[英]Firebase NullPointException when logging in
您好,我嘗試使用2個不同的用戶admin和user創建一個登錄auth的firebase。 但是就像我嘗試登錄時,該應用程序將崩潰。 我認為這是繼承人的錯誤
這是我登錄時的代碼
public class LoginActivity extends AppCompatActivity {
private EditText inputEmail, inputPassword;
private FirebaseAuth auth;
private ProgressBar progressBar;
private Button btnSignup, btnLogin, btnReset;
private DatabaseReference mFirebaseDatabase;
private FirebaseDatabase mFirebaseInstance;
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_login);
getSupportActionBar().setDisplayShowHomeEnabled(true);
getSupportActionBar().setIcon(R.mipmap.ic_launcher);
auth = FirebaseAuth.getInstance();
setContentView(R.layout.activity_login);
inputEmail = (EditText) findViewById(R.id.email);
inputPassword = (EditText) findViewById(R.id.password);
progressBar = (ProgressBar) findViewById(R.id.progressBar);
btnSignup = (Button) findViewById(R.id.btn_signup);
btnLogin = (Button) findViewById(R.id.btn_login);
btnReset = (Button) findViewById(R.id.btn_reset_password);
//db
mFirebaseInstance = FirebaseDatabase.getInstance();
//Get Firebase auth instance
auth = FirebaseAuth.getInstance();
btnSignup.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
startActivity(new Intent(LoginActivity.this, signup.class));
}
});
btnReset.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
startActivity(new Intent(LoginActivity.this, ResetPasswordActivity.class));
}
});
btnLogin.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
String email = inputEmail.getText().toString();
final String password = inputPassword.getText().toString();
if (TextUtils.isEmpty(email)) {
Toast.makeText(getApplicationContext(), "Enter email address!", Toast.LENGTH_SHORT).show();
return;
}
if (TextUtils.isEmpty(password)) {
Toast.makeText(getApplicationContext(), "Enter password!", Toast.LENGTH_SHORT).show();
return;
}
progressBar.setVisibility(View.VISIBLE);
//authenticate user
auth.signInWithEmailAndPassword(email, password)
.addOnCompleteListener(LoginActivity.this, new OnCompleteListener<AuthResult>() {
@Override
public void onComplete(@NonNull Task<AuthResult> task) {
// If sign in fails, display a message to the user. If sign in succeeds
// the auth state listener will be notified and logic to handle the
// signed in user can be handled in the listener.
progressBar.setVisibility(View.GONE);
if (!task.isSuccessful()) {
// there was an error
if (password.length() < 6) {
inputPassword.setError(getString(R.string.minimum_password));
} else {
Toast.makeText(LoginActivity.this, getString(R.string.auth_failed), Toast.LENGTH_LONG).show();
}
} else {
onAuthSuccess(task.getResult().getUser());
}
}
private void onAuthSuccess(FirebaseUser user) {
if (user !=null){
mFirebaseDatabase = FirebaseDatabase.getInstance().getReference().child("Users").child(user.getUid()).child("type");
mFirebaseDatabase.addListenerForSingleValueEvent(new ValueEventListener() {
@Override
public void onDataChange(DataSnapshot dataSnapshot) {
String value = dataSnapshot.getValue(String.class);
if(Integer.parseInt(value) == 1) {
startActivity(new Intent(LoginActivity.this, UserActivity.class));
Toast.makeText(LoginActivity.this, "Welcome User", Toast.LENGTH_SHORT).show();
finish();
}else {
startActivity(new Intent(LoginActivity.this, AdminActivity.class));
Toast.makeText(LoginActivity.this, "Welcome", Toast.LENGTH_SHORT).show();
finish();
}
}
@Override
public void onCancelled(DatabaseError databaseError) {
}
});
}
}
});
}
});
}
我覺得問題出在ondata更改之一上,但是我不知道該怎么做才能解決此問題,所以我向您尋求幫助:O
嘗試這個:
mFirebaseDatabase = FirebaseDatabase.getInstance().getReference().child("Accounts").child("Users").child(user.getUid());
mFirebaseDatabase.addListenerForSingleValueEvent(new ValueEventListener() {
@Override
public void onDataChange(DataSnapshot dataSnapshot) {
String value = dataSnapshot.child("type").getValue(String.class);
if(Integer.parseInt(value) == 1) {
startActivity(new Intent(LoginActivity.this, UserActivity.class));
Toast.makeText(LoginActivity.this, "Welcome User", Toast.LENGTH_SHORT).show();
finish();
}else {
startActivity(new Intent(LoginActivity.this, AdminActivity.class));
Toast.makeText(LoginActivity.this, "Welcome", Toast.LENGTH_SHORT).show();
finish();
}
}
嘗試上述操作,在userid
處具有引用,然后在onDataChange內檢索type
。 您需要按順序引用並指定子名稱,如下所示:
String value = dataSnapshot.child("type").getValue(String.class);
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