MPAndroidChart CombinedChart随机崩溃（BarChartRenderer）

Question

我正在使用MPAndroidChart中的CombinedChart，而我很难找到导致此次崩溃的原因。

似乎BarBuffer[] mBarBuffers类中的BarChartRenderer通常应该在initBuffers()方法中进行初始化，如下所示：

BarData barData = mChart.getBarData();
mBarBuffers = new BarBuffer[barData.getDataSetCount()];

我在做什么：

if (!data.isEmpty()){... //Making sure there is data to plot

...

    //Create the combined data with either BarData or LineData 

...

    //Add other LineData sets
    LineData lineData = combinedData.getLineData();
    if (lineData == null) {
       combinedData.setData(otherLineData);
    } else {
       lineData.addDataSet(otherLineDataSet);
       combinedData.notifyDataChanged();
    }

...

    chart.setData(combinedData);
    chart.centerViewTo(...);
}

这是 full stackTrace ：

java.lang.NullPointerException: Attempt to read from null array
    at com.github.mikephil.charting.renderer.BarChartRenderer.drawDataSet(BarChartRenderer.java:136)
    at com.github.mikephil.charting.renderer.BarChartRenderer.drawData(BarChartRenderer.java:80)
    at com.github.mikephil.charting.renderer.CombinedChartRenderer.drawData(CombinedChartRenderer.java:89)
    at com.github.mikephil.charting.charts.BarLineChartBase.onDraw(BarLineChartBase.java:232)
    at android.view.View.draw(View.java:16435)
    at android.view.View.updateDisplayListIfDirty(View.java:15388)
    at android.view.View.draw(View.java:16189)
    at android.view.ViewGroup.drawChild(ViewGroup.java:3735)
    at android.view.ViewGroup.dispatchDraw(ViewGroup.java:3525)
    at android.view.View.updateDisplayListIfDirty(View.java:15380)
    at android.view.View.draw(View.java:16189)
    at android.view.ViewGroup.drawChild(ViewGroup.java:3735)
    at android.view.ViewGroup.dispatchDraw(ViewGroup.java:3525)
    at android.view.View.draw(View.java:16447)
    at android.support.v4.view.ViewPager.draw(ViewPager.java:2420)
    at android.view.View.updateDisplayListIfDirty(View.java:15388)
    at android.view.View.draw(View.java:16189)
    at android.view.ViewGroup.drawChild(ViewGroup.java:3735)
    at android.view.ViewGroup.dispatchDraw(ViewGroup.java:3525)
    at android.view.View.updateDisplayListIfDirty(View.java:15380)
    at android.view.View.draw(View.java:16189)
    at android.view.ViewGroup.drawChild(ViewGroup.java:3735)
    at android.view.ViewGroup.dispatchDraw(ViewGroup.java:3525)
    at android.view.View.updateDisplayListIfDirty(View.java:15380)
    at android.view.View.draw(View.java:16189)
    at android.view.ViewGroup.drawChild(ViewGroup.java:3735)
    at android.view.ViewGroup.dispatchDraw(ViewGroup.java:3525)
    at android.view.View.updateDisplayListIfDirty(View.java:15380)
    at android.view.View.draw(View.java:16189)
    at android.view.ViewGroup.drawChild(ViewGroup.java:3735)
    at android.view.ViewGroup.dispatchDraw(ViewGroup.java:3525)
    at android.view.View.updateDisplayListIfDirty(View.java:15380)
    at android.view.View.draw(View.java:16189)
    at android.view.ViewGroup.drawChild(ViewGroup.java:3735)
    at android.view.ViewGroup.dispatchDraw(ViewGroup.java:3525)
    at android.view.View.updateDisplayListIfDirty(View.java:15380)
    at android.view.View.draw(View.java:16189)
    at android.view.ViewGroup.drawChild(ViewGroup.java:3735)
    at android.view.ViewGroup.dispatchDraw(ViewGroup.java:3525)
    at com.android.internal.policy.PhoneWindow$DecorView.dispatchDraw(PhoneWindow.java:2766)
    at android.view.View.draw(View.java:16447)
    at com.android.internal.policy.PhoneWindow$DecorView.draw(PhoneWindow.java:2752)
    at android.view.View.updateDisplayListIfDirty(View.java:15388)
    at android.view.ThreadedRenderer.updateViewTreeDisplayList(ThreadedRenderer.java:286)
    at android.view.ThreadedRenderer.updateRootDisplayList(ThreadedRenderer.java:292)
    at android.view.ThreadedRenderer.draw(ThreadedRenderer.java:327)
    at android.view.ViewRootImpl.draw(ViewRootImpl.java:3030)
    at android.view.ViewRootImpl.performDraw(ViewRootImpl.java:2834)
    at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:2446)
    at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1323)
    at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:6718)
    at android.view.Choreographer$CallbackRecord.run(Choreographer.java:894)
    at android.view.Choreographer.doCallbacks(Choreographer.java:696)
    at android.view.Choreographer.doFrame(Choreographer.java:631)
    at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:880)
    at android.os.Handler.handleCallback(Handler.java:815)
    at android.os.Handler.dispatchMessage(Handler.java:104)
    at android.os.Looper.loop(Looper.java:207)
    at android.app.ActivityThread.main(ActivityThread.java:5765)
    at java.lang.reflect.Method.invoke(Native Method)
    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:789)
    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:679)`

感谢您的帮助！ ： - ）