在用MPAndroidChart 中发现 x轴 数据会出现重复，于是乎各种找答案，最后还是在源码中发现了有一个方法
xAxis.setGranularity(1f); //设置x轴每最小刻度
/**
* Set a minimum interval for the axis when zooming in. The axis is not allowed to go below
* that limit. This can be used to avoid label duplicating when zooming in（PS:这个是关键，幸好我一眼认出了 duplicating,否则还在这个问题上困扰着呢）
*@param granularity
*/
public void setGranularity(float granularity) {
mGranularity = granularity;
// set this to true if it was disabled, as it makes no sense to call this method with granularity disabled
mGranularityEnabled =true;
}
