Tuesday, February 10, 2015

Stabilising LibreOffice Viewer for Android

At the end of the last week we released the new version of LibreOffice Viewer for Android, and I must say, it is a pretty solid release. The app is still in Beta, and some problems (like occasional crashes) should be anticipated, but overall there have been so many stability improvements that I am confident that it's now very usable for daily work.

New components

How does the Viewer look from the technical point of view?  It is the complete LibreOffice that we use on the desktop, but cross-compiled to Android, stripped down to its bare bones, and accessed from the Java part via LibreOfficeKit to provide rendering of 'tiles' -- 256x256 bitmaps that together compose what the user views as a document.

Spot the problem in the above description? "Stripped down to bare bones".  When we initially released, some hard compromises were made, which led to many documents crashing. Did that document contain a drop down box? Ouch! How about a custom shape? Ouch! You get the idea.

To address that, I used the same approach that Markus Mohrard is using for import and export crash testing.  I have collected over 55,000 documents - not so far from the 75,000 that we test with desktop LibreOffice. I discarded documents that were not applicable to the Android Viewer, stripped down the desktop application the same way we are stripping the LibreOffice core that is on Android, and let the tests run for several days.

Based on the output, I have added all the necessary services for text documents; so crashes due to missing components should now be rare.

Documents that remain difficult

Some documents internally provide bindings to features that are intentionally left out of the Android Viewer; namely functionality relating to databases. These documents are still missing the components described above, and thus unfortunately still crash.

We could theoretically add those services too; the problem is that currently we are hitting the 50M .apk size limit that Google imposes on Play store apps.

But don't worry - we have several tricks still up our sleeves. We'll work on them in the following weeks, and eventually include more of the services that are still missing.

More stability improvements

Intents for documents opened from Gmail:  opening documents directly from GMail now works nicely. This was an important use case that we missed in the initial release, and we caught it thanks to the feedback of the users using the Viewer.

Several smaller things have also been fixed, like presentations used with Notes view now switch to the presenting view. We also added preset shape definitions, so .docx files with preset shapes now display nice images.

And finally, we improved recovery from failure -- previously, when the document failed to open, the subsequent open of a document lead to a crash; not any more.

Overall, while the latest LibreOffice Viewer for Android is still a Beta release (and the usual warnings apply), I'm confident it's a really good Beta. Many thanks to Miklos Vajna and Tomaž Vajngerl for their hard work!

Install LibreOffice Viewer Beta from Google Play and enjoy!