如果你想添加边框的一些文本的容器，那么你可以很容易地通过应用BoxDecoration容器。

代码:

Container(
  decoration: BoxDecoration(
    border: Border.all(
      color: Colors.redAccent,
      width: 1,
    ),
  ),
  child: Text('Some Text'),
);

用容器包装小部件

Container(
        margin: const EdgeInsets.all(30.0),
        padding: const EdgeInsets.all(10.0),
        decoration: BoxDecoration(border: Border.all(
        color: Colors.black,
        width: 1,
      ),
    ), 
        child: Text(
          "text",
          style: TextStyle(fontSize: 30.0),
        ),
      );

使用带有Boxdercoration的容器。

 BoxDecoration(
    border: Border.all(
      width: 3.0
    ),
    borderRadius: BorderRadius.circular(10.0)
  );

总结

我已经尝试总结了在BoxDecoration中使用边框时所有重要的可能性。

以下解释边界的结果:

---

解释

基本

  Container(
    decoration: BoxDecoration(border: Border.all()),
    child: const Text("Text"),
 ),    

---

BorderColor, width和strokeAlign

Container(
   decoration: BoxDecoration(
   border: Border.all(
       width: 4,
       color: Colors.green,
       strokeAlign: BorderSide.strokeAlignCenter)),
   child: const Text("Text"),
),

---

只在特定的一侧划定边界

      Row(
        mainAxisAlignment: MainAxisAlignment.spaceAround,
        children: [
          Container(
            decoration: const BoxDecoration(
                border: Border(top: BorderSide(width: 2))),
            child: const Text("Text"),
          ),
          Container(
            decoration: const BoxDecoration(
                border: Border(bottom: BorderSide(width: 2))),
            child: const Text("Text"),
          ),
          Container(
            decoration: const BoxDecoration(
                border: Border(
                    top: BorderSide(width: 2),
                    bottom: BorderSide(width: 4))),
            child: const Text("Text"),
          ),
        ],
      ),

---

不同的形状

      Row(
        mainAxisAlignment: MainAxisAlignment.spaceEvenly,
        children: [
          Container(
            padding: const EdgeInsets.all(10),
            decoration: BoxDecoration(
                border: Border.all(),
                shape: BoxShape.circle),
            child: const Text("Text"),
          ),
          Container(
            padding: const EdgeInsets.all(10),
            decoration: BoxDecoration(
              border: Border.all(),
              borderRadius: BorderRadius.circular(10),
            ),
            child: const Text("Text"),
          ),
        ],
      ),

---

弯曲边界半径

    Row(
        mainAxisAlignment: MainAxisAlignment.spaceEvenly,
        children: [
          Container(
            padding: const EdgeInsets.all(10),
            decoration: BoxDecoration(
                border: Border.all(),
                borderRadius: const BorderRadius.horizontal(
                    left: Radius.circular(5), right: Radius.circular(20))
                ),
            child: const Text("Text"),
          ),
          Container(
            padding: const EdgeInsets.all(10),
            decoration: BoxDecoration(
                border: Border.all(),
                borderRadius: const BorderRadius.only(
                    topLeft: Radius.circular(10),
                    bottomRight: Radius.circular(20))),
            child: const Text("Text"),
          ),
        ],
      ),

你可以把那个小部件包装到DecoratedBox，在这种情况下，DecoratedBox为那个小部件提供装饰

Widget textDecoration(String text){
    return DecoratedBox(
        decoration: BoxDecoration(
            border: Border.all(
                color: Colors.red,
                width: 10,
            ),
        ),
        child: Text(text)
    );
}

上面的答案也是正确的，但是如果您想在同一个小部件上添加多个边框，那么您可以设置这个选项

Container(
      child: const Center(
        child: Text(
          'This is your Container',
        ),
      ),
      decoration: BoxDecoration(
        borderRadius: BorderRadius.circular(10),
        color: Colors.white,
        boxShadow: const [
          BoxShadow(color: Colors.green, spreadRadius: 8),
          BoxShadow(color: Colors.yellow, spreadRadius: 5),
        ],
      ),
      height: 50,
    )