颤振中的帧布局替代

Question

I want to add a Flutter Container in top of another Container and top container will be transparent. Basically I do that in native Android using FrameLayout. How to implement this in Flutter?

Answer 1

Stack is most likely what you want.

Stack allows to put widgets on the top of others however you like. And, combined with Positioned , have custom positions.

Let's draw a real frame in flutter :

Stack(
  alignment: Alignment.center,
  children: <Widget>[
    Container(
      width: 200.0,
      height: 300.0,
      decoration: BoxDecoration(
        color: Colors.black12,
        border: Border.all(
          color: Colors.black,
          width: 3.0,
        ),
      ),
    ),
    Container(
      width: 100.0,
      height: 100.0,
      color: Colors.blue,
    ),
    Positioned(
      bottom: 10.0,
      right: 10.0,
      child: Card(
        child: Padding(
          padding: const EdgeInsets.all(8.0),
          child: Text("Title"),
        ),
      ),
    )
  ],
),

Answer 2

You can use Align to better control the position of your widget based on alignment.

Stack(
  children: <Widget>[
    Align(alignment: Alignment.center, child: Text("Center"),),
    Align(alignment: Alignment.topRight, child: Text("Top\nRight"),),
    Align(alignment: Alignment.centerRight, child: Text("Center\nRight"),),
    Align(alignment: Alignment.bottomRight, child: Text("Bottom\nRight"),),
    Align(alignment: Alignment.topLeft, child: Text("Top\nLeft"),),
    Align(alignment: Alignment.centerLeft, child: Text("Center\nLeft"),),
    Align(alignment: Alignment.bottomLeft, child: Text("Bottom\nLeft"),),
    Align(alignment: Alignment.topCenter, child: Text("Top\nCenter"),),
    Align(alignment: Alignment.bottomCenter, child: Text("Bottom\nCenter"),),
    Align(alignment: Alignment(0.0, 0.5), child: Text("Custom\nPostition", style: TextStyle(color: Colors.red, fontSize: 20.0, fontWeight: FontWeight.w800),),),
  ],
);

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Output: