Update to Gradle 3.3+ and Android Plugin for Gradle 2.3.3.

This also migrates the building of native code to cmake/ninja (included with the Android SDK
Tools), getting rid of the deprecated gradle-experimental plugin.

README.md

@@ -4,9 +4,6 @@ This project contains several sub-projects:
 
  * __wallet__:
      The Android app itself. This is probably what you're searching for.
- * __native-scrypt__:
-     Native code implementation for Scrypt. The C files are copied from the
-     Java Scrypt project at [GitHub](https://github.com/wg/scrypt).
  * __market__:
      App description and promo material for the Google Play app store.
  * __integration-android__:

build.gradle

@@ -4,8 +4,7 @@ buildscript {
     }
 
     dependencies {
-        classpath 'com.android.tools.build:gradle:2.1.2'
-        classpath 'com.android.tools.build:gradle-experimental:0.7.0'
+        classpath 'com.android.tools.build:gradle:2.3.3'
         classpath('fr.avianey.androidsvgdrawable:gradle-plugin:3.0.0') {
             exclude group: 'xerces'
         }

settings.gradle

@@ -1,4 +1,3 @@
 include 'wallet'
 include 'integration-android'
 include 'sample-integration-android'
-include 'native-scrypt'

wallet/.gitignore

@@ -1 +1,2 @@
 res/mipmap-*hdpi/
+.externalNativeBuild/

wallet/README.md

@@ -53,21 +53,21 @@ is world readable/writeable. The goal is to be able to debug easily.
 
 You can probably skip some steps, especially if you built Android apps before.
 
-You'll need git, a Java SDK 6 (or later) and Gradle 2.10 (or later) for this. I'll assume Ubuntu Xenial Linux
+You'll need git, a Java6 SDK (or later) and Gradle 3.4 (or later) for this. I'll assume Ubuntu 18.04 LTS (Bionic Beaver)
 for the package installs, which comes with slightly more recent versions.
 
     # first time only
-    sudo apt install git gradle openjdk-8-jdk libstdc++6:i386 zlib1g:i386
+    sudo apt install git gradle openjdk-8-jdk
 
-Download the [Android SDK Tools](https://developer.android.com/studio/index.html#command-tools)
-and unpack to your workspace directory. Point your `ANDROID_HOME` variable to the unpacked Android SDK directory
-and switch to it.
+Create a directory for the Android SDK (e.g. `android-sdk`) and point the `ANDROID_HOME` variable to it.
 
-Download and install the required Android dependencies:
+Download the [Android SDK Tools](https://developer.android.com/studio/index.html#command-tools)
+and unpack it to `$ANDROID_HOME/`.
 
-    tools/android update sdk --no-ui --force --all --filter tool,platform-tool,build-tools-27.0.3,android-15,android-27
+Install the NDK:
 
-Download the [Android NDK](https://developer.android.com/ndk/downloads/), then unpack it to your workspace directory. Point your `ANDROID_NDK_HOME` variable to the unpacked Android NDK directory.
+    # first time only
+    $ANDROID_HOME/bin/tools/sdkmanager ndk-bundle
 
 Finally, you can build Bitcoin Wallet and sign it with your development key. Again in your workspace,
 use:
@@ -78,15 +78,12 @@ use:
     # each time
     cd bitcoin-wallet
     git pull
-    gradle clean :native-scrypt:copy test build
+    gradle clean test build
 
 To install the app on your Android device, use:
 
-    # first time only
-    sudo apt install android-tools-adb
-
     # each time
-    adb install wallet/build/outputs/apk/bitcoin-wallet-debug.apk
+    gradle installDebug
 
 If installation fails, make sure "Developer options" and "USB debugging" are enabled on your Android device, and an ADB
 connection is established.
@@ -106,7 +103,7 @@ separate 'prod' branch that gets rebased against master with each released versi
     cd bitcoin-wallet
     git fetch origin
     git checkout origin/prod
-    gradle clean :native-scrypt:copy test build
+    gradle clean test build
 
 
 ### SETTING UP FOR DEVELOPMENT

wallet/build.gradle

@@ -45,9 +45,20 @@ android {
     defaultConfig {
         applicationId 'de.schildbach.wallet_test'
         generatedDensities = ['hdpi', 'xhdpi']
+
         dexOptions {
             preDexLibraries false
         }
+
+        ndk {
+            abiFilters 'armeabi', 'armeabi-v7a', 'x86'
+        }
+
+        externalNativeBuild {
+            cmake {
+                cFlags '-DHAVE_CONFIG_H'
+            }
+        }
     }
 
     buildTypes {
@@ -74,6 +85,12 @@ android {
         }
     }
 
+    externalNativeBuild {
+        cmake {
+            path 'cpp/CMakeLists.txt'
+        }
+    }
+
     packagingOptions {
         exclude 'lib/x86_64/darwin/libscrypt.dylib'
         exclude 'okhttp3/internal/publicsuffix/publicsuffixes.gz'

wallet/cpp/CMakeLists.txt

@@ -0,0 +1,3 @@
+cmake_minimum_required(VERSION 3.6.0)
+add_library(scrypt SHARED scrypt_jni.c crypto_scrypt-nosse.c sha256.c)
+include_directories(.)