I am using firebase database, but I am newbie with it. I am following this tutorial,
Now, my question is how can I check the email if it is already exist in the database? If email is already there data should not be add to db.
public class MainActivity extends AppCompatActivity {
private static final String TAG = MainActivity.class.getSimpleName();
private TextView txtDetails;
private EditText inputName, inputEmail;
private Button btnSave;
private DatabaseReference mFirebaseDatabase;
private FirebaseDatabase mFirebaseInstance;
private String userId;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
// Displaying toolbar icon
getSupportActionBar().setDisplayShowHomeEnabled(true);
getSupportActionBar().setIcon(R.mipmap.ic_launcher);
txtDetails = (TextView) findViewById(R.id.txt_user);
inputName = (EditText) findViewById(R.id.name);
inputEmail = (EditText) findViewById(R.id.email);
btnSave = (Button) findViewById(R.id.btn_save);
mFirebaseInstance = FirebaseDatabase.getInstance();
// get reference to 'users' node
mFirebaseDatabase = mFirebaseInstance.getReference("users");
// store app title to 'app_title' node
mFirebaseInstance.getReference("app_title").setValue("Realtime");
// app_title change listener
mFirebaseInstance.getReference("app_title").addValueEventListener(new ValueEventListener() {
@Override
public void onDataChange(DataSnapshot dataSnapshot) {
Log.e(TAG, "App title updated");
String appTitle = dataSnapshot.getValue(String.class);
// update toolbar title
getSupportActionBar().setTitle(appTitle);
}
@Override
public void onCancelled(DatabaseError error) {
// Failed to read value
Log.e(TAG, "Failed to read app title value.", error.toException());
}
});
// Save / update the user
btnSave.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
final String name = inputName.getText().toString();
final String email = inputEmail.getText().toString();
// Check for already existed userId
if (TextUtils.isEmpty(userId)) {
createUser(name, email);
} else {
updateUser(name, email);
}
mFirebaseDatabase.addListenerForSingleValueEvent(new ValueEventListener() {
@Override
public void onDataChange(DataSnapshot dataSnapshot) {
//Your Logic here
for (DataSnapshot eventSnapshot : dataSnapshot.getChildren()) {
User mModel = eventSnapshot.getValue(User.class);
// Log.e("DATA" ,""+ mModel.getName());
}
}
@Override
public void onCancelled(DatabaseError databaseError) {
}
});
}
});
toggleButton();
}
// Changing button text
private void toggleButton() {
if (TextUtils.isEmpty(userId)) {
btnSave.setText("Save");
} else {
btnSave.setText("Update");
}
}
private void filter()
{
}
/**
* Creating new user node under 'users'
*/
private void createUser(String name, String email) {
// TODO
// In real apps this userId should be fetched
// by implementing firebase auth
if (TextUtils.isEmpty(userId)) {
userId = mFirebaseDatabase.push().getKey();
}
User user = new User(name, email);
mFirebaseDatabase.child(userId).setValue(user);
addUserChangeListener();
}
/**
* User data change listener
*/
private void addUserChangeListener() {
// User data change listener
mFirebaseDatabase.child(userId).addValueEventListener(new ValueEventListener() {
@Override
public void onDataChange(DataSnapshot dataSnapshot) {
User user = dataSnapshot.getValue(User.class);
if(!dataSnapshot.child("users").child("email").exists())
{
Log.e(TAG, "User not exists");
}
else
{
Log.e(TAG, "User exists");
}
// Check for null
if (user == null) {
Log.e(TAG, "User data is null!");
return;
}
Log.e(TAG, "User data is changed!" + user.name + ", " + user.email);
// Display newly updated name and email
txtDetails.setText(user.name + ", " + user.email);
// clear edit text
inputEmail.setText("");
inputName.setText("");
toggleButton();
}
@Override
public void onCancelled(DatabaseError error) {
// Failed to read value
Log.e(TAG, "Failed to read user", error.toException());
}
});
}
private void updateUser(String name, String email) {
// updating the user via child nodes
if (!TextUtils.isEmpty(name))
mFirebaseDatabase.child(userId).child("name").setValue(name);
if (!TextUtils.isEmpty(email))
mFirebaseDatabase.child(userId).child("email").setValue(email);
}
}
