Android firebase创建帐户

Question

I don't know how to write the if statement if I want to check if the account had been create or not. Here is my code. I don't know how to judge if it is existed or not. Please help me to solve it.

public class MainActivity extends AppCompatActivity {

DatabaseReference mRef = FirebaseDatabase.getInstance().getReference();
private Button Go;
private EditText account;
private EditText password;
private EditText pass2;
private FirebaseAuthException mAuth;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    account = (EditText) findViewById(R.id.editText);
    password = (EditText) findViewById(R.id.editText2);
    pass2 = (EditText) findViewById(R.id.editText3);
    Go = (Button) findViewById(R.id.button2);
    Go.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            startSignin();
            Intent intent = new Intent();
            intent.setClass(MainActivity.this,MemberCenter.class);
            startActivity(intent);
        }
    });
}

    private void startSignin(){
        String value = account.getText().toString();
        String mvalue = password.getText().toString();
        String two = pass2.getText().toString();

        if(mvalue.equals("")||value.equals(""))
        {
            Toast.makeText(getApplicationContext(),"cant be empty!",Toast.LENGTH_LONG).show();
        }
        else if(!mvalue.equals(two))
        {
            Toast.makeText(getApplicationContext(),"password are different",Toast.LENGTH_LONG).show();
        }

I don't know how to type this code.

        else if(mRef==null)
        {
            Toast.makeText(getApplicationContext(),"account is existed",Toast.LENGTH_LONG).show();
        }
        else{
            mRef.child("Account").child(value).setValue(mvalue);
        }

}

}

Answer 1

To check if the user is authenticated ie it is in your list of users in Firebase Account or not just use this.

FirebaseAuth auth=FirebaseAuth.getInstance();
if(auth!=null){
   //account exist
   //do your work here
   checkIfUserExists();

}
else {
   //account does not exist.You may exit the app or do whatever you want
}

void checkIfUserExists(){
    FirebaseAuth mFirebaseAuth=FirebaseAuth.getInstance();
    mFirebaseAuth.createUserWithEmailAndPassword(email,password)
            .addOnCompleteListener(this, new OnCompleteListener<AuthResult>() {
                @Override
                public void onComplete(@NonNull Task<AuthResult> task) {
                    if(task.isSuccessful()){
                        //User registered successfully
                    }else{
                        Log.e("Response","Failed to create user:"+task.getException().getMessage());
                    }
                }
            });
}

This should do the trick.