应用程序支持的最大宽高比。
This value is expressed as (longer dimension / shorter dimension) in decimal form. It can not be set to a value lower than 1.86 which matches the aspect ratio of 16:9. By default it is set to 2.1 which means the application supports all devices with aspect ratio up to 18.5:9. For more information, see Declare a maximum aspect ratio.