bogon:xiangmukaungjia ybd$ pod install

Analyzing dependencies

Downloading dependencies

Installing Kingfisher (4.2.0)

[!] Pods written in Swift can only be integrated as frameworks; add `use_frameworks!` to your Podfile or target to opt into using it. The Swift Pod being used is: Kingfisher

解決辦法：就是要加 use_frameworks!

target 'xiangmukuangjia' do

pod 'Kingfisher','~> 4.2.0'

use_frameworks!  

end