添加background_fetch后Android资源链接失败问题求助

问题描述 #

添加background_fetch: ^1.1.1依赖后，执行Android Release版本构建时出现资源链接失败，具体报错为找不到android:attr/lStar资源，任务:background_fetch:verifyReleaseResources执行失败。已将Gradle从7.1.0升级至7.3.0，尝试相关修复方案后问题仍存在。

报错详情 #

FAILURE: Build failed with an exception.

* What went wrong:
Execution failed for task ':background_fetch:verifyReleaseResources'.

> A failure occurred while executing com.android.build.gradle.tasks.VerifyLibraryResourcesTask$Action
   Android resource linking failed
   ERROR:/Users/musamaashraf/dev/projects/BuddyPark/build/background_fetch/intermediates/merged_res/release/values/values.xml:2520: AAPT: error: resource android:attr/lStar not found.

* Try:
> Run with --stacktrace option to get the stack trace.
> Run with --info or --debug option to get more log output.
> Run with --scan to get full insights.

* Get more help at https://help.gradle.org

BUILD FAILED in 1m 41s
Running Gradle task 'assembleRelease'...                          102.3s
Gradle task assembleRelease failed with exit code 1

当前配置文件 #

android/build.gradle #

buildscript {
    ext.kotlin_version = '1.6.10'
    repositories {
        google()
        jcenter()
        mavenCentral()
    }

    dependencies {
        classpath 'com.google.gms:google-services:4.3.13'
        classpath 'com.android.tools.build:gradle:7.3.0'
        classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
    }
}

allprojects {
    repositories {
        google()
        mavenCentral()
        maven {
            // [required] background_fetch
            url "${project(':background_fetch').projectDir}/libs"
        }
    }
}

rootProject.buildDir = '../build'
subprojects {
    project.buildDir = "${rootProject.buildDir}/${project.name}"
}
subprojects {
    project.evaluationDependsOn(':app')
}

task clean(type: Delete) {
    delete rootProject.buildDir
}

gradle.properties #

org.gradle.jvmargs=-Xmx2048m -Dfile.encoding=UTF-8
android.useAndroidX=true
android.enableJetifier=true
android.jetifier.ignorelist=bcprov-jdk15on

修复方案 #

1. 统一所有子项目的SDK版本 #

在android/build.gradle中修改subprojects块，强制所有子项目使用与主App一致的compileSdkVersion和targetSdkVersion（至少为31，因为lStar是Android 12/API 31新增属性）：

rootProject.buildDir = '../build'
subprojects {
    project.buildDir = "${rootProject.buildDir}/${project.name}"
    // 添加以下配置
    project.ext {
        compileSdkVersion = 33 // 可根据主App实际版本调整，最低31
        targetSdkVersion = 33
    }
    afterEvaluate {
        if (project.hasProperty('android')) {
            android {
                compileSdkVersion project.ext.compileSdkVersion
                targetSdkVersion project.ext.targetSdkVersion
            }
        }
    }
}
subprojects {
    project.evaluationDependsOn(':app')
}

2. 确认主App的SDK版本配置 #

打开android/app/build.gradle，确保compileSdkVersion和targetSdkVersion不低于31：

android {
    compileSdkVersion 33
    defaultConfig {
        targetSdkVersion 33
        // 其他原有配置...
    }
    // 其他原有配置...
}

3. 清理缓存并重新构建 #

执行以下命令清理构建缓存，然后重新生成Release版本：

flutter clean
flutter build apk --release

原因说明 #

android:attr/lStar是Android 12（API 31）引入的资源属性，background_fetch库的依赖可能引用了该属性，但项目中部分子模块的compileSdkVersion低于31，导致AAPT无法识别该资源，从而触发链接失败。通过统一所有模块的SDK版本，确保构建环境支持该属性即可解决问题。

内容的提问来源于stack exchange，提问作者Muhammad Usama Ashraf