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

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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)
                    }
                }
            }

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**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

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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.

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解决方案三：

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

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

转：
https://blog.csdn.net/CHITTY1993/article/details/78667069

---

Cannot set the value of read-only property 'outputFile' for ApkVariantOutputImpl_Decorated

今天升级了AS3.0以后，在项目编译的时候发现Gradle中报错了，错误如下：

Error:(60, 0) Cannot set the value of read-only property 'outputFile' for ApkVariantOutputImpl_Decorated{apkData=Main{type=MAIN, fullName=xiaomiRelease, filters=[]}} of type com.android.build.gradle.internal.api.ApkVariantOutputImpl.

<a href="openFile:E:\Studio\MyApplication\CodeBook\build.gradle">Open File</a>

经过一番折腾，网上找大牛的解读，弄明白了output.outputFile变成了只读属性，不能再往里面写东西了，以下是3.0之前的配置：

applicationVariants.all { variant ->    //批量修改Apk名字

    variant.outputs.each { output ->

        def outputFile = output.outputFile

        if (outputFile != null && outputFile.name.endsWith('.apk') && 'release'.equals(variant.buildType.name)) {

            def fileName = outputFile.name.replace("${variant.flavorName}", "V${defaultConfig.versionName}-${variant.flavorName}")

            fileName = fileName.replace('.apk', "-${buildTime()}.apk")

            output.outputFile = new File(outputFile.parent, fileName)

        }

    }

}

下面是经过修改之后3.0里面批量修改APK名字的配置：

applicationVariants.all { variant ->    //批量修改Apk名字

    variant.outputs.all { output ->

        if (!variant.buildType.isDebuggable()) {

            //获取签名的名字 variant.signingConfig.name

            //要被替换的源字符串

            def sourceFile = "-${variant.flavorName}-${variant.buildType.name}"

            //替换的字符串

            def replaceFile = "_V${variant.versionName}_${variant.flavorName}_${variant.buildType.name}_${buildTime()}"

            outputFileName = output.outputFile.name.replace(sourceFile, replaceFile);

            //遗留问题：如何获取当前module的name，如CodeBooke这个名字怎么获取到

        }

    }

}

问题：对于如何在gradle中获取module的name，还是没有找到相关的方法，希望有知道的大神留言交流。

gradle API：https://developer.android.google.cn/studio/build/gradle-plugin-3-0-0-migration.html#variant_api

这是一个对AS 3.0变化总结比较全的博客：

https://mp.weixin.qq.com/s?__biz=MzAwNzc0NjAxMg==&mid=2653391711&idx=1&sn=821eff3f98ab52fc442c6218794b203e&chksm=80aa53ecb7dddafa522d4ebfdf67af2f473365bb0fa2d50ae6df5d00499926ae0d32a5a448d2&mpshare=1&scene=23&srcid=10308c4ICo7GCwuVc683H6eZ#rd