更新平移和缩放图 - achartengine

Question

我终于在我的应用程序中添加了三角图。图表很好地显示但是在缩放或平移时它没有更新，所以我添加了更新代码，但是当它更新时它会显示奇怪的行，如照片中所示：

我的代码：

    public void addFunction() {
    layout.removeAllViewsInLayout();
    layout.addView(mChartView, new LayoutParams(
            LayoutParams.MATCH_PARENT, LayoutParams.MATCH_PARENT));
    undo.setVisibility(View.VISIBLE);
    mChartView.setOnClickListener(new OnClickListener() {
        public void onClick(View v) {

        }
    });
    mRenderer.setZoomEnabled(true);
    double[] Xs;
    double[] values;
    int step = 4;
    int count = 360 / step + 1;
    Xs = (new double[count]);
    values = new double[count];
    for (int i = 0; i < count; i++) {
        int angle = i * step;
        Xs[i] = angle;
        double rAngle = Math.toRadians(angle);
        values[i] = Math.sin(rAngle);
    }
        XYSeriesRenderer renderer = new XYSeriesRenderer();
        // set some renderer properties
        renderer.setPointStyle(PointStyle.CIRCLE);
        renderer.setFillPoints(true);
        XYSeries series = new XYSeries("Trig", 0);
        int seriesLength = Xs.length;
        for (int k = 0; k < seriesLength; k++) {
            series.add(Xs[k], values[k]);
        }
        mRenderer.addSeriesRenderer(renderer);
        mDataset.addSeries(series);
    mCurrentSeries = series;
    mChartView.repaint();
    mChartView.addPanListener(new PanListener() {
        @Override
        public void panApplied() {
            updateGraph();
        }
    });
    mChartView.addZoomListener(new ZoomListener() {
        @Override
        public void zoomReset() {
            updateGraph();
        }

        @Override
        public void zoomApplied(ZoomEvent e) {
            updateGraph();
        }
    }, true, true);
}

这是更新图表的代码：

    public void updateGraph() {
    final double minY = mRenderer.getYAxisMin();
    final double maxY = mRenderer.getYAxisMax();
    final double minX = mRenderer.getXAxisMin();
    final double maxX = mRenderer.getXAxisMax();
    double lastX = (maxX-minX)/2+minX;
    double lastY = (maxY-minY)/2+minY;
    for(double x=minX;x<=maxX;x+=(0.00125*(maxX-minX))) {
        double rAngle = Math.toRadians(x);
        double y = Math.sin(rAngle);
        if(pointIsNaN(lastY, y, maxY, minY)) {
            mCurrentSeries.add(x, MathHelper.NULL_VALUE);
        }
        else if(pointIsNaN(lastX, x, maxX, minX)) {
            mCurrentSeries.add(MathHelper.NULL_VALUE, y);
        }
        else{
            mCurrentSeries.add(x, y);
        }
    }
    mChartView.repaint();
}