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您好我正在开发一款带有蜂窝电话的iPad Mini 1st Gen,并且需要使用其内部GPS获取纬度/经度坐标。我会在船上,并按下一个按钮,将坐标保存到iPad(文档目录)上的文本文件中。然后,我将航行10英里,然后再次按下按钮,将新的坐标附加到文本文件。我会这样做8次,应该有8对不同的坐标。然而,该应用程序是非常不一致的,要么保持相同的坐标,要么根本不获取。作为提醒,我没有使用WiFi /蜂窝,只有内部GPS(船上的GPS能够获取信号,因此它不是硬件问题)。我的代码如下。提前致谢!使用GPS进行CoreLocation更新
//in viewDidLoad
self.locman = [[CLLocationManager alloc] init];
self.locman.delegate = self;
self.locman.desiredAccuracy = kCLLocationAccuracyBest;
self.locman.distanceFilter = kCLDistanceFilterNone;
self.locman.desiredAccuracy = kCLLocationAccuracyHundredMeters;
//委托方法
#define REQ_ACC 10
#define REQ_TIME 10
-(void)locationManager:(CLLocationManager *)manager didUpdateLocations:(NSArray *)locations {
CLLocation* loc = locations.lastObject;
CLLocationAccuracy acc = loc.horizontalAccuracy;
NSDate* time = loc.timestamp;
CLLocationCoordinate2D coord = loc.coordinate;
if (!self.startTime) {
self.startTime = [NSDate date];
return; // ignore first attempt
}
NSLog(@"%f", acc);
NSTimeInterval elapsed = [time timeIntervalSinceDate:self.startTime];
if (elapsed > REQ_TIME) {
NSLog(@"%@", @"This is taking too long");
[self stopTrying];
return;
}
if (acc < 0 || acc > REQ_ACC) {
return; // wait for the next one
}
// got it
NSLog(@"You are at: %f %f", coord.latitude, coord.longitude);
self.lat = [NSString stringWithFormat:@"%.8f",coord.latitude];
self.longString = [NSString stringWithFormat:@"%.8f",coord.longitude];
[self stopTrying];
}
-(void) stopTrying {
[self.locman stopUpdatingLocation];
self.startTime = nil;
self.trying = NO;
}
//这是在IBAction为
[self.locman startUpdatingLocation];
那么你保持位置更新在后台运行?你想在记录状态前几分钟开始更新? – Wain
不,一旦按下UIButton,更新立即开始,并在达到stopTrying方法时停止。 – user2402616
所以你最多允许10秒钟锁定一个位置 - 这样做不够... – Wain