How to use Nserror in Swift

Step one: Declare the nserror variable. Be sure to add "?", without adding or adding "!" Not even. Because optional is used, you need to use VAR instead of let.

var error:nserror?

Step Two: Add "&" to the variable before using it.

Nsjsonserialization.jsonobjectwithdata (data!, Options:. Mutablecontainers, Error: &error)

Before the pit was Nserror used is "!", the compiler always said "Could not find member" Mutablecontainers ", the wrong lure me to other places.

In Objective-c, the type of the method that accepts Nserror is (nserror ), and the compiler then converts it to (nserror *__autoreleasing *).

In Swift, the type of method accepts Nserror is (Nserrorpointer), Nserrorpointer is autoreleasingunsafemutablepointer< nserrorThe alias of the?>. (alias)

Typealias Nserrorpointer = autoreleasingunsafemutablepointer<nserror?>

andAutoreleasingunsafemutablepointer<Nserror?> is actually a struct.

Here is a simple example to use.

Let jsonstring = "[{\" name\ ": \" benson\ ", \" age\ ": +]" let data = jsonstring.datausingencoding (nsutf8stringencoding) var error:nserror?let jsonobject:anyobject? = Nsjsonserialization.jsonobjectwithdata (data!, Options:. Mutablecontainers, Error: &ERROR) if let error = error {        println (error.localizeddescription)}println ( Jsonobject)

WWDC2015 introduced Swift2.0, and declared the end of the open source. One of the new features is the error handling Model, where we can use the do try catch to handle methods that might be thrown wrong. Many of the methods in OC that contain nserror parameters are not converted to Swift2.0, but the method declares a throw error (throws).

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How to use Nserror in Swift