build: Add apk_package target for building Android APK

depends/Makefile

@@ -241,6 +241,8 @@ $(host_prefix)/toolchain.cmake : toolchain.cmake.in $(host_prefix)/.stamp_$(fina
             -e 's|@multiprocess@|$(MULTIPROCESS)|' \
             -e 's|@android_abi@|$(android_abi)|' \
             -e 's|@android_ndk@|$(ANDROID_NDK)|' \
+            -e 's|@android_toolchain_bin_dir@|$(android_toolchain_bin_dir)|' \
+            -e 's|@android_libcxx_shared_dir@|$(android_libcxx_shared_dir)|' \
             $< > $@
 	touch $@
 

depends/hosts/android.mk

@@ -5,9 +5,11 @@ android_toolchain_bin_dir := $(ANDROID_NDK)/toolchains/llvm/prebuilt/$(build_os)
 ifeq ($(HOST),armv7a-linux-android)
 android_CXX := $(android_toolchain_bin_dir)/$(HOST)eabi$(ANDROID_API_LEVEL)-clang++
 android_CC  := $(android_toolchain_bin_dir)/$(HOST)eabi$(ANDROID_API_LEVEL)-clang
+android_libcxx_shared_dir := arm-linux-androideabi
 else
 android_CXX := $(android_toolchain_bin_dir)/$(HOST)$(ANDROID_API_LEVEL)-clang++
 android_CC  := $(android_toolchain_bin_dir)/$(HOST)$(ANDROID_API_LEVEL)-clang
+android_libcxx_shared_dir := $(host_arch)-linux-android
 endif
 
 android_CXXFLAGS := -std=$(CXX_STANDARD)

depends/packages/qt.mk

@@ -287,6 +287,9 @@ endef
 define $(package)_stage_cmds
   cmake --install . --prefix $($(package)_staging_prefix_dir)
 endef
+ifeq ($(host_os),android)
+  $(package)_stage_cmds += && cp -r $($(package)_extract_dir)/qtbase/src/android/jar/src $($(package)_staging_prefix_dir)/src/android/java
+endif
 
 define $(package)_postprocess_cmds
   rm -rf doc/

depends/toolchain.cmake.in

@@ -8,6 +8,18 @@ if("@host_system_name@" STREQUAL "Android")
   set(ANDROID_ABI @android_abi@)
   set(ANDROID_PLATFORM android-@host_system_version@)
   include(@android_ndk@/build/cmake/android.toolchain.cmake)
+  # Qt's Java sources for Android Application Package (APK).
+  cmake_path(SET ANDROID_APK_SRC "${CMAKE_CURRENT_LIST_DIR}/src/android/java")
+  # The libc++_shared.so shared library, provided by the Android SDK,
+  # is required to build an Android Application Package (APK).
+  cmake_path(SET ANDROID_SHARED_CXX_LIB NORMALIZE "@android_toolchain_bin_dir@/../sysroot/usr/lib/@android_libcxx_shared_dir@/libc++_shared.so")
+  # Qt recommends using the same Gradle version that it comes with.
+  # Therefore, we use the Gradle wrapper provided by Qt to build
+  # an Android Application Package (APK).
+  # See:
+  # - https://doc.qt.io/qt-6/deployment-android.html
+  # - https://doc.qt.io/qt-6/qtcore-attribution-android-gradle-wrapper.html
+  cmake_path(SET GRADLEW_EXECUTABLE "${CMAKE_CURRENT_LIST_DIR}/src/3rdparty/gradle/gradlew")
 else()
   # If CMAKE_SYSTEM_NAME is set within a toolchain file, CMake will also
   # set CMAKE_CROSSCOMPILING to TRUE, even if CMAKE_SYSTEM_NAME matches

src/qt/CMakeLists.txt

@@ -362,3 +362,7 @@ else()
     VERBATIM
   )
 endif()
+
+if(ANDROID)
+  add_subdirectory(android)
+endif()

src/qt/android/AndroidManifest.xml

@@ -0,0 +1,35 @@
+<?xml version='1.0' encoding='utf-8'?>
+<manifest xmlns:android="http://schemas.android.com/apk/res/android" android:versionName="1.0" android:versionCode="1" android:installLocation="auto">
+    <uses-permission android:name="android.permission.INTERNET" />
+    <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
+
+    <uses-feature android:glEsVersion="0x00020000" android:required="true" />
+
+    <supports-screens android:largeScreens="true" android:normalScreens="true" android:anyDensity="true" android:smallScreens="true"/>
+
+    <application android:hardwareAccelerated="true" android:name="org.qtproject.qt.android.bindings.QtApplication" android:label="Bitcoin Core" android:icon="@drawable/bitcoin">
+        <activity android:configChanges="orientation|uiMode|screenLayout|screenSize|smallestScreenSize|layoutDirection|locale|fontScale|keyboard|keyboardHidden|navigation|mcc|mnc|density"
+                  android:name="org.bitcoincore.qt.BitcoinQtActivity"
+                  android:screenOrientation="unspecified"
+                  android:launchMode="singleTop"
+                  android:exported="true">
+            <intent-filter>
+                <action android:name="android.intent.action.MAIN"/>
+                <category android:name="android.intent.category.LAUNCHER"/>
+            </intent-filter>
+
+            <meta-data android:name="android.app.arguments" android:value="-testnet"/>
+            <meta-data android:name="android.app.lib_name" android:value="bitcoin-qt"/>
+            <meta-data android:name="android.app.repository" android:value="default"/>
+            <meta-data android:name="android.app.bundle_local_qt_libs" android:value="1"/>
+            <meta-data android:name="android.app.use_local_qt_libs" android:value="1"/>
+            <meta-data android:name="android.app.libs_prefix" android:value="/data/local/tmp/qt/"/>
+            <meta-data android:name="android.app.system_libs_prefix" android:value="/system/lib/"/>
+            <meta-data android:name="android.app.background_running" android:value="true"/>
+            <meta-data android:name="android.app.auto_screen_scale_factor" android:value="true"/>
+            <meta-data android:name="android.app.extract_android_style" android:value="default"/>
+            <meta-data android:name="android.app.load_local_libs_resource_id" android:resource="@array/load_local_libs"/>
+        </activity>
+
+    </application>
+</manifest>

src/qt/android/CMakeLists.txt

@@ -0,0 +1,19 @@
+# Copyright (c) 2025 The Bitcoin Core developers
+# Distributed under the MIT software license, see the accompanying
+# file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+file(COPY ${CMAKE_CURRENT_SOURCE_DIR}/ DESTINATION ${CMAKE_CURRENT_BINARY_DIR}
+  PATTERN "CMakeLists.txt" EXCLUDE
+)
+
+file(COPY ${ANDROID_APK_SRC}/src/org DESTINATION ${CMAKE_CURRENT_BINARY_DIR}/src)
+
+file(COPY ${ANDROID_SHARED_CXX_LIB} DESTINATION libs/${CMAKE_ANDROID_ARCH_ABI})
+
+cmake_path(RELATIVE_PATH GRADLEW_EXECUTABLE BASE_DIRECTORY ${CMAKE_CURRENT_BINARY_DIR})
+
+add_custom_target(apk_package
+  COMMAND ${CMAKE_COMMAND} -E copy $<TARGET_FILE:bitcoin-qt> libs/${CMAKE_ANDROID_ARCH_ABI}/libbitcoin-qt_${CMAKE_ANDROID_ARCH_ABI}.so
+  COMMAND ${GRADLEW_EXECUTABLE} build
+  VERBATIM
+)

src/qt/android/build.gradle

@@ -0,0 +1,51 @@
+buildscript {
+    repositories {
+        google()
+        mavenCentral()
+    }
+
+    dependencies {
+        classpath 'com.android.tools.build:gradle:8.0.2'
+    }
+}
+
+repositories {
+    google()
+    mavenCentral()
+}
+
+apply plugin: 'com.android.application'
+
+dependencies {
+    implementation fileTree(dir: 'libs', include: ['*.jar'])
+}
+
+android {
+    compileSdkVersion androidCompileSdkVersion.toInteger()
+
+    buildToolsVersion androidBuildToolsVersion
+
+    namespace 'org.bitcoincore.qt'
+
+    sourceSets {
+        main {
+            manifest.srcFile 'AndroidManifest.xml'
+            java.srcDirs = [qtAndroidDir + '/src', 'src', 'java']
+            aidl.srcDirs = [qtAndroidDir + '/src', 'src', 'aidl']
+            res.srcDirs = [qtAndroidDir + '/res', 'res']
+            resources.srcDirs = ['src']
+            renderscript.srcDirs = ['src']
+            assets.srcDirs = ['assets']
+            jniLibs.srcDirs = ['libs']
+       }
+    }
+
+    lintOptions {
+        abortOnError false
+    }
+
+    defaultConfig {
+        minSdkVersion 26
+        targetSdk 33
+    }
+}

src/qt/android/gradle.properties

@@ -0,0 +1,4 @@
+androidBuildToolsVersion=33.0.3
+androidCompileSdkVersion=33
+qtAndroidDir=new File(".").absolutePath
+org.gradle.jvmargs=-Xmx4608M

src/qt/android/res/values/libs.xml

@@ -0,0 +1,14 @@
+<?xml version="1.0" encoding="utf-8"?>
+<resources>
+    <array name="load_local_libs">
+        <item>
+            arm64-v8a;libbitcoin-qt_arm64-v8a.so
+        </item>
+        <item>
+            armeabi-v7a;libbitcoin-qt_armeabi-v7a.so
+        </item>
+        <item>
+            x86_64;libbitcoin-qt_x86_64.so
+        </item>
+    </array>
+</resources>

src/qt/android/src/org/bitcoincore/qt/BitcoinQtActivity.java

@@ -0,0 +1,23 @@
+package org.bitcoincore.qt;
+
+import android.os.Bundle;
+import android.system.ErrnoException;
+import android.system.Os;
+
+import org.qtproject.qt.android.bindings.QtActivity;
+
+import java.io.File;
+
+public class BitcoinQtActivity extends QtActivity
+{
+    @Override
+    public void onCreate(Bundle savedInstanceState)
+    {
+        final File bitcoinDir = new File(getFilesDir().getAbsolutePath() + "/.bitcoin");
+        if (!bitcoinDir.exists()) {
+            bitcoinDir.mkdir();
+        }
+
+        super.onCreate(savedInstanceState);
+    }
+}