Merge pull request #3061 from satya164/signed-apk

[Android] Added docs about generating a signed APK

docs/RunningOnDeviceAndroid.md

@@ -4,7 +4,7 @@ title: Running On Device
 layout: docs
 category: Guides (Android)
 permalink: docs/running-on-device-android.html
-next: activityindicatorios
+next: signed-apk-android
 ---
 
 ## USB Debugging

docs/SignedAPKAndroid.md

@@ -0,0 +1,77 @@
+---
+id: signed-apk-android
+title: Generating Signed APK
+layout: docs
+category: Guides (Android)
+permalink: docs/signed-apk-android.html
+next: activityindicatorios
+---
+
+To distribute your Android application via [Google Play store](https://play.google.com/store), you'll need to generate a signed release APK. The [Signing Your Applications](https://developer.android.com/tools/publishing/app-signing.html) page on Android Developers documentation describe the topic in detail. This guide covers the process in brief, as well as lists the steps required to retrieve and package the JavaScript bundle.
+
+### Generating a signing key
+
+You can generate a private signing key using `keytool`.
+
+    $ keytool -genkey -v -keystore my-release-key.keystore -alias alias_name -keyalg RSA -keysize 2048 -validity 10000
+
+This command prompts you for passwords for the keystore and key, and to provide the Distinguished Name fields for your key. It then generates the keystore as a file called `my-release-key.keystore`.
+
+The keystore contains a single key, valid for 10000 days. The alias is a name that you will use later when signing your app, so remember to take note of the alias.
+
+_Note: Remember to keep your keystore file private and never commit it to version control._
+
+### Setting up gradle variables
+
+1. Place the `my-release-key.keystore` file under the `android/app` directory in your project folder.
+2. Edit the file `~/.gradle/gradle.properties` and add the following (replace `*****` with the correct keystore password, alias and key password),
+
+```
+MYAPP_RELEASE_STORE_FILE=my-release-key.keystore
+MYAPP_RELEASE_STORE_PASSWORD=*****
+MYAPP_RELEASE_KEY_ALIAS=*****
+MYAPP_RELEASE_KEY_PASSWORD=*****
+```
+
+These are going to be global gradle variables, which we can later use in our gradle config to sign our app.
+
+_Note: Once you publish the app on the Play Store, you will need to republish your app under a different package name (loosing all downloads and ratings) if you want to change the signing key at any point. So backup your keystore and don't forget the passwords._
+
+### Adding signing config to your app's gradle config
+
+Edit the file `android/app/build.gradle` in your project folder and add the signing config,
+
+```
+...
+android {
+    ...
+    defaultConfig { ... }
+    signingConfigs {
+        release {
+            storeFile file(MYAPP_RELEASE_STORE_FILE)
+            storePassword MYAPP_RELEASE_STORE_PASSWORD
+            keyAlias MYAPP_RELEASE_KEY_ALIAS
+            keyPassword MYAPP_RELEASE_KEY_PASSWORD
+        }
+    }
+    buildTypes {
+        release {
+            ...
+            signingConfig signingConfigs.release
+        }
+    }
+}
+...
+```
+
+### Generating the APK
+
+1. Start the packager by running `npm start` in your project folder
+2. In your project folder, run the following in a Terminal,
+
+```sh
+$ curl "http://localhost:8081/index.android.bundle?platform=android&dev=false&minify=true" -o "android/app/src/main/assets/index.android.bundle"
+$ cd android && ./gradlew assembleRelease
+```
+
+The generated APK can be found under `android/app/build/outputs/apk/app-release.apk`, and is ready to distribute.