Question

我是Firebase的新手，我创建了我的第一个应用程序。

我有2个问题，我想得到一些帮助。

我已将Android Studio应用程序链接到Firebase项目，并为新用户的Sigup创建了代码。

SignupActivity.java

    package com.company.fbaseapp.activities;

    import android.content.Intent;
    import android.support.annotation.NonNull;
    import android.support.v7.app.AppCompatActivity;
    import android.os.Bundle;
    import android.util.Log;
    import android.view.View;
    import android.view.WindowManager;
    import android.widget.Button;
    import android.widget.EditText;
    import android.widget.ProgressBar;
    import android.widget.Toast;

    import com.google.android.gms.tasks.OnCompleteListener;
    import com.google.android.gms.tasks.Task;
    import com.google.firebase.auth.AuthResult;
    import com.google.firebase.auth.FirebaseAuth;
    import com.company.fbaseapp.R;

    public class SignupActivity extends AppCompatActivity {

        private static final String TAG = "SignupActivity";

        private EditText mUsername;
        private EditText mEmail;
        private EditText mPassword;

        private Button mSignup;

        private ProgressBar mProgressBar;

        @Override
        protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.activity_signup);

            //mUsername = (EditText) findViewById(R.id.input_username);

            mEmail = (EditText) findViewById(R.id.input_email);
            mPassword = (EditText) findViewById(R.id.input_password);
            mSignup = (Button) findViewById(R.id.btn_signup);

            mSignup.setOnClickListener(new View.OnClickListener() {

                @Override
                public void onClick(View view) {

                    Log.d(TAG, "onClick: attempting to signup.");

                    // Check for null valued EditText fields
                    if (!isEmpty (mEmail.getText().toString()) && !isEmpty (mPassword.getText().toString())) {

                        signupNewUser(mEmail.getText().toString(), mPassword.getText().toString());

                        //Toast.makeText(SignupActivity.this, "Thank you for signing up", Toast.LENGTH_SHORT).show();
                    }
                    else {
                        Toast.makeText(SignupActivity.this, "You must fill out all the fields", Toast.LENGTH_SHORT).show();
                    }

                }

            } );

            hideSoftKeyboard();

        }

        private void signupNewUser(String email, String password) {

            showDialog();

            FirebaseAuth.getInstance().createUserWithEmailAndPassword(email, password)
                    .addOnCompleteListener( new OnCompleteListener<AuthResult>() {

                        @Override
                        public void onComplete(@NonNull Task<AuthResult> task) {

                            Log.d(TAG, "onComplete: onComplete: " + task.isSuccessful());

                            if (task.isSuccessful()) {

                                Log.d(TAG, "onComplete: AuthState: " + FirebaseAuth.getInstance()
                                        .getCurrentUser()
                                        .getUid());

FirebaseUser currentperson=FirebaseAuth.getInstance().getCurrentUser();
                            DatabaseReference ref=FirebaseDatabase.getInstance().getReference().child("Users").child(currentperson.getUid());
                            ref.child("Username").setValue(name);

                                FirebaseAuth.getInstance().signOut();

                                redirectLoginScreen();

                            }
                            if (!task.isSuccessful()) {

                                Toast.makeText(SignupActivity.this, "Unable to signup", Toast.LENGTH_SHORT).show();

                            }

                        }

                    });

        }

        /**
         * Return true if the @param is null
         * @param string
         * @return
         */
        private boolean isEmpty(String string){
            return string.equals("");
        }

        /**
         * Redirects the user to the login screen
         */
        private void redirectLoginScreen(){
            Log.d(TAG, "redirectLoginScreen: redirecting to login screen.");

            Intent intent = new Intent(SignupActivity.this, LoginActivity.class);
            startActivity(intent);
            finish();
        }

        private void showDialog(){
            mProgressBar.setVisibility(View.VISIBLE);

        }

        private void hideDialog(){
            if(mProgressBar.getVisibility() == View.VISIBLE){
                mProgressBar.setVisibility(View.INVISIBLE);
            }
        }

        private void hideSoftKeyboard(){
            this.getWindow().setSoftInputMode(WindowManager.LayoutParams.SOFT_INPUT_STATE_ALWAYS_HIDDEN);
        }

    }

logcat的

12-30 01:19:18.492 31917-31917/com.company.fbaseapp D/SignupActivity: onClick: attempting to signup.
12-30 01:19:18.493 31917-31917/com.company.fbaseapp D/AndroidRuntime: Shutting down VM
12-30 01:19:18.497 31917-31917/com.company.fbaseapp E/AndroidRuntime: FATAL EXCEPTION: main

Process: com.company.fbaseapp, PID: 31917
java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.ProgressBar.setVisibility(int)' on a null object reference
at com.company.fbaseapp.activities.SignupActivity.showDialog(SignupActivity.java:126)
at com.company.fbaseapp.activities.SignupActivity.signupNewUser(SignupActivity.java:72)
at com.company.fbaseapp.activities.SignupActivity.access$300(SignupActivity.java:21)
at com.company.fbaseapp.activities.SignupActivity$1.onClick(SignupActivity.java:54)
at android.view.View.performClick(View.java:6289)
at android.view.View$PerformClick.run(View.java:24800)
at android.os.Handler.handleCallback(Handler.java:789)
at android.os.Handler.dispatchMessage(Handler.java:98)
at android.os.Looper.loop(Looper.java:164)
at android.app.ActivityThread.main(ActivityThread.java:6809)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.Zygote$MethodAndArgsCaller.run(Zygote.java:240)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:767)
12-30 01:19:18.499 31917-31917/com.company.fbaseapp D/AppTracker: App Event: crash

第一个问题是当我点击 mSignup 按钮时应用程序崩溃。

第二个问题是，我想知道如何为每个注册用户添加唯一用户名。

请帮我弄清楚如何解决这两个问题。

由于

Answer 1

这是错误：

`Attempt to invoke virtual method 'void android.widget.ProgressBar.setVisibility(int)' on a null object reference`

进度条为空，您需要添加：

mProgressBar = (ProgressBar) findViewById(R.id.progressBar); //your id in xml

关于每个用户的唯一用户名，您可以这样做：

 FirebaseUser currentperson=FirebaseAuth.getInstance().getCurrentUser();

然后，如果要保存到数据库，则可以执行以下操作：

      DatabaseReference ref=FirebaseDatabase.getInstance().getReference().child("Users");
   ref.child(currentperson.getUid());

以上内容将为每个用户名添加唯一的用户ID。

如果您要在身份验证中添加唯一的用户名，则无法执行此操作。但默认情况下，该电子邮件是唯一的，因此如果您尝试使用相同的电子邮件注册其他用户，那么您将获得error:authentication failed

编辑：

您无法在身份验证中添加username，如果您转到控制台，则会看到添加了userid和email。身份验证为您提供userid但无法在身份验证中添加用户名，只能在数据库中添加，可以执行此操作：

     DatabaseReference ref=FirebaseDatabase.getInstance().getReference().child("Users").child(currentperson.getUid());
   ref.child("Username").setValue(name);

然后在你的firebase数据库中你会得到这个：

    Users
         LA0rRvP4TrewYbMSl0bDA3ork8h2
                    Username: hisname_here

Firebase用户注册/使用用户名进行身份验证

1 个答案: