1、Center介紹

Center將子控件放在其內部中心，里面只能放一個child，但是child里面可以放Container

Center繼承勒Align，然后Align默認是center.

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2、測試代碼

測試1、

  @overrideWidget build(BuildContext context) {return MaterialApp(title: 'open url',home: Scaffold(appBar: AppBar(// Here we take the value from the MyHomePage object that was created by// the App.build method, and use it to set our appbar title.title: Text('hello flutter'),),body: Center(child: Text("chenyu"),),),);}
}

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測試2、

  @overrideWidget build(BuildContext context) {return MaterialApp(title: 'open url',home: Scaffold(appBar: AppBar(// Here we take the value from the MyHomePage object that was created by// the App.build method, and use it to set our appbar title.title: Text('hello flutter'),),body: Center(child: Container(color: Colors.blue,width: 200,height: 200,),),),);}
}

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3、運行結果

測試1效果、

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測試2效果、

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