core-location - 在哪里实现 CLLocationManager

Question

我有一个带有标签栏和 3 个标签的应用程序。需要在三个选项卡中的任何一个上知道用户的当前位置。最好的实现地点CLLocationManager在这种情况下是在应用程序委托(delegate)中吗？

将 CLLocationManager 委托(delegate)方法放在应用程序委托(delegate) m 文件中是否可以(好的做法？)？

您建议我将 CLLocationManager 放在哪里？因为我要调用-startUpdatingLocation从三个选项卡中的任何一个？

谢谢

Answer 1

应用程序委托(delegate)是放置它的合理位置。另一种选择是创建一个自定义单例工厂类，该工厂类具有一个类方法，该类方法返回您的位置管理器委托(delegate)并在那里实现委托(delegate)方法。这将使您的应用程序委托(delegate)类更清洁。

这是一个基于 Peter Hosey 的 "Singletons in Cocoa: Doing them wrong" 的骨架单例类实现。 .这可能有点矫枉过正，但这是一个开始。最后添加您的委托(delegate)方法。

static MyCLLocationManagerDelegate *sharedInstance = nil; 

+ (void)initialize {
    if (sharedInstance == nil)
        sharedInstance = [[self alloc] init];
}

+ (id)sharedMyCLLocationManagerDelegate {
    //Already set by +initialize.
    return sharedInstance;
}

+ (id)allocWithZone:(NSZone*)zone {
    //Usually already set by +initialize.
    @synchronized(self) {
        if (sharedInstance) {
            //The caller expects to receive a new object, so implicitly retain it
            //to balance out the eventual release message.
            return [sharedInstance retain];
        } else {
            //When not already set, +initialize is our caller.
            //It's creating the shared instance, let this go through.
            return [super allocWithZone:zone];
        }
    }
}

- (id)init {
    //If sharedInstance is nil, +initialize is our caller, so initialze the instance.
    //If it is not nil, simply return the instance without re-initializing it.
    if (sharedInstance == nil) {
        if ((self = [super init])) {
            //Initialize the instance here.
        }
    }
    return self;
}

- (id)copyWithZone:(NSZone*)zone {
    return self;
}
- (id)retain {
    return self;
}
- (unsigned)retainCount {
    return UINT_MAX; // denotes an object that cannot be released
}
- (void)release {
    // do nothing 
}
- (id)autorelease {
    return self;
}
#pragma mark -
#pragma mark CLLLocationManagerDelegateMethods go here...