如何使用Objective C在iphone中获取GPS坐标 [英] how to get GPS Coordinates in iphone using Objective C

问题描述

我想从iphone获取GPS坐标并将这些GPS坐标发送到网络服务。这个网络服务将从我当前的位置获取我的GPS坐标并向我发送最近的ATM的位置。
现在我想分两个阶段完成。
第一阶段，我想将GPS坐标发送到网络服务，作为回报，我想要ATM位置的地址。
第二阶段，我想把这台ATM指向iphone应用程序中显示的MAP。

i want to get the GPS coordinates from iphone and send these GPS coordinates to web service. This web service, will take my GPS Coordinates and send me the location of the nearest ATM, from the current location. now i want to do this in 2 phases. First phase , i want to just send the GPS Coordinates to web service, and in return i want the address of the ATM location. Second phase , i want to point this ATM on the MAP displayed in iphone app.

我开发了Web服务，它有2个输入参数：lat和隆吉。
并以字符串格式返回ATM位置的地址。

I have the web service developed, which take 2 input parameters : lat and longi. and returns me the address of the ATM location in a string format.

从第1阶段开始：请帮助我了解如何获得GPS坐标和将其发送到Web服务。
这样我就可以在视图上以字符串格式显示地址（我从Web服务获得的结果）。

To start with Phase 1 : Please help me with how to get the GPS cordinates and send it to the web service. so that i can just display the address in string format(Result i get from web service) on the view.

推荐答案

来自apple的示例代码（编辑：链接已移动）： https：// developer .apple.com / library / content / samplecode / LocateMe /

This sample code from apple (edit: link moved) : https://developer.apple.com/library/content/samplecode/LocateMe/

您必须询问用户权限，在plist中添加此属性：NSLocationWhenInUseUsageDescription

You have to ask user permission, adding this property in you plist : NSLocationWhenInUseUsageDescription

然后，这里基本上是苹果在viewController中的作用（从上面的链接复制）：

then, here is basically how apple does in a viewController (copied from link above) :

/*
Copyright (C) 2014 Apple Inc. All Rights Reserved.
See LICENSE.txt for this sample’s licensing information

*/

#import "GetLocationViewController.h"
#import "LocationDetailViewController.h"
#import "SetupViewController.h"
#import "CLLocation+Strings.h"

@interface GetLocationViewController () <SetupViewControllerDelegate, CLLocationManagerDelegate>

@property (nonatomic, weak) IBOutlet UIButton *startButton;
@property (nonatomic, weak) IBOutlet UILabel *descriptionLabel;
@property (nonatomic, weak) IBOutlet UITableView *tableView;
@property (nonatomic, strong) SetupViewController* setupViewController;
@property (nonatomic, copy) NSString *stateString;

@property (nonatomic, strong) CLLocationManager *locationManager;
@property (nonatomic, strong) NSDateFormatter *dateFormatter;
@property (nonatomic, strong) NSMutableArray *locationMeasurements;
@property (nonatomic, strong) CLLocation *bestEffortAtLocation;

@end


#pragma mark -

@implementation GetLocationViewController

- (void)viewDidLoad {
    [super viewDidLoad];

    _locationMeasurements = [NSMutableArray array];
}

- (NSDateFormatter *)dateFormatter {
    if (_dateFormatter == nil) {
        _dateFormatter = [[NSDateFormatter alloc] init];
        [_dateFormatter setDateStyle:NSDateFormatterMediumStyle];
        [_dateFormatter setTimeStyle:NSDateFormatterLongStyle];
    }
    return _dateFormatter;
}

- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender {
    UINavigationController *nv = segue.destinationViewController;
    _setupViewController = nv.viewControllers[0];
    self.setupViewController.delegate = self;
}


#pragma mark - Actions

// The reset method allows the user to repeatedly test the location functionality.
// In addition to discarding all of the location measurements from the previous "run",
// it animates a transition in the user interface between the table which displays location
// data and the start button and description label presented at launch.
//
- (void)reset {
    _bestEffortAtLocation = nil;
    [self.locationMeasurements removeAllObjects];

    // fade in the rest of the UI and fade out the table view
    [UIView animateWithDuration:0.6f animations:^(void) {
        self.startButton.alpha = 1.0;
        self.descriptionLabel.alpha = 1.0;
        self.tableView.alpha = 0.0;
        [self.navigationItem setLeftBarButtonItem:nil animated:YES];
    } completion:^(BOOL finished) {
        if (finished) {
            //..
        }
    }];
}


#pragma mark - Location Manager Interactions

// This method is invoked when the user hits "Done" in the setup view controller.
// The options chosen by the user are passed in as a dictionary. The keys for this dictionary
// are declared in SetupViewController.h.
//
- (void)setupViewController:(SetupViewController *)controller didFinishSetupWithInfo:(NSDictionary *)setupInfo {
    self.startButton.alpha = 0.0;
    self.descriptionLabel.alpha = 0.0;
    self.tableView.alpha = 1.0;

    // Create the core location manager object
    _locationManager = [[CLLocationManager alloc] init];
    self.locationManager.delegate = self;

    // This is the most important property to set for the manager. It ultimately determines how the manager will
    // attempt to acquire location and thus, the amount of power that will be consumed.
    self.locationManager.desiredAccuracy = [setupInfo[kSetupInfoKeyAccuracy] doubleValue];

    // Once configured, the location manager must be "started"
    //
    // for iOS 8, specific user level permission is required,
    // "when-in-use" authorization grants access to the user's location
    //
    // important: be sure to include NSLocationWhenInUseUsageDescription along with its
    // explanation string in your Info.plist or startUpdatingLocation will not work.
    //
    if ([self.locationManager respondsToSelector:@selector(requestWhenInUseAuthorization)]) {
        [self.locationManager requestWhenInUseAuthorization];
    }
    [self.locationManager startUpdatingLocation];

    [self performSelector:@selector(stopUpdatingLocationWithMessage:)
               withObject:@"Timed Out"
               afterDelay:[setupInfo[kSetupInfoKeyTimeout] doubleValue]];
    self.stateString = NSLocalizedString(@"Updating", @"Updating");

    [self.tableView reloadData];
}

// We want to get and store a location measurement that meets the desired accuracy.
// For this example, we are going to use horizontal accuracy as the deciding factor.
// In other cases, you may wish to use vertical accuracy, or both together.
//
- (void)locationManager:(CLLocationManager *)manager didUpdateToLocation:(CLLocation *)newLocation fromLocation:(CLLocation *)oldLocation {
    // store all of the measurements, just so we can see what kind of data we might receive
    [self.locationMeasurements addObject:newLocation];

    // test the age of the location measurement to determine if the measurement is cached
    // in most cases you will not want to rely on cached measurements
    //
    NSTimeInterval locationAge = -[newLocation.timestamp timeIntervalSinceNow];
    if (locationAge > 5.0) {
        return;
    }

    // test that the horizontal accuracy does not indicate an invalid measurement
    if (newLocation.horizontalAccuracy < 0) {
        return;
    }

    // test the measurement to see if it is more accurate than the previous measurement
    if (self.bestEffortAtLocation == nil || self.bestEffortAtLocation.horizontalAccuracy > newLocation.horizontalAccuracy) {
        // store the location as the "best effort"
        _bestEffortAtLocation = newLocation;

        // test the measurement to see if it meets the desired accuracy
        //
        // IMPORTANT!!! kCLLocationAccuracyBest should not be used for comparison with location coordinate or altitidue 
        // accuracy because it is a negative value. Instead, compare against some predetermined "real" measure of 
        // acceptable accuracy, or depend on the timeout to stop updating. This sample depends on the timeout.
        //
        if (newLocation.horizontalAccuracy <= self.locationManager.desiredAccuracy) {
            // we have a measurement that meets our requirements, so we can stop updating the location
            // 
            // IMPORTANT!!! Minimize power usage by stopping the location manager as soon as possible.
            //
            [self stopUpdatingLocationWithMessage:NSLocalizedString(@"Acquired Location", @"Acquired Location")];
            // we can also cancel our previous performSelector:withObject:afterDelay: - it's no longer necessary
            [NSObject cancelPreviousPerformRequestsWithTarget:self selector:@selector(stopUpdatingLocationWithMessage:) object:nil];
        }
    }

    // update the display with the new location data
    [self.tableView reloadData];    
}

- (void)locationManager:(CLLocationManager *)manager didFailWithError:(NSError *)error {
    // The location "unknown" error simply means the manager is currently unable to get the location.
    // We can ignore this error for the scenario of getting a single location fix, because we already have a 
    // timeout that will stop the location manager to save power.
    //
    if ([error code] != kCLErrorLocationUnknown) {
        [self stopUpdatingLocationWithMessage:NSLocalizedString(@"Error", @"Error")];
    }
}

- (void)stopUpdatingLocationWithMessage:(NSString *)state {
    self.stateString = state;
    [self.tableView reloadData];
    [self.locationManager stopUpdatingLocation];
    self.locationManager.delegate = nil;

    UIBarButtonItem *resetItem = [[UIBarButtonItem alloc] initWithTitle:NSLocalizedString(@"Reset", @"Reset")
                                                                  style:UIBarButtonItemStylePlain
                                                                 target:self
                                                                 action:@selector(reset)];
    [self.navigationItem setLeftBarButtonItem:resetItem animated:YES];
}


#pragma mark - UITableViewDataSource

// The table view has three sections. The first has 1 row which displays status information.
// The second has 1 row which displays the most accurate valid location measurement received.
// The third has a row for each valid location object received
// (including the one displayed in the second section) from the location manager.
//
- (NSInteger)numberOfSectionsInTableView:(UITableView *)table {
    return (self.bestEffortAtLocation != nil) ? 3 : 1;
}

- (NSString *)tableView:(UITableView *)tableView titleForHeaderInSection:(NSInteger)section {
    NSString *headerTitle = nil;
    switch (section) {
        case 0: {
            headerTitle = NSLocalizedString(@"Status", @"Status");
            break;
        }
        case 1: {
            headerTitle = NSLocalizedString(@"Best Measurement", @"Best Measurement");
            break;
        }
        default: {
            headerTitle = NSLocalizedString(@"All Measurements", @"All Measurements");
            break;
        }
    }
    return headerTitle;
}

- (NSInteger)tableView:(UITableView *)table numberOfRowsInSection:(NSInteger)section {
    NSInteger numRows = 0;
    switch (section) {
        case 0: {
            numRows = 1;
            break;
        }
        case 1: {
            numRows = 1;
            break;
        }
        default: {
            numRows = self.locationMeasurements.count;
            break;
        }
    }
    return numRows;
}

- (UITableViewCell *)tableView:(UITableView *)table cellForRowAtIndexPath:(NSIndexPath *)indexPath {
    UITableViewCell *cell = nil;

    switch (indexPath.section) {
        case 0: {
            // The cell for the status row uses the cell style "UITableViewCellStyleValue1", which has a label on the left side of the cell with left-aligned and black text; on the right side is a label that has smaller blue text and is right-aligned. An activity indicator has been added to the cell and is animated while the location manager is updating. The cell's text label displays the current state of the manager.
            static NSString * const kStatusCellID = @"StatusCellID";
            static NSInteger const kStatusCellActivityIndicatorTag = 2;
            UIActivityIndicatorView *activityIndicator = nil;

            cell = [table dequeueReusableCellWithIdentifier:kStatusCellID];
            if (cell == nil) {
                cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleValue1 reuseIdentifier:kStatusCellID];
                cell.selectionStyle = UITableViewCellSelectionStyleNone;
                activityIndicator = [[UIActivityIndicatorView alloc] initWithActivityIndicatorStyle:UIActivityIndicatorViewStyleGray];
                CGRect frame = activityIndicator.frame;
                frame.origin = CGPointMake(290.0, 12.0);
                activityIndicator.frame = frame;
                activityIndicator.autoresizingMask = UIViewAutoresizingFlexibleLeftMargin;
                activityIndicator.tag = kStatusCellActivityIndicatorTag;
                [cell.contentView addSubview:activityIndicator];
            } else {
                activityIndicator = (UIActivityIndicatorView *)[cell.contentView viewWithTag:kStatusCellActivityIndicatorTag];
            }

            cell.textLabel.text = self.stateString;
            if ([self.stateString isEqualToString:NSLocalizedString(@"Updating", @"Updating")]) {
                if (activityIndicator.isAnimating == NO) {
                    [activityIndicator startAnimating];
                }
            } else {
                if (activityIndicator.isAnimating) {
                    [activityIndicator stopAnimating];
                }
            }
            break;
        }

        case 1: {
            // The cells for the location rows use the cell style "UITableViewCellStyleSubtitle", which has a left-aligned label across the top and a left-aligned label below it in smaller gray text. The text label shows the coordinates for the location and the detail text label shows its timestamp.
            static NSString * const kBestMeasurementCellID = @"BestMeasurementCellID";
            cell = [table dequeueReusableCellWithIdentifier:kBestMeasurementCellID];
            if (cell == nil) {
                cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleSubtitle reuseIdentifier:kBestMeasurementCellID];
                cell.accessoryType = UITableViewCellAccessoryDisclosureIndicator;
            }
            cell.textLabel.text = self.bestEffortAtLocation.localizedCoordinateString;
            cell.detailTextLabel.text = [self.dateFormatter stringFromDate:self.bestEffortAtLocation.timestamp];
            break;
        }

        default: {
            // The cells for the location rows use the cell style "UITableViewCellStyleSubtitle", which has a left-aligned label across the top and a left-aligned label below it in smaller gray text. The text label shows the coordinates for the location and the detail text label shows its timestamp.
            static NSString * const kOtherMeasurementsCellID = @"OtherMeasurementsCellID";
            cell = [table dequeueReusableCellWithIdentifier:kOtherMeasurementsCellID];
            if (cell == nil) {
                cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleSubtitle reuseIdentifier:kOtherMeasurementsCellID];
                cell.accessoryType = UITableViewCellAccessoryDisclosureIndicator;
            }
            CLLocation *location = self.locationMeasurements[indexPath.row];
            cell.textLabel.text = location.localizedCoordinateString;
            cell.detailTextLabel.text = [self.dateFormatter stringFromDate:location.timestamp];
            break;
        }
    }

    return cell;
}


#pragma mark - UITableViewDelegate

// Delegate method invoked before the user selects a row.
// In this sample, we use it to prevent selection in the first section of the table view.
//
- (NSIndexPath *)tableView:(UITableView *)tableView willSelectRowAtIndexPath:(NSIndexPath *)indexPath {
    return (indexPath.section == 0) ? nil : indexPath;
}

// Delegate method invoked after the user selects a row. Selecting a row containing a location object
// will navigate to a new view controller displaying details about that location.
//
- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath {
    [self.tableView deselectRowAtIndexPath:indexPath animated:YES];
    CLLocation *location = self.locationMeasurements[indexPath.row];
    LocationDetailViewController *detailVC = [[LocationDetailViewController alloc] initWithStyle:UITableViewStyleGrouped];
    detailVC.location = location;
    [self.navigationController pushViewController:detailVC animated:YES];
}

@end

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