flutter控件之---------container

介绍

container:一个拥有绘制、定位、调整大小的 widget。

数据结构

Container({
  Key key,
  this.alignment,
  this.padding,
  Color color,
  Decoration decoration,
  this.foregroundDecoration,
  double width,
  double height,
  BoxConstraints constraints,
  this.margin,
  this.transform,
  this.child}

属性

1. alignment
让子元素在container容器内对齐方式(这里以center为例---更多对齐方式看源码)
2. child
子控件，这里先以最简单的text为例
3. margin
4. padding
5. width
6. height
以上几种属性不多做介绍，均为double类型值，具体样式看代码加图

 body: new Container(
        alignment: Alignment.center,
        child: new Container(
          color: Colors.yellow,
          child: new Text("聆听璇律", style: new TextStyle(fontSize: 20.0)),
        ),
        color: Colors.green,
        padding: const EdgeInsets.all(60.0),
        margin: const EdgeInsets.all(20.0),
        width: 180.0,
        height: 180.0,
      ),

1.png

7. decoration
container的背景色，注意decoration和color不能共存，只能设置一个，decoration不仅能设置颜色还能设置渐变色。

body: new Container(
        alignment: Alignment.center,
        child: new Container(
          color: Colors.yellow,
          child: new Text("聆听璇律", style: new TextStyle(fontSize: 20.0)),
        ),
//        color: Colors.green,
        padding: const EdgeInsets.all(60.0),
        margin: const EdgeInsets.all(20.0),
        width: 180.0,
        height: 180.0,
        decoration: new BoxDecoration(
            gradient: const LinearGradient(
                colors: [Colors.lightBlue, Colors.greenAccent,Colors.purple])),
      ),

2.png

**不止线型的渐变，还有圆形扇形，自己看源码，这里就不上图了
8. foregroundDecoration
container的前景色

foregroundDecoration: new BoxDecoration(
          border: new Border.all(
              color: Colors.redAccent, width: 10.0, style: BorderStyle.solid),
          shape: BoxShape.circle,
        ),

3.png

9. constraints
约束，可以对宽高进行约束

//        constraints: new BoxConstraints.loose(new Size(150.0, 150.0)),
        constraints: new BoxConstraints.expand(width: 200.0,height: 300.0),

10. transform
用来改变container位置，可以添加位移，旋转等（这里只写基础的）

transform: new Matrix4.translationValues(100.0,0.0,0.0)