調用方法：
Container(
height: 200,
width: MediaQuery
.of(context)
.size
.width * 0.9 * (8 / 12),
child: new Sparkline(
data: lineValuesList,
allLength: lineCount,
fillMode: FillMode.below,
fillColor: Colors.grey,
lineColor: Colors.deepOrangeAccent,
lineWidth: 1.0,
yMax: yMax,
yMin: yMin,
)
)
