如何在适配器类中使用 get getApplicationContext() [英] How to use get getApplicationContext() in Adapter Class

问题描述

我正在使用 Firebase 用博客文章填充我的 BlogRecycleadapter 并从 Like Buttons 获得 Likes 但当设备离线并且用户按下 Like Button 时，应用程序崩溃......所以我也在尝试实现 isNetworkavailaible 的第二个条件if 语句..如下

if (!task.getResult().exists() && isNetworkStatusAvialable(getApplicationContext())){映射<字符串，对象>likesMap = new HashMap<>();likesMap.put("timestamp", FieldValue.serverTimestamp());firebaseFirestore.collection("Posts/" + blogPostId + "/Likes").document(currentUserId).set(likesMap);} 别的 {firebaseFirestore.collection("Posts/" + blogPostId + "/Likes").document(currentUserId).delete();}

但是我在 getApplicationContext() 中遇到了错误，从几个谷歌搜索中，我发现 getApplicationContext() 不适用于 Class，而只能用于活动.

那么我如何在这里实现 getApplicationContext??

我的 Recycle 适配器的全部代码是

package com.nepalpolice.cdp;导入 android.content.Context;导入 android.net.ConnectivityManager;导入 android.net.NetworkInfo;导入 android.os.Build;导入 android.support.annotation.NonNull;导入 android.support.v7.widget.RecyclerView；导入 android.text.format.DateFormat;导入 android.view.LayoutInflater;导入 android.view.View;导入 android.view.ViewGroup;导入 android.widget.ImageView;导入 android.widget.TextView;进口 com.bumptech.glide.Glide;导入 com.bumptech.glide.request.RequestOptions;导入 com.google.android.gms.tasks.OnCompleteListener;导入 com.google.android.gms.tasks.Task;导入 com.google.firebase.auth.FirebaseAuth;导入 com.google.firebase.firestore.DocumentSnapshot;导入 com.google.firebase.firestore.EventListener;导入 com.google.firebase.firestore.FieldValue;导入 com.google.firebase.firestore.FirebaseFirestore;导入 com.google.firebase.firestore.FirebaseFirestoreException;导入 com.google.firebase.firestore.QuerySnapshot;导入 java.util.Date;导入 java.util.HashMap;导入 java.util.List;导入 java.util.Map;导入 de.hdodenhof.circleimageview.CircleImageView;公共类 BlogRecyclerAdapter 扩展 RecyclerView.Adapter{公共列表<博客帖子>博客列表；公共上下文上下文；私有 FirebaseFirestore firebaseFirestore;私有 FirebaseAuth firebaseAuth；public BlogRecyclerAdapter(List blog_list,Context context){this.blog_list = blog_list;this.context=上下文；}@覆盖公共 ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {查看视图 = LayoutInflater.from(parent.getContext()).inflate(R.layout.blog_list_item, parent, false);上下文 = parent.getContext();firebaseFirestore = FirebaseFirestore.getInstance();firebaseAuth = FirebaseAuth.getInstance();返回新的 ViewHolder(view);}@覆盖公共无效 onBindViewHolder(最终 ViewHolder 持有人，int 位置){holder.setIsRecyclable(false);final String blogPostId = blog_list.get(position).BlogPostId;final String currentUserId = firebaseAuth.getCurrentUser().getUid();String desc_data = blog_list.get(position).getDesc();holder.setDescText(desc_data);String image_url = blog_list.get(position).getImage_url();holder.setBlogImage(image_url);String user_id = blog_list.get(position).getUser_id();//用户数据将在此处检索...firebaseFirestore.collection("Users").document(user_id).get().addOnCompleteListener(new OnCompleteListener() {@覆盖public void onComplete(@NonNull Task task) {如果(任务.isSuccessful()){String userName = task.getResult().getString("name");String userImage = task.getResult().getString("image");holder.setUserData(userName, userImage);} 别的 {//Firebase 异常}}});长毫秒 = blog_list.get(position).getTimestamp().getTime();String dateString = DateFormat.format("MM/dd/yyyy", new Date(millisecond)).toString();holder.setTime(dateString);//获取点赞数firebaseFirestore.collection("Posts/" + blogPostId + "/Likes").addSnapshotListener(((Main2Activity) context),new EventListener() {@覆盖public void onEvent(QuerySnapshot documentSnapshots, FirebaseFirestoreException e) {如果 (!documentSnapshots.isEmpty()){int count = documentSnapshots.size();holder.updateLikesCount(count);}别的{持有者.updateLikesCount(0);}}});//获取赞firebaseFirestore.collection("Posts/" + blogPostId + "/Likes").document(currentUserId).addSnapshotListener(((Main2Activity) context),new EventListener() {@覆盖public void onEvent(DocumentSnapshot documentSnapshot, FirebaseFirestoreException e) {如果(documentSnapshot.exists()){如果 (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {holder.blogLikeBtn.setImageDrawable(context.getDrawable(R.mipmap.action_like_accent));}别的 {holder.blogLikeBtn.setImageDrawable(context.getResources().getDrawable(R.mipmap.action_like_accent));}} 别的 {如果 (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {holder.blogLikeBtn.setImageDrawable(context.getDrawable(R.mipmap.action_like_gray));}别的{holder.blogLikeBtn.setImageDrawable(context.getResources().getDrawable(R.mipmap.action_like_gray));}}}});//喜欢特征holder.blogLikeBtn.setOnClickListener(new View.OnClickListener() {@覆盖公共无效onClick(查看视图){firebaseFirestore.collection("Posts/" + blogPostId + "/Likes").document(currentUserId).get().addOnCompleteListener(new OnCompleteListener<DocumentSnapshot>() {@覆盖public void onComplete(@NonNull Task task) {if (!task.getResult().exists() && isNetworkStatusAvialable(getApplicationContext())){映射<字符串，对象>likesMap = new HashMap<>();likesMap.put("timestamp", FieldValue.serverTimestamp());firebaseFirestore.collection("Posts/" + blogPostId + "/Likes").document(currentUserId).set(likesMap);} 别的 {firebaseFirestore.collection("Posts/" + blogPostId + "/Likes").document(currentUserId).delete();}}});}});}@覆盖公共 int getItemCount() {返回 blog_list.size();}公共类 ViewHolder 扩展 RecyclerView.ViewHolder {私人视图 mView；私有 TextView descView；私有 ImageView 博客ImageView；私人 TextView 博客日期；私人 TextView 博客用户名；私有 CircleImageView 博客用户图像；私人 ImageView blogLikeBtn;私人 TextView blogLikeCount;公共 ViewHolder(查看 itemView){超级(项目视图)；mView = itemView;}公共无效setDescText(字符串descText){descView = mView.findViewById(R.id.blog_desc);descView.setText(descText);blogLikeBtn = mView.findViewById(R.id.blog_like_btn);}public void setBlogImage(String downloadUri){blogImageView = mView.findViewById(R.id.blog_image);RequestOptions requestOptions = new RequestOptions();requestOptions.placeholder(R.drawable.image_placeholder);Glide.with(context).applyDefaultRequestOptions(requestOptions).load(downloadUri).into(blogImageView);}公共无效设置时间(字符串日期){blogDate = mView.findViewById(R.id.blog_date);blogDate.setText(date);}public void setUserData(字符串名称，字符串图像){blogUserImage = mView.findViewById(R.id.blog_user_image);blogUserName = mView.findViewById(R.id.blog_user_name);blogUserName.setText(name);RequestOptions placeholderOption = new RequestOptions();placeholderOption.placeholder(R.drawable.profile_placeholder);Glide.with(context).applyDefaultRequestOptions(placeholderOption).load(image).into(blogUserImage);}public void updateLikesCount (int count){blogLikeCount = mView.findViewById(R.id.blog_like_count);blogLikeCount.setText(count + "喜欢");}}public static boolean isNetworkStatusAvialable(上下文上下文){连接管理器厘米 =(ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE);NetworkInfo activeNetwork = cm.getActiveNetworkInfo();返回 activeNetwork != null &&activeNetwork.isConnectedOrConnecting();}}

我调用适配器类的 HOmeFragment 是

package com.nepalpolice.cdp;导入 android.os.Bundle;导入 android.support.v4.app.Fragment;导入 android.support.v7.widget.LinearLayoutManager;导入 android.support.v7.widget.RecyclerView；导入 android.view.LayoutInflater;导入 android.view.View;导入 android.view.ViewGroup;导入 android.widget.Toast;导入 com.google.firebase.auth.FirebaseAuth;导入 com.google.firebase.firestore.DocumentChange;导入 com.google.firebase.firestore.DocumentSnapshot;导入 com.google.firebase.firestore.EventListener;导入 com.google.firebase.firestore.FirebaseFirestore;导入 com.google.firebase.firestore.FirebaseFirestoreException;导入 com.google.firebase.firestore.Query;导入 com.google.firebase.firestore.QuerySnapshot;导入 java.util.ArrayList;导入 java.util.List;/*** 一个简单的 {@link Fragment} 子类.*/公共类 HomeFragment 扩展 Fragment {私人 RecyclerView blog_list_view;私人列表<BlogPost>博客列表；私有 FirebaseFirestore firebaseFirestore;私有 FirebaseAuth firebaseAuth；私人 BlogRecyclerAdapter blogRecyclerAdapter;私有 DocumentSnapshot lastVisible；私人布尔 isFirstPageFirstLoad = true;公共 HomeFragment() {//必需的空公共构造函数}@覆盖公共视图 onCreateView(LayoutInflater inflater，最终的 ViewGroup 容器，捆绑savedInstanceState) {查看视图 = inflater.inflate(R.layout.fragment_home, container, false);blog_list = new ArrayList<>();blog_list_view = view.findViewById(R.id.blog_list_view);firebaseAuth = FirebaseAuth.getInstance();blogRecyclerAdapter = new BlogRecyclerAdapter(blog_list);blog_list_view.setLayoutManager(new LinearLayoutManager(container.getContext()));blog_list_view.setAdapter(blogRecyclerAdapter);if(firebaseAuth.getCurrentUser() != null) {firebaseFirestore = FirebaseFirestore.getInstance();blog_list_view.addOnScrollListener(new RecyclerView.OnScrollListener() {@覆盖public void onScrolled(RecyclerView recyclerView, int dx, int dy) {super.onScrolled(recyclerView, dx, dy);布尔达到底部 = !recyclerView.canScrollVertically(1);如果(到达底部){String desc = lastVisible.getString("desc");Toast.makeText(container.getContext(), "Reached : " + desc, Toast.LENGTH_SHORT).show();loadMorePost();}}});查询 firstQuery = firebaseFirestore.collection("Posts").orderBy("timestamp", Query.Direction.DESCENDING).limit(3);firstQuery.addSnapshotListener(getActivity(), new EventListener() {@覆盖public void onEvent(QuerySnapshot documentSnapshots, FirebaseFirestoreException e) {如果(isFirstPageFirstLoad){lastVisible = documentSnapshots.getDocuments().get(documentSnapshots.size() - 1);}for (DocumentChange doc : documentSnapshots.getDocumentChanges()){if (doc.getType() == DocumentChange.Type.ADDED) {字符串 blogPostId = doc.getDocument().getId();BlogPost blogPost = doc.getDocument().toObject(BlogPost.class).withId(blogPostId);如果(isFirstPageFirstLoad){blog_list.add(blogPost);}别的 {blog_list.add(0,blogPost);}blogRecyclerAdapter.notifyDataSetChanged();;}}isFirstPageFirstLoad = false;}});}//膨胀这个片段的布局返回视图；}public void loadMorePost(){查询 nextQuery = firebaseFirestore.collection("Posts").orderBy("时间戳", Query.Direction.DESCENDING).startAfter(lastVisible).limit(3);nextQuery.addSnapshotListener(getActivity(), new EventListener() {@覆盖public void onEvent(QuerySnapshot documentSnapshots, FirebaseFirestoreException e) {如果 (!documentSnapshots.isEmpty()){lastVisible = documentSnapshots.getDocuments().get(documentSnapshots.size() - 1);for (DocumentChange doc : documentSnapshots.getDocumentChanges()) {if (doc.getType() == DocumentChange.Type.ADDED) {字符串 blogPostId = doc.getDocument().getId();BlogPost blogPost = doc.getDocument().toObject(BlogPost.class).withId(blogPostId);blog_list.add(blogPost);blogRecyclerAdapter.notifyDataSetChanged();}}}}});}}

提前致谢.

解决方案

试试这个

<块引用>

您可以在 BlogRecyclerAdapter

的构造函数中传递 Context

public BlogRecyclerAdapter(List < BlogPost > blog_list, Context context) {this.blog_list = blog_list;this.context = 上下文；}

<块引用>

这样使用

firebaseFirestore = FirebaseFirestore.getInstance(context);firebaseAuth = FirebaseAuth.getInstance(context);Glide.with(context).applyDefaultRequestOptions(placeholderOption).load(image).into(blogUserImage);

<块引用>

像这样调用您的BlogRecyclerAdapter

BlogRecyclerAdapter adapter= new BlogRecyclerAdapter( blog_list, YourActivity.this );

I am using Firebase to populate my BlogRecycleadapter with blog post and get Likes from Like Buttons but when device is offline and user press Like Button , then app crashes...So I'm trying to implement second condition of isNetworkavailaible too in if statement ..as below

if (!task.getResult().exists() && isNetworkStatusAvialable(getApplicationContext())){

                        Map<String, Object> likesMap = new HashMap<>();
                        likesMap.put("timestamp", FieldValue.serverTimestamp());


                        firebaseFirestore.collection("Posts/" + blogPostId + "/Likes").document(currentUserId).set(likesMap);

                    } else {
                        firebaseFirestore.collection("Posts/" + blogPostId + "/Likes").document(currentUserId).delete();

                    }

But I'm gettning errror in getApplicationContext(), from few google search , I found that getApplicationContext() is not availaibe for Class but only for activity.

So how can I implement getApplicationContext here??

My whole code of Recycle adapter is

package com.nepalpolice.cdp;

import android.content.Context;
import android.net.ConnectivityManager;
import android.net.NetworkInfo;
import android.os.Build;
import android.support.annotation.NonNull;
import android.support.v7.widget.RecyclerView;
import android.text.format.DateFormat;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ImageView;
import android.widget.TextView;

import com.bumptech.glide.Glide;
import com.bumptech.glide.request.RequestOptions;
import com.google.android.gms.tasks.OnCompleteListener;
import com.google.android.gms.tasks.Task;
import com.google.firebase.auth.FirebaseAuth;
import com.google.firebase.firestore.DocumentSnapshot;
import com.google.firebase.firestore.EventListener;
import com.google.firebase.firestore.FieldValue;
import com.google.firebase.firestore.FirebaseFirestore;
import com.google.firebase.firestore.FirebaseFirestoreException;
import com.google.firebase.firestore.QuerySnapshot;

import java.util.Date;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import de.hdodenhof.circleimageview.CircleImageView;

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

    public List<BlogPost> blog_list;
    public Context context;

    private FirebaseFirestore firebaseFirestore;
private FirebaseAuth firebaseAuth;


    public BlogRecyclerAdapter(List<BlogPost> blog_list,Context context){

        this.blog_list = blog_list;
        this.context=context;

    }

    @Override
    public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {

        View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.blog_list_item, parent, false);
        context = parent.getContext();
        firebaseFirestore = FirebaseFirestore.getInstance();
        firebaseAuth = FirebaseAuth.getInstance();
        return new ViewHolder(view);
    }

    @Override
    public void onBindViewHolder(final ViewHolder holder, int position) {

        holder.setIsRecyclable(false);

        final String blogPostId = blog_list.get(position).BlogPostId;
        final String currentUserId = firebaseAuth.getCurrentUser().getUid();

        String desc_data = blog_list.get(position).getDesc();
        holder.setDescText(desc_data);

        String image_url = blog_list.get(position).getImage_url();
        holder.setBlogImage(image_url);

        String user_id = blog_list.get(position).getUser_id();
        //User Data will be retrieved here...
        firebaseFirestore.collection("Users").document(user_id).get().addOnCompleteListener(new OnCompleteListener<DocumentSnapshot>() {
            @Override
            public void onComplete(@NonNull Task<DocumentSnapshot> task) {

                if(task.isSuccessful()){

                    String userName = task.getResult().getString("name");
                    String userImage = task.getResult().getString("image");

                    holder.setUserData(userName, userImage);


                } else {

                    //Firebase Exception

                }

            }
        });

        long millisecond = blog_list.get(position).getTimestamp().getTime();
        String dateString = DateFormat.format("MM/dd/yyyy", new Date(millisecond)).toString();
        holder.setTime(dateString);

        //Get Likes Count
        firebaseFirestore.collection("Posts/" + blogPostId + "/Likes").addSnapshotListener(((Main2Activity) context),new EventListener<QuerySnapshot>() {
            @Override
            public void onEvent(QuerySnapshot documentSnapshots, FirebaseFirestoreException e) {

                if (!documentSnapshots.isEmpty()){

int count = documentSnapshots.size();
holder.updateLikesCount(count);

                }else{
holder.updateLikesCount(0);

                }

            }
        });



        //Get Likes

        firebaseFirestore.collection("Posts/" + blogPostId + "/Likes").document(currentUserId).addSnapshotListener(((Main2Activity) context),new EventListener<DocumentSnapshot>() {
            @Override
            public void onEvent(DocumentSnapshot documentSnapshot, FirebaseFirestoreException e) {

                if (documentSnapshot.exists()){

                    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
                        holder.blogLikeBtn.setImageDrawable(context.getDrawable(R.mipmap.action_like_accent));
                    }
                    else {
                        holder.blogLikeBtn.setImageDrawable(context.getResources().getDrawable(R.mipmap.action_like_accent));
                    }
                } else {

                    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
                        holder.blogLikeBtn.setImageDrawable(context.getDrawable(R.mipmap.action_like_gray));
                    }else{
                        holder.blogLikeBtn.setImageDrawable(context.getResources().getDrawable(R.mipmap.action_like_gray));
                    }
                }

            }
        });

        //like Feature



        holder.blogLikeBtn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {



                firebaseFirestore.collection("Posts/" + blogPostId + "/Likes").document(currentUserId).get().addOnCompleteListener(new OnCompleteListener<DocumentSnapshot>() {
                    @Override
                    public void onComplete(@NonNull Task<DocumentSnapshot> task) {
                        if (!task.getResult().exists() && isNetworkStatusAvialable(getApplicationContext())){

                            Map<String, Object> likesMap = new HashMap<>();
                            likesMap.put("timestamp", FieldValue.serverTimestamp());


                            firebaseFirestore.collection("Posts/" + blogPostId + "/Likes").document(currentUserId).set(likesMap);

                        } else {
                            firebaseFirestore.collection("Posts/" + blogPostId + "/Likes").document(currentUserId).delete();

                        }

                    }
                });



            }
        });

    }

    @Override
    public int getItemCount() {

        return blog_list.size();
    }

    public class ViewHolder extends RecyclerView.ViewHolder {

        private View mView;

        private TextView descView;
        private ImageView blogImageView;
        private TextView blogDate;

        private TextView blogUserName;
        private CircleImageView blogUserImage;
        private ImageView blogLikeBtn;
        private  TextView blogLikeCount;

        public ViewHolder(View itemView) {
            super(itemView);
            mView = itemView;



        }

        public void setDescText(String descText){

            descView = mView.findViewById(R.id.blog_desc);
            descView.setText(descText);

            blogLikeBtn = mView.findViewById(R.id.blog_like_btn);
        }

        public void setBlogImage(String downloadUri){

            blogImageView = mView.findViewById(R.id.blog_image);
            RequestOptions requestOptions = new RequestOptions();
            requestOptions.placeholder(R.drawable.image_placeholder);
            Glide.with(context).applyDefaultRequestOptions(requestOptions).load(downloadUri).into(blogImageView);

        }

        public void setTime(String date) {

            blogDate = mView.findViewById(R.id.blog_date);
            blogDate.setText(date);

        }

        public void setUserData(String name, String image){

            blogUserImage = mView.findViewById(R.id.blog_user_image);
            blogUserName = mView.findViewById(R.id.blog_user_name);

            blogUserName.setText(name);

            RequestOptions placeholderOption = new RequestOptions();
            placeholderOption.placeholder(R.drawable.profile_placeholder);

            Glide.with(context).applyDefaultRequestOptions(placeholderOption).load(image).into(blogUserImage);

        }

public void  updateLikesCount (int count){

            blogLikeCount = mView.findViewById(R.id.blog_like_count);
            blogLikeCount.setText(count + "Likes");
}

    }
    public static boolean isNetworkStatusAvialable (Context context) {
        ConnectivityManager cm =
                (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE);

        NetworkInfo activeNetwork = cm.getActiveNetworkInfo();
        return activeNetwork != null &&
                activeNetwork.isConnectedOrConnecting();

    }
}

and my HOmeFragment from where I'm calling adapter class is

package com.nepalpolice.cdp;


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 android.widget.Toast;

import com.google.firebase.auth.FirebaseAuth;
import com.google.firebase.firestore.DocumentChange;
import com.google.firebase.firestore.DocumentSnapshot;
import com.google.firebase.firestore.EventListener;
import com.google.firebase.firestore.FirebaseFirestore;
import com.google.firebase.firestore.FirebaseFirestoreException;
import com.google.firebase.firestore.Query;
import com.google.firebase.firestore.QuerySnapshot;

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


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

    private RecyclerView blog_list_view;
    private List<BlogPost> blog_list;

    private FirebaseFirestore firebaseFirestore;
    private FirebaseAuth firebaseAuth;
    private BlogRecyclerAdapter blogRecyclerAdapter;

    private DocumentSnapshot lastVisible;
    private Boolean isFirstPageFirstLoad = true;

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


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

        View view = inflater.inflate(R.layout.fragment_home, container, false);

        blog_list = new ArrayList<>();
        blog_list_view = view.findViewById(R.id.blog_list_view);

        firebaseAuth = FirebaseAuth.getInstance();

        blogRecyclerAdapter = new BlogRecyclerAdapter(blog_list);
        blog_list_view.setLayoutManager(new LinearLayoutManager(container.getContext()));
        blog_list_view.setAdapter(blogRecyclerAdapter);

        if(firebaseAuth.getCurrentUser() != null) {

            firebaseFirestore = FirebaseFirestore.getInstance();

            blog_list_view.addOnScrollListener(new RecyclerView.OnScrollListener() {
                @Override
                public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
                    super.onScrolled(recyclerView, dx, dy);

                    Boolean reachedBottom = !recyclerView.canScrollVertically(1);

                    if(reachedBottom){

                        String desc = lastVisible.getString("desc");
                        Toast.makeText(container.getContext(), "Reached : " + desc, Toast.LENGTH_SHORT).show();

                        loadMorePost();

                    }

                }
            });

            Query firstQuery = firebaseFirestore.collection("Posts").orderBy("timestamp", Query.Direction.DESCENDING).limit(3);
            firstQuery.addSnapshotListener(getActivity(), new EventListener<QuerySnapshot>() {
                @Override
                public void onEvent(QuerySnapshot documentSnapshots, FirebaseFirestoreException e) {
                    if (isFirstPageFirstLoad){

                        lastVisible = documentSnapshots.getDocuments().get(documentSnapshots.size() - 1);

                    }
                    for (DocumentChange doc : documentSnapshots.getDocumentChanges()){
                        if (doc.getType() == DocumentChange.Type.ADDED) {

                            String blogPostId = doc.getDocument().getId();
                            BlogPost blogPost = doc.getDocument().toObject(BlogPost.class).withId(blogPostId);

                            if (isFirstPageFirstLoad){
                                blog_list.add(blogPost);

                            }else {
                                blog_list.add(0,blogPost);

                            }
                           blogRecyclerAdapter.notifyDataSetChanged();;
                        }
                    }
isFirstPageFirstLoad = false;
                }
            });

        }

        // Inflate the layout for this fragment
        return view;
    }

    public void loadMorePost(){

        Query nextQuery = firebaseFirestore.collection("Posts")
                .orderBy("timestamp", Query.Direction.DESCENDING)
                .startAfter(lastVisible)
                .limit(3);

        nextQuery.addSnapshotListener(getActivity(), new EventListener<QuerySnapshot>() {
            @Override
            public void onEvent(QuerySnapshot documentSnapshots, FirebaseFirestoreException e) {

                    if (!documentSnapshots.isEmpty()){


                        lastVisible = documentSnapshots.getDocuments().get(documentSnapshots.size() - 1);
                    for (DocumentChange doc : documentSnapshots.getDocumentChanges()) {
                        if (doc.getType() == DocumentChange.Type.ADDED) {
                            String blogPostId = doc.getDocument().getId();
                            BlogPost blogPost = doc.getDocument().toObject(BlogPost.class).withId(blogPostId);
                            blog_list.add(blogPost);

                            blogRecyclerAdapter.notifyDataSetChanged();

                        }
                    }

                }

            }
        });

    }

}

Thanks in advance.

解决方案

Try this

You can pass Context in your Constructor of your BlogRecyclerAdapter

public BlogRecyclerAdapter(List < BlogPost > blog_list, Context context) {

    this.blog_list = blog_list;
    this.context = context;

 }

use like this

firebaseFirestore = FirebaseFirestore.getInstance(context);
firebaseAuth = FirebaseAuth.getInstance(context);



Glide.with(context).applyDefaultRequestOptions(placeholderOption).load(image).into(blogUserImage);

call your BlogRecyclerAdapter like this

BlogRecyclerAdapter adapter= new BlogRecyclerAdapter( blog_list, YourActivity.this );

这篇关于如何在适配器类中使用 get getApplicationContext()的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！