我要检查Firebase中是否存在用户mailkey（不带特殊字符“ @”和“。”的电子邮件地址）。如果是这样，则返回true。我在DatabaseProfileManager类中调用方法mailKeyExisting（）。这包含onDataChannge方法的async（这使我很麻烦）。实际上，问题是fireKey中存在mailKey，但它返回false。布尔值在方法中设置为true，但返回false，因为在构造函数中，我将其设置为false以防止NPE。如果Firebase包含布尔值，则布尔值将被设置为true，但是某个地方存在问题，并且此问题与异步事物有关。我在这里读了很多文章，现在我已经工作了好几天。
我尝试了CountdownLatch。我尝试过移动单行并更早地初始化了某些部分，但是那太荒谬了，只是愚蠢...我插入了很多Log.d（）...
DatabaseProfileManager
public class DatabaseProfileManager {
/**
* TODO [DONE] 1 Constructor with GoogleSignInAccount
* TODO [DONE] 2 Generate MailKey
* TODO [DONE] 3 Check if Firebase already contains this MailKey
* if not, return a false (rest will be handled in GoogleSignInActivity)
* if yes, return true (rest will be handled in GoogleSignInActivity)
**/
private GoogleSignInAccount account;
private DatabaseReference root;
private String mailKey;
private Boolean mailKeyExisting;
public DatabaseProfileManager(GoogleSignInAccount account) {
this.account = account;
this.root = FirebaseDatabase.getInstance().getReference("profiles");
this.mailKey = account.getEmail().replace("@", "").replace(".", "");
this.mailKeyExisting = false;
}
public Boolean mailKeyExisting() {
Log.d("HMDebugInfo", "DatabaseProfileManager.mailKeyExisting() method got called, it should return true or false");
root.addListenerForSingleValueEvent(new ValueEventListener() {
@Override
public void onDataChange(@NonNull DataSnapshot dataSnapshot) {
Log.d("HMDebugInfo", "DatabaseProfileManager.mailKeyExisting() --> onDataChange() got called, its a void");
if (dataSnapshot == null) {
Log.d("HMDebugInfo", "DatabaseProfileManager.mailKeyExisting() --> onDataChange(): dataSnapshot (from type DataSnapshot) is NULL");
} else {
Log.d("HMDebugInfo", "DatabaseProfileManager.mailKeyExisting() --> onDataChange(): dataSnapshot (from type DataSnapshot) is NOT NULL, so start checking if mailKey already exists");
if (dataSnapshot.hasChild(mailKey)) {
Log.d("HMDebugInfo", "DatabaseProfileManager.mailKeyExisting() --> onDataChange(): mailKey is already in FireBase, set mailKeyExisting (from type Boolean) to true");
mailKeyExisting = true;
} else {
Log.d("HMDebugInfo", "DatabaseProfileManager.mailKeyExisting() --> onDataChange(): mailKey is NOT in FireBase, set mailKeyExisting (from type Boolean) to false");
mailKeyExisting = false;
}
}
}
@Override
public void onCancelled(@NonNull DatabaseError databaseError) {
Log.d("HMDebugInfo", "DatabaseProfileManager.mailKeyExisting() --> onCancelled(): DatabaseError: " + databaseError.getMessage());
}
});
Log.d("HMDebugInfo", "Before return mailKeyExisting: " + mailKeyExisting);
return mailKeyExisting;
}
GoogleSignInActivity
public class GoogleSignInActivity extends AppCompatActivity implements GoogleApiClient.OnConnectionFailedListener {
public static final int REQ_CODE = 9001;
public static GoogleSignInAccount account;
public static DatabaseProfileManager dbProfile;
public Intent home;
public SignInButton btn_signin;
public GoogleApiClient client;
public GoogleSignInOptions options;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_google_sign_in);
getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN, WindowManager.LayoutParams.FLAG_FULLSCREEN);
getSupportActionBar().hide();
setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_PORTRAIT);
// Java Init
home = new Intent(this, HomeActivity.class);
options = new GoogleSignInOptions.Builder(GoogleSignInOptions.DEFAULT_SIGN_IN).requestEmail().build();
client = new GoogleApiClient.Builder(this).enableAutoManage(this, this).addApi(Auth.GOOGLE_SIGN_IN_API, options).build();
// UI INIT
btn_signin = findViewById(R.id.btn_login);
btn_signin.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
signIn();
}
});
}
@Override
public void onConnectionFailed(@NonNull ConnectionResult connectionResult) {
}
public void signIn() {
Intent intent = Auth.GoogleSignInApi.getSignInIntent(client);
startActivityForResult(intent, REQ_CODE);
}
public void handleResult(GoogleSignInResult result) {
if (result.isSuccess()) {
account = result.getSignInAccount();
/* String name = account.getDisplayName();
String email = account.getEmail();
editor.putString("loginToken", account.getIdToken());
editor.commit();*/
updateUI(true);
} else {
updateUI(false);
}
}
public void updateUI(Boolean isLoggedIn) {
if (isLoggedIn) {
dbProfile = new DatabaseProfileManager(account);
Boolean b = dbProfile.mailKeyExisting();
Intent home = new Intent(this, HomeActivity.class);
Intent profil = new Intent(this, ProfilActivity.class);
// TODO 1 entry is in Firebase, but mailKeyExisting() returns false
if (b) {
Log.d("HMDebugInfo", "GoogleSignInActivity.updateUI() if part");
startActivity(home);
finish();
} else {
Log.d("HMDebugInfo", "GoogleSignInActivity.mailKeyExisting returns: " + b);
Log.d("HMDebugInfo", "GoogleSignInActivity.updateUI() else part");
startActivity(home);
finish();
startActivity(profil);
Log.i("HMDebugInfo", "GoogleSignInActivity user has no or no complete entry");
}
} else {
Toast.makeText(this, "Login failed", Toast.LENGTH_LONG).show();
}
}
@Override
protected void onActivityResult(int requestCode, int resultCode, @Nullable Intent data) {
super.onActivityResult(requestCode, resultCode, data);
if (requestCode == REQ_CODE) {
GoogleSignInResult result = Auth.GoogleSignInApi.getSignInResultFromIntent(data);
handleResult(result);
}
}
登录后当前的日志输出：
D/HMDebugInfo: DatabaseProfileManager.mailKeyExisting() method got called, it should return true or false
D/HMDebugInfo: Before return mailKeyExisting: false
D/HMDebugInfo: GoogleSignInActivity.mailKeyExisting returns: false
D/HMDebugInfo: GoogleSignInActivity.updateUI() else part
I/HMDebugInfo: GoogleSignInActivity user has no or no complete entry
D/HMDebugInfo: onCreate(): init EditTexts and Button
D/HMDebugInfo: onCreate(): init databaseProfileManager (from type DatabaseProfileManager)
D/HMDebugInfo: DatabaseProfileManager.mailKeyExisting() --> onDataChange() got called, its a void
D/HMDebugInfo: DatabaseProfileManager.mailKeyExisting() --> onDataChange(): dataSnapshot (from type DataSnapshot) is NOT NULL, so start checking if mailKey already exists
D/HMDebugInfo: DatabaseProfileManager.mailKeyExisting() --> onDataChange(): mailKey is already in FireBase, set mailKeyExisting (from type Boolean) to true