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
最佳答案
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。
关于android - achartengine toScreenPoint(double) 总是返回 nullPointerException，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/17721044/
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我一直在研究RubyKoans，我发现about_open_classes.rbkoan很有趣。特别是他们修改Integer#even?方法的最后一个测试。我想尝试一下这个概念，所以我打开了Irb并尝试运行Integer.respond_to?(:even?)，但令我惊讶的是我得到了错误。然后我尝试了Fixnum.respond_to?(:even?)并得到了错误。我还尝试了Integer.respond_to?(:respond_to?)并得到了true，当我执行2.even?时，我也得到了true。我不知道发生了什么。谁能告诉我缺少什么？ 最佳答案
无论时间在哪个时区表示，时区差异是否总是被忽略？直觉上，对于那些使用UTC+2的人来说，从EPOCH开始经过的秒数应该更高。然而，事实并非如此。 最佳答案 Epoch基于utc时区https://en.wikipedia.org/wiki/Unix_time它与您当前所在的时区无关。 关于ruby-Time.to_i是否总是以UTC返回自EPOCH以来的秒数？，我们在StackOverflow上找到一个类似的问题： https://stackoverflow.
我在思考流量控制的最佳实践。我应该走哪条路？1)不要检查任何东西并让程序失败(更清晰的代码，自然的错误消息):defself.fetch(feed_id)feed=Feed.find(feed_id)feed.fetchend2)通过返回nil静默失败(但是，“CleanCode”说，你永远不应该返回null):defself.fetch(feed_id)returnunlessfeed_idfeed=Feed.find(feed_id)returnunlessfeedfeed.fetchend3)抛出异常(因为不按id查找feed是异常的):defself.fetch(feed_id