Android 向Firebase添加新项目后的ListView复制
我正在尝试将教师添加到firebase实时数据库，并在listView中检索教师，如下图所示： 但是，当添加一个新项目时，我两次检索到现有数据，一次检索到新数据，如下图所示： 此方法在ADMINHELPER中用于添加教师Android 向Firebase添加新项目后的ListView复制,android,firebase,listview,firebase-realtime-database,Android,Firebase,Listview,Firebase Realtime Database,我正在尝试将教师添加到firebase实时数据库，并在listView中检索教师，如下图所示： 但是，当添加一个新项目时，我两次检索到现有数据，一次检索到新数据，如下图所示： 此方法在ADMINHELPER中用于添加教师 private void addingteacher() { progressBar.setVisibility(View.VISIBLE); // opening the Custom dialog to get the information of
private void addingteacher() {
progressBar.setVisibility(View.VISIBLE);
// opening the Custom dialog to get the information of the new Teachers
Dialog mydialog = new Dialog(teacher_admin.this);
mydialog.setContentView(R.layout.addteachers);
mydialog.getWindow().setBackgroundDrawable(new ColorDrawable(Color.TRANSPARENT));
progressBar.setVisibility(View.GONE);
mydialog.show();
mydialog.setOnDismissListener(dialog -> progressBar.setVisibility(View.GONE));
// hooking all the views of the dialog
EditText teache5rName = mydialog.findViewById(R.id.teacherssname_dialogbox);
EditText registrationNumber = mydialog.findViewById(R.id.teachersReg_dialogbox);
EditText passwordteacher = mydialog.findViewById(R.id.teacherspassword_dialogbox);
EditText department = mydialog.findViewById(R.id.teachersDepartment_dialogbox);
EditText mobilenumber = mydialog.findViewById(R.id.teacherMobilenumber_dialogbox);
NeumorphButton addteachersButton = mydialog.findViewById(R.id.add_teachersDialog);
// when the add button on the dialog is pressed
addteachersButton.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
// dilog and progress bar
progressBar.setVisibility(View.VISIBLE);
//converting the edittext the String Literals
String tnamez = teache5rName.getEditableText().toString().trim();
String tregNu = registrationNumber.getEditableText().toString().trim();
String tpassw = passwordteacher.getEditableText().toString().trim();
String tdepartment = department.getEditableText().toString().trim();
String tmobileNum = "+91" + mobilenumber.getEditableText().toString().trim();
// validating the fields wheather they are empty or not
if (!validateFields(tnamez, tregNu, tpassw, tdepartment, tmobileNum)) {
// if empty then show a error custom dialog
donedialogboxMeathod(false);
progressBar.setVisibility(View.GONE);
return;
}
donedialogboxMeathod(true);
// where the teachers are under so the adding teacher fuction is in admin so
// adminhelper is created and called the function
AdminHelper adminHelper = new AdminHelper();
// adding the teacher
adminHelper.addTEachers(tnamez, tregNu, tpassw, "No", tdepartment,
"No", tmobileNum, "No");
// notifyin the adpater that we added new ber
teacher_adapter.notifyDataSetChanged();
// dissmissing the progressbar and Custom dialog
progressBar.setVisibility(View.GONE);
mydialog.dismiss();
}
});
public teachersHelper addteacher(String tName, String tregNumber, String tPassword,String
imageId, String tDepartment,String tEmail, String
tphoneNumber, String tadress) {
// creating the teachers Helper Class
teachersHelper teachersHelpers = new teachersHelper(tName, tregNumber, tPassword, imageId, tDepartment,
tEmail, tphoneNumber, tadress);
// database stuff
DatabaseReference teacherreferenc = FirebaseDatabase.getInstance().
getReference("Admin").child(mAuth.getUid()).child("INSTITUTE");
//adding value
teacherreferenc.child("TEACHERS").child(tregNumber).setValue(teachersHelpers);
return teachersHelpers;
}
public void设置视图（）{
//用于检索教师数据的Firebase变量
FirebaseAuth mAuth=FirebaseAuth.getInstance（）；
DatabaseReference DatabaseReference=FirebaseDatabase.getInstance（）
.getReference（“Admin”）.child（mAuth.getUid（））.child（“INSTITUTE”）
.儿童（“教师”）；
//教师与registrationNumber节点一起存储，因此我创建了一个arraylist
ArrayList RegistrationNumber=新的ArrayList（）；
//valueevent以重新修改数据
databasereference.addValueEventListener（新的ValueEventListener（）{
@凌驾
public void onDataChange（@NonNull DataSnapshot snapshot snapshot）{
//检查快照是否存在
if（snapshot.exists（））{
//拿到所有的注册号
对于（DataSnapshot regis:snapshot.getChildren（））{
//将注册号添加到arraylist
registrationnumber.add（regis.getKey（））；
}
//根据注册号的arraylist，我们将进行检索
//特定注册编号教师的数据
对于（int i=0；i数据库引用进行更改时，您的onDataChange
都会被调用，并在该路径上显示数据的完整快照。因此，即使只更改/添加/删除了一个子节点，快照也会包含所有其他节点（未修改）已添加到RegistrationNumber
的子节点
最简单的解决方案是清除onDataChange顶部的RegistrationNumber
public teachersHelper addteacher(String tName, String tregNumber, String tPassword,String
imageId, String tDepartment,String tEmail, String
tphoneNumber, String tadress) {
// creating the teachers Helper Class
teachersHelper teachersHelpers = new teachersHelper(tName, tregNumber, tPassword, imageId, tDepartment,
tEmail, tphoneNumber, tadress);
// database stuff
DatabaseReference teacherreferenc = FirebaseDatabase.getInstance().
getReference("Admin").child(mAuth.getUid()).child("INSTITUTE");
//adding value
teacherreferenc.child("TEACHERS").child(tregNumber).setValue(teachersHelpers);
return teachersHelpers;
}
public void settingViews(){
// Firebase variables to retreive the data of the teacher
FirebaseAuth mAuth = FirebaseAuth.getInstance();
DatabaseReference databasereference = FirebaseDatabase.getInstance()
.getReference("Admin").child(mAuth.getUid()).child("INSTITUTE")
.child("TEACHERS");
//the teachers are stored with the node of registrationNumber so i created a arraylist
ArrayList<String> registrattionNumber = new ArrayList<>();
// valueevent to retreving the data
databasereference.addValueEventListener(new ValueEventListener() {
@Override
public void onDataChange(@NonNull DataSnapshot snapshot) {
// cheching if the snapshot exists
if (snapshot.exists()) {
// getting all the registration Number
for (DataSnapshot regis : snapshot.getChildren()) {
// adding the registrationNumbers to the arraylist
registrattionNumber.add(regis.getKey());
}
// based on the arraylist of the registrationNUmber we will be retriving
// the data of teachers of particular registrartion Number
for (int i = 0; i < registrattionNumber.size(); i++) {
//firebase stuff
Query teacherssdata = FirebaseDatabase.getInstance()
.getReference("Admin").child(mAuth.getUid()).child("INSTITUTE")
.child("TEACHERS").child(registrattionNumber.get(i));
// value evnet listener
teacherssdata.addValueEventListener(new ValueEventListener() {
@Override
public void onDataChange(@NonNull DataSnapshot snapshot) {
if (snapshot.exists()) {
// retreiving all the teachers data from the snapshot
String _name = snapshot.child("tName").getValue().toString();
String _regno = snapshot.child("tregNumber").getValue().toString();
String _pass = snapshot.child("tPassword").getValue().toString();
String _img = snapshot.child("image").getValue().toString();
String _depart = snapshot.child("tDepartment").getValue().toString();
String _phonenumber = snapshot.child("tphoneNumber").getValue().toString();
String _adress = snapshot.child("tadress").getValue().toString();
String _emai = snapshot.child("tEmail").getValue().toString();
// creating the teacherclass and adding all the info from the firebase
teachersHelper teachersHelperzzzz = new
teachersHelper(_name, _regno, _pass, _img, _depart, _emai
, _phonenumber, _adress);
// adding the teacher objects to the Golbal Variable
teachersFromdatabase.add(teachersHelperzzzz);
// creating listview
// creating the adapter
teacher_adapter = new teacher_adapter(teacher_admin.this,
teachersFromdatabase);
// setting the adapter to the listview
listView.setAdapter(teacher_adapter);
progressBar.setVisibility(View.GONE);
} else {
progressBar.setVisibility(View.VISIBLE);
StyleableToast.makeText(teacher_admin.this, "Deleted Sucessfully"
, R.style.exampleToast).show();
}
}
@Override
public void onCancelled(@NonNull DatabaseError error) {
dialogboxMeathod(teacher_admin.this, error.getMessage());
}
});}
databasereference.addValueEventListener(new ValueEventListener() {
@Override
public void onDataChange(@NonNull DataSnapshot snapshot) {
registrattionNumber.clear();
...