CMAltimeter回调永远不会触发

Question

使用我的6+我一直在尝试使用CoreMotion的新CMAltimeter读取相对高度和压力.然而,回调永远不会解雇.我有一个非常相似的设置,而是使用加速度计,陀螺仪和磁力计.他们似乎都很好.

想知道是否有人设法获得阅读？

- (void)viewDidLoad {
    [super viewDidLoad];

    if([CMAltimeter isRelativeAltitudeAvailable]){
        CMAltimeter *altimeterManager = [[CMAltimeter alloc]init];
        [altimeterManager startRelativeAltitudeUpdatesToQueue:[NSOperationQueue mainQueue] withHandler:^(CMAltitudeData *altitudeData, NSError *error) {
            // This never fires.
            NSString *data = [NSString stringWithFormat:@"Altitude: %f %f", altitudeData.relativeAltitude.floatValue, altitudeData.pressure.floatValue];
            NSLog(@"%@", data);
            self.altimeterLabel.text = data;
        }];
        NSLog(@"Started altimeter");
        self.altimeterLabel.text = @"-\n-";
    } else {
        NSLog(@"Altimeter not available");
    }
}

我已经尝试过快速步行,但是这里只有一个高度失去/获得的故事.

Answer 1

我非常尴尬地以如此巨大的疏忽来回答我自己的问题.

在原始帖子中,我在viewDidLoad的范围内声明了CMAltimiter,因此它超出了范围并被取消分配.我把它变成了iVar,现在回调了.

#import "ViewController.h"
@import CoreMotion;

@interface ViewController ()
@property (nonatomic, strong) CMAltimeter *altimeterManager;
@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];

    if([CMAltimeter isRelativeAltitudeAvailable]){
        self.altimeterManager = [[CMAltimeter alloc]init];
        [self.altimeterManager startRelativeAltitudeUpdatesToQueue:[NSOperationQueue mainQueue] withHandler:^(CMAltitudeData *altitudeData, NSError *error) {
            // This now fires properly
            NSString *data = [NSString stringWithFormat:@"Altitude: %f %f", altitudeData.relativeAltitude.floatValue, altitudeData.pressure.floatValue];
            NSLog(@"%@", data);
            self.altimeterLabel.text = data;
        }];
        NSLog(@"Started altimeter");
        self.altimeterLabel.text = @"-\n-";
    } else {
        NSLog(@"Altimeter not available");
    }
}