MPAndroidChart的K线图上添加均线
- 效果图
均线计算方法：
通常说的5日均线，10日均线，其实就是根据当前K线节点的时间维度来说的，当前每个节点代表一天，那么上面的均线就叫做日均线(几日均线)，下面就统一说成几节点均线
那么5节点均线，10节点均线等等，是怎么计算出来的呢
以5节点均线为例，5节点均线是从第五根柱子开始画，一直画到最后一柱子（10节点均线就是从第10根柱子开始画，画到最后一根）
用第1、2、3、4、5个节点的收盘价之和，算出一个平均值，点在第5个节点上
用第2、3、4、5、6个节点的收盘价之和，算出一个平均值，点在低6个节点上
依此类推……最后将画在5、6、7、8……上的点连起来，就是5节点均线。（如果当前一个节点代表一天，那这条线就是5日均线）
源码
MPAndroidChart地址：https://github.com/PhilJay/MPAndroidChart
在CandleStickChartRenderer.java下添加画均线的方法
思路：在draw K线柱子的时候获取每个柱子的收盘值，根据收盘值，计算均值
Demo Code
均线的实现，请移步到在MPAndroidChart库K线图的基础上画均线
下面实现的均线是第一版，见效果图，实现逻辑上略有问题，可直接忽略
@Override
public void drawData(Canvas c) {
CandleData candleData = mChart.getCandleData();
for (CandleDataSet set : candleData.getDataSets()) {
if (set.isVisible() && set.getEntryCount() > 0)
drawDataSet(c, set);
}
}
protected void drawDataSet(Canvas c, CandleDataSet dataSet) {
Transformer trans = mChart.getTransformer(dataSet.getAxisDependency());
float phaseX = mAnimator.getPhaseX();
float phaseY = mAnimator.getPhaseY();
int dataSetIndex = mChart.getCandleData().getIndexOfDataSet(dataSet);
List<CandleEntry> entries = dataSet.getYVals();
int minx = Math.max(mMinX, 0);
int maxx = Math.min(mMaxX + 1, entries.size());
int range = (maxx - minx) * 4;
int to = (int) Math.ceil((maxx - minx) * phaseX + minx);
CandleBodyBuffer bodyBuffer = mBodyBuffers[dataSetIndex];
bodyBuffer.setBodySpace(dataSet.getBodySpace());
bodyBuffer.setPhases(phaseX, phaseY);
bodyBuffer.limitFrom(minx);
bodyBuffer.limitTo(maxx);
bodyBuffer.feed(entries);
trans.pointValuesToPixel(bodyBuffer.buffer);
CandleShadowBuffer shadowBuffer = mShadowBuffers[dataSetIndex];
shadowBuffer.setPhases(phaseX, phaseY);
shadowBuffer.limitFrom(minx);
shadowBuffer.limitTo(maxx);
shadowBuffer.feed(entries);
trans.pointValuesToPixel(shadowBuffer.buffer);
mRenderPaint.setStrokeWidth(dataSet.getShadowWidth());
ArrayList<Float> closes = new ArrayList<Float>();
ArrayList<Float> jx = new ArrayList<Float>();
// draw the body
for (int j = 0; j < range; j += 4) {
// get the entry
CandleEntry e = entries.get(j / 4 + minx);
if (!fitsBounds(e.getXIndex(), mMinX, to))
continue;
if (dataSet.getShadowColorSameAsCandle()) {
if (e.getOpen() > e.getClose())
mRenderPaint.setColor(
dataSet.getDecreasingColor() == ColorTemplate.COLOR_NONE ?
dataSet.getColor(j) :
dataSet.getDecreasingColor()
);
else if (e.getOpen() < e.getClose())
mRenderPaint.setColor(
dataSet.getIncreasingColor() == ColorTemplate.COLOR_NONE ?
dataSet.getColor(j) :
dataSet.getIncreasingColor()
);
else
mRenderPaint.setColor(
dataSet.getShadowColor() == ColorTemplate.COLOR_NONE ?
dataSet.getColor(j) :
dataSet.getShadowColor()
);
} else {
mRenderPaint.setColor(
dataSet.getShadowColor() == ColorTemplate.COLOR_NONE ?
dataSet.getColor(j) :
dataSet.getShadowColor()
);
}
mRenderPaint.setStyle(Paint.Style.STROKE);
// draw the shadow
c.drawLine(shadowBuffer.buffer[j], shadowBuffer.buffer[j + 1],
shadowBuffer.buffer[j + 2], shadowBuffer.buffer[j + 3],
mRenderPaint);
float leftBody = bodyBuffer.buffer[j];
float open = bodyBuffer.buffer[j + 1];
float rightBody = bodyBuffer.buffer[j + 2];
float close = bodyBuffer.buffer[j + 3];
closes.add(close);
jx.add((leftBody + rightBody) / 2);
// draw body differently for increasing and decreasing entry
if (open > close) { // decreasing
if (dataSet.getDecreasingColor() == ColorTemplate.COLOR_NONE) {
mRenderPaint.setColor(dataSet.getColor(j / 4 + minx));
} else {
mRenderPaint.setColor(dataSet.getDecreasingColor());
}
mRenderPaint.setStyle(dataSet.getDecreasingPaintStyle());
// draw the body
c.drawRect(leftBody, close, rightBody, open, mRenderPaint);
} else if (open < close) {
if (dataSet.getIncreasingColor() == ColorTemplate.COLOR_NONE) {
mRenderPaint.setColor(dataSet.getColor(j / 4 + minx));
} else {
mRenderPaint.setColor(dataSet.getIncreasingColor());
}
mRenderPaint.setStyle(dataSet.getIncreasingPaintStyle());
// draw the body
c.drawRect(leftBody, open, rightBody, close, mRenderPaint);
} else { // equal values
mRenderPaint.setColor(dataSet.getShadowColor());
c.drawLine(leftBody, open, rightBody, close, mRenderPaint);
}
// 5节点均线
drawLine(c, 5, closes, jx);
// 10节点均线
drawLine(c, 10, closes, jx);
// 30节点均线
drawLine(c, 30, closes, jx);
}
}
/**
* 画均线
* @param c
* @param i
* @param closes
* @param jx
*/
private void drawLine(Canvas c, int i, ArrayList<Float> closes, ArrayList<Float> jx) {
Paint paint = new Paint();
// 画线宽度
paint.setStrokeWidth(1);
// 画线颜色
if (5 == i) {
paint.setColor(Color.BLUE);
} else if (10 == i) {
paint.setColor(Color.RED);
} else if (30 == i) {
paint.setColor(Color.BLACK);
} else {
paint.setColor(Color.GREEN);
}
if (closes.size() >= i + 1) {
float startX = jx.get(closes.size() - 2);
float startY = 0;
for (int x = 0; x < i; x++) {
startY += closes.get(closes.size() - 2 - x);
}
startY = startY / i;
float endX = jx.get(closes.size() - 1);
float endY = 0;
for (int y = 0; y < i; y++) {
endY += closes.get(closes.size() - 1 - y);
}
endY = endY / i;
c.drawLine(startX, startY, endX, endY, paint);
}
}
