1.Downcast from ‘UIViewController‘ only unwraps optionals;did you mean to use‘!‘?
原： let view = mainStory.instantiateInitialViewController() as! UIViewController
window?.rootViewController = view
修改：
if let view = mainStory.instantiateInitialViewController(){
window?.rootViewController = view
}
2.Call can throw, but it is not marked with ‘try‘ and the error is not handled 或者 ambiguous reference to member ‘appendpartwithfileurl‘
原：formData.appendPartWithFileURL(filePath, name: "file")
修改：do {
try formData.appendPartWithFileURL(filePath, name: "file")
} catch {
// TODO: handle error
}
3.Cannot convert value of type ‘[String : String?]‘ to expected argument type ‘AnyObject?‘
原：
let params = [ "url": urlTf.text ]
修改：let params = [ "url": urlTf.text ?? "" ]
原文：http://www.cnblogs.com/-yfan/p/5223142.html