加速计和校准 - iPhone SDK

Question

我需要在我的iphone游戏中使用加速度计的功能。我只需通过倾斜设备来移动图像。但是，YouTube上的大多数视频仅显示以某种方式倒置的倾斜功能，并忘记包含校准。我希望用户能够将他们的设备校准到他们所在的任何位置。有谁知道我应该如何开始？

你的帮助是极大的赞赏，

凯文

Answer 1

我犯了这样的一个应用程序一次。 我将它张贴在这里，但它是为iOS 4 ...

http://localhostr.com/files/7ca39c/Tilter.zip

校准：

int tapCount = 0; 
- (void)cancelDoubleTap { 
    if (tapCount < 2) { 
     tapCount = 0; 
    } 
} 
- (void)reset { 
    [[NSUserDefaults standardUserDefaults] setFloat:0 forKey:@"X-Calibrate"]; 
    [[NSUserDefaults standardUserDefaults] setFloat:0 forKey:@"Y-Calibrate"]; 
    UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"Reset!" message:@"Calibration reset." delegate:nil cancelButtonTitle:@"Okay." otherButtonTitles:nil]; 
    [alert show]; 
    [alert release]; 
} 
- (void)calibrate { 
    if (tapCount == 3) { 
     tapCount = 0; 
     return; 
    } 
    [[NSUserDefaults standardUserDefaults] setFloat:accelX forKey:@"X-Calibrate"]; 
    [[NSUserDefaults standardUserDefaults] setFloat:accelY forKey:@"Y-Calibrate"]; 
    UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"Calibrated!" message:[NSString stringWithFormat:@"Calibrated to: %.2f %.2f.", accelX, accelY] delegate:nil cancelButtonTitle:@"Okay." otherButtonTitles:nil]; 
    [alert show]; 
    [alert release]; 
    tapCount = 0; 
} 
- (BOOL)canBecomeFirstResponder { 
    return YES; 
} 
- (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event { 
    NSTimer *timer = [NSTimer scheduledTimerWithTimeInterval:1.0 target:self selector:@selector(cancelDoubleTap) userInfo:nil repeats:NO]; 
    tapCount ++; 
    if (tapCount == 3) { 
     [timer invalidate]; 
     [self reset]; 
     return; 
    } 
    if (tapCount == 2) { 
     [timer invalidate]; 
     timer = [NSTimer scheduledTimerWithTimeInterval:0.5 target:self selector:@selector(calibrate) userInfo:nil repeats:NO]; 
    } 
} 

而且......

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions { 
    but = [[UIButton alloc] initWithFrame:window.frame]; 
    [but addTarget:self action:@selector(touchesEnded:withEvent:) forControlEvents:UIControlEventTouchUpInside]; 
    [window addSubview:but]; 
    // Override point for customization after application launch. 
    box = [[UIView alloc] initWithFrame:CGRectMake(self.window.center.x - 50, self.window.center.y - 50, 100, 100)]; 
    [window makeKeyAndVisible]; 
    box.backgroundColor = [UIColor colorWithRed:1.0 green:0.0 blue:0.0 alpha:0.75]; 
    [window addSubview:box]; 
    [[UIAccelerometer sharedAccelerometer] setDelegate:self]; 
    [[UIAccelerometer sharedAccelerometer] setUpdateInterval:(1/100.0)]; 
    slider = [[UISlider alloc] initWithFrame:CGRectMake(20, 438, 280, 22)]; 
    [slider setMinimumValue:2.0]; 
    [slider setMaximumValue:50.0]; 
    [window addSubview:slider]; 
    return YES; 
} 

.h文件中：

#import <UIKit/UIKit.h> 

@interface TilterAppDelegate : NSObject <UIApplicationDelegate, UIAccelerometerDelegate> { 
    UIWindow *window; 
    UIView *box; 
    UISlider *slider; 
    UIButton *but; 
} 

@property (nonatomic, retain) IBOutlet UIButton *but; 
@property (nonatomic, retain) IBOutlet UISlider *slider; 
@property (nonatomic, retain) IBOutlet UIView *box; 
@property (nonatomic, retain) IBOutlet UIWindow *window; 

@end 

移动代码：

- (void)moveBoxByX:(float)x byY:(float)y { 
    float newX = box.center.x + x; 
    float newY = box.center.y + y; 
    if (newX < 50) 
     newX = 50; 
    if (newX > 270) 
     newX = 270; 
    if (newY < 50) 
     newY = 50; 
    if (newY > 430) 
     newY = 430; 
    box.center = CGPointMake(newX, newY); 
} 

大部分时间应该工作。