MAC 

第一步:从微软官网下载:https://www.visualstudio.com/vs/visual-studio-mac/

第二步:安装软件过程出现

It was not possible to complete an automatic installation. This might be due to a problem with your network, proxy servers or an unsolvable installation conflict. At this point, you can continue the installation by manually downloading and installing the independent pieces. The list below shows each component that you need to install.

Mono Framework

Download the Mono Framework v4.8.0 archive to any directory on your disk, double-click it and follow the instructions on screen. Please accept all the defaults during the installation, including the target drive.

Java SDK

Mac OS X uses its own version of Java and in order to install it you need to start the terminal app and type the following command:javac -versionAfter typing it you should see a Mac OS X system popup which will guide you to install the Java software.

Android SDK

Download the Android SDK for Mac OS X version 24.4.1, open the downloaded archive and copy the contents of the folder found at its root directory (most probably named android-sdk-macosx) to the /Users/cong/Library/Developer/Xamarin/android-sdk-macosx directory.

Click here in order to start