flutter:
  uses-material-design: true
  assets:
    - assets/images/

 Container(
              width: 400.0,//容器寬度
              height: 100.0,//容器高度
              margin: const EdgeInsets.all(10.0),
              child: Image.asset('assets/images/bg.jpg'),
            ),

Container(
              decoration: ShapeDecoration(
                image: const DecorationImage(
                  image: AssetImage('assets/images/bg.jpg'),//加載本地圖片
                  fit: BoxFit.cover
                ),
                  shape:RoundedRectangleBorder(borderRadius: BorderRadiusDirectional.circular(10.0))
              ),
              width: 400.0,//容器寬度
              height: 100.0,//容器高度
              margin: const EdgeInsets.all(10.0),//外邊距
            )

Container(//使用本地的圖片作為占位圖
              width: 500.0,//容器寬度
              height: 200.0,//容器高度
              child: FadeInImage.assetNetwork(
                  placeholder: "assets/images/bg.jpg", //默認占位圖
                  imageErrorBuilder: (context, error, stackTrace) {//如果加載網(wǎng)絡錯誤，顯示錯誤背景
                    return Container(
                      width: 500.0,
                      height: 200.0,
                      color: Colors.grey,
                    );
                  },
                  image: "https://i0.hdslb.com/bfs/album/85dcfb9ae68ec58b447d823448b27f26e3d69b23.jpg"),
            ),

 Container(//使用加載loading作為占位圖
              width: 500.0,
              height: 150.0,
              margin: const EdgeInsets.only(top: 10.0),
              child: Image.network(
                "https://i0.hdslb.com/bfs/album/85dcfb9ae68ec58b447d823448b27f26e3d69b23.jpg",
                errorBuilder: (context,error,stackTrace){
                  return CircularProgressIndicator();
                },
                loadingBuilder: (context,child,loadingProgress){
                  if(loadingProgress == null)return child;
                  return Container(
                    alignment: Alignment.center,
                    child: CircularProgressIndicator(
                      value: loadingProgress.expectedTotalBytes != null ?
                      loadingProgress.cumulativeBytesLoaded / loadingProgress.expectedTotalBytes! : null,
                    ),
                  );
                },
              ),
            ),

Container( //單組件布局容器，只允許有一個子組件
              alignment: Alignment.center,//對齊方式：居中
              width: 500.0,//容器寬度
              height: 200.0,//容器高度
              //color: Colors.blue,容器背景顏色
              padding: const EdgeInsets.all(10.0),//外邊距
              margin: const EdgeInsets.all(10.0),//內(nèi)邊距
              decoration:  BoxDecoration(//類似原生Android的XML創(chuàng)建樣式一樣
                  gradient: const LinearGradient(colors: [Colors.red,Colors.green,Colors.amber]),//線性漸變，需要先注釋原有存在的背景顏色語句
                  border: Border.all(color:Colors.black,width: 5.0),//繪制邊框，邊框顏色為黑色，邊框?qū)挾葹?
                  borderRadius: const BorderRadius.all(Radius.circular(10.0)),//設置邊框圓角
                  shape: BoxShape.rectangle//盒子樣式形狀
              ),
              child: const Text(容器內(nèi)子組建
                'Hello World!',
                style: TextStyle(fontSize: 20.0,color: Colors.white),
              ),
            ),

 padding: const EdgeInsets.all(10.0),//外邊距
 margin: const EdgeInsets.all(10.0),//內(nèi)邊距