LibreOffice Android ******************* Bootstrap ********* Contains common code for all projects on Android to bootstrap LibreOffice. In addition it is a home to LibreOfficeKit (LOK - see libreofficekit/README) JNI classes. LOAndroid3 (in experimental) **************************** LibreOffice Android application - the code is based on Fennec (Firefox for Android). It uses OpenGL ES 2 for rendering of the document tiles which are gathered from LibreOffice using LOK. The application contains the LibreOffice core in one shared library: liblo-native-code.so, which is bundled together with the application. TiledRendering ************** Tiled rendering is a technique that splits the document to bitmaps of same size (typically 256x256) which are fetched on demand. Architecture and Threading ************************** The application implements editing support using 4 threads: 1. The Android UI thread, we can't perform anything here that would take a considerable amount of time. 2. An OpenGL thread which contains the OpenGL context and is responsible for drawing all layers (including tiles) to the screen. 3. A thread (LOKitThread), that performs LibreOfficeKit calls, which may take more time to complete. In addition it also receives events from the soffice thread (see below) when the callback emits an event. Events are stored in a blocking queue (thread processes events in FCFS order, goes to sleep when no more event is available and awakens when there are events in queue again). 4. A native thread created by LibreOfficeKit (we call it the soffice thread), where LibreOffice itself runs. It receives calls from LOKitThread, and may emit callback events as necessary. Android-specific notes ********************** Note that this document has not necessarily been updated to match reality... For instructions on how to build for Android, see README.cross. * Getting something running on an emulated device Create an AVD in the android UI, don't even try to get the data partition size right in the GUI, that is doomed to producing an AVD that doesn't work. Instead start it from the console: LD_LIBRARY_PATH=$(pwd)/lib emulator-arm -avd -partition-size 500 In order to have proper acceleration, you need the 32-bit libGL.so: sudo zypper in Mesa-libGL-devel-32bit Where is the literal name of the AVD that you entered. Then: cd android/experimental/LOAndroid3 ant debug install adb logcat And if all goes well - you should have some nice debug output to enjoy when you start the app. After a while of this loop you might find that you have lost a lot of space on your emulator's or device's /data volume. If using the emulator, you can do: adb shell stop; adb shell start but on a (non-rooted) device you probably just need to reboot it. On the other hand, this phenomenon might not happen on actual devices. * What about using a real device? That works fine, too. * Debugging First of all, you need to configure the build with --enable-debug or --enable-dbgutil. You may want to provide --enable-selective-debuginfo too, like --enable-selective-debuginfo="sw/" or so, in order to fit into the memory during linking. Building with all symbols is also possible but the linking is currently slow (around 10 to 15 minutes) and you need lots of memory (around 16GB + some swap). You also want to avoid --with-android-package-name (or when you use that, you must set it to "org.libreoffice"), otherwise ndk-gdb will complain that ERROR: Could not extract package's data directory. Are you sure that your installed application is debuggable? When you have all this, install the .apk to the device, and: cd android/experimental/LOAndroid3 /ndk-gdb --adb=/platform-tools/adb --start Pretty printers aren't loaded automatically due to the single shared object, but you can still load them manually. E.g. to have a pretty-printer for rtl::OString, you need: (gdb) python sys.path.insert(0, "/master/solenv/gdb") (gdb) source /master/instdir/program/libuno_sal.so.3-gdb.py * Debuggint the Java part At the moment the code is not organized in a way that would make Eclipse or Android Studio happy as-is, so the quickest way is to use the jdb command-line debugger. Steps to use it: 1) Find out the JDWP ID of a debuggable application: adb jdwp From the list of currently active JDWP processes, the last number is the just started debuggable application. 2) Forward the remote JDWP port/process ID to a local port: adb forward tcp:7777 jdwp:31739 3) Connect to the running application: jdb -sourcepath src/java/ -attach localhost:7777 Assuming that you're already in the LOAndroid3 directory in your shell. * Common Errors / Gotchas lo_dlneeds: Could not read ELF header of /data/data/org.libreoffice...libfoo.so This (most likely) means that the install quietly failed, and that the file is truncated; check it out with adb shell ls -l /data/data/.... * Detailed explanation Note: the below talk about unit tests is obsolete; we no longer have any makefilery etc to build unit tests for Android. Unit tests are the first thing we want to run on Android, to get some idea how well, if at all, the basic LO libraries work. We want to build even unit tests as normal Android apps, i.e. packaged as .apk files, so that they run in a sandboxed environment like that of whatever eventual end-user Android apps there will be that use LO code. Sure, we could quite easily build unit tests as plain Linux executables (built against the Android libraries, of course, not GNU/Linux ones), push them to the device or emulator with adb and run them from adb shell, but that would not be a good test as the environment such processs run in is completely different from that in which real end-user apps with GUI etc run. We have no intent to require LibreOffice code to be used only on "rooted" devices etc. All Android apps are basically Java programs. They run "in" a Dalvik (or on Android 5 or newer - ART) virtual machine. Yes, you can also have apps where all *your* code is native code, written in a compiled language like C or C++. But also also such apps are actually started by system-provided Java bootstrapping code (NativeActivity) running in a Dalvik VM. Such a native app (or actually, "activity") is not built as a executable program, but as a shared object. The Java NativeActivity bootstrapper loads that shared object with dlopen. Anyway, our current "experimental" apps are not based on NativeActivity. They have normal Java code for the activity, and just call out to a single, app-specific native library (called liblo-native-code.so) to do all the heavy lifting.