iphone - 如何使用 iPhone 中已安装的 GPS 系统

Question

我想询问用户他想要使用哪个 GPS 应用程序来将他带到特定位置。我想我必须首先检查安装了哪些 GPS 应用程序...我该怎么做？当用户选择特定应用程序时，我如何激活它并告诉它路由到特定目的地？

Answer 1

它缺乏资源，但它是可行的...复制并粘贴我的旧源代码...只需将 Tip 替换为其他内容即可。这是一个简单的类，其中包含 locLatitude 和 locLongitude 值以及一些更多详细信息。不支持 TomTom，因为我无法找到它的 URL 方案。由于我不再需要它，所以我没有尝试再次搜索它。

typedef enum {
    ExternalNavigationAppGoogleMaps,
    ExternalNavigationAppNavigon,
    ExternalNavigationAppTomTom
} ExternalNavigationApp;

+ (BOOL)isSupported:(ExternalNavigationApp)navigationApp;
+ (BOOL)navigateTo:(Tip *)tip viaApp:(ExternalNavigationApp)navigationApp;
+ (BOOL)navigateTo:(Tip *)tip from:(CLLocationCoordinate2D)from viaApp:(ExternalNavigationApp)navigationApp;

...实现部分...

+ (NSString *)googleMapsUrl:(Tip *)tip from:(CLLocationCoordinate2D)from {  
    NSString *urlString = [NSString stringWithFormat:@"http://maps.google.com/maps?saddr=%1.6f,%1.6f&daddr=%1.6f,%1.6f",
                           from.latitude, from.longitude,
                           [tip.locLatitude floatValue], [tip.locLongitude floatValue]];
    return urlString;
}

+ (NSString *)navigonAppUrl:(Tip *)tip {
    NSString *urlString = [NSString stringWithFormat:@"navigon://%@|%@||||||%f|%f",
                           [[[NSBundle mainBundle] infoDictionary] objectForKey:@"CFBundleName"],
                           tip.name,
                           [tip.locLongitude floatValue],
                           [tip.locLatitude floatValue]];

    return urlString;
}

+ (NSString *)tomtomAppUrl:(Tip *)tip {
    return nil;
}

+ (NSURL *)urlForApp:(ExternalNavigationApp)navigationApp withTip:(Tip *)tip from:(CLLocationCoordinate2D)from {
    NSString *urlString = nil;
    if ( ExternalNavigationAppNavigon == navigationApp ) {
        urlString = [self navigonAppUrl:tip];
    } else if ( ExternalNavigationAppTomTom == navigationApp ) {
        urlString = [self tomtomAppUrl:tip];
    } else if ( ExternalNavigationAppGoogleMaps == navigationApp ) {
        urlString = [self googleMapsUrl:tip from:from];
    }

    if ( urlString == nil )
        return nil;

    return [NSURL URLWithString:[urlString stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding]];
}

+ (BOOL)isSupported:(ExternalNavigationApp)navigationApp {
    CLLocationCoordinate2D coord;
    NSURL *url = [self urlForApp:navigationApp withTip:nil from:coord];

    if ( url == nil )
        return NO;

    return [[UIApplication sharedApplication]canOpenURL:url];
}

+ (BOOL)navigateTo:(Tip *)tip viaApp:(ExternalNavigationApp)navigationApp {
    CLLocationCoordinate2D coord;
    NSURL *url = [self urlForApp:navigationApp withTip:tip from:coord];

    if ( url == nil )
        return NO;

    return [[UIApplication sharedApplication] openURL:url]; 
}

+ (BOOL)navigateTo:(Tip *)tip from:(CLLocationCoordinate2D)from viaApp:(ExternalNavigationApp)navigationApp {
    NSURL *url = [self urlForApp:navigationApp withTip:tip from:from];

    if ( url == nil )
        return NO;

    return [[UIApplication sharedApplication] openURL:url]; 
}