是logcat

05-10 19:06:51.637 18514-18514/com.example.aninesoft.meltwishbeta E/AndroidRuntime: FATAL EXCEPTION: main
                                                                                Process: com.example.aninesoft.meltwishbeta, PID: 18514
                                                                                java.lang.NullPointerException
                                                                                    at com.aninesoft.meltwishbeta.RecyclerViewDataAdapter$1.onClick(RecyclerViewDataAdapter.java:83)
                                                                                    at android.view.View.performClick(View.java:4446)
                                                                                    at android.view.View$PerformClick.run(View.java:18437)
                                                                                    at android.os.Handler.handleCallback(Handler.java:733)
                                                                                    at android.os.Handler.dispatchMessage(Handler.java:95)
                                                                                    at android.os.Looper.loop(Looper.java:136)
                                                                                    at android.app.ActivityThread.main(ActivityThread.java:5413)
                                                                                    at java.lang.reflect.Method.invokeNative(Native Method)
                                                                                    at java.lang.reflect.Method.invoke(Method.java:515)
                                                                                    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:970)
                                                                                    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:786)
                                                                                    at dalvik.system.NativeStart.main(Native Method)

这里是我调用适配器的类

public class Pants extends Fragment {

//Creating a List of superheroes

public Context context;
public List<ListOfData> listSuperHeroes;

//Creating Views
private RecyclerView recyclerView;
private GridLayoutManager glm;
private RecyclerView.Adapter adapter;


public Pants() {
    // Required empty public constructor
}

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

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

    recyclerView = (RecyclerView) view.findViewById(
            R.id.recycler_view);
    recyclerView.setLayoutManager(new GridLayoutManager(context, 2));

    //Calling method to get data
    getData();
    return view;
}


private void getData() {
    //Showing a progress dialog
    final ProgressDialog loading = ProgressDialog.show(getActivity(), "Loading Data", "Please wait...", false, false);

    //Creating a json array request
    JsonArrayRequest jsonArrayRequest = new JsonArrayRequest(ProductConfig.DATA_URL,

            new Response.Listener<JSONArray>() {
                @Override
                public void onResponse(JSONArray response) {
                    //Dismissing progress dialog
                    loading.dismiss();

                    //calling method to parse json array
                    parseData(response);
                }
            },
            new Response.ErrorListener() {
                @Override
                public void onErrorResponse(VolleyError error) {

                }
            });

    //Creating request queue
    RequestQueue requestQueue = Volley.newRequestQueue(getActivity());

    //Adding request to the queue
    requestQueue.add(jsonArrayRequest);
}

//This method will parse json data
private void parseData(JSONArray array) {
    listSuperHeroes = new ArrayList<>();
    for (int i = 0; i < array.length(); i++) {
        ListOfData superHero = new ListOfData();
        JSONObject json = null;
        try {
            json = array.getJSONObject(i);
            superHero.setImageUrl(json.getString(ProductConfig.TAG_IMAGE_URL));
            superHero.setName(json.getString(ProductConfig.TAG_NAME));
            /*superHero.setRank(json.getInt(ProductConfig.TAG_RANK));
            superHero.setRealName(json.getString(ProductConfig.TAG_REAL_NAME));
            superHero.setCreatedBy(json.getString(ProductConfig.TAG_CREATED_BY));
            superHero.setFirstAppearance(json.getString(ProductConfig.TAG_FIRST_APPEARANCE));
            */

            ArrayList<String> powers = new ArrayList<String>();

            JSONArray jsonArray = json.getJSONArray(ProductConfig.TAG_POWERS);

            for (int j = 0; j < jsonArray.length(); j++) {
                powers.add(((String) jsonArray.get(j)) + "\n");
            }
            superHero.setPowers(powers);


        } catch (JSONException e) {
            e.printStackTrace();
        }
        listSuperHeroes.add(superHero);
    }
    adapter = new RecyclerViewDataAdapter(listSuperHeroes, context);

    //Adding adapter to recyclerview
    recyclerView.setAdapter(adapter);
    //Initializing our superheroes list


}

}

这是xml

<FrameLayout
    android:id="@+id/behind_the_layout_fragment"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <ScrollView xmlns:android="http://schemas.android.com/apk/res/android"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:fillViewport="true">

        <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:orientation="vertical"
            android:paddingLeft="2dp"
            android:paddingRight="2dp"
            android:paddingTop="2dp"
            android:weightSum="100">


            <ImageView
                android:id="@+id/iv_men"
                android:layout_width="match_parent"
                android:layout_height="match_parent"
                android:adjustViewBounds="true"
                android:src="@drawable/mens_wear">

            </ImageView>

            <ImageView
                android:id="@+id/iv_women"
                android:layout_width="match_parent"
                android:layout_height="match_parent"
                android:layout_marginTop="10dp"
                android:adjustViewBounds="true"
                android:src="@drawable/womens_wear">

            </ImageView>

            <ImageView
                android:id="@+id/iv_other"
                android:layout_width="match_parent"
                android:layout_height="match_parent"
                android:layout_marginTop="10dp"
                android:adjustViewBounds="true"
                android:src="@drawable/ic_launcher">

            </ImageView>
        </LinearLayout>
    </ScrollView>
</FrameLayout>

Answer 1

在Pants片段中，我没有看到context已初始化。只需使用

getActivity()代替您Pants Fragment中所有地方的背景信息。可以使用getActivity()方法在片段上下文中找到它。

Answer 2

使用它 FragmentTransaction ft = getActivity（）。getFragmentManager（）。beginTransaction（）;

新片段没有开放

2 个答案: