等待CLLocationManager在发送推文之前完成

Question

我想在发送推文之前等待latitude.text和longtitude.text填充，此代码正常工作，但我宁愿不将tweeting部分放在locationManager中，因为我也想要有时更新当前位置而不发送推文。我怎么才能确保在发送推文之前没有这样做txt被填充？

- (IBAction)update { 
    latitude.text =@""; 
    longitude.text =@""; 
    locmanager = [[CLLocationManager alloc] init]; 
    [locmanager setDelegate:self]; 
    [locmanager setDesiredAccuracy:kCLLocationAccuracyBest]; 
    [locmanager startUpdatingLocation]; 
} 

- (void)locationManager:(CLLocationManager *)manager didUpdateToLocation:(CLLocation *)newLocation fromLocation:(CLLocation *)oldLocation { 
    CLLocationCoordinate2D location = [newLocation coordinate]; 
    latitude.text = [NSString stringWithFormat: @"%f", location.latitude]; 
    longitude.text = [NSString stringWithFormat: @"%f", location.longitude]; 

    TwitterRequest * t = [[TwitterRequest alloc] init]; 
    t.username = @"****"; 
    t.password = @"****"; 
    [twitterMessageText resignFirstResponder]; 
    loadingActionSheet = [[UIActionSheet alloc] initWithTitle:@"Posting To Twitter..." delegate:nil cancelButtonTitle:nil destructiveButtonTitle:nil otherButtonTitles:nil]; 
    [loadingActionSheet showInView:self.view]; 
    [t statuses_update:twitterMessageText.text andLat:latitude.text andLong:longitude.text delegate:self requestSelector:@selector(status_updateCallback:)]; 
twitterMessageText.text=@""; 
} 

Answer 1

您可以在您的类中注册实现CLLocationManagerDelegate的侦听器。例如，

@interface GPS : NSObject <CLLocationManagerDelegate> { 

    CLLocationManager *locationManager; 

    NSMutableArray *listeners; 
} 

- (void) addListener:(id<GPSListener>)listener; 
@end 

@implementation GPS 
- (IBAction)update { 
    latitude.text =@""; 
    longitude.text =@""; 
    locmanager = [[CLLocationManager alloc] init]; 
    [locmanager setDelegate:self]; 
    [locmanager setDesiredAccuracy:kCLLocationAccuracyBest]; 
    [locmanager startUpdatingLocation]; 
} 

- (void)locationManager:(CLLocationManager *)manager didUpdateToLocation:(CLLocation *)newLocation fromLocation:(CLLocation *)oldLocation 
{ 
    CLLocationCoordinate2D location = [newLocation coordinate]; 
    latitude.text = [NSString stringWithFormat: @"%f", location.latitude]; 
    longitude.text = [NSString stringWithFormat: @"%f", location.longitude]; 

    // Inform the listeners. 
    NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init]; 
    for (id<GPSListener> listener in listeners) 
    { 
    @try 
    { 
     [listener onLocationChangeForLatitude:latitude.text longitude:longitude]; 
    } 
    @catch (NSException *e) 
    { 
     NSLog(@"Unhandled exception in onLocationChange"); 
    } 
    } 
    [pool release]; 
} 

- (void) addListener:(id<GPSListener>)listener 
{ 
    [listeners addObject:listener]; 
} 
@end 

您可以有一组侦听器，它们将自己注册到您的GPS对象。

@protocol GPSListener { 
- (void) onLocationChangeForLatitude:(NSString *)latitude longitude:(NSString *)longitude; 
} 

所以，现在你可以有一个TweetGPSListener

@interface TweetGPSListener : NSObject <GPSListener> { 
} 
@end 

@implementation TweetGPSListener 
- (void) onLocationChangeForLatitude:(NSString *)latitude longitude:(NSString *)longitude { 
    TwitterRequest * t = [[TwitterRequest alloc] init]; 
    t.username = @"****"; 
    t.password = @"****"; 
    [twitterMessageText resignFirstResponder]; 
    loadingActionSheet = [[UIActionSheet alloc] initWithTitle:@"Posting To Twitter..."  delegate:nil cancelButtonTitle:nil destructiveButtonTitle:nil otherButtonTitles:nil]; 
    [loadingActionSheet showInView:self.view]; 
    [t statuses_update:twitterMessageText.text andLat:latitude andLong:longitude delegate:self requestSelector:@selector(status_updateCallback:)]; 
    twitterMessageText.text=@""; 
} 
@end 

因此，对于你不想鸣叫或者不注册侦听器，删除监听或添加一些逻辑到TweetListener知道案件什么时候适合推特。