Update kivy docs to current build process

gui/kivy/Readme.md

@@ -0,0 +1,80 @@
+# Kivy GUI
+
+The Kivy GUI is used with Electrum on Android devices. To generate an APK file, follow these instructions.
+
+## 1. Install python-for-android (p4a)
+p4a is used to package Electrum, Python, SDL and a bootstrap Java app into an APK file. 
+We patched p4a to add some functionality we need for Electrum. Until those changes are
+merged into p4a, you need to merge them locally (into the stable branch):
+
+1. [kivy/python-for-android#1213](https://github.com/kivy/python-for-android/pull/1213)
+2. [kivy/python-for-android#1217](https://github.com/kivy/python-for-android/pull/1217)
+
+Something like this should work:
+
+```sh
+cd /opt
+git clone https://github.com/kivy/python-for-android
+cd python-for-android
+git remote add agilewalker https://github.com/agilewalker/python-for-android
+git remote add bauerj https://github.com/bauerj/python-for-android
+git checkout stable
+git fetch agilewalker
+git merge agilewalker/master
+git fetch bauerj
+git merge bauerj/add-activity
+```
+
+## 2. Install buildozer
+Buildozer is a frontend to p4a. Of course it needs to be patched too:
+
+1. [kivy/buildozer#612](https://github.com/kivy/python-for-android/pull/1213)
+
+```sh
+cd /opt
+git clone https://github.com/kivy/buildozer
+cd buildozer
+git remote add bauerj https://github.com/bauerj/buildozer
+git fetch bauerj
+git merge bauerj/add-activity
+```
+
+You also want to install it:
+
+```sh
+sudo python3 setup.py install
+```
+
+## 3. Update the Android SDK build tools
+3.1 Start the Android SDK manager:
+
+      ~/.buildozer/android/platform/android-sdk-20/tools/android
+      
+3.2 Check the latest SDK available and install it.
+
+3.3 Close the SDK manager.
+
+3.3 Reopen the SDK manager, scroll to the bottom and install the latest build tools (probably v27)
+
+## 4. Install the Support Library Repository
+Install "Android Support Library Repository" from the SDK manager.
+
+## 5. Create the UI Atlas
+In the `gui/kivy` directory of Electrum, run `make theming`.
+
+## 6. Download Electrum dependencies
+Run `contrib/make_packages`.
+
+## 7. Build the APK
+Run `contrib/make_apk`.
+
+# FAQ
+## Why do I get errors like `package me.dm7.barcodescanner.zxing does not exist` while compiling?
+Update your Android build tools to version 27 like described above.
+
+## Why do I get errors like  `(use -source 7 or higher to enable multi-catch statement)` while compiling?
+Use the `stable` branch of python-for-android. 
+[This commit](https://github.com/kivy/python-for-android/commit/3534a761b17040755accf941f898cc66b905e8db) in master is the culprit.
+
+## I changed something but I don't see any differences on the phone. What did I do wrong?
+You probably need to clear the cache: `rm -rf .buildozer/android/platform/build/{build,dists}`

gui/kivy/Readme.txt

@@ -1,24 +0,0 @@
-Before compiling, create packages: `contrib/make_packages`
-
-Commands::
-
-    `make theming` to make a atlas out of a list of pngs
-
-    `make apk` to make a apk
-
-
-If something in included modules like kivy or any other module changes
-then you need to rebuild the distribution. To do so:
-
-  rm -rf .buildozer/android/platform/python-for-android/dist
-
-
-how to build with ssl:
-
-  rm -rf .buildozer/android/platform/build/
-  ./contrib/make_apk
-  pushd /opt/electrum/.buildozer/android/platform/build/build/libs_collections/Electrum/armeabi-v7a
-  cp libssl1.0.2g.so /opt/crystax-ndk-10.3.2/sources/openssl/1.0.2g/libs/armeabi-v7a/libssl.so
-  cp libcrypto1.0.2g.so /opt/crystax-ndk-10.3.2/sources/openssl/1.0.2g/libs/armeabi-v7a/libcrypto.so
-  popd
-  ./contrib/make_apk