我有一个分级错误
错误：（21，0）未找到Gradle DSL方法：'buildConfigField（）'可能的原因：

<ul><li>The project 'Sunshine' may be using a version of Gradle that does not contain the method.

<a href="openGradleSettings">Gradle settings</a></li><li>The build file may be missing a Gradle plugin.

<a href="apply.gradle.plugin">Apply Gradle plugin</a></li>

我建筑.Gradle代码在这里

apply plugin: 'com.android.application'

android {
    compileSdkVersion 23
    buildToolsVersion "23.0.3"

    defaultConfig {
        applicationId "com.example.boxerrebellion.sunshine.app"
        minSdkVersion 15
        targetSdkVersion 23
        versionCode 1
        versionName "1.0"
    }
    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
        }
    }
    buildTypes.each {
         it.buildConfigField 'String', 'OPEN_WEATHER_MAP_API_KEY'
    }
}

dependencies {
    compile fileTree(dir: 'libs', include: ['*.jar'])
    compile 'com.android.support:appcompat-v7:23.3.0'
}

有人知道吗？先谢谢了