Application Transport Security has blocked a cleartext HTTP (http://) resource load since it is insecure. Temporary exceptions can be configured via your app's Info.plist file.
解决：
在info.plist中添加 <key>NSAppTransportSecurity</key> <dict> <key>NSAllowsArbitraryLoads</key><true/> </dict>
App Transport Security Settings 》 Allow Arbitrary Loads 》YES