Merge pull request #494 from juanjoseleca/master

Add function to get responsive value

@@ -431,6 +431,14 @@ context.isLargeTablet()
 
 /// True if the current device is Tablet
 context.isTablet()
+
+/// Returns a value according to the screen size
+/// can give value for
+/// swatch: if the shortestSide is smaller than 300
+/// mobile: if the shortestSide is smaller than 600
+/// tablet: if the shortestSide is smaller than 1200
+/// desktop: if width is largest than 1200  
+context.responsiveValue<T>()
 ```
 
 ### Optional Global Settings and Manual configurations

 import 'package:flutter/material.dart';
 import 'package:flutter/widgets.dart';
+import 'package:flutter/foundation.dart';
 
 extension ContextExtensionss on BuildContext {
   /// The same of [MediaQuery.of(context).size]
@@ -102,4 +103,27 @@ extension ContextExtensionss on BuildContext {
 
   /// True if the current device is Tablet
   bool get isTablet => isSmallTablet || isLargeTablet;
+
+  /// Returns a specific value according to the screen size
+  /// if the device width is higher than or equal to 1200 return [desktop] value.
+  /// if the device width is higher than  or equal to 600 and less than 1200
+  /// return [tablet] value.
+  /// if the device width is less than 300  return [watch] value.
+  /// in other cases return [mobile] value.
+  T responsiveValue<T>({
+    T mobile,
+    T tablet,
+    T desktop,
+    T watch,
+  }) {
+    double deviceWidth = mediaQuerySize.shortestSide;
+
+    if (kIsWeb) {
+      deviceWidth = mediaQuerySize.width;
+    }
+    if (deviceWidth >= 1200 && desktop != null) return desktop;
+    if (deviceWidth >= 600 && tablet != null) return tablet;
+    if (deviceWidth < 300 && watch != null) return watch;
+    return mobile;
+  }
 }