How can i update my firebase database fields? - java

Good Day.
I have tried my level best but failed to update the data whenever i enter new "Name","Age" or anything the data entered before is wiped.I want to use push or something else to update the data.But still failing to do that.
nameRef.addValueEventListener(new com.google.firebase.database.ValueEventListener() {
#Override
public void onDataChange(com.google.firebase.database.DataSnapshot dataSnapshot) {
String text = dataSnapshot.getValue(String.class);
String ho = name.getText().toString();
nameRef.setValue(ho);
}
#Override
public void onCancelled(DatabaseError databaseError) {
}
});
genderRef.addValueEventListener(new com.google.firebase.database.ValueEventListener() {
#Override
public void onDataChange(com.google.firebase.database.DataSnapshot dataSnapshot) {
String text = dataSnapshot.getValue(String.class);
String ho = gender.getText().toString();
genderRef.setValue(ho);
}
#Override
public void onCancelled(DatabaseError databaseError) {
}
});
ageRef.addValueEventListener(new com.google.firebase.database.ValueEventListener() {
#Override
public void onDataChange(com.google.firebase.database.DataSnapshot dataSnapshot) {
`enter code here` String text = dataSnapshot.getValue(String.class);
String ho = age.getText().toString();
ageRef.setValue(ho);
}
#Override
public void onCancelled(DatabaseError databaseError) {
}
});
EmailRef.addValueEventListener(new com.google.firebase.database.ValueEventListener() {
#Override
public void onDataChange(com.google.firebase.database.DataSnapshot dataSnapshot) {
String text = dataSnapshot.getValue(String.class);
String ho = email.getText().toString();
EmailRef.setValue(ho);
}
#Override
public void onCancelled(DatabaseError databaseError) {
}
});

If you have a JSON tree like this:
->users
->uid
->name
->age
->gender
->email
Then to update the values in the database you should do something like this:
DatabaseReference mFirebaseDBRef = FirebaseDatabase.getInstance().getReference();
FirebaseAuth mFirebaseAuth = FirebaseAuth.getInstance();
FirebaseUser mFirebaseUser = mFirebaseAuth.getCurrentUser();
//use a POJO and make sure to have a default empty constructor in that class definition
User user = new User(name, age, gender, email)
mFirebaseDBRef.child("users").child(mFirebaseUser.getUid()).setValue(user);
And that should update your database! If something is not clear, feel free to ask.

Related

Unable to retrieve and compare data from firebase in android studio

I am trying to get Data and comparing it to the input data but it doesn't do anything. Pls Help me!`btn_login.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
DatabaseReference databaseReference = FirebaseDatabase.getInstance().getReference().child("Routes").child("route1").child("Students").child("driver");
databaseReference.addValueEventListener(new ValueEventListener() {
#Override
public void onDataChange(#NonNull DataSnapshot dataSnapshot) {
String phoneNumber = et_phone.getText().toString();
String password = et_password.getText().toString();
String phone = dataSnapshot.child("Phone_No").getValue().toString();
String pass = dataSnapshot.child("Password").getValue().toString();
if(phone.equals(phoneNumber)){
if(pass.equals(password)){
startActivity(new Intent(Authentication.this, Home.class));
}else{
Toast.makeText(Authentication.this, "Worng Password!!!", Toast.LENGTH_LONG).show();
}
}else{
Toast.makeText(Authentication.this, "Invalid PhoneNumber![enter image description here][1]", Toast.LENGTH_LONG).show();
}*/
}
#Override
public void onCancelled(#NonNull DatabaseError error) {
}
});`

How to check if value exists in firebase databse

I have this Database:
I want to find out if a Email (value in database) already exists. So I have to iterate through each child of "email" and check if the value equals to the String inputMail.
I tried the following Code, but It doesn´t work, can anybody help me please? Thank u
final String input_mail = et_email.getText().toString();
DatabaseReference email = FirebaseDatabase.getInstance().getReference().child("email");
email.addListenerForSingleValueEvent(new ValueEventListener() {
#Override
public void onDataChange(#NonNull DataSnapshot dataSnapshot) {
for (DataSnapshot ds : dataSnapshot.getChildren()) {
String emailVal = ds.getValue(String.class);
if (emailVal.equals(input_mail)) {
//Toast exists
}
else {
//Toast not exists
}
}
}
#Override
public void onCancelled(#NonNull DatabaseError databaseError) {
}
});
In conclusion if I enter person1#m.de it should give out a toast that it exist
Here is a very easy way . Make your email as child . You have to replace the dot from the email and set it as child. (you can't use the email directly to a child)
static String encodeUserEmail(String userEmail) {
return userEmail.replace(".", ",");
}
static String decodeUserEmail(String userEmail) {
return userEmail.replace(",", ".");
}
Then you can easily match it like this :
final String input_mail = et_email.getText().toString();
DatabaseReference email = FirebaseDatabase.getInstance().getReference().child("email");
email.addListenerForSingleValueEvent(new ValueEventListener() {
#Override
public void onDataChange(#NonNull DataSnapshot dataSnapshot) {
if(datasnapshot.child(input_mail).exits){
//Toast exists
}else {
//Toast not exists
}
}
}
#Override
public void onCancelled(#NonNull DatabaseError databaseError) {
}
});

Why am I receiving empty strings after receiving valid data from Firebase?

Using Firebase, I'm trying to display to the user people they have matched with. I already have valid data for testing this and I have already run tests with sample data to see if everything else works.
Now, when I use real data from Firebase, problems occur.
This is what I have for code:
public String username = "";
public String profileImage = "";
public String discussion = "";
private void FetchMatchInformation(final String key, final String choice) {
DatabaseReference matchDb = FirebaseDatabase.getInstance().getReference().child("answers").child(key);
matchDb.addListenerForSingleValueEvent(new ValueEventListener() {
#Override
public void onDataChange(#NonNull DataSnapshot dataSnapshot) {
for (DataSnapshot postSnapshot: dataSnapshot.getChildren()) {
String opposite = postSnapshot.getValue(String.class);
if(opposite.equals("agree") && choice.equals("disagree")) {
DatabaseReference found = FirebaseDatabase.getInstance().getReference().child("users").child(postSnapshot.getKey());
found.addListenerForSingleValueEvent(new ValueEventListener() {
#Override
public void onDataChange(#NonNull DataSnapshot dataSnapshot) {
for (DataSnapshot postSnapshot: dataSnapshot.getChildren()) {
if(postSnapshot.getKey().equals("username")) {
username = postSnapshot.getValue(String.class);
}
if(postSnapshot.getKey().equals("providerId")) {
String provider = postSnapshot.getValue(String.class);
if(provider.equals("google.com")) {
Uri photoUrl = FirebaseAuth.getInstance().getCurrentUser().getPhotoUrl();
String originalPieceOfUrl = "s96-c/photo.jpg";
String newPieceOfUrlToAdd = "s400-c/photo.jpg";
String photoPath = photoUrl.toString();
String newString = photoPath.replace(originalPieceOfUrl, newPieceOfUrlToAdd);
profileImage = newString;
} else if(provider.equals("facebook.com")) {
profileImage = FirebaseAuth.getInstance().getCurrentUser().getPhotoUrl().toString() + "?type=large";
}
}
}
}
#Override
public void onCancelled(#NonNull DatabaseError databaseError) {
}
});
FirebaseDatabase.getInstance().getReference().child("debates").addListenerForSingleValueEvent(new ValueEventListener() {
#Override
public void onDataChange(#NonNull DataSnapshot dataSnapshot) {
for (DataSnapshot postSnapshot: dataSnapshot.getChildren()) {
if(postSnapshot.getKey().equals(key)) {
discussion = postSnapshot.getValue(String.class);
break;
}
break;
}
}
#Override
public void onCancelled(#NonNull DatabaseError databaseError) {
}
});
MessagesObject objDisc = new MessagesObject(username, discussion, profileImage);
resultsMessages.add(objDisc);
mMessagesAdapter.notifyDataSetChanged();
} else if(opposite.equals("disagree") && choice.equals("agree")) {
DatabaseReference found = FirebaseDatabase.getInstance().getReference().child("users").child(postSnapshot.getKey());
found.addListenerForSingleValueEvent(new ValueEventListener() {
#Override
public void onDataChange(#NonNull DataSnapshot dataSnapshot) {
for (DataSnapshot postSnapshot: dataSnapshot.getChildren()) {
if(postSnapshot.getKey().equals("username")) {
username = postSnapshot.getValue(String.class);
}
if(postSnapshot.getKey().equals("providerId")) {
String provider = postSnapshot.getValue(String.class);
if(provider.equals("google.com")) {
Uri photoUrl = FirebaseAuth.getInstance().getCurrentUser().getPhotoUrl();
String originalPieceOfUrl = "s96-c/photo.jpg";
String newPieceOfUrlToAdd = "s400-c/photo.jpg";
String photoPath = photoUrl.toString();
String newString = photoPath.replace(originalPieceOfUrl, newPieceOfUrlToAdd);
profileImage = newString;
} else if(provider.equals("facebook.com")) {
profileImage = FirebaseAuth.getInstance().getCurrentUser().getPhotoUrl().toString() + "?type=large";
}
}
}
}
#Override
public void onCancelled(#NonNull DatabaseError databaseError) {
}
});
FirebaseDatabase.getInstance().getReference().child("debates").addListenerForSingleValueEvent(new ValueEventListener() {
#Override
public void onDataChange(#NonNull DataSnapshot dataSnapshot) {
for (DataSnapshot postSnapshot: dataSnapshot.getChildren()) {
if(postSnapshot.getKey().equals(key)) {
discussion = postSnapshot.getValue(String.class);
break;
}
break;
}
}
#Override
public void onCancelled(#NonNull DatabaseError databaseError) {
}
});
MessagesObject objDisc = new MessagesObject(username, discussion, profileImage);
resultsMessages.add(objDisc);
mMessagesAdapter.notifyDataSetChanged();
}
}
}
#Override
public void onCancelled(#NonNull DatabaseError databaseError) {
}
});
}
So what's happening is I'm getting the user's username, their profile image, and figuring out the value, which I called discussion after determining the valid key. These values are all being accessed from different tree structures from the same real-time database.
Now, at the end of the if or else-if statement, I create and instantiate the MessagesObject by passing in the username, profile image, and discussion variables. I then add this object to the List<MessagesObject> called resultMessages. I then notify my custom adapter mMessagesAdapter that the data has changed.
Like I said, all the other pieces of code work perfectly fine. It's just when I pass username, discussion, and profileImage it always passes an empty string. I know this from using the debugger.
Why is that? It should not be doing that.

How to get all child's data in firebase and show it into my android app?

I have this structure in my Firebase Real-time database :
How can I count the data and show it in my app, which listener shall I use to get all childrens?
There are a few ways in which you could achieve this.
I use the following way:
FirebaseDatabase.getInstance()
.getReference()
.child("demografi")
.addListenerForSingleValueEvent(new ValueEventListener() {
#Override
public void onDataChange(DataSnapshot dataSnapshot) {
for (DataSnapshot dataSnap : dataSnapshot.getChildren()) {
YourObject object = dataSnap.getValue(YourObject.class);
// Use your object as needed
}
}
#Override
public void onCancelled(DatabaseError databaseError) {
}
});
dataSnapshot returns the child referenced. Once you have it, all you have to do is iterate through them and you have access to "all children" as you wanted.
FirebaseDatabase.getInstance()
.getReference()
.child("demografi")
.addListenerForSingleValueEvent(new ValueEventListener() {
#Override
public void onDataChange(DataSnapshot dataSnapshot) {
if (dataSnapshot.exists()) {
/** Qty of data in demografi, this is what you want. */
long Count = dataSnapshot.getChildrenCount();
}
}
#Override
public void onCancelled(DatabaseError databaseError) {
}
});
if you want to monitor the count of data in realtime way,
you have to replace [addListenerForSingleValueEvent] with [addValueEventListener].
I will prefer this way -
String email, gender, nama;
DatabaseReference databaseReference = FirebaseDatabase.getInstance().getReference("demografi");
databaseReference.addChildEventListener(new ChildEventListener() {
#Override
public void onChildAdded(DataSnapshot dataSnapshot, String s) {
// To get children count
dataSnapshot.getChildrenCount();
email = dataSnapshot.child("email").getValue().toString();
gender = dataSnapshot.child("gender").getValue().toString();
nama = dataSnapshot.child("nama").getValue().toString();
// and so on..
}
#Override
public void onChildChanged(DataSnapshot dataSnapshot, String s){
}
#Override
public void onChildRemoved(DataSnapshot dataSnapshot) {
}
#Override
public void onChildMoved(DataSnapshot dataSnapshot, String s) {
}
#Override
public void onCancelled(DatabaseError databaseError) {
}
});
If you don't have a model class, you can simply use the String class. So to get all child's data, please use the following code:
DatabaseReference rootRef = FirebaseDatabase.getInstance().getReference();
DatabaseReference demografiRef = rootRef.child("demografi");
ValueEventListener valueEventListener = new ValueEventListener() {
#Override
public void onDataChange(DataSnapshot dataSnapshot) {
for(DataSnapshot ds : dataSnapshot.getChildren()) {
String nama = ds.child("nama").getValue(String.class);
Log.d("TAG", nama);
}
Log.d("TAG", String.valueOf(dataSnapshot.getChildrenCount()));
}
#Override
public void onCancelled(DatabaseError databaseError) {}
};
demografiRef.addListenerForSingleValueEvent(valueEventListener);
The output in your logcat will be all the names of all your users. As you can see, there is a second log statement which will print the total number of your children.

Firebase realtime database - how to get parent name based on a value of one of its keys

The structure looks like this:
users
|----username1
|----uid:value
username2
|----uid:value
I'm trying to find the best way to get the username value based of the value of it's uid,
This need to be in Java code (Android), So far I found the following code:
Query uid = reference.child("users").orderByChild("uid").equalTo(uid);
uid.addListenerForSingleValueEvent(new ValueEventListener() {
#Override
public void onDataChange(DataSnapshot dataSnapshot) {
for(DataSnapshot datas: dataSnapshot.getChildren()){
String keys=datas.getKey();
if (keys.equals(uid)) {
// uid found
} else {
}
}
}
#Override
public void onCancelled(DatabaseError databaseError) {
}
});
Try this code and create a model class to fetch value of Uid
DatabaseReference users= FirebaseDatabase.getInstance().getReference().child("users");
users.orderByChild("uid").equalTo(uid).addListenerForSingleValueEvent(new ValueEventListener() {
#Override
public void onDataChange(DataSnapshot dataSnapshot) {
for(DataSnapshot post:dataSnapshot.getChildren()){
//Use a model class to fetch user id like below
UIDDetails u=post.getValue(UIDDetails.class);
String user_id=u.getUid();
//Here all values will be equal to youy required uid if exists more than one
}
}
#Override
public void onCancelled(DatabaseError databaseError) {
}
});
Please add below code into your file:
DatabaseReference users= FirebaseDatabase.getInstance().getReference().child("users");
final Query userQuery = users.orderByChild("uid");
userQuery.addChildEventListener(new ChildEventListener() {
#Override
public void onChildAdded(DataSnapshot dataSnapshot, String s) {
map.clear();
if(child.getkey().toString().equalsIgnoreCase(uid)){
//Get the node from the datasnapshot
String myParentNode = dataSnapshot.getKey();
for (DataSnapshot child: dataSnapshot.getChildren())
{
String key = child.getKey().toString();
String value = child.getValue().toString();
map.put(key,value);
}
}
}
#Override
public void onCancelled(DatabaseError databaseError) {
databaseError.toException();
}
});

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