Firebase_RealtimeDatabase 사용 해보기.

google play service out of date 오류날때

 

-sdk manager 에서 google-play-service 삭제후 재설치.

-안드로이드 애뮬을 삭제후 재설치.

-build-gradle.zip install error >> 안드로이드 스튜디오 재설치.

google-service.json 갱신

 

consle페이지에서 realtime database만들기

테스트모드- region은 미국으로

어제 만들던 프로젝트에 이어서 작성

realTimeDB패키지 생성

package com.example.fcmtest.realTimeDB;

public class UserInfo {
    private String userpwd;
    private String username;
    private String emailaddr;

    public String getUserpwd() {
        return userpwd;
    }

    public void setUserpwd(String userpwd) {
        this.userpwd = userpwd;
    }

    public String getUsername() {
        return username;
    }

    public void setUsername(String username) {
        this.username = username;
    }

    public String getEmailaddr() {
        return emailaddr;
    }

    public void setEmailaddr(String emailaddr) {
        this.emailaddr = emailaddr;
    }
}

userInfo.java

package com.example.fcmtest.realTimeDB;

public class MemoItem {
    private String user;
    private String memotitle;
    private String memocontents;

    public String getUser() {
        return user;
    }

    public void setUser(String user) {
        this.user = user;
    }

    public String getMemotitle() {
        return memotitle;
    }

    public void setMemotitle(String memotitle) {
        this.memotitle = memotitle;
    }

    public String getMemocontents() {
        return memocontents;
    }

    public void setMemocontents(String memocontents) {
        this.memocontents = memocontents;
    }
}

MemoItem.java

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <TextView
        android:id="@+id/memotitle"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

    <TextView
        android:id="@+id/memocontents"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/memotitle" />
</androidx.constraintlayout.widget.ConstraintLayout>

memo_item_list.xml

package com.example.fcmtest.realTimeDB;

import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;

import androidx.annotation.NonNull;
import androidx.recyclerview.widget.RecyclerView;

import com.example.fcmtest.R;

import java.util.ArrayList;

public class MemoAdapter extends RecyclerView.Adapter<MemoAdapter.ViewHolder> {
    private Context context = null;
    private ArrayList<MemoItem> memoItems = null;
    private MemoViewListener memoViewListener = null;


    public MemoAdapter(Context context, ArrayList<MemoItem> memoItems, MemoViewListener memoViewListener) {
        this.context = context;
        this.memoItems = memoItems;
        this.memoViewListener = memoViewListener;
    }


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

    @Override
    public void onBindViewHolder(@NonNull MemoAdapter.ViewHolder holder, int position) {
        holder.titleView.setText(memoItems.get(position).getMemotitle());
        holder.contentsView.setText(memoItems.get(position).getMemocontents());

    }

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

    public class ViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener{
        public TextView titleView = null;
        public TextView contentsView = null;

        public ViewHolder(@NonNull View itemView) {
            super(itemView);
            titleView = itemView.findViewById(R.id.memotitle);
            contentsView = itemView.findViewById(R.id.memocontents);
        }

        @Override
        public void onClick(View v) {
            memoViewListener.onItemClick(getAdapterPosition(), v);

        }
    }
}

MemoAdapter.java

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    tools:context=".realTimeDB.MemoActivity">

    <EditText
        android:id="@+id/memotitle"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:hint="메모 타이틀" />

    <EditText
        android:id="@+id/memocontents"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:hint="메모 내용" />

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="horizontal">

        <Button
            android:id="@+id/memobtn"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:text="메모 등록" />

        <Button
            android:id="@+id/reguser"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:text="사용자 등록" />
    </LinearLayout>

    <TextView
        android:id="@+id/memolisttitle"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="메모 리스트" />

    <androidx.recyclerview.widget.RecyclerView
        android:id="@+id/memolist"
        android:layout_width="match_parent"
        android:layout_height="match_parent" />
</LinearLayout>

activity_memo.xml

package com.example.fcmtest.realTimeDB;

import androidx.annotation.NonNull;
import androidx.annotation.Nullable;
import androidx.appcompat.app.AppCompatActivity;
import androidx.recyclerview.widget.LinearLayoutManager;
import androidx.recyclerview.widget.RecyclerView;

import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;

import com.example.fcmtest.R;
import com.google.firebase.auth.FirebaseAuth;
import com.google.firebase.auth.FirebaseUser;
import com.google.firebase.database.ChildEventListener;
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.ValueEventListener;

import java.util.ArrayList;
import java.util.Random;

public class MemoActivity extends AppCompatActivity
        implements View.OnClickListener, MemoViewListener {
    private ArrayList<MemoItem> memoItems = null;
    private MemoAdapter memoAdapter = null;
    private String username = null;
    FirebaseDatabase firebaseDatabase = FirebaseDatabase.getInstance();
    DatabaseReference databaseReference = firebaseDatabase.getReference();

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_memo);
        Log.d("jaeho", databaseReference.toString());
        init();
        initView();
    }

    @Override
    protected void onStart() {
        super.onStart();
        addChildEvent();
        addValueEventListener();
    }

    private void addValueEventListener() {
        databaseReference.addValueEventListener(new ValueEventListener() {
            @Override
            public void onDataChange(@NonNull DataSnapshot snapshot) {
                //Log.d("jaeho", "Value = " +snapshot.getValue().toString());
            }

            @Override
            public void onCancelled(@NonNull DatabaseError error) {
            }
        });
    }

    private void addChildEvent() {
        databaseReference.child("memo").addChildEventListener(new
              ChildEventListener() {
                  @Override
                  public void onChildAdded(@NonNull DataSnapshot snapshot
                          , @Nullable String previousChildName) {
                      Log.d("jaeho", "addChildEvent in");
                      MemoItem item = snapshot.getValue(MemoItem.class);
                      memoItems.add(item);
                      memoAdapter.notifyDataSetChanged();
                  }

                  @Override
                  public void onChildChanged(@NonNull DataSnapshot snapshot
                          , @Nullable String previousChildName) {
                  }

                  @Override
                  public void onChildRemoved(@NonNull DataSnapshot snapshot) {
                  }

                  @Override
                  public void onChildMoved(@NonNull DataSnapshot snapshot
                          , @Nullable String previousChildName) {
                  }

                  @Override
                  public void onCancelled(@NonNull DatabaseError error) {
                  }
              });
    }

    private void initView() {
        Button regbtn = findViewById(R.id.memobtn);
        regbtn.setOnClickListener(this);
        Button userbtn = findViewById(R.id.reguser);
        userbtn.setOnClickListener(this);
        RecyclerView.LayoutManager layoutManager = new
                LinearLayoutManager(this);
        RecyclerView recyclerView = findViewById(R.id.memolist);
        memoAdapter = new MemoAdapter(this, memoItems, this);
        recyclerView.setLayoutManager(layoutManager);
        recyclerView.setAdapter(memoAdapter);
    }

    private void init() {
        memoItems = new ArrayList<>();
        username = "user_" + new Random().nextInt(1000);
    }

    @Override
    public void onClick(View v) {
        switch (v.getId()) {
            case R.id.memobtn:
                regMemo();
                break;
            case R.id.reguser:
                writeNewUser();
                break;
        }
    }

    private void writeNewUser() {
        FirebaseUser user = FirebaseAuth.getInstance().getCurrentUser();
        if (user != null) {
            // User is signed in
            String name = user.getDisplayName();
            String email = user.getEmail();
            String uid = user.getUid();
            Log.d("jaeho", "name = " + name);
            Log.d("jaeho", "email = " + email);
            Log.d("jaeho", "uid = " + uid);
            UserInfo userInfo = new UserInfo();
            userInfo.setUserpwd("1234");
            userInfo.setUsername(name);
            userInfo.setEmailaddr(email);
            databaseReference.child("users").child(uid).setValue(userInfo);
        } else {
            // No user is signed in
            Log.d("jaeho", "user null");
        }
    }

    private void regMemo() {
        EditText titleedit = findViewById(R.id.memotitle);
        EditText contentsedit = findViewById(R.id.memocontents);
        if (titleedit.getText().toString().length() == 0 ||
                contentsedit.getText().toString().length() == 0) {
            Toast.makeText(this,
                    "메모 제목 또는 메모 내용이 입력되지 않았습니다. 입력 후 다시 시작해주세요.",
                    Toast.LENGTH_LONG).show();
            return;
        }
        MemoItem item = new MemoItem();
        item.setUser(this.username);
        item.setMemotitle(titleedit.getText().toString());
        item.setMemocontents(contentsedit.getText().toString());
        databaseReference.child("memo").push().setValue(item);
    }

    @Override
    public void onItemClick(int position, View view) {
    }
}

MemoActivity.java

 

실행 후 app 내에서 메모 작성시 실시간 DB에 반영.