So i'm new to android studio and firebase and i'm doing an android application where i am required to create user roles to see different features in the app (client & trainer). I know that this isn't available through firebase authentication so i was advised to insert the user details into the database and assign/access roles from there. I'm trying to make the database look something like this...
How i'm trying to structure the real-time database (manually added to database)
//Where 'User1Email' can be either email of user or user id (as i think you cannot include @ into database)
However my code seems to be crashing the application. The way i've tried to input the data in my .java file looks like this..
//ESTABLISH THE CONNECTIONS TO DATABASE AND GET TE USER ID
FirebaseUser user = FirebaseAuth.getInstance().getCurrentUser();
String uid = user.getUid();
FirebaseDatabase database = FirebaseDatabase.getInstance();
final DatabaseReference mRef = database.getReference("users");
EditText emailField = findViewById(R.id.email);
EditText passwordField = findViewById(R.id.password);
//Get email and password from text views
final String email = emailField.getText().toString();
final String password = passwordField.getText().toString();
mRef.child("password").setValue(password);
mRef.child("role").setValue("Trainer");
// I DID ALSO TRY THIS BUT UID STAYS UNDERLINED RED- mRef.child(uid).child("password").setValue(password);
ERROR:
E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.example.finalyearapp, PID: 13903
java.lang.IllegalStateException: Could not execute method for android:onClick
at androidx.appcompat.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:402)
at android.view.View.performClick(View.java:6597)
at android.view.View.performClickInternal(View.java:6574)
at android.view.View.access$3100(View.java:778)
at android.view.View$PerformClick.run(View.java:25885)
at android.os.Handler.handleCallback(Handler.java:873)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:193)
at android.app.ActivityThread.main(ActivityThread.java:6669)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:493)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:858)
Caused by: java.lang.reflect.InvocationTargetException
at java.lang.reflect.Method.invoke(Native Method)
at androidx.appcompat.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:397)
at android.view.View.performClick(View.java:6597)
at android.view.View.performClickInternal(View.java:6574)
at android.view.View.access$3100(View.java:778)
at android.view.View$PerformClick.run(View.java:25885)
at android.os.Handler.handleCallback(Handler.java:873)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:193)
at android.app.ActivityThread.main(ActivityThread.java:6669)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:493)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:858)
Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'java.lang.String com.google.firebase.auth.FirebaseUser.getUid()' on a null object reference
at com.example.finalyearapp.SignUpActivity.onClick(SignUpActivity.java:53)
at java.lang.reflect.Method.invoke(Native Method)
at androidx.appcompat.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:397)
at android.view.View.performClick(View.java:6597)
at android.view.View.performClickInternal(View.java:6574)
at android.view.View.access$3100(View.java:778)
at android.view.View$PerformClick.run(View.java:25885)
at android.os.Handler.handleCallback(Handler.java:873)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:193)
at android.app.ActivityThread.main(ActivityThread.java:6669)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:493)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:858)
You must authenticate an user before getting his instance.
To make sure that user is logged before doing anything, call getCurrentUser() method in
createUserWithEmailAndPassword() (if you are using email and password authentication).
First of all create and initialize a Firebase Auth object :
FirebaseAuth mAuth = FirebaseAuth.getInstance();
Then when you want to sign up (supposed with a button) call createUserWithEmailAndPassword() method :
mAuth.createUserWithEmailAndPassword(email, password)
.addOnCompleteListener(this, new OnCompleteListener<AuthResult>() {
@Override
public void onComplete(@NonNull Task<AuthResult> task) {
if (task.isSuccessful()) {
//Successfully created user
FirebaseUser user = FirebaseAuth.getInstance().getCurrentUser();
String uid = user.getUid();
FirebaseDatabase database = FirebaseDatabase.getInstance();
final DatabaseReference mRef = database.getReference("users");
EditText emailField = findViewById(R.id.email);
//Get email from EditText
final String email = emailField.getText().toString();
mRef.child("role").setValue("Trainer");
} else {
//User not created,
//Print exception
Log.e("Sign up", task.getException().getMessage())
//Write your code to handle user creation fail
}
}
});
If you want to learn more of Firebase Authentication, look here
Remember that this solution is only for users creation.
Hope it helps! Write a comment to more explanation or if you have another question!