升级到 Android Studio 3.0 + Gradle 4.1 遇到的一些坑及解决方案

问题一:

Cannot set the value of read-only property 'outputFile' for ApkVariantOutputImpl_Decorated{apkData=Main{type=MAIN, fullName=commonDebug, filters=[]}} of type com.android.build.gradle.internal.api.ApkVariantOutputImpl. Open File

解决方案一：

https://stackoverflow.com/questions/44239235/android-gradle-3-0-0-alpha2-plugin-cannot-set-the-value-of-read-only-property

I used this code

 applicationVariants.all { variant ->                variant.outputs.each { output ->                    def outputFile = output.outputFile                    if (outputFile != null && outputFile.name.endsWith('.apk')) {                        //输出apk名称为：应用名.apk                        def fileName = "xxx.apk"                        output.outputFile = new File(outputFile.parent, fileName)                    }                }            }

**Use all() instead of each()
Use outputFileName instead of output.outputFile if you change only file name (that is your case)**

Example from the guide:

// If you use each() to iterate through the variant objects,// you need to start using all(). That's because each() iterates// through only the objects that already exist during configuration time—// but those object don't exist at configuration time with the new model.// However, all() adapts to the new model by picking up object as they are// added during execution.android.applicationVariants.all { variant ->                variant.outputs.all {                    outputFileName = "xxx.apk"                }            }

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问题二:

Error:All flavors must now belong to a named flavor dimension. Learn more at https://d.android.com/r/tools/flavorDimensions-missing-error-message.html

解决方案二：

http://blog.csdn.net/syif88/article/details/75009663

大致是说，Plugin 3.0.0之后有一种自动匹配消耗库的机制，便于debug variant 自动消耗一个库，然后就是必须要所有的flavor 都属于同一个维度。
为了避免flavor 不同产生误差的问题，应该在所有的库模块都使用同一个foo尺寸。

但是我们从中已经知道解决方案了：

在主 app 的 build.gradle 里面的

defaultConfig { targetSdkVersion：*** minSdkVersion ：*** versionCode：*** versionName ：***//版本名后面加句话，意思是flavor dimension 它的维度就是该版本号，//这样维度就是都是统一的了 **flavorDimensions "versionCode"**}

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问题三：

Error:Execution failed for task ':youyoubao:javaPreCompileCommonDebug'.> Annotation processors must be explicitly declared now.  The following dependencies on the compile classpath are found to contain annotation processor.  Please add them to the annotationProcessor configuration.    - butterknife-compiler-8.6.0.jar (com.jakewharton:butterknife-compiler:8.6.0)  Alternatively, set android.defaultConfig.javaCompileOptions.annotationProcessorOptions.includeCompileClasspath = true to continue with previous behavior.  Note that this option is deprecated and will be removed in the future.  See https://developer.android.com/r/tools/annotation-processor-error-message.html for more details.

解决方案三：

在 app 下的 build.gradle 的 defaultConfig 中加一句话：

defaultConfig {   ...   javaCompileOptions { annotationProcessorOptions { includeCompileClasspath = true } }}