Using Xcode, create a new View-based Application project and name it Accelerometer.

Double-click the AccelerometerViewController.xib file to edit it in Interface Builder.

Populate the View window with the six Label views, as shown in Figure 17-2.

Figure 17.2. Figure 17-2

In the AccelerometerViewController.h file, add the following statements that appear in bold:

#import <UIKit/UIKit.h>

@interface AccelerometerViewController :
UIViewController
    <UIAccelerometerDelegate> {

    IBOutlet UILabel *labelX;
    IBOutlet UILabel *labelY;
    IBOutlet UILabel *labelZ;
}

@property (nonatomic, retain) UILabel *labelX;
@property (nonatomic, retain) UILabel *labelY;
@property (nonatomic, retain) UILabel *labelZ;

@end

Back in Interface Builder, Control-click and drag the File's Owner item to each of the three Label views and select labelX, labelY, and labelZ, respectively.

In the AccelerometerViewController.m file, add the following statements that appear in bold:

#import "AccelerometerViewController.h"

@implementation AccelerometerViewController

@synthesize labelX, labelY, labelZ;

- (void)viewDidLoad {
    UIAccelerometer *acc = [UIAccelerometer sharedAccelerometer];
    acc.delegate = self;
    acc.updateInterval = 1.0f/60.0f;
    [super viewDidLoad];
}

- (void)accelerometer:(UIAccelerometer *) acc
    didAccelerate:(UIAcceleration *)acceleration {

    NSString *str = [[NSString alloc] initWithFormat:@"%g", acceleration.x];
    labelX.text = str;
    str = [[NSString alloc] initWithFormat:@"%g", acceleration.y];
    labelY.text = str;
    str = [[NSString alloc] initWithFormat:@"%g", acceleration.z];
    labelZ.text = str;
    [str release];
}

- (void)dealloc {
    [labelX release];
    [labelY release];
    [labelZ release];
    [super dealloc];
}

Press Command-R to test the application on an iPhone device. Figure 17-3 shows the data displayed on the application when my iPhone is resting on the iPhone docking cradle.

Using Xcode, create a new View-based Application project and name it Shake.

Double-click the ShakeViewController.xib file to edit it in Interface Builder.

Populate the View window with the following views (see Figure 17-4):

Insert the following statements that appear in bold into the ShakeViewController.h file:

#import <UIKit/UIKit.h>

@interface ShakeViewController : UIViewController {
    IBOutlet UITextField *textField;
    IBOutlet UIDatePicker *datePicker;
}

@property (nonatomic, retain) UITextField *textField;
@property (nonatomic, retain) UIDatePicker *datePicker;

-(IBAction) doneEditing: (id) sender;

@end

In Interface Builder, control-click and drag the File's Owner item to the TextField view and select textField.

Control-click and drag the File's Owner item to the DatePicker view and select datePicker.

Right-click the TextField view and connect its Did End on Exit event to the File's Owner item (see Figure 17-5). Select doneEditing:.

Figure 17.5. Figure 17-5

Insert the following statements that appear in bold to the ShakeViewController.m file:

#import "ShakeViewController.h"

@implementation ShakeViewController

@synthesize textField, datePicker;

- (void) viewDidAppear:(BOOL)animated
{
    [self.view becomeFirstResponder];
    [super viewDidAppear:animated];
}

- (IBAction) doneEditing: (id) sender {
    //---when keyboard is hidden, make the view the first responder
    // or else the Shake API will not work---
    [self.view becomeFirstResponder];
}

- (void)motionBegan:(UIEventSubtype)motion withEvent:(UIEvent *)event {

if (event.subtype == UIEventSubtypeMotionShake )
    {
        NSLog(@"motionBegan:");
    }
}

- (void)motionCancelled:(UIEventSubtype)motion withEvent:(UIEvent *)event {
    if (event.subtype == UIEventSubtypeMotionShake )
    {
        NSLog(@"motionCancelled:");
    }
}

- (void)motionEnded:(UIEventSubtype)motion withEvent:(UIEvent *)event {
    if (event.subtype == UIEventSubtypeMotionShake )
    {
        NSLog(@"motionEnded:");
    }
}

- (void)dealloc {
    [textField release];
    [datePicker release];
    [super dealloc];
}

Right-click the Classes group in Xcode and choose Add

Figure 17.6. Figure 17-6

Click Next and name the file ShakeView.m.

Insert the following statements in bold in ShakeView.m:

#import "ShakeView.h"

@implementation ShakeView

- (id)initWithFrame:(CGRect)frame {
    if (self = [super initWithFrame:frame]) {
        // Initialization code
    }
    return self;
}

- (void)drawRect:(CGRect)rect {
    // Drawing code
}

- (void)dealloc {
    [super dealloc];
}

- (BOOL)canBecomeFirstResponder {
    return YES;
}

@end

In Interface Builder, select the View window and view its Identity Inspector window. Select its class name as ShakeView (see Figure 17-7).

Figure 17.7. Figure 17-7

Save the file in Interface Builder.

Press Command-R to test the application on the iPhone Simulator. Open the Debugger Console window by pressing Command-Shift-R in Xcode.

With the application in the iPhone Simulator, choose Hardware

Figure 17.8. Figure 17-8

Tap the TextField view to make the keyboard appear. Choose Hardware

Close the keyboard by tapping the return key on the keyboard. Simulate shaking the simulator again and observe the output on the Debugger Console.

In the ShakeViewController.m file, add the following statements that appear in bold:

- (void)ResetDatePicker {
    [datePicker setDate:[NSDate date]];
}

- (void)motionEnded:(UIEventSubtype)motion withEvent:(UIEvent *)event {
    if (event.subtype == UIEventSubtypeMotionShake )
    {
        NSLog(@"motionEnded:");
        [self ResetDatePicker];
    }
}

Press Command-R to test the application on the iPhone Simulator. Set the DatePicker view to some date. Choose Hardware

Figure 17.9. Figure 17-9

Using Xcode, create a new View-based Application project and name it GPS.

Double-click the GPSViewController.xib file to edit it in Interface Builder.

Populate the View window with the following views (see Figure 17-10):

Right-click the Frameworks group in Xcode and choose Add

Insert the following statements that appear in bold into the GPSViewController.h file:

#import <UIKit/UIKit.h>
#import <CoreLocation/CoreLocation.h>

@interface GPSViewController : UIViewController
    <CLLocationManagerDelegate> {

    IBOutlet UITextField *latitudeTextField;
    IBOutlet UITextField *longitudeTextField;
    IBOutlet UITextField *accuracyTextField;
    CLLocationManager *lm;
}

@property (retain, nonatomic) UITextField *latitudeTextField;
@property (retain, nonatomic) UITextField *longitudeTextField;
@property (retain, nonatomic) UITextField *accuracyTextField;

@end

Back in Interface Builder, Control-click and drag the File's Owner item to each of the three TextField views and select latitudeTextField, longitudeTextField, and accuracyTextField, respectively.

Insert the following statements that appear in bold into the GPSViewController.m file:

#import "GPSViewController.h"

@implementation GPSViewController

@synthesize latitudeTextField, longitudeTextField, accuracyTextField;

- (void) viewDidLoad {
    lm = [[CLLocationManager alloc] init];
    if ([lm locationServicesEnabled]) {
        lm.delegate = self;
        lm.desiredAccuracy = kCLLocationAccuracyBest;
        lm.distanceFilter = 1000.0f;
        [lm startUpdatingLocation];
    }
}

- (void) locationManager: (CLLocationManager *) manager
    didUpdateToLocation: (CLLocation *) newLocation

fromLocation: (CLLocation *) oldLocation{

    NSString *lat = [[NSString alloc] initWithFormat:@"%g",
        newLocation.coordinate.latitude];
    latitudeTextField.text = lat;

    NSString *lng = [[NSString alloc] initWithFormat:@"%g",
        newLocation.coordinate.longitude];
    longitudeTextField.text = lng;

    NSString *acc = [[NSString alloc] initWithFormat:@"%g",
        newLocation.horizontalAccuracy];
    accuracyTextField.text = acc;

    [acc release];
    [lat release];
    [lng release];
}

- (void) locationManager: (CLLocationManager *) manager
    didFailWithError: (NSError *) error {

    NSString *msg = [[NSString alloc] initWithString:@"Error obtaining location"];
    UIAlertView *alert = [[UIAlertView alloc]
                          initWithTitle:@"Error"
                          message:msg
                          delegate:nil
                          cancelButtonTitle: @"Done"
                          otherButtonTitles:nil];
    [alert show];
    [msg release];
    [alert release];
}

- (void) dealloc{
    [lm release];
    [latitudeTextField release];
    [longitudeTextField release];
    [accuracyTextField release];
    [super dealloc];
}

Press Command-R to test the application on the iPhone Simulator. Figure 17-11 shows the simulator displaying the latitude and longitude of the location returned. It also shows the accuracy of the result.

Figure 17.11. Figure 17-11