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

我看到图表的mScreenR为空

不使用此方法toScreenPoint(双)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 });
        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>

第二编辑：

我想做这样的事情：

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,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(),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 });
        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);

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

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

任何人都知道我怎么能：

1 – 退出底部边框

2 – 退出粉红色图表的线条

3 – 触摸点时图表不移动

4-当我询问屏幕点时为什么多次y值返回无穷大

另请注意,调用方法时必须已显示图表.如果图表没有显示在屏幕上,那么就无法计算出来.

:hce_entry:extractReleaseAnnotations Failed
Error:Execution Failed for task '':hce_entry:extractReleaseAnnotations''.
> java.lang.NullPointerException (no error message)

我尝试使用–stacktrace选项获取更多信息来执行gradle构建,这是输出：

...
:hce_entry:extractReleaseAnnotations Failed

FAILURE: Build Failed with an exception.

What went wrong:
Execution Failed for task '':hce_entry:extractReleaseAnnotations''.
java.lang.NullPointerException (no error message)

Try:
Run with --info or --debug option to get more log output.

Exception is:
org.gradle.api.tasks.TaskExecutionException: Execution Failed for task '':hce_entry:extractReleaseAnnotations''.
        at org.gradle.api.internal.tasks.execution.ExecuteActionsTaskExecuter.executeActions(ExecuteActionsTaskExecuter.java:69)
        at org.gradle.api.internal.tasks.execution.ExecuteActionsTaskExecuter.execute(ExecuteActionsTaskExecuter.java:46)
        at org.gradle.api.internal.tasks.execution.PostExecutionAnalysisTaskExecuter.execute(PostExecutionAnalysisTaskExecuter.java:35)
        at org.gradle.api.internal.tasks.execution.SkipUpToDateTaskExecuter.execute(SkipUpToDateTaskExecuter.java:64)
        at org.gradle.api.internal.tasks.execution.ValidatingTaskExecuter.execute(ValidatingTaskExecuter.java:58)
        at org.gradle.api.internal.tasks.execution.SkipEmptySourceFilesTaskExecuter.execute(SkipEmptySourceFilesTaskExecuter.java:52)
        at org.gradle.api.internal.tasks.execution.SkipTaskWithNoActionsExecuter.execute(SkipTaskWithNoActionsExecuter.java:52)
        at org.gradle.api.internal.tasks.execution.SkipOnlyIfTaskExecuter.execute(SkipOnlyIfTaskExecuter.java:53)
        at org.gradle.api.internal.tasks.execution.ExecuteAtMostOnceTaskExecuter.execute(ExecuteAtMostOnceTaskExecuter.java:43)
        at org.gradle.execution.taskgraph.DefaultTaskGraphExecuter$EventFiringTaskWorker.execute(DefaultTaskGraphExecuter.java:203)
        at org.gradle.execution.taskgraph.DefaultTaskGraphExecuter$EventFiringTaskWorker.execute(DefaultTaskGraphExecuter.java:185)
        at org.gradle.execution.taskgraph.AbstractTaskPlanExecutor$TaskExecutorWorker.processtask(AbstractTaskPlanExecutor.java:62)
        at org.gradle.execution.taskgraph.AbstractTaskPlanExecutor$TaskExecutorWorker.run(AbstractTaskPlanExecutor.java:50)
        at org.gradle.execution.taskgraph.DefaultTaskPlanExecutor.process(DefaultTaskPlanExecutor.java:25)
        at org.gradle.execution.taskgraph.DefaultTaskGraphExecuter.execute(DefaultTaskGraphExecuter.java:110)
        at org.gradle.execution.SelectedTaskExecutionAction.execute(SelectedTaskExecutionAction.java:37)
        at org.gradle.execution.DefaultBuildExecuter.execute(DefaultBuildExecuter.java:37)
        at org.gradle.execution.DefaultBuildExecuter.access$000(DefaultBuildExecuter.java:23)
        at org.gradle.execution.DefaultBuildExecuter$1.proceed(DefaultBuildExecuter.java:43)
        at org.gradle.execution.DryRunBuildExecutionAction.execute(DryRunBuildExecutionAction.java:32)
        at org.gradle.execution.DefaultBuildExecuter.execute(DefaultBuildExecuter.java:37)
        at org.gradle.execution.DefaultBuildExecuter.execute(DefaultBuildExecuter.java:30)
        at org.gradle.initialization.DefaultGradleLauncher$4.run(DefaultGradleLauncher.java:154)
        at org.gradle.internal.Factories$1.create(Factories.java:22)
        at org.gradle.internal.progress.DefaultBuildOperationExecutor.run(DefaultBuildOperationExecutor.java:90)
        at org.gradle.internal.progress.DefaultBuildOperationExecutor.run(DefaultBuildOperationExecutor.java:52)
        at org.gradle.initialization.DefaultGradleLauncher.dobuildStages(DefaultGradleLauncher.java:151)
        at org.gradle.initialization.DefaultGradleLauncher.access$200(DefaultGradleLauncher.java:32)
        at org.gradle.initialization.DefaultGradleLauncher$1.create(DefaultGradleLauncher.java:99)
        at org.gradle.initialization.DefaultGradleLauncher$1.create(DefaultGradleLauncher.java:93)
        at org.gradle.internal.progress.DefaultBuildOperationExecutor.run(DefaultBuildOperationExecutor.java:90)
        at org.gradle.internal.progress.DefaultBuildOperationExecutor.run(DefaultBuildOperationExecutor.java:62)
        at org.gradle.initialization.DefaultGradleLauncher.dobuild(DefaultGradleLauncher.java:93)
        at org.gradle.initialization.DefaultGradleLauncher.run(DefaultGradleLauncher.java:82)
        at org.gradle.launcher.exec.InProcessBuildActionExecuter$DefaultBuildController.run(InProcessBuildActionExecuter.java:94)
        at org.gradle.tooling.internal.provider.ExecuteBuildActionRunner.run(ExecuteBuildActionRunner.java:28)
        at org.gradle.launcher.exec.ChainingBuildActionRunner.run(ChainingBuildActionRunner.java:35)
        at org.gradle.launcher.exec.InProcessBuildActionExecuter.execute(InProcessBuildActionExecuter.java:43)
        at org.gradle.launcher.exec.InProcessBuildActionExecuter.execute(InProcessBuildActionExecuter.java:28)
        at org.gradle.launcher.exec.ContinuousBuildActionExecuter.execute(ContinuousBuildActionExecuter.java:77)
        at org.gradle.launcher.exec.ContinuousBuildActionExecuter.execute(ContinuousBuildActionExecuter.java:47)
        at org.gradle.launcher.exec.DaemonUsageSuggestingBuildActionExecuter.execute(DaemonUsageSuggestingBuildActionExecuter.java:51)
        at org.gradle.launcher.exec.DaemonUsageSuggestingBuildActionExecuter.execute(DaemonUsageSuggestingBuildActionExecuter.java:28)
        at org.gradle.launcher.cli.RunBuildAction.run(RunBuildAction.java:43)
        at org.gradle.internal.Actions$RunnableActionAdapter.execute(Actions.java:170)
        at org.gradle.launcher.cli.CommandLineActionFactory$ParseAndBuildAction.execute(CommandLineActionFactory.java:237)
        at org.gradle.launcher.cli.CommandLineActionFactory$ParseAndBuildAction.execute(CommandLineActionFactory.java:210)
        at org.gradle.launcher.cli.JavaRuntimeValidationAction.execute(JavaRuntimeValidationAction.java:35)
        at org.gradle.launcher.cli.JavaRuntimeValidationAction.execute(JavaRuntimeValidationAction.java:24)
        at org.gradle.launcher.cli.CommandLineActionFactory$WithLogging.execute(CommandLineActionFactory.java:206)
        at org.gradle.launcher.cli.CommandLineActionFactory$WithLogging.execute(CommandLineActionFactory.java:169)
        at org.gradle.launcher.cli.ExceptionReportingAction.execute(ExceptionReportingAction.java:33)
        at org.gradle.launcher.cli.ExceptionReportingAction.execute(ExceptionReportingAction.java:22)
        at org.gradle.launcher.Main.doAction(Main.java:33)
        at org.gradle.launcher.bootstrap.EntryPoint.run(EntryPoint.java:45)
        at org.gradle.launcher.bootstrap.ProcessBootstrap.runNoExit(ProcessBootstrap.java:54)
        at org.gradle.launcher.bootstrap.ProcessBootstrap.run(ProcessBootstrap.java:35)
        at org.gradle.launcher.GradleMain.main(GradleMain.java:23)
Caused by: java.lang.NullPointerException
        at com.android.build.gradle.tasks.annotations.Extractor$AnnotationData.appendExpression(Extractor.java:1603)
        at com.android.build.gradle.tasks.annotations.Extractor$AnnotationData.attributeString(Extractor.java:1592)
        at com.android.build.gradle.tasks.annotations.Extractor$AnnotationData.write(Extractor.java:1545)
        at com.android.build.gradle.tasks.annotations.Extractor$Item.write(Extractor.java:1792)
        at com.android.build.gradle.tasks.annotations.Extractor.writeExternalAnnotations(Extractor.java:769)
        at com.android.build.gradle.tasks.annotations.Extractor.export(Extractor.java:271)
        at com.android.build.gradle.tasks.annotations.Extractor$export$0.call(UnkNown Source)
        at com.android.build.gradle.tasks.ExtractAnnotations.compile(ExtractAnnotations.groovy:172)
        at org.gradle.internal.reflect.JavaMethod.invoke(JavaMethod.java:75)
        at org.gradle.api.internal.project.taskfactory.AnnotationProcessingTaskFactory$StandardTaskAction.doExecute(AnnotationProcessingTaskFactory.java:227)
        at org.gradle.api.internal.project.taskfactory.AnnotationProcessingTaskFactory$StandardTaskAction.execute(AnnotationProcessingTaskFactory.java:220)
        at org.gradle.api.internal.project.taskfactory.AnnotationProcessingTaskFactory$StandardTaskAction.execute(AnnotationProcessingTaskFactory.java:209)
        at org.gradle.api.internal.AbstractTask$TaskActionWrapper.execute(AbstractTask.java:585)
        at org.gradle.api.internal.AbstractTask$TaskActionWrapper.execute(AbstractTask.java:568)
        at org.gradle.api.internal.tasks.execution.ExecuteActionsTaskExecuter.executeAction(ExecuteActionsTaskExecuter.java:80)
        at org.gradle.api.internal.tasks.execution.ExecuteActionsTaskExecuter.executeActions(ExecuteActionsTaskExecuter.java:61)
        ... 57 more


BUILD Failed

这是我的build.gradle文件

apply plugin: ''com.android.library''

android {
    compileSdkVersion 19
    buildToolsversion ''19.1.0''

    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile(''proguard-android.txt''),''proguard-rules.pro''
        }
        debug {
            debuggable true
            minifyEnabled false
        }
    }
}

dependencies {
    compile project('':core'')
    compile project('':lib'')
    compile ''com.android.support:support-v4:23.2.0''
}

有人可以给我任何建议吗？我有点迷茫,无法找到解决问题的方法.

先感谢您.