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I crashed when I was quick to show and hide the content of the chart。
The source code is similar to the following:
public void show(){
if(!surface.getRenderableSeries().contains(lineUpSeries)) {
Collections.addAll(surface.getRenderableSeries(), lineUpSeries);
Collections.addAll(surface.getRenderableSeries(), lineDownSeries);
Collections.addAll(surface.getRenderableSeries(), line20Series);
Collections.addAll(surface.getAnnotations(), upTextMarker);
Collections.addAll(surface.getAnnotations(), downTextMarker);
Collections.addAll(surface.getAnnotations(), ma20TextMarker);
Collections.addAll(surface.getAnnotations(), upAxisMarker);
Collections.addAll(surface.getAnnotations(), downAxisMarker);
Collections.addAll(surface.getAnnotations(), ma20AxisMarker);
}
}
public void hide(){
if(surface.getRenderableSeries().contains(lineUpSeries)) {
surface.getRenderableSeries().remove(lineUpSeries);
surface.getRenderableSeries().remove(lineDownSeries);
surface.getRenderableSeries().remove(line20Series);
surface.getAnnotations().remove(upTextMarker);
surface.getAnnotations().remove(downTextMarker);
surface.getAnnotations().remove(ma20TextMarker);
surface.getAnnotations().remove(upAxisMarker);
surface.getAnnotations().remove(downAxisMarker);
surface.getAnnotations().remove(ma20AxisMarker);
}
}
error log:
java.lang.NullPointerException: Attempt to invoke interface method ‘boolean com.scichart.charting.visuals.annotations.IAnnotationPlacementStrategy.isInBounds(com.scichart.charting.visuals.annotations.AnnotationCoordinates, com.scichart.charting.visuals.annotations.IAnnotationSurface)’ on a null object reference
at com.scichart.charting.visuals.annotations.AnnotationBase.a(SourceFile:1207)
at com.scichart.charting.visuals.annotations.AnnotationBase.update(SourceFile:1105)
at com.scichart.charting.visuals.annotations.AxisMarkerAnnotation.update(SourceFile:246)
at com.scichart.charting.visuals.annotations.AnnotationBase.update(SourceFile:1083)
at com.scichart.charting.visuals.rendering.RenderSurfaceRenderer.a(SourceFile:327)
at com.scichart.charting.visuals.rendering.RenderSurfaceRenderer.a(SourceFile:218)
at com.scichart.charting.visuals.rendering.RenderSurfaceRenderer.a(SourceFile:132)
at com.scichart.charting.visuals.rendering.RenderSurfaceRenderer.onDraw(SourceFile:123)
at com.scichart.drawing.opengl.RenderSurfaceGL$a.onDraw(SourceFile:228)
at com.scichart.drawing.opengl.MyGLRenderer.b(SourceFile:293)
at com.scichart.drawing.opengl.MyGLRenderer.onDrawFrame(SourceFile:277)
at android.opengl.GLSurfaceView$GLThread.guardedRun(GLSurfaceView.java:1548)
at android.opengl.GLSurfaceView$GLThread.run(GLSurfaceView.java:1259)
Hi Huang,
Thanks for your question. It is known issue which is caused by fact that ObservableCollection which is used as base class for annotation collection is not thread safe. There is a race condition when annotation collection changes at the same time when chart redraws itself on another thread. Usually to prevent this exception you just need to suspend updates of chart which is modified so chart won’t be redrawn while you add/remove annotations:
public void hide(){
// suspend surface during update of of renderable series and annotation collections
UpdateSuspender.using(surface, new Runnable() {
@Override
public void run() {
if(surface.getRenderableSeries().contains(lineUpSeries)) {
surface.getRenderableSeries().remove(lineUpSeries);
surface.getRenderableSeries().remove(lineDownSeries);
surface.getRenderableSeries().remove(line20Series);
surface.getAnnotations().remove(upTextMarker);
surface.getAnnotations().remove(downTextMarker);
surface.getAnnotations().remove(ma20TextMarker);
surface.getAnnotations().remove(upAxisMarker);
surface.getAnnotations().remove(downAxisMarker);
surface.getAnnotations().remove(ma20AxisMarker);
}
}
});
}
Can you try and let me know if this workaround fixes the exception?
Best regards,
Yura
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