How to navigate to the next Material page after getting Successful API response using Multipart requ-CodePudding

I believe response.statusCode == 200 from my Api because its printing Uploaded! How can I store my API response in a variable (Lets say "jsonResponse") so that I can pass it to my new MaterialPage DieticianAfterDateSelectPage?

The Error:

    The method '[]' was called on null.
Receiver: null
Tried calling: []("Status")
The relevant error-causing widget was
MaterialApp
lib\main.dart:19

      Future<void> SaveCustomTestBooking() async {


var jsonResponse;
if (EncUserId.isNotEmpty) {
   var postUri = Uri.parse("http://medbo.digitalicon.in/json/SaveCustomTestBooking");
  var request  = http.MultipartRequest('POST',postUri);
  request.fields['VisitDate'] = '_selectedDate';
  request.fields['EncUserId'] = 'EncUserId';

    request.files.add(new http.MultipartFile.fromBytes(
    "UserFile", File(image!.path).readAsBytesSync(),
    filename:"Image.jpg",
    contentType: MediaType('image', 'jpg')));

   request.send().then((response){
     if (response.statusCode == 200) {

       print("Uploaded!"); //From here.............
        Navigator.push(context, MaterialPageRoute(builder: (context) => DieticianAfterDateSelectPage(rresponse:DieticianEncBookingIdModel.fromJson(jsonResponse),)));
       
   } else {
    ScaffoldMessenger.of(context).showSnackBar(
        SnackBar(content: Text("Somthing went wrong")));
    throw Exception("Faild to fetch");

   }
   }


   );}

My variable image contain my gallery image after method call.

    final ImagePicker _picker = ImagePicker();
  File? image;
  var fileContent;
  var fileContentBase64;

Function to get image from gallery

    void filePicker() async {
final File? selectedImage =
    await ImagePicker.pickImage(source: ImageSource.gallery);
print(selectedImage!.path);
setState(() {
  image = selectedImage;
  
   fileContent = image!.readAsBytesSync();
   fileContentBase64 = base64.encode(fileContent); 
});
}

CodePudding user response：

It's not very clear how to help. I can see that you are passing a value to DieticianAfterDateSelectPage, and your error message. But you are asking how to store the value in a variable!

What you probably need is to understand the error message. You are getting it because you are calling the [] operator on null. You need to check how that's happening, and check the line number 19 in your main.dart as in the error message.

CodePudding user response：

This is how I print my Multipart request body

   Future<void> SaveCustomTestBooking() async {
var jsonResponse;
if (EncUserId.isNotEmpty) {
  var response = http.MultipartRequest('POST',Uri.parse("http://myApiTestBooking"));

  response.fields['VisitDate'] = _selectedDate;
  response.fields['EncUserId'] = EncUserId;
  response.fields['Description'] = testTextController.text;

  response.files.add(new http.MultipartFile.fromBytes(
    "UserFile", File(image!.path).readAsBytesSync(),
    filename:"Image.jpg",
    contentType: MediaType('image', 'jpg')));



  response.send().then((response) async {
  if (response.statusCode == 200){
    isApiCallProcess = false;
    final respBody = await response.stream.bytesToString();// this is how we print body for Multipart request
     jsonResponse = json.decode(respBody.toString());
    print(respBody);
    print("Uploaded!");

    ScaffoldMessenger.of(context).showSnackBar(
        SnackBar(
          content: Text("Booked"),
          backgroundColor: Color(0xFF00b3a4),
          ));

       //  Navigator.push(context,new MaterialPageRoute( builder: (context) =>new MyTestReqDetailsPage(),));
         Navigator.push(context,new MaterialPageRoute( builder: (context) =>new Home2(),));

  } 
});


}
}