flutter控件之--------text

介绍
text,文本控件，用来展示文本内容

构造

const Text(this.data, {
    Key key,
    this.style,
    this.textAlign,
    this.textDirection,
    this.locale,
    this.softWrap,
    this.overflow,
    this.textScaleFactor,
    this.maxLines,
    this.semanticsLabel,
  }

const Text.rich(this.textSpan, {
    Key key,
    this.style,
    this.textAlign,
    this.textDirection,
    this.locale,
    this.softWrap,
    this.overflow,
    this.textScaleFactor,
    this.maxLines,
    this.semanticsLabel,
  }

它有两种构造方法，一种是text 一种是 text.rich，第一种就是简单的文本，第二种是段落式的文本，可以给文本中的每个textSpan设置其样式。（以上两种构造方式区别等下面介绍属性的时候一并介绍）

属性
1.data
文本的内容

2.style
文本的样式

const TextStyle({
    this.inherit = true,
    this.color,
    this.fontSize,
    this.fontWeight,
    this.fontStyle,
    this.letterSpacing,
    this.wordSpacing,
    this.textBaseline,
    this.height,
    this.locale,
    this.foreground,
    this.background,
    this.decoration,
    this.decorationColor,
    this.decorationStyle,
    this.debugLabel,
    String fontFamily,
    String package,
  }) 

①inherit
默认为true，设置为false时候表示不显示
②color
字体颜色

③fontSize fontSize.png
fontSize默认是14.0的
④fontWeight
字体的粗体
⑤fontStyle

normal正常 italic 斜体

fontStyle.png
⑥letterSpacing
字符间距
⑦wordSpacing
单词间距
⑧textBaseline
alphabetic：用于对齐字母字符底部的水平线
ideographic：用于对齐表意字符的水平线
textBaseline.png
⑨height
用在Text控件上的时候，会乘以fontSize做为行高,

⑩locale
国际化
⑪foreground
用paint来渲染text，也可以用他来改变字体颜色等
⑫background
⑬decoration
有四种下划线、删除线、上划线，默认是无

decoration.png
⑭decorationStyle
线的样式，源码中有这些样式
decorationStyle.png
⑮fontFamily和package（自定义字体的时候用的到，后面再详解）

children: <Widget>[
              new Text('聆听璇律', style: new TextStyle(inherit: true),),
              //color颜色--fontSize字体大小--fontWeight粗细
              new Text('李一桐黄蓉',
                style: new TextStyle(color: Colors.red,
                    fontSize: 18.0,
                    fontWeight: FontWeight.w800),),
              //fontStyle斜体
              new Text('陆雪琪', style: new TextStyle(
                  fontSize: 18.0, fontStyle: FontStyle.italic)),
              //letterSpacing字符间距
              new Text('三十年河东，三十年河西。莫欺少年穷！',
                style: new TextStyle(letterSpacing: 10.0),),
              //单词间距
              new Text('i hit you',
                style: new TextStyle(wordSpacing: 30.0),),
              new Text('七里香textBaseline',
                //style: new TextStyle(textBaseline: TextBaseline.alphabetic),)
                style: new TextStyle(textBaseline: TextBaseline.ideographic),),
              //'height: 用在Text控件上的时候，会乘以fontSize做为行高,
              new Text('夜空中最亮的星',
                style: new TextStyle(height: 2.0),),
              //decoration和decorationStyle
              new Text(
                  '烟花易冷', style: new TextStyle(
                  decoration: TextDecoration.lineThrough,
                  decorationStyle: TextDecorationStyle.wavy)),
            ],

textStyle.png

3.textAlign

enum TextAlign {
  /// Align the text on the left edge of the container.
  left,

  /// Align the text on the right edge of the container.
  right,

  /// Align the text in the center of the container.
  center,

  /// Stretch lines of text that end with a soft line break to fill the width of
  /// the container.
  ///
  /// Lines that end with hard line breaks are aligned towards the [start] edge.
  justify,

  /// Align the text on the leading edge of the container.
  ///
  /// For left-to-right text ([TextDirection.ltr]), this is the left edge.
  ///
  /// For right-to-left text ([TextDirection.rtl]), this is the right edge.
  start,

  /// Align the text on the trailing edge of the container.
  ///
  /// For left-to-right text ([TextDirection.ltr]), this is the right edge.
  ///
  /// For right-to-left text ([TextDirection.rtl]), this is the left edge.
  end,
}

textAlignRight.png

body: new Container(
        width: 200.0,
        height: 200.0,
        color: Colors.green,
        child: new Text('4588856125146s 848fsf4sd6fa46fa4sf4a6sfsf46sf1a1',
          textAlign: TextAlign.right,),
      ),

4.textDirection
This decides how textAlign values like TextAlign.start and TextAlign.end are interpreted.
如文档介绍，他和textAlign.start 和textAlign.end一样，这里不多做介绍。

5.softWrap
文本是否能换行,bool类型

5.overflow

enum TextOverflow {
  /// Clip the overflowing text to fix its container.
  clip,

  /// Fade the overflowing text to transparent.
  fade,

  /// Use an ellipsis to indicate that the text has overflowed.
  ellipsis,
}

overflow 用来指定超出文本的表示方式，是截断文本啊还是用三个点显示等

6.maxLines
用来指定文本最多显示多少行

7.textScaleFactor
文本字体的缩放倍数，如：1.5则在默认字体上变成1.5倍大小字体，0.5则是0.5倍

下面讲解第二种构造方式textSpan

new Text.rich(
            new TextSpan(
              text: '聆听璇律测试',
              children: <TextSpan>[
                new TextSpan(
                  text: '测试1',
                  style: new TextStyle(color: Colors.red)
                ),
                new TextSpan(
                    text: '哈哈',
                    style: new TextStyle(color: Colors.yellow)
                ),
              ]
            )
        )

textSpan.png