android - achartengine toScreenPoint(double) 总是返回 nullPointerException

Question

每次我调用这个方法时它都会返回 nullpointerexception:

org.achartengine.chart.XYChart.toScreenPoint(XYChart.java:867) 出现 java.lang.NullPointerException

我看到图表的 mScreenR 为空

如果不使用此方法 toScreenPoint(double)，图表运行良好，这是代码:

    package com.insights.insights.gui;

import java.util.ArrayList;

import org.achartengine.ChartFactory;
import org.achartengine.GraphicalView;
import org.achartengine.chart.LineChart;
import org.achartengine.chart.PointStyle;
import org.achartengine.chart.XYChart;
import org.achartengine.model.XYMultipleSeriesDataset;
import org.achartengine.model.XYSeries;
import org.achartengine.renderer.XYMultipleSeriesRenderer;
import org.achartengine.renderer.XYSeriesRenderer;

import com.insights.insights.R;
import com.insights.insights.local.ApplicationsController;
import com.insights.insights.model.AppMetrics;
import com.insights.insights.model.Application;
import com.insights.insights.model.Applications;
import com.insights.insights.model.Day;

import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.AbsoluteLayout;
import android.widget.LinearLayout;
import android.widget.Toast;

public class ChartFragment extends Fragment {

    private XYMultipleSeriesRenderer renderer;
    private XYMultipleSeriesDataset dataset;
    private GraphicalView graphicalView;
    private XYSeries firstSeries;
    private XYChart chart=null;

    private String apiKey;
    private ArrayList<Day> days;

    private View view;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        apiKey = getArguments().getString(getString(R.string.tabs_activity_api_key));
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        View v = inflater.inflate(R.layout.chart_fragment, container, false);

        v.findViewById(R.idChartFragment.container).requestFocus();

        this.view = v;

        return v;
    }

    @Override
    public void onActivityCreated(Bundle savedInstanceState) {
        super.onActivityCreated(savedInstanceState);

        //      Obtaining data to plot
        Applications applications = ApplicationsController.getInstance(getActivity()).getApplications();
        ArrayList<Application> applicationArray = applications.getApplication();

        if (applicationArray != null && !applicationArray.isEmpty()) {
            for (int i = 0; i < applicationArray.size(); i++) {
                if (applicationArray.get(i).getApiKey().equals(apiKey)) {
                    ArrayList<AppMetrics> appMetrics = applicationArray.get(i).getAppMetrics();
                    for (int j = 0; j < appMetrics.size(); j++) {
                        if (appMetrics.get(j).getMetric().equals("Sessions")) {
                            days = appMetrics.get(j).getDay();
                            break;
                        }
                    }
                }
            }
        }

        // If there isn't any item to plot and show a toast
        if (days == null) {
            Toast toast = Toast.makeText(getActivity(), R.string.chart_fragment_no_items, Toast.LENGTH_LONG);
            toast.show();
            return;
        }

        // Ploting the items
        dataset = getDataset(days);
        renderer = getRenderer();
        setRendererStyling(renderer);

        // add plot to the layout
        if (graphicalView == null) {
            LinearLayout layout = (LinearLayout) view.findViewById(R.idChartFragment.Chart);
            chart= new LineChart(dataset, renderer);
            graphicalView = new GraphicalView(getActivity(), chart);
            renderer.setSelectableBuffer(11);

            layout.addView(graphicalView);
        } else{
            graphicalView.repaint();
        }


        if(chart!=null&&firstSeries!=null){
            for(int i=0;i<firstSeries.getItemCount();i++){
                double x = firstSeries.getX(i);
                double y = firstSeries.getY(i);

                double[] screenPoint = chart.toScreenPoint(new double[] { x, y },0);

                Log.i("puntos", x + "," + y + " = "+" ("+screenPoint[0]+", "+screenPoint[1]+")");
            }
        }
    }

    /**
     * Method for set the style of the plotter window and the string at the x
     * axis
     * 
     * @param mRenderer
     *            render to put style in
     * 
     * @param dataSetX
     *            string to set at x axis
     */
    private void setRendererStyling(XYMultipleSeriesRenderer mRenderer) {
        mRenderer.setApplyBackgroundColor(false);
        mRenderer.setMarginsColor(R.drawable.transperent_color);
        mRenderer.setMargins(new int[] { 0, 0, 0, 0 });
        mRenderer.setShowAxes(false);
        mRenderer.setZoomButtonsVisible(false);
        mRenderer.setExternalZoomEnabled(false);
        mRenderer.setPointSize(20);
        mRenderer.setClickEnabled(false);
        mRenderer.setDisplayValues(false);
        mRenderer.setXLabels(0);
        mRenderer.setYLabels(0);
        mRenderer.setPanEnabled(false);
        mRenderer.setZoomEnabled(false);
        mRenderer.setShowLegend(false);

    }

    /**
     * Method to introduce the values of the y axis
     * 
     * @param dataSetY
     *            data to set at axis y
     * @return the data to set
     */
    private XYMultipleSeriesDataset getDataset(ArrayList<Day> days) {

        XYMultipleSeriesDataset dataset = new XYMultipleSeriesDataset();
        firstSeries = new XYSeries("");

        for (int i = 0; i < 12; i++) {

            int value = Integer.parseInt(days.get(days.size() - (13 - i)).getValue());
            firstSeries.add(i, value);

        }
        dataset.addSeries(firstSeries);
        return dataset;
    }

    /**
     * Method for set the style of the line you want to plot and create a new
     * renderer
     * 
     * @return the renderer
     */
    private XYMultipleSeriesRenderer getRenderer() {
        XYMultipleSeriesRenderer renderer = new XYMultipleSeriesRenderer();
        XYSeriesRenderer r = new XYSeriesRenderer();
        r.setColor(getResources().getColor(R.color.grey_number_label_background));
        r.setLineWidth(getResources().getInteger(R.integer.chart_fragment_line_width));
        // r.setDisplayChartValues(true);
        r.setPointStyle(PointStyle.POINT);
        r.setFillPoints(true);
        renderer.addSeriesRenderer(r);
        return renderer;
    }
}

这是布局文件:

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+idChartFragment/container"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_gravity="center_horizontal">

    <LinearLayout
        android:id="@+idChartFragment/Chart"
        android:layout_width="300dp"
        android:layout_height="300dp"
        android:orientation="horizontal"/>


    <AbsoluteLayout 
        android:id="@+idChartFragment/absolute"
        android:layout_width="300dp"
        android:layout_height="300dp"/>

</RelativeLayout>

第二次编辑:

我想做这样的事情:

使用我的代码，我这样做:

这是我的代码:

 package com.insights.insights.gui;

import java.util.ArrayList;
import java.util.List;

import org.achartengine.GraphicalView;
import org.achartengine.chart.ClickableArea;
import org.achartengine.chart.LineChart;
import org.achartengine.chart.PointStyle;
import org.achartengine.chart.XYChart;
import org.achartengine.model.SeriesSelection;
import org.achartengine.model.XYMultipleSeriesDataset;
import org.achartengine.model.XYSeries;
import org.achartengine.renderer.SimpleSeriesRenderer;
import org.achartengine.renderer.XYMultipleSeriesRenderer;
import org.achartengine.renderer.XYSeriesRenderer;

import android.graphics.Canvas;
import android.graphics.Paint;
import android.graphics.Typeface;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.text.Layout;
import android.util.AttributeSet;
import android.util.Log;
import android.view.Gravity;
import android.view.LayoutInflater;
import android.view.View;
import android.view.View.OnClickListener;
import android.view.ViewGroup;
import android.view.ViewTreeObserver.OnGlobalLayoutListener;
import android.widget.AbsoluteLayout;
import android.widget.AbsoluteLayout.LayoutParams;
import android.widget.Button;
import android.widget.ImageView;
import android.widget.LinearLayout;
import android.widget.TextView;
import android.widget.Toast;

import com.google.android.maps.ItemizedOverlay.OnFocusChangeListener;
import com.insights.insights.R;
import com.insights.insights.local.ApplicationsController;
import com.insights.insights.model.AppMetrics;
import com.insights.insights.model.Application;
import com.insights.insights.model.Applications;
import com.insights.insights.model.Day;

/**
 * 
 * @author Manuel Plazas Palacio
 * 
 */
public class ChartFragment extends Fragment {

    private XYMultipleSeriesRenderer renderer;
    private XYMultipleSeriesDataset dataset;
    private GraphicalView graphicalView;
    private XYSeries firstSeries;
    private XYChart chart = null;

    private AbsoluteLayout absoluteLayout;
    private ImageView point;
    private LinearLayout pointInfoConatiner;
    private TextView pointNumberText;
    private TextView pointNameText;
    private TextView pointDateText;

    private Typeface avenirHeavy;
    private Typeface avenirLight;

    private String apiKey;
    private String metricName;
    private ArrayList<Day> days;

    //  The max and the min values displayed
    private double max = 0;
    private double min = 0;

    private View view;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        apiKey = getArguments().getString(getString(R.string.tabs_activity_api_key));
        metricName = "Sessions";
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        View v = inflater.inflate(R.layout.chart_fragment, container, false);

        v.findViewById(R.idChartFragment.container).requestFocus();

        this.view = v;

        absoluteLayout = (AbsoluteLayout) v.findViewById(R.idChartFragment.absolute);
        //      pointInfoConatiner = (LinearLayout) v.findViewById(R.idChartFragment.pointInfoContainer);
        //      pointNumberText = (TextView) v.findViewById(R.idChartFragment.pointNumberText);
        //      pointNameText = (TextView) v.findViewById(R.idChartFragment.pointNameText);
        //      pointDateText =  (TextView) v.findViewById(R.idChartFragment.pointDateText);
        //
        //      pointNameText.setText(metricName);

        //      Obtaining data to plot
        Applications applications = ApplicationsController.getInstance(getActivity()).getApplications();
        ArrayList<Application> applicationArray = applications.getApplication();

        if (applicationArray != null && !applicationArray.isEmpty()) {
            for (int i = 0; i < applicationArray.size(); i++) {
                if (applicationArray.get(i).getApiKey().equals(apiKey)) {
                    ArrayList<AppMetrics> appMetrics = applicationArray.get(i).getAppMetrics();
                    for (int j = 0; j < appMetrics.size(); j++) {
                        if (appMetrics.get(j).getMetric().equals(metricName)) {
                            days = appMetrics.get(j).getDay();
                            break;
                        }
                    }
                }
            }
        }

        // If there isn't any item to plot and show a toast
        if (days == null) {
            Toast toast = Toast.makeText(getActivity(), R.string.chart_fragment_no_items, Toast.LENGTH_LONG);
            toast.show();
        }

        // Ploting the items
        dataset = getDataset(days);
        renderer = getRenderer();
        setRendererStyling(renderer);

        // add plot to the layout
        if (graphicalView == null) {
            LinearLayout layout = (LinearLayout) view.findViewById(R.idChartFragment.Chart);
            chart = new LineChart(dataset, renderer);

            graphicalView = new GraphicalView(getActivity(), chart);
            renderer.setSelectableBuffer(11);

            layout.addView(graphicalView);
        } else {
            graphicalView.repaint();
        }

        return v;
    }

    @Override
    public void onActivityCreated(Bundle savedInstanceState) {
        super.onActivityCreated(savedInstanceState);

        avenirHeavy = Typeface.createFromAsset(getActivity().getAssets(), "fonts/Avenir Heavy.ttf");
        avenirLight = Typeface.createFromAsset(getActivity().getAssets(), "fonts/Avenir Light.ttf");

        graphicalView.setOnClickListener(new OnClickListener() {

            @Override
            public void onClick(View v) {

                SeriesSelection seriesSelection = graphicalView.getCurrentSeriesAndPoint();
                double[] xy = graphicalView.toRealPoint(0);
                //creating the views
                createOnClickPointsView();

                if (seriesSelection != null) {

                    //                  debug
                    Log.d("Punto", seriesSelection.getXValue() + ", " + seriesSelection.getValue());

                    double x = firstSeries.getX(seriesSelection.getPointIndex() + 1);
                    double y = firstSeries.getY(seriesSelection.getPointIndex() + 1);
                    double[] screenPoint = chart.toScreenPoint(new double[] { x, y });

                    //                  debug
                    Log.d("Chart point", "Chart element in series index " + seriesSelection.getSeriesIndex() + " data point index "
                            + seriesSelection.getPointIndex() + " was clicked" + " closest point value X=" + seriesSelection.getXValue()
                            + ", Y=" + seriesSelection.getValue() + " clicked point value X=" + (float) xy[0] + ", Y=" + (float) xy[1]);
                    Log.d("Punto pantalla", " (" + screenPoint[0] + ", " + screenPoint[1] + ")");

                    int value = Integer.parseInt(days.get((int) (days.size() - (13 - x))).getValue());
                    String date = days.get((int) (days.size() - (13 - x))).getDate();
                    pointNumberText.setText(value + "");
                    pointDateText.setText(date);

                    //                  drawing point info
                    absoluteLayout.addView(pointInfoConatiner, new LayoutParams(getResources().getDrawable(R.drawable.graficapin)
                            .getIntrinsicWidth(), getResources().getDrawable(R.drawable.graficapin).getIntrinsicHeight(),
                            (int) (screenPoint[0] - (getResources().getDrawable(R.drawable.graficapin).getIntrinsicWidth() / 2)),
                            (int) (screenPoint[1] - (getResources().getDrawable(R.drawable.graficapin).getIntrinsicHeight()))));

                    //                  drawing point clicked
                    absoluteLayout.addView(point, new LayoutParams(getResources().getDrawable(R.drawable.puntoon).getIntrinsicWidth(),
                            getResources().getDrawable(R.drawable.puntoon).getIntrinsicHeight(), (int) (screenPoint[0] - (getResources()
                                    .getDrawable(R.drawable.puntoon).getIntrinsicWidth() / 2)), (int) (screenPoint[1] - ((getResources()
                                    .getDrawable(R.drawable.puntoon).getIntrinsicHeight()) / 4))));
                }
            }
        });

    }

    /**
     * Method for set the style of the plotter window and the string at the x
     * axis
     * 
     * @param mRenderer
     *            render to put style in
     * 
     * @param dataSetX
     *            string to set at x axis
     */
    private void setRendererStyling(XYMultipleSeriesRenderer mRenderer) {
        mRenderer.setApplyBackgroundColor(false);
        mRenderer.setMarginsColor(R.drawable.transperent_color);
        mRenderer.setMargins(new int[] { 0, 0, 0, 0 });
        mRenderer.setShowAxes(false);
        mRenderer.setZoomButtonsVisible(false);
        mRenderer.setExternalZoomEnabled(false);
        mRenderer.setPointSize(getResources().getInteger(R.integer.chart_fragment_point_size));
        mRenderer.setClickEnabled(true);
        mRenderer.setDisplayValues(false);
        mRenderer.setXLabels(0);
        mRenderer.setYLabels(0);
        mRenderer.setPanEnabled(true);
        mRenderer.setZoomEnabled(false);
        mRenderer.setShowLegend(false);
        mRenderer.setYAxisMax(max + 10);
        mRenderer.setYAxisMin(min - 10);
    }

    /**
     * Method to introduce the values of the y axis
     * 
     * @param dataSetY
     *            data to set at axis y
     * @return the data to set
     */
    private XYMultipleSeriesDataset getDataset(ArrayList<Day> days) {

        XYMultipleSeriesDataset dataset = new XYMultipleSeriesDataset();
        firstSeries = new XYSeries("");

        for (int i = 0; i < 12; i++) {

            int value = Integer.parseInt(days.get(days.size() - (13 - i)).getValue());
            firstSeries.add(i, value);

        }
        dataset.addSeries(firstSeries);

        XYSeries secondSeries = new XYSeries("");
        for (int i = 1; i < 11; i++) {

            int value = Integer.parseInt(days.get(days.size() - (13 - i)).getValue());

            if (i == 1) {
                max = value;
                min = value;
            }

            if (value > max)
                max = value;
            if (value < min)
                min = value;

            secondSeries.add(i, value);

        }

        dataset.addSeries(secondSeries);
        return dataset;
    }

    /**
     * Method for set the style of the line you want to plot and create a new
     * renderer
     * 
     * @return the renderer
     */
    private XYMultipleSeriesRenderer getRenderer() {
        XYMultipleSeriesRenderer renderer = new XYMultipleSeriesRenderer();

        //First chart with the line
        XYSeriesRenderer r = new XYSeriesRenderer();
        r.setColor(getResources().getColor(R.color.grey_number_label_background));
        r.setLineWidth(getResources().getInteger(R.integer.chart_fragment_line_width));
        // r.setDisplayChartValues(true);
        r.setPointStyle(PointStyle.POINT);
        r.setFillPoints(true);
        renderer.addSeriesRenderer(r);

        //      Second chart with the points
        XYSeriesRenderer r1 = new XYSeriesRenderer();
        r1.setColor(getResources().getColor(R.color.purple_chart_points));
        r1.setLineWidth(0);
        r1.setFillPoints(true);
        r1.setPointStyle(PointStyle.CIRCLE);
        renderer.addSeriesRenderer(r1);

        return renderer;
    }

    public XYSeries getFirstSeries() {
        return firstSeries;
    }

    public void setFirstSeries(XYSeries firstSeries) {
        this.firstSeries = firstSeries;
    }

    public XYChart getChart() {
        return chart;
    }

    public void setChart(XYChart chart) {
        this.chart = chart;
    }

    /**
     * Method for create the views when clicking on a point of the chart
     */
    private void createOnClickPointsView() {
        //If the info is already visible 
        if (pointInfoConatiner != null)
            absoluteLayout.removeView(pointInfoConatiner);
        //              If the point is drawn
        if (point != null)
            absoluteLayout.removeView(point);

        pointInfoConatiner = new LinearLayout(getActivity());
        pointInfoConatiner.setBackgroundDrawable(getResources().getDrawable(R.drawable.graficapin));
        pointInfoConatiner.setOrientation(LinearLayout.VERTICAL);
        pointInfoConatiner.setGravity(Gravity.CENTER_HORIZONTAL);

        LinearLayout.LayoutParams layoutParams = new LinearLayout.LayoutParams(LinearLayout.LayoutParams.WRAP_CONTENT,
                LinearLayout.LayoutParams.WRAP_CONTENT);
        layoutParams.setMargins(0, 8, 0, 0);

        pointNumberText = new TextView(getActivity());
        pointNumberText.setTextSize(18);
        pointNumberText.setTextColor(getResources().getColor(R.color.purple_chart_points));
        pointNumberText.setTypeface(avenirHeavy);
        pointNumberText.setGravity(Gravity.CENTER);

        pointNameText = new TextView(getActivity());
        pointNameText.setTextSize(18);
        pointNameText.setTextColor(getResources().getColor(R.color.grey_users_label));
        pointNameText.setTypeface(avenirLight);
        pointNameText.setText(metricName);
        pointNameText.setGravity(Gravity.CENTER);

        pointDateText = new TextView(getActivity());
        pointDateText.setTextSize(11);
        pointDateText.setTextColor(getResources().getColor(R.color.grey_users_label));
        pointDateText.setTypeface(avenirHeavy);
        pointDateText.setGravity(Gravity.CENTER);

        pointInfoConatiner.addView(pointNumberText, 0, layoutParams);
        layoutParams.setMargins(0, 2, 0, 0);
        pointInfoConatiner.addView(pointNameText, 1, layoutParams);
        pointInfoConatiner.addView(pointDateText, 2, layoutParams);

        point = new ImageView(getActivity());
        point.setImageDrawable(getResources().getDrawable(R.drawable.puntoon));
    }
}

任何人都知道我怎样才能:

1-退出下边框

2-退出粉色图表的线

3-触摸点时图表不移动

4- 当我询问屏幕点时，为什么 y 值多次返回无穷大

Answer 1

旧版本的 AChartEngine 曾经有过这个错误。我建议你更新到 1.1.0。

另请注意，调用该方法时图表必须已经显示。如果图表未显示在屏幕上，则无法计算。