flutter - Exception caught by gesture. The getter 'email' was called on null

Question

I'm just working on the flash chat app and its already done but now there is an error in cloud firestore:

Exception caught by gesture

The following NoSuchMethodError was thrown while handling a gesture:
The getter 'email' was called on null.
Receiver: null
Tried calling: email

When the exception was thrown, this was the stack:
#0 Object.noSuchMethod (dart:core-patch/object_patch.dart:51:5)
#1 _ChatScreenState.build. (package:new_flashchat/screens/chat_screen.dart:73:48)
#2 _InkResponseState._handleTap (package:flutter/src/material/ink_well.dart:993:19)
#3 _InkResponseState.build. (package:flutter/src/material/ink_well.dart:1111:38)
#4 GestureRecognizer.invokeCallback (package:flutter/src/gestures/recognizer.dart:183:24)
...
Handler: "onTap"
Recognizer: TapGestureRecognizer#09030
debugOwner: GestureDetector
state: possible
won arena
finalPosition: Offset(351.6, 104.4)
finalLocalPosition: Offset(46.9, 16.4)
button: 1
sent tap down

W/z.new_flashcha( 2344): Accessing hidden method Ldalvik/system/CloseGuard;->close()V (greylist,core-platform-api, linking, allowed)

Answer 1

等待大神答复