如何制作实时多折线图？

Question

我想使用MPAndroidChart 制作实时多折线图。

只用一个数据做实时图是没有问题的。 （以下代码）

private void addEntry(int count) {
    LineData data = mChart.getData();

    if (data != null) {
        LineDataSet set = data.getDataSetByIndex(0);

        if (set == null) {
            set = createSet();
            data.addDataSet(set);
        }

        data.addXValue("");

        data.addEntry(new Entry(getPressure(), set.getEntryCount()), 0);

        data.setDrawValues(false);
        data.setHighlightEnabled(false);

        // let the chart know it's data has changed
        mChart.notifyDataSetChanged();

        // limit the number of visible entries
        mChart.setVisibleXRange(0, count);

        // move to the latest entry
        mChart.moveViewToX(data.getXValCount() - (count + 1));
    }
}

而且，使用以下代码制作多折线图也没有问题。

private void setData(int count, float range) {
    ArrayList<String> xValues = new ArrayList<String>();
    for (int i = 0 ; i < count ; i++) {
        xValues.add((1 + i) + "");
    }

    ArrayList<LineDataSet> dataSets = new ArrayList<LineDataSet>();

    for (int k = 0 ; k < 3 ; k++) {
        ArrayList<Entry> yValues = new ArrayList<Entry>();

        for (int i = 0 ; i < count ; i++) {
            if (k == 0) {
                yValues.add(new Entry(getSetPressure(), i));
            }
            else if (k == 1) {
                yValues.add(new Entry(getCurrentPressure(), i));
            }
            else {
                yValues.add(new Entry(getSuctionPressure(), i));
            }
        }

        String s;
        String c;
        if (k == 0) {
            s = "Set Pressure";
            c = "#ed1f24";
        }
        else if (k == 1) {
            s = "Current Pressure";
            c = "#004bf6";
        }
        else {
            s = "Suction Pressure";
            c = "#ffba00";
        }

        LineDataSet set = new LineDataSet(yValues, s);

        set.setAxisDependency(YAxis.AxisDependency.LEFT);
        set.setDrawCubic(false);
        set.setDrawCircles(false);
        set.setCircleColor(Color.parseColor(c));
        set.setCircleSize(8f);
        set.setCircleColorHole(Color.BLACK);
        set.setDrawCircleHole(false);
        set.setLineWidth(3f);
        set.setColor(Color.parseColor(c));
        set.setDrawHorizontalHighlightIndicator(false);
        set.setDrawVerticalHighlightIndicator(false);

        dataSets.add(set);
    }

    LineData data = new LineData(xValues, dataSets);

    data.setDrawValues(false);
    data.setHighlightEnabled(false);

    mChart.setData(data);
}

但是，我不知道如何制作多个实时折线图。

如何制作多个实时折线图？

Answer 1

您实际上在您的问题中发布了您的问题的答案。

这一行是关键：

data.addEntry(... , 0);

末尾的0 指定应插入条目的数据集索引。

因此，您需要做的只是创建与您想要的行一样多的空DataSets，然后使用上述方法和正确的索引将您的Entries 添加到您想要的任何DataSet。

Here您可以找到动态和实时数据的官方 wiki 条目。

Answer 2

private void addEntry(int min, int max) {
    data = mChart.getData();
    if (data != null) {
        LineDataSet dataSetGraphA = data.getDataSetByIndex(0);
        LineDataSet dataSetGraphB = data.getDataSetByIndex(1);
        LineDataSet dataSetGraphC = data.getDataSetByIndex(2);
        LineDataSet dataSetGraphD = data.getDataSetByIndex(3);
        // LineDataSet set1= data.getDataSetByIndex(1);
        // set.addEntry(...); // can be called as well
        if (dataSetGraphA == null) {
            dataSetGraphA = setLineDataSet(0);
            data.addDataSet(dataSetGraphA);
        }
        if (dataSetGraphB == null) {
            dataSetGraphB = setLineDataSet(1);
            data.addDataSet(dataSetGraphB);
        }
        if (dataSetGraphC == null) {
            dataSetGraphC = setLineDataSet(2);
            data.addDataSet(dataSetGraphC);
        }
        if (dataSetGraphD == null) {
            dataSetGraphD = setLineDataSet(3);
            data.addDataSet(dataSetGraphD);
        }
        Calendar c = Calendar.getInstance();

        // yyyy-MM-dd.HH.mm.ss.SS
        SimpleDateFormat df = new SimpleDateFormat("HH:mm:ss.SS");
        String formattedDate = df.format(c.getTime());
        // Now formattedDate have current date/time
        System.out.println("Current time = " + formattedDate);
        Toast.makeText(this, formattedDate, Toast.LENGTH_SHORT).show();
        // add a new x-value first
        data.addXValue(formattedDate);
        data.addEntry(
                new Entry(randomInRange(min, max), dataSetGraphA
                        .getEntryCount()), 0);
        data.addEntry(
                new Entry(randomInRange(min, max), dataSetGraphB
                        .getEntryCount()), 1);
        data.addEntry(
                new Entry(randomInRange(min, max), dataSetGraphC
                        .getEntryCount()), 2);
        data.addEntry(
                new Entry(randomInRange(min, max), dataSetGraphD
                        .getEntryCount()), 3);

        // let the chart know it's data has changed
        mChart.notifyDataSetChanged();

        mChart.setVisibleXRangeMaximum(6);
        mChart.setVisibleYRangeMaximum(15, AxisDependency.LEFT);
        //
        // // this automatically refreshes the chart (calls invalidate())
        mChart.moveViewTo(data.getXValCount() - 7, 50f, AxisDependency.LEFT);
    }
}

Answer 3

这是一个简单的例子：

private void addEntry() {

    LineData data = mChart.getData();

    LineDataSet set0 = (LineDataSet) data.getDataSetByIndex(0);
    LineDataSet set1 = (LineDataSet) data.getDataSetByIndex(1);

    if (set0 == null || set1 == null) {
        // creation of null
        set0 = createSet();
        set1 = createSet();

        data.addDataSet(set0);
        data.addDataSet(set1);
    }

    data.addXValue("");

    data.addEntry(new Entry((float) (Math.random() * 20) + 2f, set0.getEntryCount()), 0);
    data.addEntry(new Entry((float) (Math.random() * 20) + 2f, set1.getEntryCount()), 1);

    mChart.notifyDataSetChanged();

    mChart.setVisibleXRangeMaximum(6);

    mChart.moveViewToX(data.getXValCount() - 7);            
}