Flutter之Align，Padding，Center，Bas

/**
    const Align({
    Key key,
    this.alignment = Alignment.center,//对齐方式,系统预设了9种对齐方式，也可以自定义Alignment(0.4,0.5),
    其中第一个参数，-1.0是左边对齐，1.0是右边对齐，第二个参数，-1.0是顶部对齐，1.0是底部对齐。
    this.widthFactor,//宽是子组件的倍数,Align的宽度就是child的宽度乘以这个值
    this.heightFactor,//高是子组件的倍数,Align的高度就是child的高度乘以这个值
    Widget child
    })
 */

body:ListView(
          children: <Widget>[
            Container(
              color: Color(0xfff1f1f1),
              child: Align(
                alignment: Alignment.bottomLeft,
                widthFactor: 3,
                heightFactor: 2,
                child: Text("Alignment.bottomLeft"),
              ),
            ),
            Container(
              color: Color(0xfff1f1f1),
              margin: EdgeInsets.only(top: 10.0),
              child: Align(
                alignment: Alignment(0.4, 0.5),
                widthFactor: 3,
                heightFactor: 2,
                child: Text("Alignment(0.4, 0.5)"),
              ),
            ),

          ],
)

/**
    const Padding({
    Key key,
    @required this.padding,//padding值
    Widget child,
    })
 */

body: Container(
          color: Color(0xfff1f1f1),
          child: Padding(
            padding: EdgeInsets.all(50.0),
            child: Text("padding组件"),
          ),
)

/**
    Center继承自Align，只是将alignment设置为Alignment.center
    class Center extends Align {
    /// Creates a widget that centers its child.
    const Center({ Key key, double widthFactor, double heightFactor, Widget child })
    : super(key: key, widthFactor: widthFactor, heightFactor: heightFactor, child: child);
    }
 */

body:Container(
          color: Color(0xfff1f1f1),
          child: Center(
            widthFactor: 2,
            heightFactor: 2,
            child: Text("center组件"),
          ),
)

/**
    const Baseline({
    Key key,
    @required this.baseline,  baseline数值，必须要有，从顶部算
    @required this.baselineType,  alphabetic：对齐字符底部的水平线；  ideographic：对齐表意字符的水平线。
    Widget child
    })
 */

body: Row(
          children: <Widget>[
            Padding(
              padding: EdgeInsets.only(left: 5.0),
              child: Baseline(
                baseline: 40.0,
                baselineType: TextBaseline.alphabetic,
                child: Text("文本",),
              ),
            ),
            Padding(
              padding: EdgeInsets.only(left: 5.0),
              child: Baseline(
                baseline: 40.0,
                baselineType: TextBaseline.alphabetic,
                child: Text("ajfajf",),
              ),
            ),
            Padding(
              padding: EdgeInsets.only(left: 5.0),
              child: Baseline(
                baseline: 40.0,
                baselineType: TextBaseline.ideographic,
                child: Text("文本",),
              ),
            ),
            Padding(
              padding: EdgeInsets.only(left: 5.0),
              child: Baseline(
                baseline: 40.0,
                baselineType: TextBaseline.ideographic,
                child: Text("ajfajf",),
              ),
            ),
            Padding(
              padding: EdgeInsets.only(left: 5.0),
              child: Baseline(
                baseline: 10.0,
                baselineType: TextBaseline.ideographic,
                child: Text("ajfajf",),
              ),
            ),
            Padding(
              padding: EdgeInsets.only(left: 5.0),
              child: Baseline(
                baseline: 10.0,
                baselineType: TextBaseline.ideographic,
                child: Container(
                  color: Color(0xfff1f1f1),
                  child: Baseline(
                    baseline: 5.0,
                    baselineType: TextBaseline.ideographic,
                    child: Text("ajfajf",),
                  ),
                )
              ),
              ),
          ],
        )