feat(f-droid): split apk

config/fastlane/common.Fastfile

@@ -20,6 +20,9 @@ MAJOR_MULTIPLIER = 10000000
 MINOR_MULTIPLIER = 10000
 PATCH_MULTIPLIER = 100
 
+FDROID_ABI_VERSION_CODES = { "armeabi-v7a" => 1, "arm64-v8a" => 2, "x86" => 3, "x86_64" => 4 }.freeze
+FDROID_ABI_MULTIPLIER = 10
+
 TYPE_ALPHA = "alpha"
 TYPE_RC = "rc"
 TYPE_FINAL = "final"
@@ -60,6 +63,15 @@ platform :android do
 		uploadToHuawei(versionCode: versionInfo["versionCode"], isPrerelease: isPrerelease)
 	end
 
+    desc "Build ABI APKs for F-Droid in app/build/fdroid/"
+    lane :buildFdroid do
+        gradle(
+            task: ":app:assembleGenericRelease",
+            flags: "--init-script fastlane/fdroid.init.gradle",
+            properties: { "fdroidAbiSplit" => true }
+        )
+    end
+
     desc "Print version info"
     lane :printVersionInfo do
         versionInfo = getVersionInfo()
@@ -70,6 +82,9 @@ platform :android do
         print "Minor: #{versionComponents["minor"]}\n"
         print "Patch: #{versionComponents["patch"]}\n"
         print "Build: #{versionComponents["build"]}\n"
+        fdroidAbiVersionCodes(versionCode: versionInfo["versionCode"]).each do |abi, versionCode|
+            print "F-Droid #{abi} version code: #{versionCode}\n"
+        end
     end
 
     # Usage: fastlane incrementVersion type:(major|minor|patch|rc|final)
@@ -141,6 +156,13 @@ platform :android do
         test
     end
 
+    desc "Generate F-Droid versionCode per ABI, must match fdroid.init.gradle"
+    private_lane :fdroidAbiVersionCodes do |options|
+        versionCode = options[:versionCode]
+        base = (versionCode / MAJOR_MULTIPLIER) * MAJOR_MULTIPLIER + (versionCode % MAJOR_MULTIPLIER) * FDROID_ABI_MULTIPLIER
+        FDROID_ABI_VERSION_CODES.transform_values { |abiCode| base + abiCode }
+    end
+
     desc "Compute version name from version code"
     private_lane :generateVersionName do |versionComponents|
         suffix = ""

config/fastlane/fdroid.init.gradle

@@ -0,0 +1,46 @@
+gradle.beforeProject { project ->
+    if (project.path != ':app' || !project.providers.gradleProperty('fdroidAbiSplit').isPresent()) {
+        return
+    }
+    if (project.extensions.extraProperties.has('nextcloudFdroidConfigured')) {
+        return
+    }
+    project.extensions.extraProperties.set('nextcloudFdroidConfigured', true)
+
+    project.pluginManager.withPlugin('com.android.application') {
+        def abiVersionCodes = ['armeabi-v7a': 1, 'arm64-v8a': 2, 'x86': 3, 'x86_64': 4]
+        def majorMultiplier = 10000000
+        def abiMultiplier = 10
+        def androidComponents = project.extensions.getByName('androidComponents')
+
+        def buildDirectory = project.layout.buildDirectory.get()
+        project.layout.buildDirectory.set(buildDirectory.dir('fdroid'))
+
+        androidComponents.finalizeDsl { android ->
+            ([android.defaultConfig] + android.buildTypes.toList() + android.productFlavors.toList()).each { config ->
+                config.ndk.abiFilters.clear()
+            }
+            android.splits.abi.enable = true
+            android.splits.abi.reset()
+            android.splits.abi.include(*abiVersionCodes.keySet().toArray(new String[0]))
+            android.splits.abi.universalApk = false
+        }
+
+        androidComponents.beforeVariants(androidComponents.selector().all()) { variant ->
+            variant.enable = variant.name == 'genericRelease'
+        }
+
+        androidComponents.onVariants(androidComponents.selector().withName('genericRelease')) { variant ->
+            variant.outputs.each { output ->
+                def abi = output.filters.find { it.filterType.name() == 'ABI' }?.identifier
+                if (!abiVersionCodes.containsKey(abi)) {
+                    throw new GradleException("Unexpected F-Droid APK ABI: ${abi}")
+                }
+                def versionCode = output.versionCode.get()
+                def base = versionCode.intdiv(majorMultiplier) * majorMultiplier +
+                    (versionCode % majorMultiplier) * abiMultiplier
+                output.versionCode.set(base + abiVersionCodes[abi])
+            }
+        }
+    }
+}

config/fastlane/fdroid.init.gradle.license

@@ -0,0 +1,2 @@
+SPDX-FileCopyrightText: 2026 Nextcloud GmbH and Nextcloud contributors
+SPDX-License-Identifier: GPL-3.0-or-later