PiN73

C:\Users\Pavel\AndroidStudioProjects\test_functional_widget>flutter build apk
You are building a fat APK that includes binaries for android-arm, android-arm64.
If you are deploying the app to the Play Store, it's recommended to use app bundles or split the APK to reduce the APK
size.
    To generate an app bundle, run:
        flutter build appbundle --target-platform android-arm,android-arm64
        Learn more on: https://developer.android.com/guide/app-bundle
    To split the APKs per ABI, run:
        flutter build apk --target-platform android-arm,android-arm64 --split-per-abi
        Learn more on:  https://developer.android.com/studio/build/configure-apk-splits#configure-abi-split

PiN73

C:\Users\Pavel\AndroidStudioProjects\test_functional_widget>flutter run
Using hardware rendering with device Android SDK built for x86. If you get graphics artifacts, consider enabling
software rendering with "--enable-software-rendering".
generating build script...                                         27,9s
starting build daemon...                                            0,9s
Launching lib\main.dart on Android SDK built for x86 in debug mode...
Initializing gradle...                                              1,5s
Resolving dependencies...                                           5,6s
starting build daemon...                                            0,3s

PiN73

C:\Users\Pavel\AndroidStudioProjects\test_functional_widget>flutter doctor
Doctor summary (to see all details, run flutter doctor -v):
[√] Flutter (Channel stable, v1.9.1+hotfix.6, on Microsoft Windows [Version 10.0.18362.418], locale ru-RU)

[√] Android toolchain - develop for Android devices (Android SDK version 29.0.2)
[√] Android Studio (version 3.5)
[√] Connected device (1 available)

• No issues found!

PiN73

void main() {
  Map<int, MapEntry<String, String>> m = {};
  m[5] = MapEntry("five", "5");
  print(m);
}

PiN73

import 'package:flutter/foundation.dart';

extension NumExtension on num {
  bool greaterThan(num other) => this > other;
}

class MyClass {
  final bool a;
  final bool b;
  final bool c;

PiN73

import 'package:flutter/material.dart';

void main() {
  runApp(MyApp());
}

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(

PiN73

import 'package:flutter/material.dart';

void main() {
  runApp(MyApp());
}

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(

PiN73

import 'package:flutter/material.dart';

void main() {
  runApp(MyApp());
}

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(

PiN73

import 'package:flutter/material.dart';

void main() {
  runApp(MyApp());
}

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(

PiN73

By default, <ItemsControl>/<ScrollViewer> doesn't use virtualization. All its items are rendered at once. This causes lags/freezing on first render and each re-render (for example, if list data or window size changes).

Adding ScrollViewer.CanContentScroll="True" will enable virtualization and make loading fast. But the list will be scrolled one whole item a time, which feels like jumping if items height is big enough.

To make virtualization enabled and keep smooth scrolling, add also VirtualizingPanel.ScrollUnit="Pixel"