ionic build(run) err: your system to install the gradle wrapper. Please include gradle

(node:93136) UnhandledPromiseRejectionWarning: Unhandled promise rejection (rejection id: 1): Could not find an installed version of Gradle either in Android Studio,
or on
in your path, or install Android Studio
(node:93136) [DEP0018] DeprecationWarning: Unhandled promise rejections are deprecated. In the future, promise rejections that are not handled will terminate the Node.js process with a non-zero exit code.

image.png

解决办法：

1）去Gradle官网：https://gradle.org/install
2）下载Gradle:https://gradle.org/releases，我这里下载的是最新的3.5版本(gradle-3.5-bin.zip)；
4）配置环境变量：系统变量--Path--编辑：

image.png

image.png