如何在ios4中绘制像iphone 3gs的指南针？

Question

我想在iphone 3gs或iphone4中制作像罗盘一样的视图。你知道有人可以从头开始吗？我找不到太多关于这个问题的信息......我只想总是在北方画一个箭头。 我使用的是iOS 4.0

在此先感谢

Answer 1

开始走向更新：

if([CLLocationManager headingAvailable]) { 
    CLLocationManager *locationManager = [[CLLocationManager alloc] init]; 

    // myDelegateObject is an instance of a class implementing the CLLocationManagerDelegate protocol 
    locationManger.delegate = myDelegateObject; 
    [locationManager startUpdatingHeading]; 
} 

实现你的类之一的CLLocationManagerDelegate协议 - 尤其是这样的：

-(void)locationManager:(CLLocationManager*)manager didUpdateHeading:(CLHeading*)heading { 
    // CLLocationDirection is a double typedef 
    CLLocationDirection headingInDegrees = heading.magneticHeading; 

    // you'll have to implement this in some fashion... 
    [myCompassViewController rotateCompassImageToHeading:headingInDegrees]; 
}