Flutter常见问题

问题 1: Running Gradle task 'assembleDebug'...长时间无反应 或者 Could not determine the dependencies of task ':app:compileDebugJavaWithJavac'

此问题是因为Google被墙了,需要配置一下国内镜像,这里使用阿里云镜像.修改android\build.gradle如下即可.此问题一般只会在搭建环境后第一次创建项目并运行,此后再创建项目则不会再出现此问题.

android\build.gradle

buildscript {
    ext.kotlin_version = '1.3.50'
    repositories {
-        google()
-        jcenter()
+        maven { url 'https://maven.aliyun.com/repository/google' }
+        maven { url 'https://maven.aliyun.com/repository/jcenter' }
+        maven { url 'http://maven.aliyun.com/nexus/content/groups/public' }
+        maven { url 'http://download.flutter.io'}
    }

    dependencies {
        classpath 'com.android.tools.build:gradle:4.1.0'
        classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
    }
}

allprojects {
    repositories {
-        google()
-        jcenter()
+        maven { url 'https://maven.aliyun.com/repository/google' }
+        maven { url 'https://maven.aliyun.com/repository/jcenter' }
+        maven { url 'http://maven.aliyun.com/nexus/content/groups/public' }
+        maven { url 'http://download.flutter.io'}
    }
}

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

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

问题 2: build-tools;29.0.2 Android SDK Build-Tools 29.0.2

FAILURE: Build failed with an exception.

* What went wrong:
Could not determine the dependencies of task ':app:compileDebugJavaWithJavac'.
> Failed to install the following SDK components:
      build-tools;29.0.2 Android SDK Build-Tools 29.0.2
  Install the missing components using the SDK manager in Android Studio.
2

* 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 4s
Exception: Gradle task assembleDebug failed with exit code 1

此问题是因为 Flutter 打包使用的Android SDK和当前电脑上的不一致,通过Flutter doctor查看当前Android SDK的版本: [√] Android toolchain - develop for Android devices (Android SDK version 30.0.3),然后在android\app\build.gradle文件中的android对象中添加buildToolsVersion "30.0.3"即可解决.

android\app\build.gradle

def localProperties = new Properties()
def localPropertiesFile = rootProject.file('local.properties')
if (localPropertiesFile.exists()) {
    localPropertiesFile.withReader('UTF-8') { reader ->
        localProperties.load(reader)
    }
}

def flutterRoot = localProperties.getProperty('flutter.sdk')
if (flutterRoot == null) {
    throw new GradleException("Flutter SDK not found. Define location with flutter.sdk in the local.properties file.")
}

def flutterVersionCode = localProperties.getProperty('flutter.versionCode')
if (flutterVersionCode == null) {
    flutterVersionCode = '1'
}

def flutterVersionName = localProperties.getProperty('flutter.versionName')
if (flutterVersionName == null) {
    flutterVersionName = '1.0'
}

apply plugin: 'com.android.application'
apply plugin: 'kotlin-android'
apply from: "$flutterRoot/packages/flutter_tools/gradle/flutter.gradle"

android {
    compileSdkVersion 30
+    buildToolsVersion "30.0.3"

    sourceSets {
        main.java.srcDirs += 'src/main/kotlin'
    }

    defaultConfig {
        // TODO: Specify your own unique Application ID (https://developer.android.com/studio/build/application-id.html).
        applicationId "com.example.learn"
        minSdkVersion 16
        targetSdkVersion 30
        versionCode flutterVersionCode.toInteger()
        versionName flutterVersionName
    }

    buildTypes {
        release {
            // TODO: Add your own signing config for the release build.
            // Signing with the debug keys for now, so `flutter run --release` works.
            signingConfig signingConfigs.debug
        }
    }
}

flutter {
    source '../..'
}

dependencies {
    implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk7:$kotlin_version"
}