Examples of Async-Await

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Fri Sep 11 2020 07:50:15 GMT+0000 (UTC)

Saved by @darshjain #dart

//I think your understanding of Promises and async/await is not correct.
//When you make a function async, the await keyword before a promise make sure
//that code execution will pause until the promise fulfilled or rejected. 
//Your code can be simplified:

var currentPromise;

async function asyncFunc(promise){
    // Do some code here
    return await promise;
}

function anotherFunction(){
    asyncFunc(currentPromise);
}
//When we are calling return await promise, the execution engine waits in a
//non-blocking way until the promise fulfilled or rejected, and then it returns 
//the output to the anotherFunction function.

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Asyn-Await

@darshjain

Examples of Async-Await

#android #dart #flutter #ios #helloworld

All the code you need to run Hello World in Flutter using a Stateless widget

import 'package:flutter/material.dart';

void main() {
  runApp(
    new MaterialApp(
      title: 'Hello World App',
      home: new myApp(),
    )
  );
}

class myApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return new Scaffold(
      appBar: new AppBar(
        title: new Text('Hello World App'),
      ),
      body: new Center(
        child: new Text(
          'Hello, world!'
        ),
      ),
    );
  }
}

#dart #flutter #layouts

How to make height of all widgets inside Row equal the tallest widget

Widget build(BuildContext context) {
  return Scaffold(
    appBar: AppBar(title: Text('IntrinsicWidth')),
    body: Center(
      child: IntrinsicHeight(
        child: Row(
          crossAxisAlignment: CrossAxisAlignment.stretch,
          children: <Widget>[
            RaisedButton(
              onPressed: () {},
              child: Text('Short'),
            ),
            RaisedButton(
              onPressed: () {},
              child: Text('A bit Longer'),
            ),
            RaisedButton(
              onPressed: () {},
              child: Text('The Longest text button'),
            ),
          ],
        ),
      ),
    ),
  );
}

Capitalize the first letter of a String

String capitalize(String s) {
  if (s == null || s.isEmpty) {
    return s;
  }
  return s.length < 1 ? s.toUpperCase() : s[0].toUpperCase() + s.substring(1);
}

fix align text in flutter

Column( 
  crossAxisAlignment: CrossAxisAlignment.start, children: <Widget>[ Container( child: Text('${payment.name}',textAlign: TextAlign.left,), color: Colors.redAccent, ), ...... )

How to add a border to only one part of the container - Flutter

 decoration: BoxDecoration(
          border: Border(
            top: BorderSide(width: 16.0, color: Colors.lightBlue.shade600),
            bottom: BorderSide(width: 16.0, color: Colors.lightBlue.shade900),
          ),
          color: Colors.white,
        ),

Capitalize the first letter of a string - Flutter

extension StringExtension on String {
    String capitalize() {
      return "${this[0].toUpperCase()}${this.substring(1)}";
    }
}

The back button appears for a few moments while I replace a route

appBar: AppBar(
        automaticallyImplyLeading: false,
        title: Text(signedIn ? 'Home' : 'Sign In'),
      ),

Inserting image into a container - Flutter

Container(
      height: 120.0,
      width: 120.0,
      decoration: BoxDecoration(
        image: DecorationImage(
          image: AssetImage(
              'assets/assets/alucard.jpg'),
          fit: BoxFit.fill,
        ),
        shape: BoxShape.circle,
      ),
    )

Colour from Hex

const color = const Color(0xffb74093); // Second `const` is optional in assignments.

Flutter - Underline Text

Text(
  'Hello world',
  style: TextStyle(
    decoration: TextDecoration.underline,
  ),
)

Flutter Layout Cheat Sheet. Do you need simple layout samples for… | by Tomek Polański | Flutter Community | Medium

Widget build(BuildContext context) {
  return Scaffold(
    appBar: AppBar(title: Text('IntrinsicWidth')),
    body: Center(
      child: IntrinsicWidth(
        child: Column(
          crossAxisAlignment: CrossAxisAlignment.stretch,
          children: <Widget>[
            RaisedButton(
              onPressed: () {},
              child: Text('Short'),
            ),
            RaisedButton(
              onPressed: () {},
              child: Text('A bit Longer'),
            ),
            RaisedButton(
              onPressed: () {},
              child: Text('The Longest text button'),
            ),
          ],
        ),
      ),
    ),
  );
}

https://pub.dev/

checking internet connectivity flutter apps

try {
      final result = await InternetAddress.lookup('google.com');
      if (result.isNotEmpty && result[0].rawAddress.isNotEmpty) {
          print(' connected');
      }
    } on SocketException catch (_) {
      //NOT connected to the internet
      print('not connected');
    }

timer - Flutter - Blinking button - Stack Overflow

  class MyBlinkingButton extends StatefulWidget {
    @override
    _MyBlinkingButtonState createState() => _MyBlinkingButtonState();
  }

  class _MyBlinkingButtonState extends State<MyBlinkingButton>
      with SingleTickerProviderStateMixin {
    AnimationController _animationController;

    @override
    void initState() {
      _animationController =
          new AnimationController(vsync: this, duration: Duration(seconds: 1));
      _animationController.repeat(reverse: true);
      super.initState();
    }

    @override
    Widget build(BuildContext context) {
      return FadeTransition(
        opacity: _animationController,
        child: MaterialButton(
          onPressed: () => null,
          child: Text("Text button"),
          color: Colors.green,
        ),
      );
    }

    @override
    void dispose() {
      _animationController.dispose();
      super.dispose();
    }
  }

Flutter reversed ListView start at top - Stack Overflow

List<String> feed = List();

feed.add("AAAA");
feed.add("BBBB");
feed.add("CCCC");

ListView.builder(
  itemCount: feed.length,
  itemBuilder: (context, index) {
    return ListTile(title: feed[feed.length - 1 -index]);
  },
);

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