最近在研究一个验证码转发的app，原理是尝试读取手机中对应应用的验证码进行自动转发。本次尝试用flutter开发，因为之前没有flutter开发的经验，遇到了诸多环境方面的问题，汇总一些常见的问题如下。希望帮助到入门的flutter开发者，避免踩坑。
problems
1. running failed
1.1. Bug Description
FAILURE: Build failed with an exception.
* What went wrong:
Execution failed for task ':gradle:compileGroovy'.
> BUG! exception in phase 'semantic analysis' in source unit 'C:\dev\flutter\packages\flutter_tools\gradle\src\main\groovy\app_plugin_loader.groovy' Unsupported class file major version 65
* 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 31s
Running Gradle task 'assembleDebug'... 32.3s
┌─ Flutter Fix ──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┐
│ [!] Your project's Gradle version is incompatible with the Java version that Flutter is using for Gradle. │
│ │
│ If you recently upgraded Android Studio, consult the migration guide at https://flutter.dev/to/java-gradle-incompatibility. │
│ │
│ Otherwise, to fix this issue, first, check the Java version used by Flutter by running `flutter doctor --verbose`. │
│ │
│ Then, update the Gradle version specified in D:\Project\Verify_Code_App\verify_code_app\android\gradle\wrapper\gradle-wrapper.properties to be │
│ compatible with that Java version. See the link below for more information on compatible Java/Gradle versions: │
│ https://docs.gradle.org/current/userguide/compatibility.html#java │
│ │
│ │
└────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┘
1.2. Solution
执行flutter doctor --verbose发现
Java binary at: D:\Android\Android Studio\jbr\bin\java
说明java地址指向不对，要使用flutter config --jdk-dir <jdk目录>来指定java目录
2. settings.gradle.kts配置
2.1. Bug Description
配置gradle plugin国内镜像源时，使用了
pluginManagement {
repositories {
maven { url 'https://plugins.gradle.org/m2/' }
maven { url 'https://maven.aliyun.com/nexus/content/repositories/google' }
maven { url 'https://maven.aliyun.com/nexus/content/groups/public' }
maven { url 'https://maven.aliyun.com/nexus/content/repositories/jcenter'}
gradlePluginPortal()
google()
mavenCentral()
}
}
报错如下：
Launching lib\main.dart on sdk gphone64 x86 64 in debug mode...
e: D:\Project\Verify_Code_App\verify_code_app\android\settings.gradle.kts:14:25: Too many characters in a character literal ''https://maven.aliyun.com/nexus/content/repositories/google''
e: D:\Project\Verify_Code_App\verify_code_app\android\settings.gradle.kts:15:25: Too many characters in a character literal ''https://maven.aliyun.com/nexus/content/groups/public''
e: D:\Project\Verify_Code_App\verify_code_app\android\settings.gradle.kts:16:25: Too many characters in a character literal ''https://maven.aliyun.com/nexus/content/repositories/jcenter''
FAILURE: Build failed with an exception.
* Where:
Settings file 'D:\Project\Verify_Code_App\verify_code_app\android\settings.gradle.kts' line: 14
* What went wrong:
Script compilation errors:
Line 14: maven { url=uri('https://maven.aliyun.com/nexus/content/repositories/google') }
^ Too many characters in a character literal ''https://maven.aliyun.com/nexus/content/repositories/google''
Line 15: maven { url=uri('https://maven.aliyun.com/nexus/content/groups/public') }
^ Too many characters in a character literal ''https://maven.aliyun.com/nexus/content/groups/public''
Line 16: maven { url=uri('https://maven.aliyun.com/nexus/content/repositories/jcenter')}
^ Too many characters in a character literal ''https://maven.aliyun.com/nexus/content/repositories/jcenter''
3 errors
2.2. Solution
网上的教程大多是按build.gradle文件来配置的，然而本项目采用了build.gradle.kts，所以需要修改为
修改为
repositories {
maven { url=uri("https://plugins.gradle.org/m2/") }
maven { url=uri("https://maven.aliyun.com/nexus/content/repositories/google") }
maven { url=uri("https://maven.aliyun.com/nexus/content/groups/public") }
maven { url=uri("https://maven.aliyun.com/nexus/content/repositories/jcenter")}
gradlePluginPortal()
google()
mavenCentral()
}
3. 第三方库命名空间NameSpace问题
3.1. Bug Description
运行flutter项目时报错，提示找不到第三方库的命名空间：
Namespace not specified. Specify a namespace in the module's build file
3.2. Solution
在build.gradle.kts文件中添加如下代码，来对第三方库进行命名空间指定：
subprojects {
afterEvaluate {
if (this is org.gradle.api.Project && (plugins.hasPlugin("com.android.library") || plugins.hasPlugin("com.android.application"))) {
val androidExtension = extensions.findByType<com.android.build.gradle.BaseExtension>()
androidExtension?.let { android ->
val currentNamespace = android.namespace
println("project: ${this.name} Namespace get: $currentNamespace")
val packageName = currentNamespace
?: android.defaultConfig.applicationId
?: android.sourceSets.getByName("main").manifest.srcFile.readText().let { manifestText ->
val regex = Regex("package=\"([^\"]*)\"")
regex.find(manifestText)?.groupValues?.get(1)
}
?: group.toString()
android.namespace = packageName
println("Namespace set to: $packageName for project: ${this.name}")
val manifestFile = android.sourceSets.getByName("main").manifest.srcFile
if (manifestFile.exists()) {
var manifestText = manifestFile.readText()
if (manifestText.contains("package=")) {
manifestText = manifestText.replace(Regex("package=\"[^\"]*\""), "")
manifestFile.writeText(manifestText)
println("Package attribute removed in AndroidManifest.xml for project: ${this.name}")
} else {
println("No package attribute found in AndroidManifest.xml for project: ${this.name}")
}
} else {
println("AndroidManifest.xml not found for project: ${this.name}")
}
}
}
}
}
4. sms_advanced第三方依赖问题
4.1. Bug Description
在编写flutter项目时，引入了sms_advanced第三方库，但是在运行时，出现了如下错误：
* What went wrong:
The Android Gradle plugin supports only Kotlin Gradle plugin version 1.5.20 and higher.
The following dependencies do not satisfy the required version:
project ':sms_advanced' -> org.jetbrains.kotlin:kotlin-gradle-plugin:1.3.50
pubspec.yml中引入的依赖：
dependencies:
flutter:
sdk: flutter
http: ^1.3.0
shared_preferences: ^2.5.2
# The following adds the Cupertino Icons font to your application.
# Use with the CupertinoIcons class for iOS style icons.
cupertino_icons: ^1.0.8
sms_advanced: ^1.1.0
4.2. Solution
网上大多数解决方案是修改android/build.gradle文件，将kotlin版本修改为1.5.20以上，这个方案需要对sms_advanced依赖中的文件进行操作。我尝试前往对应插件库的github项目地址，发现作者最新的更新仅上传了github并未上传到pub，因此无法通过修改版本号的方式解决问题。
因此我尝试修改dependencies，直接从git仓库中引入依赖，如下：
dependencies:
flutter:
sdk: flutter
http: ^1.3.0
shared_preferences: ^2.5.2
# The following adds the Cupertino Icons font to your application.
# Use with the CupertinoIcons class for iOS style icons.
cupertino_icons: ^1.0.8
sms_advanced:
git:
url: git@github.com:EddieKamau/sms_advanced.git
最终得以解决。
