让 CFNotificationCenterAddObserver
在 Swift 中工作让我大吃一惊。
CFNotificationCenterAddObserver(CFNotificationCenterGetDarwinNotifyCenter(),
UnsafePointer<Void>(self),
iosLocked,
"com.apple.springboard.lockcomputer" as CFString,
nil,
CFNotificationSuspensionBehavior.DeliverImmediately)
iOS docs列出它,我已经在回调和不安全指针上尝试了无数次迭代,但没有成功。
上面的函数调用导致了这个错误消息,这似乎是正确的初始化:
Cannot invoke 'init' with an argument list of type '(CFNotificationCenter!, $T4, () -> (), CFString, NilLiteralConvertible, CFNotificationSuspensionBehavior)'
我还尝试桥接到 objc 为 this post here建议,但没有成功。
这是我的桥梁:
LockNotifierCallback.h:
#import <Foundation/Foundation.h>
@interface LockNotifierCallback : NSObject
+ (void(*)(CFNotificationCenterRef center, void *observer, CFStringRef name, const void *object, CFDictionaryRef userInfo))notifierProc;
@end
和 LockNotifierCallback.m:
#import "LockNotifierCallback.h"
static void lockcompleteChanged(CFNotificationCenterRef center, void *observer, CFStringRef name, const void *object, CFDictionaryRef userInfo) {
NSLog(@"success");
}
@implementation LockNotifierCallback
+ (void(*)(CFNotificationCenterRef center, void *observer, CFStringRef name, const void *object, CFDictionaryRef userInfo))notifierProc {
return lockcompleteChanged;
}
@end
更新后的 CFNotificationCenterAddObserver 调用如下:
CFNotificationCenterAddObserver(CFNotificationCenterGetDarwinNotifyCenter(),
LockNotifierCallback.notifierProc,
iosLocked,
"com.apple.springboard.lockcomputer" as CFString,
nil,
CFNotificationSuspensionBehavior.DeliverImmediately)
当然 LockNotifierCallback.h 在我的桥接头中。错误继续:
Cannot convert the expression's type '(CFNotificationCenter!, () -> CFunctionPointer<((CFNotificationCenter!, UnsafeMutablePointer<Void>, CFString!, UnsafePointer<Void>, CFDictionary!) -> Void)>, () -> (), CFString, NilLiteralConvertible, CFNotificationSuspensionBehavior)' to type 'StringLiteralConvertible'
最佳答案
我在使用 DarwinNotifications 时遇到了一些问题,您可以尝试使用这个包装类 只需在桥接文件中包含头文件即可。您可以快速使用它。
DarwinNotificationsManager.h :
#import <Foundation/Foundation.h>
#ifndef DarwinNotifications_h
#define DarwinNotifications_h
@interface DarwinNotificationsManager : NSObject
@property (strong, nonatomic) id someProperty;
+ (instancetype)sharedInstance;
- (void)registerForNotificationName:(NSString *)name callback:(void (^)(void))callback;
- (void)postNotificationWithName:(NSString *)name;
@end
#endif
DarwinNotificationsManager.m :
#import <Foundation/Foundation.h>
#import "DarwinNotificationsManager.h"
@implementation DarwinNotificationsManager {
NSMutableDictionary * handlers;
}
+ (instancetype)sharedInstance {
static id instance = NULL;
static dispatch_once_t onceToken;
dispatch_once(&onceToken, ^{
instance = [[self alloc] init];
});
return instance;
}
- (instancetype)init {
self = [super init];
if (self) {
handlers = [NSMutableDictionary dictionary];
}
return self;
}
- (void)registerForNotificationName:(NSString *)name callback:(void (^)(void))callback {
handlers[name] = callback;
CFNotificationCenterRef center = CFNotificationCenterGetDarwinNotifyCenter();
CFNotificationCenterAddObserver(center, (__bridge const void *)(self), defaultNotificationCallback, (__bridge CFStringRef)name, NULL, CFNotificationSuspensionBehaviorDeliverImmediately);
}
- (void)postNotificationWithName:(NSString *)name {
CFNotificationCenterRef center = CFNotificationCenterGetDarwinNotifyCenter();
CFNotificationCenterPostNotification(center, (__bridge CFStringRef)name, NULL, NULL, YES);
}
- (void)notificationCallbackReceivedWithName:(NSString *)name {
void (^callback)(void) = handlers[name];
callback();
}
void defaultNotificationCallback (CFNotificationCenterRef center,
void *observer,
CFStringRef name,
const void *object,
CFDictionaryRef userInfo)
{
NSLog(@"name: %@", name);
NSLog(@"userinfo: %@", userInfo);
NSString *identifier = (__bridge NSString *)name;
[[DarwinNotificationsManager sharedInstance] notificationCallbackReceivedWithName:identifier];
}
- (void)dealloc {
CFNotificationCenterRef center = CFNotificationCenterGetDarwinNotifyCenter();
CFNotificationCenterRemoveEveryObserver(center, (__bridge const void *)(self));
}
@end
在 swift 中你可以像这样使用它:
let darwinNotificationCenter = DarwinNotificationsManager.sharedInstance()
darwinNotificationCenter.registerForNotificationName("YourNotificationName"){
//code to execute on notification
}
关于ios - 如何在 Swift for iOS 中正确使用 CFNotificationCenterAddObserver,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/26637023/