1

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 2 种用户（学生、教师）重定向到他们各自的活动，他们使用下面的代码全部登录后，我的用户到目前为止 但现在我必须添加另一个用户（管理员），并且像其他用户一样，管理员也是登录后应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我的代码感到困惑。

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");
            }


        }
    };
4

3 回答 3

1

使用 onlyeif (dataSnapshot.exists())不会解决您的 3 类用户问题。假设第三个用户的类型是3，则需要更改您的数据库结构。因此，您的新数据库架构应如下所示：

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

现在您应该在节点上添加一个侦听uid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);
于 2018-10-24T04:40:16.707 回答
0

这是我使用 Kotlin 的最终代码，它运行良好。

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()
                }
于 2021-07-12T20:24:39.527 回答
0

您需要另一个数据结构，使用usersand 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）。

正如你所拥有的，你可以简单地删除else分支并查询所有三个节点。

于 2018-10-19T15:26:25.797 回答