Attempted to use type '_SwiperState' as a function.

[shockw4ver]

This is the part of my code that use swiper.

@override
  Widget build (BuildContext context) {
    return new Center(
      child: new Container(
        child: new Container(
          height: 280.0,
          child: new Swiper(
            itemBuilder: (BuildContext context,int index){
              return new Image.network("http://via.placeholder.com/350x150",fit: BoxFit.fill,);
            },
            itemCount: 3,
            pagination: new SwiperPagination(),
            control: new SwiperControl(),
          ),
        ),
      )
    );
  }

And cause exception:

I/flutter ( 4576): ══╡ EXCEPTION CAUGHT BY WIDGETS LIBRARY ╞═══════════════════════════════════════════════════════════
I/flutter ( 4576): The following NoSuchMethodError was thrown building Container(constraints:
I/flutter ( 4576): BoxConstraints(0.0<=w<=Infinity, h=280.0)):
I/flutter ( 4576): Attempted to use type '_SwiperState' as a function. Since types do not define a method 'call', this
I/flutter ( 4576): is not possible. Did you intend to call the _SwiperState constructor and forget the 'new' operator?
I/flutter ( 4576): Receiver: _SwiperState
I/flutter ( 4576): Tried calling: _SwiperState()
I/flutter ( 4576): 
I/flutter ( 4576): When the exception was thrown, this was the stack:
I/flutter ( 4576): #0      Object.noSuchMethod (dart:core-patch/dart:core/object_patch.dart:46)
I/flutter ( 4576): #1      Swiper.createState (package:flutter_swiper/src/swiper.dart:260:24)
I/flutter ( 4576): #2      new StatefulElement (package:flutter/src/widgets/framework.dart:3693:23)
I/flutter ( 4576): #3      StatefulWidget.createElement (package:flutter/src/widgets/framework.dart:781:42)
I/flutter ( 4576): #4      Element.inflateWidget (package:flutter/src/widgets/framework.dart:2888:40)
...

What happend...

[jzoom]

Make sure to use the latest sdk version. The keyword "new" would be optional in most of the cases.
You can find that here : dart-lang/sdk#30921 , and here : https://github.com/dart-lang/sdk/blob/master/docs/language/informal/optional-new-const.md.
I'll fix this issue by using "new" .