небольшие изменения

android/app/build.gradle

@@ -27,7 +27,7 @@ apply plugin: 'kotlin-android'
 apply from: "$flutterRoot/packages/flutter_tools/gradle/flutter.gradle"
 
 android {
-    compileSdkVersion 30
+    compileSdkVersion 31
 
     compileOptions {
         sourceCompatibility JavaVersion.VERSION_1_8
@@ -45,7 +45,7 @@ android {
     defaultConfig {
         // TODO: Specify your own unique Application ID (https://developer.android.com/studio/build/application-id.html).
         applicationId "ru.sacmi.temperature_viewer"
-        minSdkVersion 19
+        minSdkVersion 23
         targetSdkVersion 30
         versionCode flutterVersionCode.toInteger()
         versionName flutterVersionName

lib/data/api/temperature_service_api.dart

@@ -14,10 +14,12 @@ class TemperatureServiceApiClient {
 
   Uri _getUri(String url, String path,
           {Map<String, dynamic>? queryParameters}) =>
-      Uri.http(url, path, queryParameters);
+      url.contains('http://')
+          ? Uri.http(url, path, queryParameters)
+          : Uri.https(url, path, queryParameters);
 
   Future<dynamic> getRawSensorsList(String url) async {
-    final uri = Uri.http(url, '/sensor/');
+    final uri = _getUri(url, '/sensor/');
     final sensorsResponse = await _httpClient.get(uri);
 
     if (sensorsResponse.statusCode != 200) {

lib/logic/cubit/settings/settings_cubit.dart

@@ -1,6 +1,5 @@
 import 'dart:convert';
 
-import 'package:bloc/bloc.dart';
 import 'package:equatable/equatable.dart';
 import 'package:hydrated_bloc/hydrated_bloc.dart';
 

lib/presentation/view/sensor_data_view.dart

@@ -32,6 +32,12 @@ class SensorDataView extends StatelessWidget {
               child: CircularProgressIndicator(),
             );
           } else if (state is SensorDataLoaded) {
+            if (state.sensorData.length < 2) {
+              return const Center(
+                child: Text("Мало данных для построения графика"),
+              );
+            }
+
             return ListView(
               children: [
                 ListTile(

lib/presentation/view/settings_view.dart

@@ -23,7 +23,8 @@ class SettingsView extends StatelessWidget {
             padding: const EdgeInsets.all(8.0),
             child: TextField(
               controller: textController,
-              decoration: const InputDecoration(labelText: 'Хост'),
+              decoration:
+                  const InputDecoration(labelText: 'Хост (с протоколом)'),
             ),
           ),
           ListTile(

pubspec.lock

@@ -28,7 +28,7 @@ packages:
       name: async
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "2.8.1"
+    version: "2.8.2"
   bloc:
     dependency: "direct main"
     description:
@@ -56,7 +56,7 @@ packages:
       name: characters
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.1.0"
+    version: "1.2.0"
   charcode:
     dependency: transitive
     description:
@@ -267,7 +267,7 @@ packages:
       name: graphic
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "0.4.1"
+    version: "0.6.0"
   hive:
     dependency: transitive
     description:
@@ -344,7 +344,7 @@ packages:
       name: matcher
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "0.12.10"
+    version: "0.12.11"
   meta:
     dependency: transitive
     description:
@@ -587,21 +587,21 @@ packages:
       name: test
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.17.10"
+    version: "1.17.12"
   test_api:
     dependency: transitive
     description:
       name: test_api
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "0.4.2"
+    version: "0.4.3"
   test_core:
     dependency: transitive
     description:
       name: test_core
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "0.4.0"
+    version: "0.4.2"
   timezone:
     dependency: transitive
     description:
@@ -622,7 +622,7 @@ packages:
       name: vector_math
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "2.1.0"
+    version: "2.1.1"
   vm_service:
     dependency: transitive
     description:
@@ -681,4 +681,4 @@ packages:
     version: "3.1.0"
 sdks:
   dart: ">=2.14.0 <3.0.0"
-  flutter: ">=2.5.0"
+  flutter: ">=2.6.0"

pubspec.yaml

@@ -36,7 +36,7 @@ dependencies:
     sdk: flutter
   flutter_bloc: ^7.3.3
   flutter_local_notifications: ^9.1.2
-  graphic: ^0.4.1
+  graphic: ^0.6.0
   http: ^0.13.4
   hydrated_bloc: ^7.1.0
   intl: ^0.17.0