手动安装gradle
在学习andorid studio时发现编译超级无比的慢，网上有文说是因为gradle的原因，使用离线gradle可以大幅提高编译速度，准备尝试下看看如何。由于gradle的资料都是英文，而我又是英文盲，所以尝试翻译下安装过程并做个记录。
原文如下：
Install manually
Step 1. Download the latest Gradle distribution
The current Gradle release is version 4.10.2, released on 19 Sep 2018. The distribution zip file comes in two flavors:
- Binary-only
- Complete, with docs and sources
If in doubt, choose the binary-only version and browse docs and sources online.
Need to work with an older version? See the releases page.
Step 2. Unpack the distribution
Linux & MacOS users
Unzip the distribution zip file in the directory of your choosing, e.g.:
$ mkdir /opt/gradle
$ unzip -d /opt/gradle gradle-4.10.2-bin.zip
$ ls /opt/gradle/gradle-4.10.2
LICENSE NOTICE bin getting-started.html init.d lib media
Microsoft Windows users
Create a new directory C:\Gradle with File Explorer.
Open a second File Explorer window and go to the directory where the Gradle distribution was downloaded. Double-click the ZIP archive to expose the content. Drag the content folder gradle-4.10.2 to your newly created C:\Gradle folder.
Alternatively you can unpack the Gradle distribution ZIP into C:\Gradle using an archiver tool of your choice.
Step 3. Configure your system environment
Linux & MacOS users
Configure your PATH environment variable to include the bin directory of the unzipped distribution, e.g.:
$ export PATH=$PATH:/opt/gradle/gradle-4.10.2/bin
Microsoft Windows users
In File Explorer right-click on the This PC (or Computer) icon, then click Properties -> Advanced System Settings -> Environmental Variables.
Under System Variables select Path, then click Edit. Add an entry for C:\Gradle\gradle-4.10.2\bin. Click OK to save.
Step 4. Verify your installation
Open a console (or a Windows command prompt) and run gradle -v to run gradle and display the version, e.g.:
$ gradle -v
------------------------------------------------------------
Gradle 4.10.2
------------------------------------------------------------
› Proceed to next steps
中文安装过程：
手动安装：
１、下载最新的gradle安装包,gradle-4.10.2-bin.zip
2、gradle当前最新版本是4.10.2，发布于2018年9月19日，有两种发布形式，一种是仅有编译过的可执行程序，一种是源代码和帮助文档，我们选择二进制模式
3、解压下载的文件到C:\Gradle（别的文件夹应该也可以）
4、设置系统环境变量,把C:\Gradle\gradle-4.10.2\bin路径添加到path里面
5、检查安装是否成功，打开CMD，输入gradle -v看看是否成功
