Firebase query inside the If-statement in flutter

Question

I am trying to do few checkpoint in my app, i am getting the data from the firebase and with that response i am adding a checkpoint based on this checkpoint i am trying to retrieve data from firebase and display it.

The issue i am facing is that when i using the firebase query inside the if-else statement both the statement are getting executed, since i have used the async for firebase it first executes the else statement.

how to overcome this issue, can anyone help me on this issue.

Below is my code.

await firestoreInstance.collection('quizes').get().then((querySnapshot) {
  querySnapshot.docs.forEach((doc) async {
    tempPin = doc.get('quizPin').toString();
    quizDocId = doc.get('quizid').toString();
    if (tempPin.contains(pin) && tempPin == pin){
    final sessionCheck = await firestoreInstance.collection('activesessions').get();
    if(sessionCheck.docs.length == 0){
      setState(() {
        _error = "session is not active";
      });
      print(_error);
    }}
    else
    {
      setState(() {
        _error = "You have Entered an Invalid Pin";
      });
      print(_error);
    }

my console output for this code

flutter: Invalid Pin
flutter: Invalid Pin
flutter: session is not active

Solution

I faced the same issue once, this is because of foreach loop which doesn't work properly with async functions, try replacing foreach with for in loop,

try this.

await firestoreInstance.collection('quizes').get().then((querySnapshot) async{
          for (final doc in querySnapshot.docs) {

            tempPin = doc.get('quizPin').toString();
            quizDocId = doc.get('quizid').toString();
            if (tempPin.contains(pin) && tempPin == pin){
            final sessionCheck = await firestoreInstance.collection('activesessions').get();
            if(sessionCheck.docs.length == 0){
              setState(() {
                _error = "session is not active";
              });
              print(_error);
            }}
            else
            {
              setState(() {
                _error = "You have Entered an Invalid Pin";
              });
              print(_error);
            }
}

Comments

[Elam]

Sorry for the late response. In this code both the if and else statement is executed, dont know y both the statement is executing.

[Sahil Hariyani]

Hi @Elam, I have updated the code. Can you try it once?