在社交媒体Android应用程序中实现对特定博客功能的评论

这是11的“建立一个社交媒体应用程序在Android工作室”教程中的一部分，我们将要在本文中介绍了以下功能：

• 我们将在博客上发表评论。
• 在这里，我们将编写评论，然后将显示评论并更新评论计数。
• 评论功能是所有博客应用程序中最好的功能。它有助于与撰写博客以及更多内容的用户进行交互。

分步实施

步骤1：创建一个新的布局资源文件

转到应用程序> res>布局>右键单击>新建>布局资源文件，并将文件命名为row_comments。以下是row_comments.xml文件的代码。

步骤2：创建一个新的Java类，并将该类命名为ModelComment

使用ModelComment。 Java文件。创建此活动以初始化密钥，以便我们以后可以检索密钥的值。下面是ModelComment的代码。 Java文件。

Java

package com.example.socialmediaapp;
  
public class ModelComment {
      
    String cId;
      
    String comment;
  
    String ptime;
  
    String udp;
  
    public String getcId() {
        return cId;
    }
  
    public void setcId(String cId) {
        this.cId = cId;
    }
  
    public String getComment() {
        return comment;
    }
  
    public void setComment(String comment) {
        this.comment = comment;
    }
  
    public String getPtime() {
        return ptime;
    }
  
    public void setPtime(String ptime) {
        this.ptime = ptime;
    }
  
    public String getUdp() {
        return udp;
    }
  
    public void setUdp(String udp) {
        this.udp = udp;
    }
  
    public String getUemail() {
        return uemail;
    }
  
    public void setUemail(String uemail) {
        this.uemail = uemail;
    }
  
    public String getUid() {
        return uid;
    }
  
    public void setUid(String uid) {
        this.uid = uid;
    }
  
    public String getUname() {
        return uname;
    }
  
    public void setUname(String uname) {
        this.uname = uname;
    }
  
    String uemail;
  
    public ModelComment() {
    }
  
    String uid;
  
    public ModelComment(String cId, String comment, String ptime, String udp, String uemail, String uid, String uname) {
        this.cId = cId;
        this.comment = comment;
        this.ptime = ptime;
        this.udp = udp;
        this.uemail = uemail;
        this.uid = uid;
        this.uname = uname;
    }
  
    String uname;
}

步骤3：创建另一个新的Java类，并将该类命名为AdapterComment

使用AdapterComment。 Java文件。下面是AdapterComment的代码。 Java文件。

Java

package com.example.socialmediaapp;
  
import android.content.Context;
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 androidx.annotation.NonNull;
import androidx.recyclerview.widget.RecyclerView;
  
import com.bumptech.glide.Glide;
  
import java.util.Calendar;
import java.util.List;
import java.util.Locale;
  
public class AdapterComment extends RecyclerView.Adapter {
  
    Context context;
    List list;
  
    public AdapterComment(Context context, List list, String myuid, String postid) {
        this.context = context;
        this.list = list;
        this.myuid = myuid;
        this.postid = postid;
    }
  
    String myuid;
    String postid;
  
  
    @NonNull
    @Override
    public MyHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
        View view = LayoutInflater.from(context).inflate(R.layout.row_comments, parent, false);
        return new MyHolder(view);
    }
  
    @Override
    public void onBindViewHolder(@NonNull MyHolder holder, int position) {
        final String uid = list.get(position).getUid();
        String name = list.get(position).getUname();
        String email = list.get(position).getUemail();
        String image = list.get(position).getUdp();
        final String cid = list.get(position).getcId();
        String comment = list.get(position).getComment();
        String timestamp = list.get(position).getPtime();
        Calendar calendar = Calendar.getInstance(Locale.ENGLISH);
        calendar.setTimeInMillis(Long.parseLong(timestamp));
        String timedate = DateFormat.format("dd/MM/yyyy hh:mm aa", calendar).toString();
  
        holder.name.setText(name);
        holder.time.setText(timedate);
        holder.comment.setText(comment);
        try {
            Glide.with(context).load(image).into(holder.imagea);
        } catch (Exception e) {
  
        }
    }
      
    @Override
    public int getItemCount() {
        return list.size();
    }
  
    class MyHolder extends RecyclerView.ViewHolder {
  
        ImageView imagea;
        TextView name, comment, time;
  
        public MyHolder(@NonNull View itemView) {
            super(itemView);
            imagea = itemView.findViewById(R.id.loadcomment);
            name = itemView.findViewById(R.id.commentname);
            comment = itemView.findViewById(R.id.commenttext);
            time = itemView.findViewById(R.id.commenttime);
        }
    }
}

第四步： 使用PostDetailsActivity活动

使用activity_postdetails.xml文件。

使用PostDetailsActivity。 Java文件

发表评论使用此：

DatabaseReference datarf= FirebaseDatabase.getInstance().getReference("Posts").child(postId).child("Comments");
        HashMap hashMap=new HashMap<>();
        hashMap.put("cId",timestamp);
        hashMap.put("comment",commentss);
        hashMap.put("ptime",timestamp);
        hashMap.put("uid",myuid);
        hashMap.put("uemail",myemail);
        hashMap.put("udp",mydp);
        hashMap.put("uname",myname);
        datarf.child(timestamp).setValue(hashMap);

显示像这样的评论：

DatabaseReference reference= FirebaseDatabase.getInstance().getReference("Posts").child(postId).child("Comments");
        reference.addValueEventListener(new ValueEventListener() {
            @Override
            public void onDataChange(@NonNull DataSnapshot dataSnapshot) {

                commentList.clear();
                for (DataSnapshot dataSnapshot1:dataSnapshot.getChildren()){
              
                }
            }

            @Override
            public void onCancelled(@NonNull DatabaseError databaseError) {

            }
        });

下面是PostDetailsActivity的代码。 Java文件。

Java

package com.example.socialmediaapp;
  
import android.app.ProgressDialog;
import android.content.Intent;
import android.os.Bundle;
import android.text.TextUtils;
import android.text.format.DateFormat;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.ImageButton;
import android.widget.ImageView;
import android.widget.LinearLayout;
import android.widget.TextView;
import android.widget.Toast;
  
import androidx.annotation.NonNull;
import androidx.appcompat.app.ActionBar;
import androidx.appcompat.app.AppCompatActivity;
import androidx.recyclerview.widget.LinearLayoutManager;
import androidx.recyclerview.widget.RecyclerView;
  
import com.bumptech.glide.Glide;
import com.google.android.gms.tasks.OnFailureListener;
import com.google.android.gms.tasks.OnSuccessListener;
import com.google.firebase.auth.FirebaseAuth;
import com.google.firebase.database.DataSnapshot;
import com.google.firebase.database.DatabaseError;
import com.google.firebase.database.DatabaseReference;
import com.google.firebase.database.FirebaseDatabase;
import com.google.firebase.database.Query;
import com.google.firebase.database.ValueEventListener;
  
import java.util.ArrayList;
import java.util.Calendar;
import java.util.HashMap;
import java.util.List;
import java.util.Locale;
  
public class PostDetailsActivity extends AppCompatActivity {
  
  
    String hisuid, ptime, myuid, myname, myemail, mydp, uimage, postId, plike, hisdp, hisname;
    ImageView picture, image;
    TextView name, time, title, description, like, tcomment;
    ImageButton more;
    Button likebtn, share;
    LinearLayout profile;
    EditText comment;
    ImageButton sendb;
    RecyclerView recyclerView;
    List commentList;
    AdapterComment adapterComment;
    ImageView imagep;
    boolean mlike = false;
    ActionBar actionBar;
    ProgressDialog progressDialog;
  
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_post_details);
        actionBar = getSupportActionBar();
        actionBar.setTitle("Post Details");
        actionBar.setDisplayHomeAsUpEnabled(true);
        actionBar.setDisplayShowHomeEnabled(true);
        postId = getIntent().getStringExtra("pid");
        recyclerView = findViewById(R.id.recyclecomment);
        picture = findViewById(R.id.pictureco);
        image = findViewById(R.id.pimagetvco);
        name = findViewById(R.id.unameco);
        time = findViewById(R.id.utimeco);
        more = findViewById(R.id.morebtn);
        title = findViewById(R.id.ptitleco);
        myemail = FirebaseAuth.getInstance().getCurrentUser().getEmail();
        myuid = FirebaseAuth.getInstance().getCurrentUser().getUid();
        description = findViewById(R.id.descriptco);
        tcomment = findViewById(R.id.pcommenttv);
        like = findViewById(R.id.plikebco);
        likebtn = findViewById(R.id.like);
        comment = findViewById(R.id.typecommet);
        sendb = findViewById(R.id.sendcomment);
        imagep = findViewById(R.id.commentimge);
        share = findViewById(R.id.share);
        profile = findViewById(R.id.profilelayout);
        progressDialog = new ProgressDialog(this);
        loadPostInfo();
  
        loadUserInfo();
        setLikes();
        actionBar.setSubtitle("SignedInAs:" + myemail);
        loadComments();
        sendb.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                postComment();
            }
        });
        likebtn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                likepost();
            }
        });
        like.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Intent intent = new Intent(PostDetailsActivity.this, PostLikedByActivity.class);
                intent.putExtra("pid", postId);
                startActivity(intent);
            }
        });
    }
  
    private void loadComments() {
  
        LinearLayoutManager layoutManager = new LinearLayoutManager(getApplicationContext());
        recyclerView.setLayoutManager(layoutManager);
        commentList = new ArrayList<>();
        DatabaseReference reference = FirebaseDatabase.getInstance().getReference("Posts").child(postId).child("Comments");
        reference.addValueEventListener(new ValueEventListener() {
            @Override
            public void onDataChange(@NonNull DataSnapshot dataSnapshot) {
                commentList.clear();
                for (DataSnapshot dataSnapshot1 : dataSnapshot.getChildren()) {
                    ModelComment modelComment = dataSnapshot1.getValue(ModelComment.class);
                    commentList.add(modelComment);
                    adapterComment = new AdapterComment(getApplicationContext(), commentList, myuid, postId);
                    recyclerView.setAdapter(adapterComment);
                }
            }
  
            @Override
            public void onCancelled(@NonNull DatabaseError databaseError) {
  
            }
        });
    }
      
    private void setLikes() {
        final DatabaseReference liekeref = FirebaseDatabase.getInstance().getReference().child("Likes");
        liekeref.addValueEventListener(new ValueEventListener() {
            @Override
            public void onDataChange(@NonNull DataSnapshot dataSnapshot) {
  
                if (dataSnapshot.child(postId).hasChild(myuid)) {
                    likebtn.setCompoundDrawablesWithIntrinsicBounds(R.drawable.ic_liked, 0, 0, 0);
                    likebtn.setText("Liked");
                } else {
                    likebtn.setCompoundDrawablesWithIntrinsicBounds(R.drawable.ic_like, 0, 0, 0);
                    likebtn.setText("Like");
                }
            }
  
            @Override
            public void onCancelled(@NonNull DatabaseError databaseError) {
  
            }
        });
    }
  
    private void likepost() {
  
        mlike = true;
        final DatabaseReference liekeref = FirebaseDatabase.getInstance().getReference().child("Likes");
        final DatabaseReference postref = FirebaseDatabase.getInstance().getReference().child("Posts");
        liekeref.addValueEventListener(new ValueEventListener() {
            @Override
            public void onDataChange(@NonNull DataSnapshot dataSnapshot) {
  
                if (mlike) {
                    if (dataSnapshot.child(postId).hasChild(myuid)) {
                        postref.child(postId).child("plike").setValue("" + (Integer.parseInt(plike) - 1));
                        liekeref.child(postId).child(myuid).removeValue();
                        mlike = false;
  
                    } else {
                        postref.child(postId).child("plike").setValue("" + (Integer.parseInt(plike) + 1));
                        liekeref.child(postId).child(myuid).setValue("Liked");
                        mlike = false;
                    }
                }
            }
  
            @Override
            public void onCancelled(@NonNull DatabaseError databaseError) {
  
            }
        });
    }
  
    private void postComment() {
        progressDialog.setMessage("Adding Comment");
  
        final String commentss = comment.getText().toString().trim();
        if (TextUtils.isEmpty(commentss)) {
            Toast.makeText(PostDetailsActivity.this, "Empty comment", Toast.LENGTH_LONG).show();
            return;
        }
        progressDialog.show();
        String timestamp = String.valueOf(System.currentTimeMillis());
        DatabaseReference datarf = FirebaseDatabase.getInstance().getReference("Posts").child(postId).child("Comments");
        HashMap hashMap = new HashMap<>();
        hashMap.put("cId", timestamp);
        hashMap.put("comment", commentss);
        hashMap.put("ptime", timestamp);
        hashMap.put("uid", myuid);
        hashMap.put("uemail", myemail);
        hashMap.put("udp", mydp);
        hashMap.put("uname", myname);
        datarf.child(timestamp).setValue(hashMap).addOnSuccessListener(new OnSuccessListener() {
            @Override
            public void onSuccess(Void aVoid) {
                progressDialog.dismiss();
                Toast.makeText(PostDetailsActivity.this, "Added", Toast.LENGTH_LONG).show();
                comment.setText("");
                updatecommetcount();
            }
        }).addOnFailureListener(new OnFailureListener() {
            @Override
            public void onFailure(@NonNull Exception e) {
                progressDialog.dismiss();
                Toast.makeText(PostDetailsActivity.this, "Failed", Toast.LENGTH_LONG).show();
            }
        });
    }
  
    boolean count = false;
  
    private void updatecommetcount() {
        count = true;
        final DatabaseReference reference = FirebaseDatabase.getInstance().getReference("Posts").child(postId);
        reference.addListenerForSingleValueEvent(new ValueEventListener() {
            @Override
            public void onDataChange(@NonNull DataSnapshot dataSnapshot) {
                if (count) {
                    String comments = "" + dataSnapshot.child("pcomments").getValue();
                    int newcomment = Integer.parseInt(comments) + 1;
                    reference.child("pcomments").setValue("" + newcomment);
                    count = false;
  
                }
            }
  
            @Override
            public void onCancelled(@NonNull DatabaseError databaseError) {
  
            }
        });
    }
  
    private void loadUserInfo() {
  
        Query myref = FirebaseDatabase.getInstance().getReference("Users");
        myref.orderByChild("uid").equalTo(myuid).addListenerForSingleValueEvent(new ValueEventListener() {
            @Override
            public void onDataChange(@NonNull DataSnapshot dataSnapshot) {
                for (DataSnapshot dataSnapshot1 : dataSnapshot.getChildren()) {
                    myname = dataSnapshot1.child("name").getValue().toString();
                    mydp = dataSnapshot1.child("image").getValue().toString();
                    try {
                        Glide.with(PostDetailsActivity.this).load(mydp).into(imagep);
                    } catch (Exception e) {
  
                    }
                }
            }
  
            @Override
            public void onCancelled(@NonNull DatabaseError databaseError) {
  
            }
        });
    }
  
    private void loadPostInfo() {
  
        DatabaseReference databaseReference = FirebaseDatabase.getInstance().getReference("Posts");
        Query query = databaseReference.orderByChild("ptime").equalTo(postId);
        query.addValueEventListener(new ValueEventListener() {
            @Override
            public void onDataChange(@NonNull DataSnapshot dataSnapshot) {
  
                for (DataSnapshot dataSnapshot1 : dataSnapshot.getChildren()) {
                    String ptitle = dataSnapshot1.child("title").getValue().toString();
                    String descriptions = dataSnapshot1.child("description").getValue().toString();
                    uimage = dataSnapshot1.child("uimage").getValue().toString();
                    hisdp = dataSnapshot1.child("udp").getValue().toString();
                    // hisuid = dataSnapshot1.child("uid").getValue().toString();
                    String uemail = dataSnapshot1.child("uemail").getValue().toString();
                    hisname = dataSnapshot1.child("uname").getValue().toString();
                    ptime = dataSnapshot1.child("ptime").getValue().toString();
                    plike = dataSnapshot1.child("plike").getValue().toString();
                    String commentcount = dataSnapshot1.child("pcomments").getValue().toString();
                    Calendar calendar = Calendar.getInstance(Locale.ENGLISH);
                    calendar.setTimeInMillis(Long.parseLong(ptime));
                    String timedate = DateFormat.format("dd/MM/yyyy hh:mm aa", calendar).toString();
                    name.setText(hisname);
                    title.setText(ptitle);
                    description.setText(descriptions);
                    like.setText(plike + " Likes");
                    time.setText(timedate);
                    tcomment.setText(commentcount + " Comments");
                    if (uimage.equals("noImage")) {
                        image.setVisibility(View.GONE);
                    } else {
                        image.setVisibility(View.VISIBLE);
                        try {
                            Glide.with(PostDetailsActivity.this).load(uimage).into(image);
                        } catch (Exception e) {
  
                        }
                    }
                    try {
                        Glide.with(PostDetailsActivity.this).load(hisdp).into(picture);
                    } catch (Exception e) {
  
                    }
  
  
                }
            }
  
            @Override
            public void onCancelled(@NonNull DatabaseError databaseError) {
  
            }
        });
    }
  
    @Override
    public boolean onSupportNavigateUp() {
        onBackPressed();
        return super.onSupportNavigateUp();
    }
      
}

输出：

对于本文中使用的所有可绘制文件，请参考以下链接： https://drive.google.com/drive/folders/1M_knOH_ugCuwSP5nkYzeD4dRp-Honzbe?usp=sharing

下面是执行这些操作后的文件结构：