initially my code was working fine but after working more on the project , I got this error [NoSuchMethodError: The method 'where' was called on null. Receiver: null Tried calling: where(Closure: (User) => bool) See also: https://flutter.dev/docs/testing/errors]

then I changed my a funtion and wrote this - ` buildSuggestions(String query) { final List suggestionList = query.isEmpty ? [] : userList != null ? userList.where((User user) { String _getUsername = user.username.toLowerCase(); String _query = query.toLowerCase(); String _getName = user.name.toLowerCase(); bool matchesUsername = _getUsername.contains(_query); bool matchesName = _getName.contains(_query);

  return (matchesUsername || matchesName);

  // (User user) => (user.username.toLowerCase().contains(query.toLowerCase()) ||
  //     (user.name.toLowerCase().contains(query.toLowerCase()))),
}).toList()
    : [];`

but still the search screen doesnt display the user it used to display intially

The getter 'uid' was called on null. Receiver: null Tried calling: uid

When the exception was thrown, this was the stack: #0 Object.noSuchMethod (dart:core-patch/object_patch.dart:53:5) #1 _HomeScreenState.initState. (package:skypeclone/screens/home_screen.dart:33:38) #2 SchedulerBinding._invokeFrameCallback (package:flutter/src/scheduler/binding.dart:1102:15) #3 SchedulerBinding.handleDrawFrame (package:flutter/src/scheduler/binding.dart:1049:9) #4 SchedulerBinding._handleDrawFrame (package:flutter/src/scheduler/binding.dart:957:5) ...

Below error message in mobile

java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{com.example.chatbee/com.example.chatbee.MainActivity}: java.lang.ClassNotFoundException: Didn't find class "com.example.chatbee.MainActivity" on path: DexPathList[[zip file "/data/app/com.example.chatbee-E19D9G7k3x6AXtBZL8pcrg==/base.apk"],nativeLibraryDirectories=[/data/app/com.example.chatbee-E19D9G7k3x6AXtBZL8pcrg==/lib/arm64, /data/app/com.example.chatbee-E19D9G7k3x6AXtBZL8pcrg==/base.apk!/lib/arm64-v8a, /system/lib64]] at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2876) at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3081) at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:78) at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:108) at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:68) at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1831) at android.os.Handler.dispatchMessage(Handler.java:106) at android.os.Looper.loop(Looper.java:201) at android.app.ActivityThread.main(ActivityThread.java:6823) at java.lang.reflect.Method.invoke(Native Method) at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:547) at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:873) Caused by: java.lang.ClassNotFoundException: Didn't find class "com.example.chatbee.MainActivity" on path: DexPathList[[zip file "/data/app/com.example.chatbee-E19D9G7k3x6AXtBZL8pcrg==/base.apk"],nativeLibraryDirectories=[/data/app/com.example.chatbee-E19D9G7k3x6AXtBZL8pcrg==/lib/arm64, /data/app/com.example.chatbee-E19D9G7k3x6AXtBZL8pcrg==/base.apk!/lib/arm64-v8a, /system/lib64]] at dalvik.system.BaseDexClassLoader.findClass(BaseDexClassLoader.java:171) at java.lang.ClassLoader.loadClass(ClassLoader.java:379) at java.lang.ClassLoader.loadClass(ClassLoader.java:312) at android.app.AppComponentFactory.instantiateActivity(AppComponentFactory.java:69) at androidx.core.app.CoreComponentFactory.instantiateActivity(CoreComponentFactory.java:43) at android.app.Instrumentation.newActivity(Instrumentation.java:1216) at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2864) ... 11 more

Recently, I cloned the Part - 6 - Search Screen UI and Functionality where I faced one error, that is occurring in the userList where the error says

[NoSuchMethodError: The method 'toLowerCase' was called on null. Receiver: null Tried calling: toLowerCase() See also: https://flutter.dev/docs/testing/errors Below I have attached the screenshot of the error too...

This error occurred after I changed the previous error issue code

I'm studying Flutter through your videos on Youtube. Before asking many thanks for your effort to making those videos.

Recently, I cloned the last part of yours of [Part - 10 - Emojis in Flutter | Skype Clone] and I've got an error saying that

[NoSuchMethodError: The method 'where' was called on null. Receiver: null Tried calling: where(Closure: (User) => bool) See also: https://flutter.dev/docs/testing/errors]

[Error message]

[User data in my Firebase cloud-store]

I tried to research for this error in a stack overflow case which seems to be similar with this error https://stackoverflow.com/questions/52046870/flutter-the-method-was-called-on-null It looks similar with this but I can't applicable this in my code, since I'm newbie in Flutter and Dart.

Could you help me out this??

Hi,

Thanks for this example project with agora sdk. I want some suggestions to solve my requirements.

1. How to get call duration in minutes between two users? As you are saving timestamp that is call starting time.

2. How to make voice call ? Already i tried by disable video. But it didn't work. AgoraRtcEngine.disableVideo();

3. It would be great if provide pickup layout when app is in background mode/close/kill mode.

4. Incoming ringtone while second user is receiving a call.

Pickup Screen only ends call for dialler(caller){only documents were deleted for caller not of receiver when call is being ended from receivers end even from after picking the call} please help i need help for this o solve i followed your code but the issues are regarding recievers end as from pick up screen we can't end the call for recieiver himself also after picking and pressing the end call button call only ends for caller not for receiver [when call is being ended from receivers end]

Hi everyone Can anybody tell me how to implement the calling feature when the app is closed or fone is locked? I've tried many methods but couldn't implement it . Please share some code if you have done this. Thanks

Consider removing your Agora App ID from the git repo and keeping it secret. It is always best to keep your app id confidential. This is just a friendly reminder.

type 'Future' is not a subtype of type 'FutureOr'

That is the error message that is coming out in the terminal.

Instead of showing a picture after I upload, it shows Url not found.

I tried the exact same step as mentioned in the tutorial as well.

Future makeCall({Call call}) async { try { print("line 1" + call.callerId); print("line 1" + call.receiverId);

  call.hasDialled = true;
  print("call.hasDialled set to true");
  Map<String, dynamic> hasDialledMap = call.toMap(call);
  print(hasDialledMap);
  call.hasDialled = false;
  print("call.hasDialled set to true");
  Map<String, dynamic> hasNotDialledMap = call.toMap(call);
  print(hasNotDialledMap);

  await Firestore.instance.collection(CALL_COLLECTION)
      .document(call.callerId)
      .setData(hasDialledMap);
  print("call object for caller has been set");
  await Firestore.instance.collection(CALL_COLLECTION)
      .document(call.receiverId)
      .setData(hasNotDialledMap);
  print("call object for receiver has been set");

  return true;
} catch (e) {
  print("madarchod firestore mein kuch problemwa hai");
  return false;
}

The same way my call.dart is :

class Call { String callerId; String callerName; String receiverId; String receiverName; String channelId; bool hasDialled;

Call({ this.callerId, this.callerName, // this.callerPic, this.receiverId, this.receiverName, // this.receiverPic, this.channelId, this.hasDialled, });

Map<String, dynamic> toMap(Call call) { Map<String, dynamic> callMap = Map(); callMap["caller_id"] = call.callerId; callMap["caller_name"] = call.callerName; // callMap["caller_pic"] = call.callerPic; callMap["receiver_id"] = call.receiverId; callMap["receiver_name"] = call.receiverName; // callMap["receiver_pic"] = call.receiverPic; callMap["channel_id"] = call.channelId; callMap["hasDialled"] = call.hasDialled; }

Call.fromMap(Map callMap) { this.callerId = callMap["caller_id"]; this.callerName = callMap["caller_name"]; // this.callerPic = callMap["caller_pic"]; this.receiverId = callMap["receiver_id"]; this.receiverName = callMap["receiver_name"]; // this.receiverPic = callMap["receiver_pic"]; this.channelId = callMap["channel_id"]; this.hasDialled = callMap["hasDialled"]; } }

Call_utilities file: import 'package:docapp/screens/callscreens/call_screen.dart'; import 'package:flutter/material.dart'; import 'package:docapp/resources/call_methods.dart'; import 'package:docapp/models/user.dart'; import 'package:docapp/models/call.dart'; import 'dart:math';

class CallUtils { static final CallMethods callMethods = CallMethods();

static dial({String senderName, User from, User to, context}) async { print("sender name is " + senderName); print("sender uid is " + from.uid); print("receiver uid is" + to.uid); print("receiver name is " + to.name);

Call call = Call(
  callerId: from.uid,
  callerName: senderName,

// callerPic: from.profilePhoto, receiverId: to.uid, receiverName: to.name, // receiverPic: to.profilePhoto, channelId: Random().nextInt(1000).toString(), );

bool callMade = await callMethods.makeCall(call: call);
if(callMade) {
  print("callMade tak gaya");
} else {
  print("call utils mein atak gaya");
}
call.hasDialled = true;

if(callMade) {
  Navigator.push(
    context,
    MaterialPageRoute(
      builder: (context) => CallScreen(call:  call),
    ));
}

} }

the error log : I/flutter ( 4548): sender name is abcdef I/flutter ( 4548): sender uid is eKsPXt5Nr4bkxYFW7SPaRXL4xh23 I/flutter ( 4548): receiver uid isaLSb7ebMfsfAxybrwq21kXjkcJM2 I/flutter ( 4548): receiver name is abhishek I/flutter ( 4548): line 1eKsPXt5Nr4bkxYFW7SPaRXL4xh23 I/flutter ( 4548): line 1aLSb7ebMfsfAxybrwq21kXjkcJM2 I/flutter ( 4548): line 1abcdef I/flutter ( 4548): line 1abhishek I/flutter ( 4548): call.hasDialled set to true I/flutter ( 4548): null I/flutter ( 4548): call.hasDialled set to true I/flutter ( 4548): null E/MethodChannel#plugins.flutter.io/cloud_firestore( 4548): Failed to handle method call E/MethodChannel#plugins.flutter.io/cloud_firestore( 4548): java.lang.NullPointerException: Provided data must not be null. E/MethodChannel#plugins.flutter.io/cloud_firestore( 4548): at b.d.c.a.j.a(:906) E/MethodChannel#plugins.flutter.io/cloud_firestore( 4548): at com.google.firebase.firestore.h.a(:161) E/MethodChannel#plugins.flutter.io/cloud_firestore( 4548): at com.google.firebase.firestore.h.a(:146) E/MethodChannel#plugins.flutter.io/cloud_firestore( 4548): at io.flutter.plugins.firebase.cloudfirestore.a.onMethodCall(:872) E/MethodChannel#plugins.flutter.io/cloud_firestore( 4548): at c.a.b.a.j$a.a(:226) E/MethodChannel#plugins.flutter.io/cloud_firestore( 4548): at io.flutter.embedding.engine.e.b.a(:85) E/MethodChannel#plugins.flutter.io/cloud_firestore( 4548): at io.flutter.embedding.engine.FlutterJNI.handlePlatformMessage(:631) E/MethodChannel#plugins.flutter.io/cloud_firestore( 4548): at android.os.MessageQueue.nativePollOnce(Native Method) E/MethodChannel#plugins.flutter.io/cloud_firestore( 4548): at android.os.MessageQueue.next(MessageQueue.java:325) E/MethodChannel#plugins.flutter.io/cloud_firestore( 4548): at android.os.Looper.loop(Looper.java:142) E/MethodChannel#plugins.flutter.io/cloud_firestore( 4548): at android.app.ActivityThread.main(ActivityThread.java:6541) E/MethodChannel#plugins.flutter.io/cloud_firestore( 4548): at java.lang.reflect.Method.invoke(Native Method) E/MethodChannel#plugins.flutter.io/cloud_firestore( 4548): at com.android.internal.os.Zygote$MethodAndArgsCaller.run(Zygote.java:240) E/MethodChannel#plugins.flutter.io/cloud_firestore( 4548): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:767) I/flutter ( 4548): madarchod firestore mein kuch problemwa hai I/flutter ( 4548): call utils mein atak gaya

E/flutter (11754): [ERROR:flutter/lib/ui/ui_dart_state.cc(186)] Unhandled Exception: NoSuchMethodError: The method '[]' was called on null. E/flutter (11754): Receiver: null E/flutter (11754): Tried calling: E/flutter (11754): #0 Object.noSuchMethod (dart:core-patch/object_patch.dart:54:5) E/flutter (11754): #1 new Users.fromMap (package:skypeclone/models/users.dart:33:23) E/flutter (11754): #2 FirebaseMethods.getUserDetails (package:skypeclone/resources/firebasemethods.dart:31:18) E/flutter (11754): E/flutter (11754): #3 UserProvider.refreshUser (package:skypeclone/provider/userprovider.dart:12:19) E/flutter (11754): E/flutter (11754):

E/RtcEngine( 5714): onEvent: java.lang.NullPointerException: Attempt to invoke virtual method 'java.lang.Object java.util.HashMap.put(java.lang.Object, java.lang.Object)' on a null object reference E/RtcEngine( 5714): onEvent: java.lang.NullPointerException: Attempt to invoke virtual method 'java.lang.Object java.util.HashMap.put(java.lang.Object, java.lang.Object)' on a null object reference E/RtcEngine( 5714): onEvent: java.lang.NullPointerException: Attempt to invoke virtual method 'java.lang.Object java.util.HashMap.put(java.lang.Object, java.lang.Object)' on a null object reference E/RtcEngine( 5714): onEvent: java.lang.NullPointerException: Attempt to invoke virtual method 'java.lang.Object java.util.HashMap.put(java.lang.Object, java.lang.Object)' on a null object reference

On the ChatListScreen, whenever there is a new message(received or sent), the chat that has the message does not automatically relocate to the top of the list

Hi Ronak99,

I have been facing these issues, which are "The getter 'name' was called on null. Receiver: null Tried calling: name" and same issue for the uid. The relevant widget causing this problem is the UserCircle.