Firebase-Read-Database

activity_main.xml

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
              xmlns:tools="http://schemas.android.com/tools"
              android:layout_width="match_parent"
              android:layout_height="match_parent"
              android:gravity="center_horizontal"
              android:orientation="vertical"

              tools:context="com.tabian.firebasereaddata.MainActivity">

    <ScrollView
        android:id="@+id/login_form"
        android:layout_width="match_parent"
        android:layout_height="match_parent">

        <LinearLayout
            android:id="@+id/email_login_form"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:orientation="vertical">



            <EditText
                android:id="@+id/email"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:hint="Enter Email"
                android:inputType="textEmailAddress"
                android:maxLines="1"/>



            <EditText
                android:id="@+id/password"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:hint="Password"
                android:imeActionId="@+id/login"
                android:imeOptions="actionUnspecified"
                android:inputType="textPassword"
                android:maxLines="1"
                />

            <Button
                android:id="@+id/email_sign_in_button"
                style="?android:textAppearanceSmall"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:layout_marginTop="16dp"
                android:text="Sign In"
                android:textStyle="bold"/>

            <Button
                android:id="@+id/email_sign_out_button"
                style="?android:textAppearanceSmall"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:layout_marginTop="16dp"
                android:text="Sign out"
                android:textStyle="bold"/>

            <Button
                android:id="@+id/view_items_screen"
                style="?android:textAppearanceSmall"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:layout_marginTop="16dp"
                android:text="View Database Contents"
                android:textStyle="bold"/>

        </LinearLayout>
    </ScrollView>
</LinearLayout><LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
              xmlns:tools="http://schemas.android.com/tools"
              android:layout_width="match_parent"
              android:layout_height="match_parent"
              android:gravity="center_horizontal"
              android:orientation="vertical"

              tools:context="com.tabian.firebasereaddata.MainActivity">

    <ScrollView
        android:id="@+id/login_form"
        android:layout_width="match_parent"
        android:layout_height="match_parent">

        <LinearLayout
            android:id="@+id/email_login_form"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:orientation="vertical">



            <EditText
                android:id="@+id/email"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:hint="Enter Email"
                android:inputType="textEmailAddress"
                android:maxLines="1"/>



            <EditText
                android:id="@+id/password"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:hint="Password"
                android:imeActionId="@+id/login"
                android:imeOptions="actionUnspecified"
                android:inputType="textPassword"
                android:maxLines="1"
                />

            <Button
                android:id="@+id/email_sign_in_button"
                style="?android:textAppearanceSmall"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:layout_marginTop="16dp"
                android:text="Sign In"
                android:textStyle="bold"/>

            <Button
                android:id="@+id/email_sign_out_button"
                style="?android:textAppearanceSmall"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:layout_marginTop="16dp"
                android:text="Sign out"
                android:textStyle="bold"/>

            <Button
                android:id="@+id/view_items_screen"
                style="?android:textAppearanceSmall"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:layout_marginTop="16dp"
                android:text="View Database Contents"
                android:textStyle="bold"/>

        </LinearLayout>
    </ScrollView>
</LinearLayout>

AndroidManifest.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
          package="com.tabian.firebasereaddata">

    <uses-permission android:name="android.permission.INTERNET"></uses-permission>

    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:supportsRtl="true"
        android:theme="@style/AppTheme">
        <activity android:name=".MainActivity">
            <intent-filter>
                <action android:name="android.intent.action.MAIN"/>

                <category android:name="android.intent.category.LAUNCHER"/>
            </intent-filter>
        </activity>
        <activity android:name=".ViewDatabase"></activity>
    </application>

</manifest>

Firebase Database Structure

{
  "users" : {
    "YaWnTJTbhYhTAuUwPZuA15K7QSc2" : {
      "email" : "mitch@tabian.ca",
      "name" : "Mitch",
      "phone_num" : "(604)-856-9999"
    },
    "onG0BkYAm9fXJX0gaFqmgWKaMx82" : {
      "email" : "blake@tabian.ca",
      "name" : "Blake",
      "phone_num" : "(604)-857-1121"
    },
    "oyY1lhUG0ke8FBIVF4Wi2c0lk0M2" : {
      "email" : "jessica@gmail.com",
      "name" : "jessica",
      "phone_num" : "604-854-6541"
    },
    "xwfi1CJtEDaJZB3wKa4mm4q2eLp1" : {
      "email" : "Ron@telus.net",
      "name" : "Ron",
      "phone_num" : "604-444-1111"
    }
  }
}

MainActivity.java

package com.tabian.firebasereaddata;

import android.content.Intent;
import android.os.Bundle;
import android.support.annotation.NonNull;
import android.support.v7.app.AppCompatActivity;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;

import com.google.firebase.auth.FirebaseAuth;
import com.google.firebase.auth.FirebaseUser;

public class MainActivity extends AppCompatActivity {
    private static final String TAG = "MainActivity";

    private FirebaseAuth mAuth;
    private FirebaseAuth.AuthStateListener mAuthListener;

    // UI references.
    private EditText mEmail, mPassword;
    private Button btnSignIn,btnSignOut,btnViewDatabase;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        //declare buttons and edit texts in oncreate
        mEmail = (EditText) findViewById(R.id.email);
        mPassword = (EditText) findViewById(R.id.password);
        btnSignIn = (Button) findViewById(R.id.email_sign_in_button);
        btnSignOut = (Button) findViewById(R.id.email_sign_out_button);
        btnViewDatabase = (Button) findViewById(R.id.view_items_screen);


        mAuth = FirebaseAuth.getInstance();

        mAuthListener = new FirebaseAuth.AuthStateListener() {
            @Override
            public void onAuthStateChanged(@NonNull FirebaseAuth firebaseAuth) {
                FirebaseUser user = firebaseAuth.getCurrentUser();
                if (user != null) {
                    // User is signed in
                    Log.d(TAG, "onAuthStateChanged:signed_in:" + user.getUid());
                    toastMessage("Successfully signed in with: " + user.getEmail());
                } else {
                    // User is signed out
                    Log.d(TAG, "onAuthStateChanged:signed_out");
                    toastMessage("Successfully signed out.");
                }
                // ...
            }
        };

        btnSignIn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                String email = mEmail.getText().toString();
                String pass = mPassword.getText().toString();
                if(!email.equals("") && !pass.equals("")){
                    mAuth.signInWithEmailAndPassword(email,pass);
                }else{
                    toastMessage("You didn't fill in all the fields.");
                }
            }
        });

        btnSignOut.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                mAuth.signOut();
                toastMessage("Signing Out...");
            }
        });

        btnViewDatabase.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                Intent intent = new Intent(MainActivity.this, ViewDatabase.class);
                startActivity(intent);
            }
        });


    }

    @Override
    public void onStart() {
        super.onStart();
        mAuth.addAuthStateListener(mAuthListener);
    }

    @Override
    public void onStop() {
        super.onStop();
        if (mAuthListener != null) {
            mAuth.removeAuthStateListener(mAuthListener);
        }
    }


    /**
     * customizable toast
     * @param message
     */
    private void toastMessage(String message){
        Toast.makeText(this,message,Toast.LENGTH_SHORT).show();
    }
}

UserInformation.java

package com.tabian.firebasereaddata;

/**
 * Created by User on 2/8/2017.
 */

public class UserInformation {

    private String name;
    private String email;
    private String phone_num;

    public UserInformation(){

    }

    public String getEmail() {
        return email;
    }

    public void setEmail(String email) {
        this.email = email;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getPhone_num() {
        return phone_num;
    }

    public void setPhone_num(String phone_num) {
        this.phone_num = phone_num;
    }
}

view_database_layout.xml

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

    <TextView
        android:textAlignment="center"
        android:textSize="25sp"
        android:text="User Information"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:id="@+id/tvUserInfo"/>

    <ListView
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:id="@+id/listview"/>


</LinearLayout>

ViewDatabase.java

package com.tabian.firebasereaddata;

import android.os.Bundle;
import android.provider.ContactsContract;
import android.support.annotation.NonNull;
import android.support.annotation.Nullable;
import android.support.v7.app.AppCompatActivity;
import android.util.Log;
import android.widget.ArrayAdapter;
import android.widget.ListView;
import android.widget.Toast;

import com.google.firebase.auth.FirebaseAuth;
import com.google.firebase.auth.FirebaseUser;
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;

/**
 * Created by User on 2/8/2017.
 */

public class ViewDatabase extends AppCompatActivity {
    private static final String TAG = "ViewDatabase";

    //add Firebase Database stuff
    private FirebaseDatabase mFirebaseDatabase;
    private FirebaseAuth mAuth;
    private FirebaseAuth.AuthStateListener mAuthListener;
    private DatabaseReference myRef;
    private  String userID;

    private ListView mListView;

    @Override
    protected void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.view_database_layout);

        mListView = (ListView) findViewById(R.id.listview);

        //declare the database reference object. This is what we use to access the database.
        //NOTE: Unless you are signed in, this will not be useable.
        mAuth = FirebaseAuth.getInstance();
        mFirebaseDatabase = FirebaseDatabase.getInstance();
        myRef = mFirebaseDatabase.getReference();
        FirebaseUser user = mAuth.getCurrentUser();
        userID = user.getUid();

        mAuthListener = new FirebaseAuth.AuthStateListener() {
            @Override
            public void onAuthStateChanged(@NonNull FirebaseAuth firebaseAuth) {
                FirebaseUser user = firebaseAuth.getCurrentUser();
                if (user != null) {
                    // User is signed in
                    Log.d(TAG, "onAuthStateChanged:signed_in:" + user.getUid());
                    toastMessage("Successfully signed in with: " + user.getEmail());
                } else {
                    // User is signed out
                    Log.d(TAG, "onAuthStateChanged:signed_out");
                    toastMessage("Successfully signed out.");
                }
                // ...
            }
        };

        myRef.addValueEventListener(new ValueEventListener() {
            @Override
            public void onDataChange(DataSnapshot dataSnapshot) {
                // This method is called once with the initial value and again
                // whenever data at this location is updated.
                showData(dataSnapshot);
            }

            @Override
            public void onCancelled(DatabaseError databaseError) {

            }
        });

    }

    private void showData(DataSnapshot dataSnapshot) {
        for(DataSnapshot ds : dataSnapshot.getChildren()){
            UserInformation uInfo = new UserInformation();
            uInfo.setName(ds.child(userID).getValue(UserInformation.class).getName()); //set the name
            uInfo.setEmail(ds.child(userID).getValue(UserInformation.class).getEmail()); //set the email
            uInfo.setPhone_num(ds.child(userID).getValue(UserInformation.class).getPhone_num()); //set the phone_num

            //display all the information
            Log.d(TAG, "showData: name: " + uInfo.getName());
            Log.d(TAG, "showData: email: " + uInfo.getEmail());
            Log.d(TAG, "showData: phone_num: " + uInfo.getPhone_num());

            ArrayList<String> array  = new ArrayList<>();
            array.add(uInfo.getName());
            array.add(uInfo.getEmail());
            array.add(uInfo.getPhone_num());
            ArrayAdapter adapter = new ArrayAdapter(this,android.R.layout.simple_list_item_1,array);
            mListView.setAdapter(adapter);
        }
    }

    @Override
    public void onStart() {
        super.onStart();
        mAuth.addAuthStateListener(mAuthListener);
    }

    @Override
    public void onStop() {
        super.onStop();
        if (mAuthListener != null) {
            mAuth.removeAuthStateListener(mAuthListener);
        }
    }


    /**
     * customizable toast
     * @param message
     */
    private void toastMessage(String message){
        Toast.makeText(this,message,Toast.LENGTH_SHORT).show();
    }
}