ClassCastException：ApiVersionImpl 不能被强制转换为 java.lang.Integer

我有android + gradle项目。当我尝试启动应用程序时，出现以下异常：

'ClassCastException: com.android.build.gradle.internal.model.ApiVersionImpl cannot be cast to java.lang.Integer: com.android.build.gradle.internal.model.ApiVersionImpl cannot be cast to java.lang.Integer'

buildscript {
    repositories {
        mavenCentral()
    }

    dependencies {
        classpath 'com.android.tools.build:gradle:0.12.1'
        classpath 'com.neenbedankt.gradle.plugins:android-apt:1.+'
    }
}

apply plugin: 'android'
apply plugin: 'android-apt'

repositories {
    mavenCentral()
    mavenLocal()
}

dependencies {
    compile files('libs/android-support-v4.jar')
    compile 'org.androidannotations:androidannotations-api:3.0.1'
    apt 'org.androidannotations:androidannotations:3.0.1'
}

android {
    compileSdkVersion 15
    buildToolsVersion '19.1'

    defaultConfig {
        minSdkVersion 15
        targetSdkVersion 15
    }

    sourceSets {
        main {
            manifest.srcFile 'AndroidManifest.xml'
            java.srcDirs = ['src']
            res.srcDirs = ['res']
            assets.srcDirs = ['assets']
        }
    }
}