Merge branch 'update_readme' into 'master'

update README.md

Closes #9064

See merge request leap/bitmask_android!182

1 files changed, 113 insertions, 0 deletions

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+### Debian Gotchas <a name="debian-gotchas"></a>
+
+If you are running Debian on a 64-bit machine, your emulator will likely not work out of the gate. Test to see if this is the case by:
+
+* first creating an emulator in Android Studio (with name, eg, `Nexus_5_API_25`)
+* then running:
+   ```shell
+   cd ~/
+   emulator @<name_of_your_emulator>
+   ```
+If you can launch an emulator, HUZZAH! If not, you likely have one of 3 problems:
+
+#### 1. Virtualization Not Enabled <a name="virtualization-not-enabled"></a>
+
+Boo! Try turning it on. The second half of [this article](https://docs.fedoraproject.org/en-US/Fedora/13/html/Virtualization_Guide/sect-Virtualization-Troubleshooting-Enabling_Intel_VT_and_AMD_V_virtualization_hardware_extensions_in_BIOS.html) is a decent enough guide.
+
+#### 2. Unpatched Filepaths Bug <a name="unpatched-filepaths-bug"></a>
+
+**Symptoms:** If you have this bug, you will see something like the following when you try to spin up an emulator:
+
+``` shell
+[140500439390016]:ERROR:./android/qt/qt_setup.cpp:28:Qt library not found at ../emulator/lib64/qt/lib
+Could not launch '../emulator/qemu/linux-x86_64/qemu-system-i386': No such file or directory
+```
+As [documented here](https://stackoverflow.com/questions/42554337/cannot-launch-avd-in-emulatorqt-library-not-found), there is a standing bug in the version of `emulator` packaged for emulator that assumes it always runs from within the `$ANDROID_HOME/emulator` directory, and can thus safely use relative filepaths, when in fact this is almost never the case. (Cool bug!)
+
+**Fixes:**
+
+You have a couple options. The fist is more robust:
+
+1. Insert a line in your `~/.bashrc` to automatically navigate to the correct directory (and back) whenever you invoke `emulator`:
+
+ ```shell
+function emulator { pushd `pwd`; cd "$(dirname "$(which emulator)")" && ./emulator "$@"; popd;}
+```
+
+2. Always run emulator from within its own directory (clunky!):
+
+``` shell
+ cd "$(dirname "$(which emulator)")"
+ emulator <name_of_your_emulator>
+```
+
+#### 3. Outdated GL Libraries <a name="outdated-gl-libraries"></a>
+
+**Symptoms:** If you have this bug, you will see something like the following:
+
+``` shell
+libGL error: failed to load driver: swrast
+X Error of failed request:  BadValue (integer parameter out of range for  operation)
+# redacted incredibly long stack trace
+```
+
+As documented [here](http://stackoverflow.com/questions/36554322/cannot-start-emulator-in-android-studio-2-0), the current emulator package ships without outdated versions of LibGL libraries. To work around this:
+
+1. Install modern GL libriaries with:
+
+``` shell
+sudo apt-get install mesa-utils
+```
+
+2. Ensure that `emulator` always uses the correct libraries by either:
+
+a. always calling `emulator` with the `-use-system-libs` flag, like so:
+
+  ``` shell
+  emulator -use-system-libs -avd Nexus_5_API_25
+  ```
+b. adding the following line to your ~/.bashrc or ~/.bash_profile:
+
+  ```shell
+  export ANDROID_EMULATOR_USE_SYSTEM_LIBS=1
+  ```
+
+**Special Android Studio Debian Bonus Gotcha:**
+
+Assuming you have made all the above fixes (great job!), to be able to launch emulators from Android Studio, you must either:
+
+1. Use the environment variable solution above (option a), then *always* launch Android Studio from a bash shell with:
+
+``` shell
+studio
+```
+
+This means never using the desktop launcher. :(
+
+2. If you want to use the desktop launcher:
+
+* You must *always* launch emulators from the terminal. :(
+* But: you can quickly access a terminal inside of Android Studio with `OPTION-F12`
+
+## Updating Submodules <a name="updating-submodules"></a>
+
+If you need to refresh our upstream dependency on ics-openvpn, you may do so with:
+
+``` shell
+cd <path/to/bitmask_android>
+./gradlew updateIcsOpenVpn
+```
+
+Alternately:
+
+```shell
+cd <path/to/bitmask_android>
+cd ics-openvpn
+git remote add upstream https://github.com/schwabe/ics-openvpn.git
+git pull --rebase upstream master
+```
+A bunch of conflicts may arise. The guidelines are:
+
+    1. Methods in HEAD (upstream) completely removed from Bitmask should be removed again (e.g. askPW)
+    2. Sometimes, Dashboard.class is in Bitmask while in ics-openvpn it is replaced by MainActivity.class and other classes. Keep removing them to keep Dashboard.class in there.
+    3. Some resources files are stripped from several entries. Remove them if possible (check the code we compile is not using anything else new).