import com.github.mikephil.charting.interfaces.datasets.IBarDataSet; //导入方法依赖的package包/类

/**

* Groups all BarDataSet objects this data object holds together by modifying the x-position of their entries.

* Previously set x-positions of entries will be overwritten. Leaves space between bars and groups as specified

* by the parameters.

* Do not forget to call notifyDataSetChanged() on your BarChart object after calling this method.

*

* @param fromX the starting point on the x-axis where the grouping should begin

* @param groupSpace the space between groups of bars in values (not pixels) e.g. 0.8f for bar width 1f

* @param barSpace the space between individual bars in values (not pixels) e.g. 0.1f for bar width 1f

*/

public void groupBars(float fromX, float groupSpace, float barSpace) {

int setCount = mDataSets.size();

if (setCount <= 1) {

throw new RuntimeException("BarData needs to hold at least 2 BarDataSets to allow grouping.");

}

IBarDataSet max = getMaxEntryCountSet();

int maxEntryCount = max.getEntryCount();

float groupSpaceWidthHalf = groupSpace / 2f;

float barSpaceHalf = barSpace / 2f;

float barWidthHalf = mBarWidth / 2f;

float interval = getGroupWidth(groupSpace, barSpace);

for (int i = 0; i < maxEntryCount; i++) {

float start = fromX;

fromX += groupSpaceWidthHalf;

IBarDataSet set;

final int setCountJ = mDataSets.size();

for(int j = 0 ; j < setCountJ ; j++){

set = mDataSets.get(j);

fromX += barSpaceHalf;

fromX += barWidthHalf;

if (i < set.getEntryCount()) {

BarEntry entry = set.getEntryForIndex(i);

if (entry != null) {

entry.setX(fromX);

}

}

fromX += barWidthHalf;

fromX += barSpaceHalf;

}

fromX += groupSpaceWidthHalf;

float end = fromX;

float innerInterval = end - start;

float diff = interval - innerInterval;

// correct rounding errors

if (diff > 0 || diff < 0) {

fromX += diff;

}

}

notifyDataChanged();

}