Question

为什么在Objective-C中我可以在块中设置实例变量：

@interface CMVServices : UIViewController
@property (nonatomic, strong) NSMutableArray *times;

@implementation CMVServices
@synthesize times=_times;

and set the _times instance variable inside a block:
(some code )
.
.
[query findObjectsInBackgroundWithBlock:^(NSArray *objects, NSError *error) {
[_times addObjectsFromArray:objects];
}

但是我不能在斯威夫特？

class ViewController: UIViewController 
var times :AnyObject[]!

query.findObjectsInBackgroundWithBlock { (objects: AnyObject[]!, error: NSError!) -> Void in
 self.times = objects
}

信息是：（AnyObject []？）次=父无法评估：变量不可用

Answer 1

两件事：

Array声明的Swift语法已从AnyObject[]更改为[AnyObject]
如果您仍然在班级范围内，只需使用times代替self.times。

这适用于Playground文件中的XCode6-Beta4：

import UIKit

class CMVServices : UIViewController {
    var times : [AnyObject] = []

    func testFunc() {
        func findObjects(objects : [AnyObject]!, error : NSError!) {
            times = objects
            var test_str = "still evaluating in Playground here"
        }
        findObjects(["test", "string"], nil)
    }
}

var test = CMVServices()

test.testFunc()

对于闭包本身的全面测试，这也有效（再次，在XCode6-Beta4中）：

import UIKit

class CMVServices : UIViewController {
    var times: [AnyObject] = []

    func testClosure() {
        { (objects : [AnyObject]!, error : NSError!) -> Void in
            self.times = objects
            NSLog("still evaluating")
        }(["new", "test", "string"], nil)
    }
}

var test = CMVServices()

test.testClosure()
test.times // ["new", "test", "string"]

Swift访问闭包内的类变量

1 个答案: