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Author: AseemWangoo

InternetConnectivity.dart

@@ -0,0 +1,157 @@
+import 'package:flutter/material.dart';
+import 'package:http/http.dart' as http;  //for making request
+import 'dart:async';  //for asynchronous features
+import 'dart:convert';  //for converting the response to desired format. e.g: JSON
+import 'package:connectivity/connectivity.dart';  //connectivity package...also see the pubspec.yaml
+import 'package:flutter/services.dart'; //PlatForm Exception
+
+void main() {
+  runApp(new MyApp());
+}
+
+class MyApp extends StatelessWidget {
+  @override
+  Widget build(BuildContext context) {
+    return new MaterialApp(home: new ButtonOptions());
+  }
+}
+
+class ButtonOptions extends StatefulWidget {
+  @override
+  State<StatefulWidget> createState() {
+    return new ButtonOptionsState();
+  }
+}
+
+class ButtonOptionsState extends State<ButtonOptions> {
+  String _connectionStatus;
+  final Connectivity _connectivity = new Connectivity();
+
+  //For subscription to the ConnectivityResult stream
+  StreamSubscription<ConnectivityResult> _connectionSubscription;
+
+  /*
+  ConnectivityResult is an enum with the values as { wifi, mobile, none }.
+  */
+  @override
+  void initState() {
+    super.initState();
+    // initConnectivity(); before calling on button press
+    _connectionSubscription =
+        _connectivity.onConnectivityChanged.listen((ConnectivityResult result) {
+      setState(() {
+        _connectionStatus = result.toString();
+      });
+    });
+    print("Initstate : $_connectionStatus");
+  }
+
+  //For cancelling the stream subscription...Good way to release resources
+  @override
+  void dispose() {
+    _connectionSubscription.cancel();
+    super.dispose();
+  }
+
+  //called in initState
+  /*
+    _connectivity.checkConnectivity() checks the connection state of the device.
+    Recommended way is to use onConnectivityChanged stream for listening to connectivity changes.
+    It is done in initState function.
+  */
+  Future<Null> initConnectivity() async {
+    String connectionStatus;
+
+    try {
+      connectionStatus = (await _connectivity.checkConnectivity()).toString();
+    } on PlatformException catch (e) {
+      print(e.toString());
+      connectionStatus = "Internet connectivity failed";
+    }
+
+    if (!mounted) {
+      return;
+    }
+
+    setState(() {
+      _connectionStatus = connectionStatus;
+    });
+    print("InitConnectivity : $_connectionStatus");
+    if(_connectionStatus == "ConnectivityResult.mobile" || _connectionStatus == "ConnectivityResult.wifi") {
+      getData();
+    } else {
+      print("You are not connected to internet");
+    }
+  }
+
+  //makes the request
+  Future<String> getData() async {
+    http.Response response = await http.get(
+        Uri.encodeFull("https://jsonplaceholder.typicode.com/posts"),
+        headers: {"Accept": "application/json"});
+    List data = JSON.decode(response.body);
+    print(data[1]);
+  }
+
+  final TextEditingController _controller = new TextEditingController();
+  String str = "";
+  String submitStr = "";
+
+  void _changeText(String val) {
+    setState(() {
+      submitStr = val;
+    });
+    print("On RaisedButton : The text is $submitStr");
+  }
+
+  void _onSubmit(String val) {
+    print("OnSubmit : The text is $val");
+    setState(() {
+      submitStr = val;
+    });
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    void _onChanged(String value) {
+      print('"OnChange : " $value');
+    }
+
+    return new Scaffold(
+      appBar: new AppBar(
+        title: new Text('First Screen'),
+      ),
+      body: new Container(
+        padding: const EdgeInsets.all(10.0),
+        child: new Column(
+          children: <Widget>[
+            new TextField(
+              decoration: new InputDecoration(
+                hintText: "Type something...",
+              ),
+              onChanged: (String value) {
+                _onChanged(value);
+              },
+              controller: _controller,
+              onSubmitted: (String submittedStr) {
+                _onSubmit(submittedStr);
+                _controller.text = "";
+              },
+            ),
+            new Text('$submitStr'),
+            new RaisedButton(
+              child: new Text("Click me"),
+              onPressed: () {
+                //_changeText(_controller.text);
+                //getData();
+                initConnectivity();                
+                // countT();
+                _controller.text = _connectionStatus;
+              },              
+            )
+          ],
+        ),
+      ),
+    );
+  }
+}