iOS 指南针

约定不等于承诺〃 2022-05-29 23:19 224阅读 0赞

> 代码地址如下：  
> [http://www.demodashi.com/demo/11107.html][http_www.demodashi.com_demo_11107.html]
> 
> 高仿系统指南针，方向数据是地磁航向数据，有定位地理位置信息和地磁方向信息，可以和系统的指南针对比看一看。

## 一、运行效果预览 ##

![总效果.gif][.gif]  
![效果.png][.png]

## 二、实现过程 ##

#### 1.继承于UIView创建一个带刻度标注的视图ScaleView，利用UIBezierPath和CAShapeLayer、UILabel，默认0刻度(北)在最上方。 ####

//化刻度表
    - (void)paintingScale{
    
        CGFloat perAngle = M_PI/(90);
        NSArray *array = @[@"北",@"东",@"南",@"西"];
         //画圆环，每隔2°画一个弧线，总共180条
        for (int i = 0; i < 180; i++) { 
            CGFloat startAngle = (-(M_PI_2+M_PI/180/2)+perAngle*i);
            CGFloat endAngle = startAngle+perAngle/2;
            UIBezierPath *bezPath = [UIBezierPath bezierPathWithArcCenter:CGPointMake(self.frame.size.width/2, self.frame.size.height/2)
                                                                   radius:(self.frame.size.width/2 - 50)
                                                               startAngle:startAngle
                                                                 endAngle:endAngle
                                                                clockwise:YES];
            CAShapeLayer *shapeLayer = [CAShapeLayer layer];
         //每隔30°画一个白条刻度
            if (i%15 == 0) {
                shapeLayer.strokeColor = [[UIColor whiteColor] CGColor];
                shapeLayer.lineWidth = 20;
            }else{
                shapeLayer.strokeColor = [[UIColor grayColor] CGColor];
                shapeLayer.lineWidth = 10;
            }
            shapeLayer.path = bezPath.CGPath;
            shapeLayer.fillColor = [UIColor clearColor].CGColor;
            [_backgroundView.layer addSublayer:shapeLayer];
    
            //每隔30°画一个刻度的标注 0 30 60...
            if (i % 15 == 0){
                NSString *tickText = [NSString stringWithFormat:@"%d",i * 2];
                CGFloat textAngel = startAngle+(endAngle-startAngle)/2;
                CGPoint point = [self calculateTextPositonWithArcCenter:CGPointMake(self.frame.size.width/2, self.frame.size.height/2)
                                                                  Angle:textAngel andScale:1.2];
                UILabel *label = [[UILabel alloc]initWithFrame:CGRectMake(point.x, point.y, 30, 15)];
                label.center = point;
                label.text = tickText;
                label.textColor = [UIColor whiteColor];
                label.font = [UIFont systemFontOfSize:15];
                label.textAlignment = NSTextAlignmentCenter;
                [_backgroundView addSubview:label];
    
               //标注 北 东 南 西
                if (i%45 == 0){
                    tickText = array[i/45];
                    CGPoint point2 = [self calculateTextPositonWithArcCenter:CGPointMake(self.frame.size.width/2, self.frame.size.height/2)
                                                                       Angle:textAngel andScale:0.8];
                    UILabel *label = [[UILabel alloc]initWithFrame:CGRectMake(point2.x, point2.y, 30, 20)];
                    label.center = point2;
                    label.text = tickText;
                    label.textColor = [UIColor whiteColor];
                    label.font = [UIFont systemFontOfSize:20];
                    label.textAlignment = NSTextAlignmentCenter;
                    if ([tickText isEqualToString:@"北"]) {
                        UILabel * markLabel = [[UILabel alloc]initWithFrame:CGRectMake(point.x, point.y, 8, 8)];
                        markLabel.center = CGPointMake(point.x, point.y + 12);
                        markLabel.clipsToBounds = YES;
                        markLabel.layer.cornerRadius = 4;
                        markLabel.backgroundColor = [UIColor redColor];
                        [_backgroundView addSubview:markLabel]; 
                    }
                    [_backgroundView addSubview:label];
                }
            }
        } 
    
         //画十字线，参照线
        UIView *  levelView = [[UIView alloc] initWithFrame:CGRectMake(0, 0, self.frame.size.width/2/2, 1)];
        levelView.center = CGPointMake(self.frame.size.width/2, self.frame.size.height/2);
        levelView.backgroundColor = [UIColor whiteColor];
        [self addSubview:levelView];
    
        UIView *  verticalView = [[UIView alloc] initWithFrame:CGRectMake(0, 0, 1, self.frame.size.width/2/2)];
        verticalView.center = CGPointMake(self.frame.size.width/2, self.frame.size.height/2);
        verticalView.backgroundColor = [UIColor whiteColor];
        [self addSubview:verticalView];
    
        UIView * lineView = [[UIView alloc] initWithFrame:CGRectMake(self.frame.size.width/2 -1.5, self.frame.size.height/2 - (self.frame.size.width/2 - 50) - 50, 3, 30 + 30)];
        lineView.backgroundColor = [UIColor whiteColor];
        [self addSubview:lineView];
    }

#### 2、利用CLLocationManager初始化定位装置，并设置代理 ，记得在info.plist中加入隐私定位权限关键字 Privacy - Location When In Use Usage Description ####

// 注意开启手机的定位服务，隐私那里的
        self.locationManager = [[CLLocationManager alloc]init];
        self.locationManager.delegate=self;
        // 定位频率,每隔多少米定位一次
        // 距离过滤器，移动了几米之后，才会触发定位的代理函数
        self.locationManager.distanceFilter = 0;
        // 定位的精度，越精确，耗电量越高
        self.locationManager.desiredAccuracy = kCLLocationAccuracyBestForNavigation;//导航
    
        //请求允许在前台获取用户位置的授权
        [self.locationManager requestWhenInUseAuthorization];
    
        //允许后台定位更新,进入后台后有蓝条闪动
        self.locationManager.allowsBackgroundLocationUpdates = YES;
        //判断定位设备是否能用和能否获得导航数据
        if ([CLLocationManager locationServicesEnabled]&&[CLLocationManager headingAvailable]){
            [self.locationManager startUpdatingLocation];//开启定位服务
            [self.locationManager startUpdatingHeading];//开始获得航向数据
        }
        else{
            NSLog(@"不能获得航向数据");
        }

> 通过实现定位装置的代理方法：  
> \-(void)locationManager:(CLLocationManager *)manager didUpdateHeading:(CLHeading* )newHeading 来获得地理和地磁航向数据，从而转动地理刻度表以及表上的文字标注；  
> 方法-(BOOL)locationManagerShouldDisplayHeadingCalibration:(CLLocationManager \*)manager返回Yes是为了受到外来磁场干扰时，设备会自动进行校验。

#pragma mark - CLLocationManagerDelegate
    //获得地理和地磁航向数据，从而转动地理刻度表
    -(void)locationManager:(CLLocationManager *)manager didUpdateHeading:(CLHeading *)newHeading{
        //获得当前设备
        UIDevice *device =[UIDevice currentDevice];
        // 判断磁力计是否有效,负数时为无效，越小越精确
        if (newHeading.headingAccuracy>0)
        {
            //地磁航向数据-》magneticHeading
            float magneticHeading =[self heading:newHeading.magneticHeading fromOrirntation:device.orientation];
            //地理航向数据-》trueHeading
            float trueHeading =[self heading:newHeading.trueHeading fromOrirntation:device.orientation];
            //地磁北方向
            float heading = -1.0f *M_PI *newHeading.magneticHeading /180.0f;
            _angleLabel.text = [NSString stringWithFormat:@"%3.1f°",magneticHeading];
            //旋转变换
            [_scaView resetDirection:heading]; 
           //返回当前手机（摄像头)朝向方向
            [self updateHeading:newHeading]; 
        }
    }
    //判断设备是否需要校验，受到外来磁场干扰时
    -(BOOL)locationManagerShouldDisplayHeadingCalibration:(CLLocationManager *)manager
    {
        return YES;
    }
    //旋转重置刻度标志的方向
    - (void)resetDirection:(CGFloat)heading{
        _backgroundView.transform = CGAffineTransformMakeRotation(heading);
        for (UILabel * label in _backgroundView.subviews) {
            label.transform = CGAffineTransformMakeRotation(-heading);
        }
    }

#### 3、通过代理方法获得经纬度以及海拔数据，然后利用经纬度进行地理反编码获得地理位置信息。 ####

// 定位成功之后的回调方法，只要位置改变，就会调用这个方法
    - (void)locationManager:(CLLocationManager *)manager didUpdateLocations:(NSArray *)locations{
    
    
        self.currLocation = [locations lastObject];
    
        //维纬度
        NSString * latitudeStr = [NSString stringWithFormat:@"%3.2f",
                                  _currLocation.coordinate.latitude];
        //经度
        NSString * longitudeStr  = [NSString stringWithFormat:@"%3.2f",
                                    _currLocation.coordinate.longitude];
        //高度
        NSString * altitudeStr  = [NSString stringWithFormat:@"%3.2f",
                                   _currLocation.altitude];
    
        NSLog(@"纬度 %@ 经度 %@ 高度 %@", latitudeStr, longitudeStr, altitudeStr);
    
        _latitudlongitudeLabel.text = [NSString stringWithFormat:@"纬度：%@ 经度：%@ 海拔：%@", latitudeStr, longitudeStr, altitudeStr];
    
        CLGeocoder *geocoder = [[CLGeocoder alloc] init];
    
        [geocoder reverseGeocodeLocation:self.currLocation
                       completionHandler:^(NSArray *placemarks, NSError *error) {
    
                           if ([placemarks count] > 0) {
    
                               CLPlacemark *placemark = placemarks[0];
    
                               NSDictionary *addressDictionary =  placemark.addressDictionary;
    
                               NSString *street = [addressDictionary
                                                   objectForKey:(NSString *)kABPersonAddressStreetKey];
                               street = street == nil ? @"": street;
    
                               NSString *country = placemark.country;
    
                               NSString * subLocality = placemark.subLocality;
    
                               NSString *city = [addressDictionary
                                                 objectForKey:(NSString *)kABPersonAddressCityKey];
                               city = city == nil ? @"": city;
    
                               NSLog(@"%@",[NSString stringWithFormat:@"%@ \n%@ \n%@ %@ ",country, city,subLocality ,street]);
    
                               _positionLabel.text = [NSString stringWithFormat:@" %@\n %@ %@%@ " ,country, city,subLocality ,street];
    
                           }
    
                       }];
    }

## 三、项目结构截图 ##

![项目结构列表][XkoVPZJemaGdndLtV0G.png]

iOS 指南针

> 代码地址如下：  
> [http://www.demodashi.com/demo/11107.html][http_www.demodashi.com_demo_11107.html]
> 
> 注：本文著作权归作者，由demo大师发表，拒绝转载，转载需要作者授权

[http_www.demodashi.com_demo_11107.html]: http://www.demodashi.com/demo/11107.html
[.gif]: /images/20220530/a60aef76fe824b0d9885358e00748a33.png
[.png]: /images/20220530/626df07c06384f399706f8b3861d32f5.png
[XkoVPZJemaGdndLtV0G.png]: /images/20220530/a0d1447a262c49caa0fb942cc7117904.png