Add this plugin to your pubspec [device_info][1]

Human-readable way is

    if (Platform.isAndroid) {
      var androidInfo = await DeviceInfoPlugin().androidInfo;
      var release = androidInfo.version.release;
      var sdkInt = androidInfo.version.sdkInt;
      var manufacturer = androidInfo.manufacturer;
      var model = androidInfo.model;
      print(&#39;Android $release (SDK $sdkInt), $manufacturer $model&#39;);
      // Android 9 (SDK 28), Xiaomi Redmi Note 7
    }

    if (Platform.isIOS) {
      var iosInfo = await DeviceInfoPlugin().iosInfo;
      var systemName = iosInfo.systemName;
      var version = iosInfo.systemVersion;
      var name = iosInfo.name;
      var model = iosInfo.model;
      print(&#39;$systemName $version, $name $model&#39;);
      // iOS 13.1, iPhone 11 Pro Max iPhone
    }


  [1]: https://pub.dev/packages/device_info

    import &#39;dart:io&#39; show Platform;

    void main() {
      // Get the operating system as a string.
      String os = Platform.operatingSystem;
      // Or, use a predicate getter.
      if (Platform.isMacOS) {
        print(&#39;is a Mac&#39;);
      } else {
        print(&#39;is not a Mac&#39;);
      }
    }

[Dart SDK &gt; dart:io &gt; Platform][1]

Here is  the official article above, and if you want to check it is IOS or Andriod,
 you can use:

    if (Platform.isIOS) {
      print(&#39;is a IOS&#39;);
    } else if (Platform.isAndroid) {
      print(&#39;is a Andriod&#39;);
    } else {
    }


  [1]: https://api.dartlang.org/stable/1.24.3/dart-io/Platform-class.html

You can use `dart:io` 

    import &#39;dart:io&#39; show Platform;
    
    String osVersion = Platform.operatingSystemVersion;



You can use [platform channels][1] for this task. In native use os specific code to get version and resend it to flutter. Here is good [example][2] with battery level


  [1]: https://flutter.io/platform-channels/
  [2]: https://flutter.io/platform-channels/#example

&lt;!-- language-all: lang-ts --&gt;

I have two components and one with attribute selector. The child component is,

    import { Component, OnInit, Input, ElementRef } from &#39;@angular/core&#39;;
    
    
    @Component({
        selector: &#39;[app-bar-chart]&#39;,
        templateUrl: &#39;./bar-chart.component.html&#39;,
        styleUrls: [&#39;./bar-chart.component.css&#39;]
    })
    export class BarChartComponent implements OnInit {
    
        @Input() chartContainer: ElementRef;
        @Input() title: string;
        @Input() chartData: {
            title: string,
            content: {
                label: string,
                value: number,
                fill?: string
            }[]
        }[];
    
        constructor() { }
    
        ngOnInit() {
            console.log(this.chartContainer);
            console.log(this.chartContainer.nativeElement);
        }
        
    }

The parent component is,

    import { Component, OnInit, Output, ViewChild, ElementRef } from &#39;@angular/core&#39;;
    
    @Component({
        selector: &#39;app-dashboard&#39;,
        template: `&lt;div&gt;&lt;div class=&quot;graph-image&quot; style=&quot;width: 100%; height: 400px;&quot; app-bar-chart [title]=&quot;barChartTitle&quot; [chartData]=&quot;ChartData&quot; [chartContainer]=&quot;chartContainer&quot; #chartContainer&gt;&lt;/div&gt;&lt;/div&gt;`,
        styleUrls: [&#39;./dashboard.component.css&#39;]
    })
    export class DashboardComponent implements OnInit {
        barChartTitle = &#39;Transaction History&#39;;
        ChartData = [
            {
                &quot;title&quot;: &quot;May2017&quot;,
                &quot;content&quot;: [
                    {
                        &quot;label&quot;: &quot;payable&quot;,
                        &quot;value&quot;: 10
                    }
                ]
            },
            {
                &quot;title&quot;: &quot;Jun2017&quot;,
                &quot;content&quot;: [
                    {
                        &quot;label&quot;: &quot;payable&quot;,
                        &quot;value&quot;: 120
                    }
                ]
            }
        ];
        constructor() { }
    
        ngOnInit() {
        }
    
    }

I am passing the local reference from the parent component to the child component. When I am consoling the native element of this local reference it is &#39;undefined&#39;. How can I access the native element so that I can access the style width and height of the component div.

How to access the nativeElement of a Component in Angular4?

I am extremely new to Kotlin and APIs in general and can&#39;t find the syntax to create an API request using this language. I am creating a mobile version of a website so I&#39;m using Android Studio to create a new UI for an already established backend. What are the steps and syntax to creating a request? Any help is deeply appreciated.

How to make an API request in Kotlin?

`Platform.operatingSystem` will tell you whether you&#39;re running on Android or iOS. 

How can I check which version of the device OS am I running on?

How to check the device OS version from Flutter?

<p><code>Platform.operatingSystem</code> will tell you whether you're running on Android or iOS.</p>
<p>How can I check which version of the device OS am I running on?</p>


Is there a way to return several values in a function return statement (other than returning an object) like we can do in Go (or some other languages)?

For example, in Go we can do:

    func vals() (int, int) {
        return 3, 7
    }

Can this be done in Dart?  Something like this:

    int, String foo() {
        return 42, &quot;foobar&quot;;
    } 



Return multiple values from function

Tapping the container triggers the `onTap()` handler but does not show any ink splash effect.
    
    class _MyHomePageState extends State&lt;MyHomePage&gt; {
      @override
      Widget build(BuildContext context) {
        return new Scaffold(
          appBar: new AppBar(
            title: new Text(widget.title),
          ),
          body: new Center(
            child: new InkWell(
              onTap: (){print(&quot;tapped&quot;);},
              child: new Container(
                width: 100.0,
                height: 100.0,
                color: Colors.orange,
              ),
            ),
          ),
        );
      }
    }

I tried putting the `InkWell` inside the `Container` as well but in vain.


InkWell not showing ripple effect

I try to make a phone call from my Flutter app. With the following code:

    UrlLauncher.launch(&#39;tel: xxxxxxxx&#39;);

I found this Function on the GitHub flutter repo: https://github.com/flutter/flutter/issues/4856

But this doesn&#39;t work for me. Is this Function still in Flutter and in which package? Or is there a better option to do a phone call from my app? 

How to make a phone call from a flutter app

Is there any built in way in Flutter to hide a `FloatingActionButton` on `ListView` scrolling down and then showing it on scrolling up?

Flutter - Hiding FloatingActionButton

I&#39;m trying to construct a simple login page for my Flutter app.  I&#39;ve successfully built the TextFields and log in/Sign in buttons.  I want to add a horizontal ListView.  When I run the code my elements disappear, if I do it without the ListView, it&#39;s fine again. How can I do this correctly?

&lt;!-- language: dart --&gt;

    return new MaterialApp(
            home: new Scaffold(
              appBar: new AppBar(
                title: new Text(&quot;Login / Signup&quot;),
              ),
              body: new Container(
                child: new Center(
                  child: new Column(
                  mainAxisAlignment: MainAxisAlignment.center,
                    children: &lt;Widget&gt;[
                      new TextField(
                        decoration: new InputDecoration(
                          hintText: &quot;E M A I L    A D D R E S S&quot;
                        ),
                      ),
                      new Padding(padding: new EdgeInsets.all(15.00)),
                      new TextField(obscureText: true,
                        decoration: new InputDecoration(
                          hintText: &quot;P A S S W O R D&quot;
                        ),
                        ),
                      new Padding(padding: new EdgeInsets.all(15.00)),
                      new TextField(decoration: new InputDecoration(
                        hintText: &quot;U S E R N A M E&quot;
                      ),),
                      new RaisedButton(onPressed: null,
                      child:  new Text(&quot;SIGNUP&quot;),),
                      new Padding(padding: new EdgeInsets.all(15.00)),
                      new RaisedButton(onPressed: null,
                      child: new Text(&quot;LOGIN&quot;),),
                      new Padding(padding: new EdgeInsets.all(15.00)),
                      new ListView(scrollDirection: Axis.horizontal,
                      children: &lt;Widget&gt;[
                        new RaisedButton(onPressed: null,
                        child: new Text(&quot;Facebook&quot;),),
                        new Padding(padding: new EdgeInsets.all(5.00)),
                        new RaisedButton(onPressed: null,
                        child: new Text(&quot;Google&quot;),)
                      ],)
    
                    ],
                  ),
                ),
                margin: new EdgeInsets.all(15.00),
              ),
            ),
          );

How to add a ListView to a Column in Flutter?

I have a very simple Flutter app with a **TabBarView** with two views (**Tab 1** and **Tab 2**), one of them (**Tab 1**) has a ListView with many simple Text Widgets, the problem with this is that after I scroll down the ListView elements of **Tab 1**, if I swipe from **Tab 1** to **Tab 2** and finally I swipe from
**Tab 2** to **Tab 1**, the previous scroll position in the ListView of **Tab 1** get lost.

Here is the code:

```
import &#39;package:flutter/material.dart&#39;;

void main() {
  runApp(MyApp());
}

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: &#39;Flutter Demo&#39;,
      theme: ThemeData(
        primarySwatch: Colors.blue,
      ),
      home: const MyHomePage(title: &#39;Flutter Demo Home Page&#39;),
    );
  }
}

class MyHomePage extends StatefulWidget {
  const MyHomePage({Key? key, required this.title}) : super(key: key);

  final String title;

  @override
  _MyHomePageState createState() =&gt; _MyHomePageState();
}

class _MyHomePageState extends State&lt;MyHomePage&gt;
    with SingleTickerProviderStateMixin {
  late TabController controller;

  @override
  void initState() {
    super.initState();
    controller = TabController(
      length: 2,
      vsync: this,
    );
  }

  @override
  void dispose() {
    controller.dispose();
    super.dispose();
  }

  @override
  Widget build(BuildContext context) {
    var tabs = const &lt;Tab&gt;[
      Tab(icon: Icon(Icons.home), text: &#39;Tab 1&#39;),
      Tab(icon: Icon(Icons.account_box), text: &#39;Tab 2&#39;)
    ];

    return Scaffold(
      appBar: AppBar(
        title: Text(widget.title),
      ),
      body: TabBarView(controller: controller, children: &lt;Widget&gt;[
        ListView(children: &lt;Widget&gt;[
          Column(children: &lt;Widget&gt;[
            for (int i = 0; i &lt; 48; i++) Text(&#39;Data $i&#39;),
          ])
        ]),
        const Center(child: Text(&#39;Tab 2&#39;))
      ]),
      bottomNavigationBar: Material(
        color: Colors.deepOrange,
        child: TabBar(controller: controller, tabs: tabs),
      ),
    );
  }
}
```

I have even separated the **TabBarView** **childrens** (Tab 1 and Tab 2) in another classes and I have noticed that the 

    @override
      Widget build(BuildContext context) {
      ...
    }

method of each child (Tab 1 and Tab 2) is executed every time I swipe to it&#39;s container tab.

My questions are:

**1.- How can I keep the scroll of the *ListView* even if I move from tab to tab?**

**2.- Is there a way to execute the**

    @override
    Widget build(BuildContext context) {
    
    }

**method only once if I separate the *TabBarView childrens* (Tab 1 and Tab 2) to another classes?**
I mean, if I have to retrieve data when the Tab 1 and Tab 2 are created I don&#39;t want to do this every time it&#39;s Tab is swiped in. That would be expensive.

**3.- In general, Is there a way to prevent that a tab view (including it&#39;s variables, data, etc.) be rebuilt every time I swipe to that tab?**

**Thank you in advance.**


Content Type	Original Author	Original Content on Stackoverflow
Question	DogeLion	View Question on Stackoverflow
Solution 1 - Dart	Airon Tark	View Answer on Stackoverflow
Solution 2 - Dart	Julien	View Answer on Stackoverflow
Solution 3 - Dart	pankaj kumar	View Answer on Stackoverflow
Solution 4 - Dart	German Saprykin	View Answer on Stackoverflow

How to check the device OS version from Flutter?

Dart Problem Overview

Dart Solutions

Solution 1 - Dart

Solution 2 - Dart

Solution 3 - Dart

Solution 4 - Dart

How to make an API request in Kotlin?

How to access the nativeElement of a Component in Angular4?

Attributions