为什么我不能将数组上的第一条和最后一条记录记录到 Firestore

Question

我正在尝试在 Firebase Firestore 上注册 20 个用户并在我的集合中为每个用户创建一个文档。我的程序成功注册了 20 个用户，但在为他们创建文档时失败了。 18, 每次创建 19 个文档，但它几乎总是跳过为我的数组的第一个成员和最后一个成员创建一个文档。 StudentCreator 只是一个文件，它有一个父数组，有 20 个项目的学生数组。 这是一个来自 studentCreator.java 的数组

public static String parent_names[]={ "Ahmet Lola", "Hüseyin Kutlutürk", "Ümit Uğrak", "Veysel Karani", "Serkan Gotar", "Dündar Zalim", "Kadir Berkay", "Uğur Özdemir", "Bünyamin Akgün", "Kaptan Price", "Selim Tekiner", "Gökçe Yılan", "Talip Özkan", "Abdurrahman Tarikçi", "Selim Kirlier", "Hasan Can Doğan", "Erdem Gökşen", "Fatoş Ünal", "Nurgül Birtek", "Yuan Hui"};

这里是主要代码：

    public class MainActivity extends AppCompatActivity {
private static final String TAG = "MainActivity";
private FirebaseAuth mAuth;
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    final Intent LoginActivity = new Intent(this,LoginActivity.class);
    final Intent TeacherActivity = new Intent(this,TeacherActivity.class);
    final Intent ParentActivity = new Intent(this,ParentActivity.class);
    final Intent ManagerActivity = new Intent(this,ManagerActivity.class);


    for (int i = 0; i < 20; i++)
    {
        mAuth = FirebaseAuth.getInstance();
        final String username = StudentCreator.parent_names[i].replaceAll(" ", "") + StudentCreator.student_numbers[i];
        final String email = username + "@onurmail.com";
        final String password = "123456";

        final String student_name = StudentCreator.student_names[i];
        final String parent_name = StudentCreator.parent_names[i];
        //Registration is successul here.
        mAuth.createUserWithEmailAndPassword(email, password)
                .addOnCompleteListener(this, new OnCompleteListener<AuthResult>() {
                    @Override
                    public void onComplete(@NonNull Task<AuthResult> task) {
                        if (task.isSuccessful()) {
                            // Sign in success, update UI with the signed-in user's information
                            Log.d("User Registered", "createUserWithEmail:success");

                            final FirebaseUser user = mAuth.getCurrentUser();
                            final String user_id = user.getUid();
                            //I get valid userId's for 20 users.
                            //CREATE STUDENT OBJECT AND FIREBASE INSTANCES
                            final FirebaseFirestore db = FirebaseFirestore.getInstance();

                            final Map<String, Object> student = new HashMap<>();
                            student.put("student_name", student_name);
                            student.put("parent_name", parent_name);
                            //My first element of array comes here and prints its parent name and student name perfectly but cant see anything about it on database.
                            //PUT STUDENT TO THE DB
                            db.collection("TED_Ankara")
                                    .document(parent_name)
                                    .set(student)
                                    .addOnCompleteListener(new OnCompleteListener<Void>() {
                                        @Override
                                        public void onComplete(@NonNull Task<Void> task) {
                                            if (task.isSuccessful()) {
                                                Toast.makeText(getApplicationContext(), "User  inserted sucessfully: "+parent_name,
                                                        Toast.LENGTH_SHORT).show();

                                            }
                                            else {
                                                Toast.makeText(getApplicationContext(), "User cannot be inserted: "+parent_name,
                                                        Toast.LENGTH_SHORT).show();
                                            }

                                        }
                                    });

                            //PUT STUDENT TO THE DB



                        } else {
                            // If sign in fails, display a message to the user.
                            Log.w(TAG, "createUserWithEmail:failure", task.getException());
                            Toast.makeText(getApplicationContext(), "Authentication failed.",
                                    Toast.LENGTH_SHORT).show();
                        }

                    }

                });

    }
  }
}

请帮忙。我对 addOnCompleteListener 和 firebaseAuth 的使用持怀疑态度。但我不确定。感谢您的帮助。

编辑：在没有 for 循环的情况下添加第一个成员没有任何问题。所以我想问题出在 for 循环上。

Answer 1

Firebase SDK 只能有一个活跃用户。由于您在所谓的紧密循环中运行数组，我怀疑您可能正在创建下一个用户，在代码开始为前一个用户编写文档之前。为了验证这是否确实是问题，您可以尝试看看这是否解决了它？

添加创建用户的函数

void createNextUser(List<String> student_names, List<String> student_numbers, List<String> parent_names) {
  if (student_names.size() > 0 && student_numbers.size() > 0 && parent_names.size() > 0) {
    final String student_name = student_names.remove(0);
    final String student_number = student_numbers.remove(0);
    final String parent_name = parent_names.remove(0);
    final String username = parent_name.replaceAll(" ", "") + student_number;
    final String email = username + "@onurmail.com";
    final String password = "123456";


    mAuth.createUserWithEmailAndPassword(email, password)
        .addOnCompleteListener(this, new OnCompleteListener<AuthResult>() {
            @Override
            public void onComplete(@NonNull Task<AuthResult> task) {
                if (task.isSuccessful()) {
                    // Sign in success, update UI with the signed-in user's information
                    Log.d("User Registered", "createUserWithEmail:success");

                    final FirebaseUser user = mAuth.getCurrentUser();
                    final String user_id = user.getUid();
                    //I get valid userId's for 20 users.
                    //CREATE STUDENT OBJECT AND FIREBASE INSTANCES
                    final FirebaseFirestore db = FirebaseFirestore.getInstance();

                    final Map<String, Object> student = new HashMap<>();
                    student.put("student_name", student_name);
                    student.put("parent_name", parent_name);
                    //My first element of array comes here and prints its parent name and student name perfectly but cant see anything about it on database.
                    //PUT STUDENT TO THE DB
                    db.collection("TED_Ankara")
                            .document(parent_name)
                            .set(student)
                            .addOnCompleteListener(new OnCompleteListener<Void>() {
                                @Override
                                public void onComplete(@NonNull Task<Void> task) {
                                    if (task.isSuccessful()) {
                                        Toast.makeText(getApplicationContext(), "User  inserted sucessfully: "+parent_name,
                                                Toast.LENGTH_SHORT).show();

                                    }
                                    else {
                                        Toast.makeText(getApplicationContext(), "User cannot be inserted: "+parent_name,
                                                Toast.LENGTH_SHORT).show();
                                    }

                                    // Now that we're done with this user, move on to the next one
                                    createNextUser(student_names, student_number, parent_names);
                                }
                            });

                } else {
                    // If sign in fails, display a message to the user.
                    Log.w(TAG, "createUserWithEmail:failure", task.getException());
                    Toast.makeText(getApplicationContext(), "Authentication failed.",
                            Toast.LENGTH_SHORT).show();
                }

            }

        });    
  }
}

此代码的最大区别在于，它仅在创建前一个用户及其文档后才开始创建下一个用户。它通过以下方式做到这一点：

1. 在开始时从列表中删除当前学生

   final String student_name = student_names.remove(0);
   final String student_number = student_numbers.remove(0);
   final String parent_name = parent_names.remove(0);
   

2. 写完文档后调用自己

   // Now that we're done with this user, move on to the next one
   createNextUser(student_names, student_number, parent_names);
   

现在剩下要做的就是在您的onCreate 中启动进程：

createNextUser(Arrays.asList(StudentCreator.student_names), Arrays.asList(StudentCreator.student_numbers), Arrays.asList(StudentCreator.parent_names));

---

注意：为其他用户创建帐户是一项管理操作，因此通常不应从 Android 客户端执行。我强烈建议查看Firebase Admin SDK，它对此类操作有更好的支持。它必须在受信任的环境中使用，而不是在 Android 应用程序中使用，例如您的开发机器、您控制的服务器或 Cloud Functions。