flutter-animation

I am animating line in canvas in flutter.i am using AnimationController to control the animation. When i animate a single line, it is get animated without any lag or performance issue.But when i animate more than 10 lines it gets struck and lagging when rendering the line.In each frame redraw is getting called in order to animate the line .How to overcome this issue. Code Snippet class CrossPainter extends CustomPainter { Paint _paint; double _fraction; CrossPainter(this._fraction) { _paint = Paint() ..color = Colors.blue ..strokeWidth = 10.0 ..strokeCap = StrokeCap.round; } @override void

so I was following bloc login tutorial , and while I managed to complete it, I'm still fairly new to Flutter & Dart. There is a portion of the code where, depending on the state, the code returns a different widget, instead of a new Scaffold. Since it's not using routes, the transition between pages looks choppy and akward. return BlocProvider<AuthenticationBloc>( bloc: authenticationBloc, child: MaterialApp( debugShowCheckedModeBanner: false, home: BlocBuilder<AuthenticationEvent, AuthenticationState>( bloc: authenticationBloc, builder: (BuildContext context, AuthenticationState state) { if

I want to build a bottom sheet widget which is able to drag up to full screen. Can anyone tell me how to do this? Google map has a widget is able to do this. Here is the screenshot (check attached image): Before drag up: After drag up: Neither the modal nor the persistent bottomsheets can be dragged into view. The persistent bottomsheet must be triggered open (e.g., by pressing a button) & THEN it may be dragged up & down until finally out of view. I wish there was an option to allow it to be dragged into view... Rubber should meet your needs; I gave it a try but it always freaks out when I

I would like to change the child of some widget, and then see it animate to the new child's height, also with a fade transition. I can do that with AnimatedCrossFade , but then I must keep both firstChild and secondChild , which I cannot. If I use AnimatedSwitcher , it lets me simply change its child, but then it only animates the fade, not the size. The AnimatedContainer also doesn't work, since I don't know the size of the children in advance. Is there some widget I am missing that does what I need, and if not, how can I do that without resorting to AnimationController s? This solves the

I am learning Flutter allthought i dont know if it is right decition or not. Any way i want to use LinearProgressIndicator Component from Material Librery but i didnt get how to use it i tried this code: import 'dart:async'; import 'package:flutter/material.dart'; void main() { runApp(new MaterialApp( debugShowCheckedModeBanner: false, home: new MyApp(), )); } class MyApp extends StatefulWidget { @override MyAppState createState() => new MyAppState(); } class MyAppState extends State<MyApp> { @override Widget build(BuildContext context) { return new Scaffold( appBar: new AppBar( title: new

I am having trouble replicating a normal settings menu in Flutter. I am using an InkWell to try to create the splash effect that normally occurs when you tap on a settings option. The problem is that the splash effect appears way too fast compared to how it normally is. Basically, I just want to slow down the InkWell. It's possible to create what you wanted but it requires a custom splashFactory under InkWell class. As you see in the variables below, these are meant to be private values and they are not open to modification within classes. const Duration _kUnconfirmedSplashDuration = const