有时候，在写 android groovy 插件的时候，需要对 AGP 版本进行判断。从而，适配插件在不同版本的 AGP 上的运行效果。

方法一

这是从某 android groovy 插件看到的源码，我也忘了是什么插件。总之，简单粗暴。

`{r, engine='groovy', count_lines} static final String VERSION_3_ZERO_FIELD = "com.android.builder.Version" // <= 3.0 static final String VERSION_3_ONE_FIELD = "com.android.builder.model.Version" // > 3.1 static final String AGP_VERSION_FIELD = "ANDROID_GRADLE_PLUGIN_VERSION"

String gradlePluginVersion = '' try { gradlePluginVersion = Class.forName(VERSION_3_ZERO_FIELD). getDeclaredField(AGP_VERSION_FIELD). get(this). toString() } catch (Exception e) { // ingnore } try { gradlePluginVersion = Class.forName(VERSION_3_ONE_FIELD). getDeclaredField(AGP_VERSION_FIELD). get(this). toString() } catch (Exception e) { // ingnore }

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# 方法二

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这是我自己写的方法，还行。我一般作为 **方法一** 拿不到后的备选方法。也就是 **二级策略**。

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```{r, engine='groovy', count_lines}
String alpha = ''
String version = ''
project.rootProject
        .buildscript
        .configurations
        .classpath
        .resolvedConfiguration
        .firstLevelModuleDependencies.
        each {
            def name = it.name
            if (name.contains('com.android.tools.build:gradle')) {
                def moduleVersion = it.moduleVersion
                // alpha ?
                if (moduleVersion.contains("-")) {
                    def versionArray = moduleVersion.split("-")
                    version = versionArray[0]
                    alpha = versionArray[1]
                } else {
                    version = moduleVersion
                }
            }
        }
def firstVersion = version.substring(0, 1) as Integer
if (version == '3.1.0') {
    if ('' != alpha) {
        if (alpha == "alpha01") {
            // alpha01
        } else {
            // alpha02, alpha03...
        }
    } else {
        // 3.1.0 final version
    }
} else if (version == '3.0.0' || firstVersion < 3) {
    // less than or equal to 3.0.0
}

综合策略

结合 方法一 和 方法二。得出的，稍微较好的策略。

`{r, engine='groovy', count_lines} def dispatchAndroidGradlePluginVersion(Project project, Closure lessThanThreeClosure, Closure finalClousure, Closure... closures) { final String VERSION_3_ZERO_FIELD = "com.android.builder.Version" // <= 3.0 final String VERSION_3_ONE_FIELD = "com.android.builder.model.Version" // > 3.1 final String AGP_VERSION_FIELD = "ANDROID_GRADLE_PLUGIN_VERSION"

String gradlePluginVersion = ""
try {
    gradlePluginVersion = Class.forName(VERSION_3_ZERO_FIELD).
            getDeclaredField(AGP_VERSION_FIELD).
            get(this).
            toString()
} catch (Exception e) {
    // ignore
}
try {
    gradlePluginVersion = Class.forName(VERSION_3_ONE_FIELD).
            getDeclaredField(AGP_VERSION_FIELD).
            get(this).
            toString()
} catch (Exception e) {
    // ignore
}

String alpha = ''
String version = ''
if (gradlePluginVersion != "") {
    if (gradlePluginVersion.contains("-")) {
        def versionArray = gradlePluginVersion.split("-")
        version = versionArray[0]
        alpha = versionArray[1]
    } else {
        version = gradlePluginVersion
    }
} else {
    project.rootProject
            .buildscript
            .configurations
            .classpath
            .resolvedConfiguration
            .firstLevelModuleDependencies.
            each {
                def name = it.name
                if (name.contains('com.android.tools.build:gradle')) {
                    def moduleVersion = it.moduleVersion
                    // alpha ?
                    if (moduleVersion.contains("-")) {
                        def versionArray = moduleVersion.split("-")
                        version = versionArray[0]
                        alpha = versionArray[1]
                    } else {
                        version = moduleVersion
                    }
                }
            }
}
def firstVersion = version.substring(0, 1) as Integer
if (version == '3.1.0') {
    if ('' != alpha) {
        if (alpha == "alpha01") {
            // alpha01
            closures[1].call()
        } else {
            // alpha02, alpha03...
            // closures[2].call()，closures[3].call()
        }
    } else {
        // 3.1.0 final version
        finalClousure.call()
    }
} else if (version == '3.0.0' || firstVersion < 3) {
    // less than or equal to 3.0.0
    lessThanThreeClosure.call()
}

} `