MPAndroidChart的K线图上添加均线

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）

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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);
    }
}

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