"unable to locate adb" using Android Studio

 File>Project Structure>set project sdk> OK

git create a new branch and commit add all and push

 First, you create your branch locally:

git checkout -b <branch-name> # Create a new branch and check it out

===================================

git add -A && git commit -m "Your Message"


===================================

The remote branch is automatically created when you push it to the remote server. So when you feel ready for it, you can do:

git push <remote-name> <branch-name> 

Where <remote-name> is typically origin, the name which git gives to the remote you cloned from. Your colleagues would then just pull that branch, and it's automatically created locally.

Note however that formally, the format is:

git push <remote-name> <local-branch-name>:<remote-branch-name>

But when you omit one, it assumes both branch names are the same. Having said this, as a word of caution, do not make the critical mistake of specifying only :<remote-branch-name> (with the colon), or the remote branch will be deleted!

So that a subsequent git pull will know what to do, you might instead want to use:

git push --set-upstream <remote-name> <local-branch-name> 

As described below, the --set-upstream option sets up an upstream branch:

For every branch that is up to date or successfully pushed, add upstream (tracking) reference, used by argument-less git-pull(1) and other commands.

How to make a phone call

 

Call the launch method from url_launcher package:

launch("tel://214324234");

Email

launch("mailto:dfh@abdfhdfhc.com");

Flutter - Container onPressed

 new GestureDetector(

        onTap: (){
          print("Container clicked");
        },
        child: new Container(
          width: 500.0,
          padding: new EdgeInsets.fromLTRB(20.0, 40.0, 20.0, 40.0),
          color: Colors.green,
          child: new Column(
              children: [
                new Text("Ableitungen"),
              ]
          ),
        )
    );

Super Constructor

 

class Foo {
  Foo(int a, int b) {
    //Code of constructor
  }

  Foo.named(int c, int d) {
    //Code of named constructor
  }
}

class Bar extends Foo {
  Bar(int a, int b) : super(a, b);
}

class Baz extends Foo {
  Baz(int c, int d) : super.named(c, d);  
}

2 state 2 button (change value and rebuild widget)

 import 'package:flutter/material.dart';

void main() {

  runApp(const MyApp());

}

class MyApp extends StatelessWidget {

  const MyApp({Key? key}) : super(key: key);

  @override

  Widget build(BuildContext context) {

    return MaterialApp(

      title: 'Flutter Demo',

      theme: ThemeData(

        primarySwatch: Colors.blue,

      ),

      home:  const MyHomePage(),

    );

  }

}

class MyHomePage extends StatefulWidget {

  const MyHomePage({Key? key}) : super(key: key);

  @override

  State<MyHomePage> createState() => _MyHomePageState();

}

class _MyHomePageState extends State<MyHomePage> {

  int _counterA = 0;

  int _counterB = 0;

  void _incrementCounterA() {

    setState(() {

      _counterA++;

    });

  }

  void _incrementCounterB() {

    setState(() {

      _counterB++;

    });

  }

  @override

  Widget build(BuildContext context) {

    return Scaffold(

      appBar: AppBar(

        title: const Text("App title"),

      ),

      body: Center(

        child: Column(

          mainAxisAlignment: MainAxisAlignment.center,

          children: <Widget>[

            Text(

              'A:'+'$_counterA',

              style: Theme.of(context).textTheme.headline4,

            ),

            TextButton(

              onPressed: _incrementCounterA,

              child: const Text('A'),

            ),

            Text(

              'B:'+'$_counterB',

              style: Theme.of(context).textTheme.headline4,

            ),

            TextButton(

              onPressed: _incrementCounterB,

              child: const Text('B'),

            ),

          ],

        ),

      ),

    );

  }

}

Simple http request to setState Text\worldtime

 import 'package:flutter/material.dart';

import 'package:http/http.dart' as http;

import 'package:http/http.dart';

void main() {

  runApp(const MyApp());

}

class MyApp extends StatelessWidget {

  const MyApp({Key? key}) : super(key: key);

  // This widget is the root of your application.

  @override

  Widget build(BuildContext context) {

    return MaterialApp(

      title: 'Flutter Demo',

      theme: ThemeData(

        primarySwatch: Colors.blue,

      ),

      home: const MyHomePage(title: 'Flutter Demo Home Page'),

    );

  }

}

class MyHomePage extends StatefulWidget {

  const MyHomePage({Key? key, required this.title}) : super(key: key);

  final String title;

  @override

  State<MyHomePage> createState() => _MyHomePageState();

}

class _MyHomePageState extends State<MyHomePage> {

  String strcontent = "";

  void _incrementCounter () async{

    Response response = await get(Uri.parse('http://worldtimeapi.org/api/timezone/Asia/Hong_Kong') );

    setState(()  {

      print(response.body);

      strcontent = response.body;

    });

  }

  @override

  Widget build(BuildContext context) {

    return Scaffold(

      appBar: AppBar(

        title: Text(widget.title),

      ),

      body: Center(

        child: Column(

          mainAxisAlignment: MainAxisAlignment.center,

          children: <Widget>[

            Text(

              '$strcontent',

              style: Theme.of(context).textTheme.headline4,

            ),

          ],

        ),

      ),

      floatingActionButton: FloatingActionButton(

        onPressed: _incrementCounter,

        tooltip: 'Increment',

        child: const Icon(Icons.add),

      ), // This trailing comma makes auto-formatting nicer for build methods.

    );

  }

}