我有以下代码片段,我在某些设备上崩溃了:
Crashed: com.apple.root.default-qos
EXC_BAD_ACCESS KERN_INVALID_ADDRESS at 0x00000000cbd
代码:
var obj:AnyObject = command.arguments[0] as AnyObject!
var theData:AnyObject = obj["getContactImagesByEmails"] as AnyObject!
if let contactImagesByEmails:AnyObject = obj["emails"]{
if contactImagesByEmails is Array<String>{
/*line 176*/ let array:Array<String> =
contactImagesByEmails as Array<String> // CRASH happens here
results = WmSqliteImagesModel.getInstance.getImagesByEmailAsWmContactImage(array) as Dictionary<String,AnyObject>
}
}
完整堆栈跟踪
Thread : Crashed: com.apple.root.default-qos
0 libswiftCore.dylib 0x0000000100559794 swift_unknownRetain + 32
1 MyApp 0x000000010017c8a0 MyApp.Plugin.(getContactImagesByEmails (MyApp.Plugin) -> (ObjectiveC.CDVInvokedUrlCommand) -> ()).(closure #1) (Plugin.swift:176)
2 MyApp 0x000000010017c8a0 MyApp.Plugin.(getContactImagesByEmails (MyApp.Plugin) -> (ObjectiveC.CDVInvokedUrlCommand) -> ()).(closure #1) (Plugin.swift:176)
3 MyApp 0x00000001001790b0 partial apply forwarder for reabstraction thunk helper from @callee_owned () -> (@unowned ()) to @callee_owned (@in ()) -> (@out ()) with unmangled suffix "125" (Plugin.swift:62)
4 MyApp 0x0000000100179120 partial apply forwarder for reabstraction thunk helper from @callee_owned (@in ()) -> (@out ()) to @callee_owned () -> (@unowned ()) with unmangled suffix "128" (Plugin.swift:62)
5 libdispatch.dylib 0x00000001937e13ac _dispatch_call_block_and_release + 24
6 libdispatch.dylib 0x00000001937e136c _dispatch_client_callout + 16
7 libdispatch.dylib 0x00000001937ed40c _dispatch_root_queue_drain + 1152
8 libdispatch.dylib 0x00000001937ee75c _dispatch_worker_thread3 + 108
9 libsystem_pthread.dylib 0x00000001939bd2e4 _pthread_wqthread + 816
Plugin.swift:176
指向:
let array:Array<String> = contactImagesByEmails as Array<String>
我错过了什么吗?我认为这段代码应该是安全的。
如果contactImagesByEmails is Array<String>
返回true
,为什么contactImagesByEmails as Array<String>
会失败?
请帮忙,
[编辑]
command
的类型为CDVInvokedUrlCommand
@interface CDVInvokedUrlCommand : NSObject {
NSString* _callbackId;
NSString* _className;
NSString* _methodName;
NSArray* _arguments;
}
答案 0 :(得分:2)
我不知道这是否能真正解决问题,但2 if
和以下let
中存在一些冗余。它可以简单地写成:
if let contactImagesByEmails = obj["emails"] as? Array<String> {
results = WmSqliteImagesModel.getInstance.getImagesByEmailAsWmContactImage(contactImagesByEmails) as Dictionary<String,AnyObject>
}
此外,在调用getImagesByEmailAsWmContactImage
if let results = WmSqliteImagesModel.getInstance.getImagesByEmailAsWmContactImage(contactImagesByEmails) as? Dictionary<String,AnyObject> {
...
}
最后,您确定getInstance
是属性而不是方法吗?不应该是:
if let results = WmSqliteImagesModel.getInstance().getImagesByEmailAsWmContactImage(contactImagesByEmails) as? Dictionary<String,AnyObject> {
...
}
答案 1 :(得分:1)
也许尝试另一种获取转换值的方法:
if let contactImagesByEmails = obj["emails"] as? [String] {
results = WmSqliteImagesModel.getInstance.getImagesByEmailAsWmContactImage(contactImagesByEmails) as Dictionary<String,AnyObject>
}
我也想知道你的崩溃是不是在原始代码中命名你的变量“array”......
答案 2 :(得分:1)
逐步简化此操作,减少对AnyObject
的引用(当然不是AnyObject!
)。编译器可能会放弃一些非法的东西,因为当你开始拔出AnyObject
时,你会说“我确切地知道我在做什么;不要检查这个。”
您希望此代码类似于:
let obj = command.arguments[0]
if let contactImagesByEmails = obj["emails"] as? [String] {
results = WmSqliteImagesModel.getInstance.getImagesByEmailAsWmContactImage(array) as? [String: AnyObject]
}
最后results
将是[String:AnyObject]?
这里的关键点是你应该尽可能多地删除对AnyObject
的引用,你应该使用if-let-as?
来确定类型是否符合预期。
事件command.arguments
充满了各种类型的东西,你必须进行类型检查是非常危险的,并且是严重设计问题的标志。如果那里确实存在多种类型,则应使用枚举而不是对[String:AnyObject]
之类的随机事物进行类型检查。这就是枚举明确的目的。 (如果这是来自ObjC的桥接;这里的枚举可能不可能,但即使在ObjC中,正确的答案很少会让NSArray
填充异构类型。你在那里创建一个类来保存它们而不是枚举。)