java如何将多种类型的用户重定向到各自的活动？

Question

我正在Firebase上创建一个投票应用程序。我有3种类型的用户。到目前为止，我可以成功地将两种用户（学生、教师）重定向到各自的活动，在他们使用下面的代码登录之后，MY Users so far 但现在我必须添加另一个用户（管理员），和其他用户一样，管理员也应该在登录后重定向到他们自己的特定活动。我对如何为第三个用户修改代码感到困惑

mAuthListener = new FirebaseAuth.AuthStateListener() {
        @Override
        public void onAuthStateChanged(FirebaseAuth firebaseAuth) {
            FirebaseUser firebaseUser = FirebaseAuth.getInstance().getCurrentUser();
            if (mAuth.getCurrentUser() != null) {

                String uid = mAuth.getInstance().getCurrentUser().getUid();
                DatabaseReference rootRef = FirebaseDatabase.getInstance().getReference();
                uidRef = rootRef.child("STUDENTS").child(uid);

                ValueEventListener valueEventListener = new ValueEventListener() {
                    @Override
                    public void onDataChange(com.google.firebase.database.DataSnapshot dataSnapshot) {
                        if (dataSnapshot.exists()) {
                            //start students activity
                            startActivity(new Intent(MainActivity.this, student.class));

                        } else {
                            //start teachers activity
                            startActivity(new Intent(MainActivity.this, teacher.class));
                        }
                    }

                    //
                    @Override
                    public void onCancelled(DatabaseError databaseError) 
                    {
                    }
                };


uidRef.addListenerForSingleValueEvent(valueEventListener);

            }
            else{
                Log.d("TAG", "firebaseUser is null");
            }


        }
    };

Answer 1

您需要另一个数据结构，带有users和roles/admin，roles/teacher，roles/student，然后检查哪个节点具有密钥（也与安全规则兼容）

现在，您可以简单地删除else分支并查询所有三个节点

Answer 2

这是我使用Kotlin的最后一段代码，它工作得非常好

mAuth.signInWithEmailAndPassword(Email, Password).addOnCompleteListener { task ->
                if (task.isSuccessful) {



                    val uid = FirebaseAuth.getInstance().currentUser!!.uid
                    val rootRef = FirebaseDatabase.getInstance().reference
                    val uidRef = rootRef.child("Users").child(uid)
                    val spin: String = userchioce.selectedItem.toString()
                val valueEventListener: ValueEventListener = object : ValueEventListener {
                    override fun onDataChange(dataSnapshot: DataSnapshot) {
                        when {
                                dataSnapshot.child("users").getValue(String::class.java) == "Admin" -> {
                                    if (spin.equals("Admin")){
                                val intent = Intent(this@Login, Admin::class.java)
                                startActivity(intent)}
                                    else{
                                        Toast.makeText(this@Login, "Select Your User-Type", Toast.LENGTH_SHORT)
                                            .show()
                                    }
                            }

                            dataSnapshot.child("users").getValue(String::class.java) == "Lecturer" -> {
                                if (spin.equals("Lecturer")) {
                                    val intent = Intent(this@Login, Lecturer::class.java)
                                    startActivity(intent)
                                }else{
                                    Toast.makeText(this@Login, "Select Your User-Type", Toast.LENGTH_SHORT)
                                        .show()
                                }
                            }
                            dataSnapshot.child("users").getValue(String::class.java) == "Parent" -> {
                                if (spin.equals("Parent")) {
                                    val intent = Intent(this@Login, Parent::class.java)
                                    startActivity(intent)
                                }else{
                                    Toast.makeText(this@Login, "Select Your User-Type", Toast.LENGTH_SHORT)
                                        .show()
                                }
                            }
                            dataSnapshot.child("users").getValue(String::class.java) == "Student" -> {
                                if (spin.equals("Student")) {
                                    val intent = Intent(this@Login, Student::class.java)
                                    startActivity(intent)
                                }else{
                                    Toast.makeText(this@Login, "Select Your User-Type", Toast.LENGTH_SHORT)
                                        .show()
                                }
                            }
                        }
                    }

                    override fun onCancelled(databaseError: DatabaseError) {
                        Log.d(TAG, databaseError.message)
                    }
                }
                uidRef.addListenerForSingleValueEvent(valueEventListener)
                    progressDialog.dismiss()
                }

Answer 3

使用onlyeif (dataSnapshot.exists())无法解决3种类型的用户问题。假设第三个用户的类型为3，则需要更改数据库结构。因此，您的新数据库架构应该如下所示：

Firebase-root
    |
     - users
          |
           - uidOne
          |     |
          |      - name: "Ed"
          |     |
          |      - type: 1
          |
           - uidTwo
          |     |
          |      - name: "Tyff"
          |     |
          |      - type: 2
          |
           - uidOne
                |
                 - name: "Admin"
                |
                 - type: 3

现在，您应该在uid节点上添加一个侦听器，并检查用户的类型，如下所示：

String uid = FirebaseAuth.getInstance().getCurrentUser().getUid();
DatabaseReference rootRef = FirebaseDatabase.getInstance().getReference();
DatabaseReference uidRef = rootRef.child("users").child(uid);
ValueEventListener valueEventListener = new ValueEventListener() {
    @Override
    public void onDataChange(DataSnapshot dataSnapshot) {
        if(dataSnapshot.child("Type").getValue(Long.class) == 1) {
            startActivity(new Intent(MainActivity.this, student.class));
        } else if (dataSnapshot.child("TYPE").getValue(Long.class) == 2) {
            startActivity(new Intent(MainActivity.this, teacher.class));
        } else if (dataSnapshot.child("TYPE").getValue(Long.class) == 3) {
            startActivity(new Intent(MainActivity.this, admin.class));
        }
    }

    @Override
    public void onCancelled(@NonNull DatabaseError databaseError) {
        Log.d(TAG, databaseError.getMessage());
    }
};
uidRef.addListenerForSingleValueEvent(valueEventListener);