Try to fix NPE:

java.lang.NullPointerException:
at org.coolreader.crengine.ReaderView.preparePageImage (ReaderView.java:3250)
at org.coolreader.crengine.ReaderView.access$1700 (ReaderView.java:42)
at org.coolreader.crengine.ReaderView$LoadDocumentTask$6.run (ReaderView.java:4907)

Author: virxkane

android/src/org/coolreader/crengine/ReaderView.java

@@ -3246,6 +3246,8 @@ private BitmapInfo preparePageImage(int offset) {
 			return currentImageViewer.prepareImage();
 
 		PositionProperties currpos = doc.getPositionProps(null);
+		if (null == currpos)
+			return null;
 
 		boolean isPageView = currpos.pageMode != 0;