MPAndroidChart LineChart x轴的取值问题。

我自定义了一个IAxisValueFormatter来自定义X轴的值,

 /**
 * Created by Philipp Jahoda on 20/09/15.
 * Custom formatter interface that allows formatting of
 * axis labels before they are being drawn.
 */
public interface IAxisValueFormatter
{

    /**
     * Called when a value from an axis is to be formatted
     * before being drawn. For performance reasons, avoid excessive calculations
     * and memory allocations inside this method.
     *
     * @param value the value to be formatted
     * @param axis  the axis the value belongs to
     * @return
     */
    String getFormattedValue(float value, AxisBase axis);
}

就是这个接口,刚开始我以为它传给我的只会是1.0,2.0,3.0这样的浮点值,结果发现不是的,什么样的值都会有。
情况是这样的,我的界面中有个LineChart这个控件,这个控件第一次显示是正常的,也就是说

   String getFormattedValue(float value, AxisBase axis);

这个方法里传给我的value都是1.0,2.0,3.0这样的值,由于项目功能需要,有的时候需要清除掉之前的数据,重新加载数据并显示所以我就先清除数据。


     //清除数据
     private void clearChartData(LineChart chart) {
        LineData data = chart.getLineData();
        if (data != null) {
            //data.clearValues();
            //chart.getXAxis().resetAxisMaximum();
           // chart.clearValues();
            chart.clear();
           // chart.setVisibleXRangeMaximum(10);
            //chart.moveViewToX(0);
            //chart.setLeft(0);
        }

    }

再重新加载数据:

    /**
     * 增加数据
     *
     * @param data 增加的数据的y轴的值
     */
    public static void addDataForTime(float data, LineChart chart, Context context) {
        if (chart.getData() == null ||
                chart.getData().getDataSetCount() < 1 || chart.getData().getEntryCount() == 0) {
            ChartUtils.initMPChart(chart, context, data, 10, new DayAxisValueFormatter(20));
            return;
        }

        chart.getData().getDataSetByIndex(0).addEntry(new Entry(chart.getData().getDataSetByIndex(0).getEntryCount(),
                data, context.getResources().getDrawable(R.drawable.ic_launcher)));
        chart.getData().notifyDataChanged();
        chart.notifyDataSetChanged();
        if (chart.getData().getDataSetByIndex(0).getEntryCount() > 10) {
            Log.e("infoo", "maxAxis = " + chart.getXAxis().getAxisMaximum() + " entryCount = "
                    + chart.getData().getDataSetByIndex(0).getEntryCount() + " left = " + chart.getLeft());
            chart.getXAxis().resetAxisMaximum();
            chart.setVisibleXRangeMaximum(10);
            chart.moveViewToX(chart.getData().getDataSetByIndex(0).getEntryCount() - 10);
            // chart.setLeft(chart.getData().getDataSetByIndex(0).getEntryCount() - 10);
        } else {
            chart.invalidate();
        }
    }


            /**
     * 对表格进行初始化
     *
     * @param chart   初始化的MPChart
     * @param context activity上下文
     * @param value   第一个值
     */
    public static void initMPChart(LineChart chart, Context context, float value, int count, IAxisValueFormatter iAxisValueFormatter) {
        Log.e("infoo", "初始化表格");
        ArrayList<Entry> values = new ArrayList<>();
        values.add(new Entry(0, value, context.getResources().getDrawable(R.drawable.ic_launcher)));

        LineDataSet set1;


        // create a dataset and give it a type
        set1 = new LineDataSet(values, "");

        set1.setDrawIcons(false);

        // 设置数据的说明
        chart.getLegend().setForm(Legend.LegendForm.EMPTY);
        Description description = new Description();
        description.setText("");
        chart.setDescription(description);


        //禁用缩放图表上的两个轴
        chart.setScaleEnabled(false);

        //修改x轴线的样式
        XAxis xAxis = chart.getXAxis();
        xAxis.setAxisLineWidth(1);
        xAxis.setPosition(XAxis.XAxisPosition.BOTTOM);
        xAxis.setAxisLineColor(ContextCompat.getColor(context, R.color.black));
        xAxis.setGridColor(ContextCompat.getColor(context, R.color.LightGrey));
        xAxis.setGridLineWidth(1);
        xAxis.enableGridDashedLine(3, 3, 0);
        xAxis.setTextSize(18);
        xAxis.setAxisMaximum(count);
        xAxis.setAxisMinimum(0);
        if (iAxisValueFormatter != null) {
            xAxis.setValueFormatter(iAxisValueFormatter);
        }

        //修改y轴的样式
        YAxis leftAxis = chart.getAxisLeft();
        YAxis rightAxis = chart.getAxisRight();
        rightAxis.setEnabled(false);
        leftAxis.setGridLineWidth(1);
        leftAxis.enableGridDashedLine(3, 3, 0);
        leftAxis.setAxisLineColor(ContextCompat.getColor(context, R.color.black));
        leftAxis.setStartAtZero(true);
        leftAxis.setTextSize(18);


        //设置折线的一些属性
        set1.setDrawValues(false);
        set1.setColor(ContextCompat.getColor(context, R.color.DeepSkyBlue));
        set1.setLineWidth(1f);
        set1.setCircleRadius(3f);
        set1.setDrawCircleHole(false);
        set1.setDrawCircles(false);
        set1.setValueTextSize(9f);
        set1.setDrawFilled(true);
        set1.setFormLineWidth(1f);
        set1.setFormLineDashEffect(new DashPathEffect(new float[]{10f, 5f}, 0f));
        set1.setFormSize(15.f);

        if (Utils.getSDKInt() >= 18) {
            // 填充 drawable
            Drawable drawable = ContextCompat.getDrawable(context, R.drawable.fade_red);
            set1.setFillDrawable(drawable);
        } else {
            set1.setFillColor(ContextCompat.getColor(context, R.color.LightBLue));
        }

        // create a data object with the datasets
        LineData data = new LineData(set1);

        // set data
        chart.setData(data);
        chart.setNoDataText("还没有任何数据哦");
        chart.moveViewToX(0);
        //chart.invalidate();
/*        for (float f : xAxis.mEntries) {
            Log.e("infoo", "float = " + f);
        }*/
    }

有的时候是正常的,还是会传给我1.0,2.0,3.0这样的值,但是有的时候,会传给我一些莫名其妙的float值,比如说,0,02,0,32这样的,很无赖。然后去看它的源码,发现它会在BarLineChartBase.java里面调用这样一个方法:

         if (mXAxis.isEnabled()){
           // Log.e("infoo", "min = " + mXAxis.mAxisMinimum + " max = " + mXAxis.mAxisMaximum);
            mXAxisRenderer.computeAxis(mXAxis.mAxisMinimum, mXAxis.mAxisMaximum, false);
        }

然后一直往里面走,会发现是这样的方法:

     /**
     * Transforms the given array of touch positions (pixels) (x, y, x, y, ...)
     * into values on the chart.
     *
     * @param pixels
     */
    public void pixelsToValue(float[] pixels) {

        Matrix tmp = mPixelToValueMatrixBuffer;
        tmp.reset();

        mMatrixOffset.invert(tmp);
        tmp.mapPoints(pixels);

        mViewPortHandler.getMatrixTouch().invert(tmp);
        tmp.mapPoints(pixels);


        mMatrixValueToPx.invert(tmp);
        tmp.mapPoints(pixels);

    }

看着很懵逼,有没有人遇到过这个情况的?

1个回答

Csdn user default icon
上传中...
上传图片
插入图片
抄袭、复制答案,以达到刷声望分或其他目的的行为,在CSDN问答是严格禁止的,一经发现立刻封号。是时候展现真正的技术了!
立即提问
相关内容推荐