Question

我正在尝试从Firebase中检索一些数据，但它不适用于我的某个节点

请注意，UnverifiedEmployees节点工作正常但“公司”节点不正常我能够在事件监听器之前看到Log RIGHT，但它内部没有打印出来我指的是这个区域：

public void addDataToFirebase() {

                Log.i("BEFORE", "BEFORE COMPANIES REF");
                companiesRef.addListenerForSingleValueEvent(new ValueEventListener() {
                    @Override
                    public void onDataChange(DataSnapshot dataSnapshot) {
                        Log.i("COMPANIESREF", "INSIDE COMPANIES REF ONDATACHANGE");

我在另一部手机上试过这个。我已经尝试过wifi和4g。我也尝试过登录其他用户我也尝试从手机上卸载应用程序并重新安装。我尝试过编写addListener的不同实现。我也尝试过查找，但没有找到很多（例如Android Firebase addListenerForSingleValueEvent not called）（Firebase Android addListenerForSingleValueEvent sometimes not returning data）

数据库:(如果存在UserID，请抓取与其相关的CompanyID）

代码的完整性：AddEmployeeActivity.java：

    public class AddEmployeeActivity extends Activity {

        private EditText firstNameET, lastNameET, phoneNumberET, emailET, ssnET;
        private ImageView checkmarkImage;

        private static FirebaseUser currentUser;
        private static final String TAG = "RealtimeDB";
        private FirebaseDatabase database;
        private DatabaseReference unverifiedRef, companiesRef;

        String emailKey, ssnKey, phoneKey, companyId;

        int num;
        private FirebaseMethods firebaseMethods;
        private Context mContext;

        ArrayList<EmployeeUser> myListItems;

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

            mContext = AddEmployeeActivity.this;

            firstNameET = (EditText) findViewById(R.id.firstNameET);
            lastNameET = (EditText) findViewById(R.id.lastNameET);
            phoneNumberET = (EditText) findViewById(R.id.phoneNumberET);
            emailET = (EditText) findViewById(R.id.emailET);
            ssnET = (EditText) findViewById(R.id.ssnET);

            checkmarkImage = (ImageView) findViewById(R.id.checkmarkImage);

            database = FirebaseDatabase.getInstance();
            unverifiedRef = database.getReference("/Unverified Employees");
            companiesRef = database.getReference("/Companies");
            currentUser =
                    FirebaseAuth.getInstance().getCurrentUser();

            checkmarkImage.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View view) {

                    final String email = emailET.getText().toString().trim();
                    final String ssn = ssnET.getText().toString().trim();
                    final String phone = phoneNumberET.getText().toString().trim();

                    //Add EditText info to Firebase UnverifiedEmployees Node
                    addDataToFirebase();               

                }
            });



        } //End of ONCREATE


        public void addDataToFirebase() {

            Log.i("BEFORE", "BEFORE COMPANIES REF");
            //companiesRef.addValueEventListener(new ValueEventListener(){
            companiesRef.addListenerForSingleValueEvent(new ValueEventListener() {
                @Override
                public void onDataChange(DataSnapshot dataSnapshot) {
                    Log.i("COMPANIESREF", "INSIDE COMPANIES REF ONDATACHANGE");

                    EmployeeUser user = new EmployeeUser();

                    for (DataSnapshot ds : dataSnapshot.getChildren()) {
                        for (DataSnapshot ds2 : ds.getChildren()) {
                            for (DataSnapshot ds3 : ds2.getChildren()) {
                                for (DataSnapshot ds4 : ds3.getChildren()) {
                                    for (DataSnapshot ds5 : ds4.getChildren()) {


                                        Log.i(TAG, "checkIfUsernameExists: datasnapshot: " + ds5);

                                        //user.setCompanyId(ds5.getValue(EmployeeUser.class).getCompanyId());
                                        user.setCompanyId(ds5.getValue(String.class));

                                        Log.i(TAG, "checkIfUsernameExists: ID: " + user.getCompanyId());
                                        //callback.gotDataSnapshot(dataSnapshot);

    if (user.getCompanyId() != null) {
                                            companyId = user.getCompanyId();
                                        }
                                    }
                                }
                            }

                        }
                    }


                }

                @Override
                public void onCancelled(DatabaseError databaseError) {
                    Log.i("Cancelled", "In onCancelled: " + databaseError);

                }
            //};
            }); //END OF ADDLISTENER

           // companiesRef.addListenerForSingleValueEvent(eventListener);


            emailKey = unverifiedRef.child(currentUser.getUid()).push().getKey();
            unverifiedRef.child(currentUser.getUid()).child(emailKey).child("emailAddress").setValue(emailET.getText().toString(), completionListener);
            Log.i("getKey EMAIL", emailKey);

            ssnKey = unverifiedRef.child(currentUser.getUid()).push().getKey();
            unverifiedRef.child(currentUser.getUid()).child(ssnKey).child("socialSecurityNumber").setValue(ssnET.getText().toString(), completionListener);
            unverifiedRef.child(currentUser.getUid()).child(ssnKey).child("CompanyID").setValue(companyId, completionListener);
            Log.i("getKey SSN", ssnKey);
            Log.i("get COMPANY ID", companyId);

            phoneKey = unverifiedRef.child(currentUser.getUid()).push().getKey();
            unverifiedRef.child(currentUser.getUid()).child(phoneKey).child("phoneNumber").setValue(phoneNumberET.getText().toString(), completionListener);
            Log.i("getKey Phone", phoneKey);

        }

Answer 1

你无法以你的方式实现这一目标。根据其中一个孩子的价值，您无法获得父母。换句话说，如果ID L4bs8bH5...下方存在RC9zI1...，则无法获得RewriteEngine On RewriteRule ^$ view/pages/login [L] RewriteRule (.*) view/pages/$1 [L]的值。要解决这个问题，您需要考虑使用非规范化，这是Firebase的常见做法。这意味着您需要复制数据才能获得这些结果。为此，我建议您看一下本教程Denormalization is normal with the Firebase Database，以便更好地理解。

因此，在这种情况下，您通常应考虑扩充数据结构以允许反向查找。例如，在您的方案中，我在userId下添加公司列表。这样做，您就可以查询属于单个用户的所有公司（如果存在的话）。

Firebase事件监听器从未触发过

1 个答案: