android端在執(zhí)行flutter build aar命令時棉钧,有時候會遇到如下錯誤(問題版本1.17.1屿脐,目前最新的flutter版本1.22.4已不存在此問題)
FAILURE: Build failed with an exception.
- Where:
Initialization script '....\packages\flutter_tools\gradle\aar_init_script.gradle' line: 15
aar_init_script.gradle中修改相關代碼如下
void configureProject(Project project, String outputDir) {
if (!project.hasProperty("android")) {
throw new GradleException(project.toString())
// throw new GradleException("Android property not found.")
}
...
}
再次執(zhí)行flutter build aar掰盘,可定位到具體出錯插件項目。如:
引入path_provider:1.6.8的項目愧捕,執(zhí)行以上命令時會有如下錯誤信息提示
- What went wrong:
project ':path_provider_macos'
由此猜測可能是某些插件依賴了macos相關申钩,查看path_provider-1.6.8中的pubspec.yaml,可發(fā)現(xiàn)其依賴了path_provider_macos
dependencies:
flutter:
sdk: flutter
path_provider_platform_interface: ^1.0.1
path_provider_macos: ^0.0.4
目前我們的項目中這三個插件path_provider:1.6.8撒遣、shared_preferences: 0.5.7+2、webview_flutter: 0.3.22+1
都會有同樣的"Android property not found."問題义黎。
在網(wǎng)上搜了一下,大部分解決辦法都是說臨時刪除掉.pub-cache/hosted/pub.flutter-io.cn下出錯的相關包泻云,
這個的確可以解決狐蜕,但下次執(zhí)行flutter clean, flutter pub get后,再次執(zhí)行flutter build aar時還會有同樣的問題层释,
于是想看能否看下源碼了解下有沒有好的解決辦法。
在flutter的packages/flutter_tools/gradle/flutter.gradle中廉白,看到如下項目配置的代碼
/**
* Configures the Flutter plugin dependencies.
*
* The plugins are added to pubspec.yaml. Then, upon running `flutter pub get`,
* the tool generates a `.flutter-plugins` file, which contains a 1:1 map to each plugin location.
* Finally, the project's `settings.gradle` loads each plugin's android directory as a subproject.
*/
private void configurePlugins() {
if (!buildPluginAsAar()) {
getPluginList().each this.&configurePluginProject
getPluginDependencies().each this.&configurePluginDependencies
return
}
project.repositories {
maven {
url "${getPluginBuildDir()}/outputs/repo"
}
}
getPluginList().each { pluginName, pluginPath ->
configurePluginAar(pluginName, pluginPath, project)
}
}
配置插件依賴部分的代碼如下猴蹂,其會過濾掉不支持android platform的依賴插件
// Add the dependencies on other plugin projects to the plugin project.
// A plugin A can depend on plugin B. As a result, this dependency must be surfaced by
// making the Gradle plugin project A depend on the Gradle plugin project B.
private void configurePluginDependencies(Object dependencyObject) {
...
dependencyObject.dependencies.each { pluginDependencyName ->
...
Project dependencyProject = project.rootProject.findProject(":$pluginDependencyName")
if (dependencyProject == null ||
!doesSupportAndroidPlatform(dependencyProject.projectDir.parentFile.path)) {
return
}
// Wait for the Android plugin to load and add the dependency to the plugin project.
pluginProject.afterEvaluate {
pluginProject.dependencies {
implementation dependencyProject
}
}
}
}
關鍵代碼doesSupportAndroidPlatform如下晕讲,主要是判斷插件項目中是否有android目錄和android/build.gradle文件
// Returns `true` if the given path contains an `android/build.gradle` file.
//
// TODO(egarciad): Fix https://github.com/flutter/flutter/issues/39657.
// Android Studio may create empty android directories due to the logic in <app>/android/settings.gradle,
// which imports all plugins regardless of whether they support the android platform.
private Boolean doesSupportAndroidPlatform(String path) {
File editableAndroidProject = new File(path, 'android' + File.separator + 'build.gradle')
return editableAndroidProject.exists()
}
根據(jù)之前代碼configurePlugins中的注釋,我們大概了解項目中插件配置流程如下
1.首先在pubspec.yaml中添加相關插件
2.執(zhí)行flutter pub get命令生成.flutter-plugins文件
3.項目的settings.gradle加載每一個插件的android目錄作為子項目
在.android項目中弄息,我們先查看生成的settings.gradle文件
// Generated file. Do not edit.
include ':app'
rootProject.name = 'android_generated'
setBinding(new Binding([gradle: this]))
evaluate(new File(settingsDir, 'include_flutter.groovy'))
再查看生成的文件include_flutter.groovy勤婚,部分代碼如下
def plugins = new Properties()
def pluginsFile = new File(flutterProjectRoot, '.flutter-plugins')
if (pluginsFile.exists()) {
pluginsFile.withReader('UTF-8') { reader -> plugins.load(reader) }
}
plugins.each { name, path ->
def pluginDirectory = flutterProjectRoot.toPath().resolve(path).resolve('android').toFile()
gradle.include ":$name"
gradle.project(":$name").projectDir = pluginDirectory
}
其先從.flutter-plugins文件中加載插件,然后配置插件項目作為subproject
其中可以看到缨称,在添加插件的android目錄作為子目錄時祝迂,并未判斷插件是否含有android目錄,
這樣上面的path_provider_macos就會被添加到子項目中作為依賴項目当凡,然后在構建時校驗失敗纠俭。
projectsEvaluated {
...
// Gets the plugin subprojects.
Set<Project> modulePlugins = rootProject.subprojects.findAll {
it.name != "flutter" && it.name != "app"
}
// When a module is built as a Maven artifacts, plugins must also be built this way
// because the module POM's file will include a dependency on the plugin Maven artifact.
// This is due to the Android Gradle Plugin expecting all library subprojects to be published
// as Maven artifacts.
modulePlugins.each { pluginProject ->
configureProject(pluginProject, moduleProject.property("output-dir"))
moduleProject.android.libraryVariants.all { variant ->
// Configure the `assembleAar<variantName>` task for each plugin's projects and make
// the module's equivalent task depend on the plugin's task.
String variantName = variant.name.capitalize()
moduleProject.tasks.findByPath("assembleAar$variantName")
.dependsOn(pluginProject.tasks.findByPath("assembleAar$variantName"))
}
}
}
大概了解依賴配置流程后冤荆,我們可以想到如下解決辦法
1.修改include_flutter.groovy中的插件項目配置規(guī)則,加上android目錄的校驗
2.修改aar_init_script.gradle中的配置規(guī)則
具體修改如下:
1.include_flutter.groovy是通過模版生成的乌妒,修改的話可修改flutter下packages/flutter_tools/templates/module/android/library_new_embedding/include_flutter.groovy.copy.tmpl
plugins.each { name, path ->
def pluginDirectory = flutterProjectRoot.toPath().resolve(path).resolve('android').toFile()
if (pluginDirectory.exists()) {
gradle.include ":$name"
gradle.project(":$name").projectDir = pluginDirectory
} else {
println("plugins " + name + " pluginDirectory : " + pluginDirectory + " does not exist")
}
}
2.修改flutter下文件packages/flutter_tools/gradle/aar_init_script.gradle中projectsEvaluated配置部分代碼:
Set<Project> modulePlugins = rootProject.subprojects.findAll {
it.name != "flutter" && it.name != "app" && it.hasProperty("android")
}
以上兩個方式都需要修改flutter中的代碼涌庭,暫時沒找到更好的解決方法,有了解其他解決辦法的拴魄,也希望分享下。
追記:
flutter 1.22.4版本生成的include_flutter.groovy中代碼變更
gradle.apply from: "$flutterSdkPath/packages/flutter_tools/gradle/module_plugin_loader.gradle"
查看module_plugin_loader.gradle代碼可見其中添加插件依賴時夏漱,檢查了是否支持android
def pluginsFile = new File(moduleProjectRoot, '.flutter-plugins-dependencies')
if (pluginsFile.exists()) {
def object = new JsonSlurper().parseText(pluginsFile.text)
assert object instanceof Map
assert object.plugins instanceof Map
assert object.plugins.android instanceof List
// Includes the Flutter plugins that support the Android platform.
object.plugins.android.each { androidPlugin ->
assert androidPlugin.name instanceof String
assert androidPlugin.path instanceof String
def pluginDirectory = new File(androidPlugin.path, 'android')
assert pluginDirectory.exists()
include ":${androidPlugin.name}"
project(":${androidPlugin.name}").projectDir = pluginDirectory
}
}