CoreMotion框架

Question

我最近做了一个指南针，涉及CoreMotion框架，但是我查了很久没找到关于如何实现这个框架指南针效果的信息，希望得到大家的帮助。

Answer 1

• Apple的Core Motion Framework Reference
• Apple的Event Handling Guide for iOS: Core Motion
• Apple的CoreMotionTeaPot来自WWDC ’10 Sample Code
• Get Moving with Core Motion - Jonathan Blocksom
• Getting you started with CoreMotion - 路德维希舒伯特
• 一个类似的问题：make a compass application in iPad

Answer 2

我的“Helloworld”CoreMotion：

1）添加CoreMotion.framework

2）在.h文件中：

#import <CoreMotion/CoreMotion.h>

3）在.m文件中：

CMMotionManager *myMotionManager= [[CMMotionManager alloc] init];
myMotionManager.deviceMotionUpdateInterval = 1/60;
[myMotionManager startDeviceMotionUpdatesUsingReferenceFrame:CMAttitudeReferenceFrameXMagneticNorthZVertical  toQueue:[NSOperationQueue currentQueue] withHandler:^(CMDeviceMotion *motion, NSError *error) {
     double x = myMotionManager.deviceMotion.magneticField.field.x;
     double y = myMotionManager.deviceMotion.magneticField.field.y;
     double z = myMotionManager.deviceMotion.magneticField.field.z;
    NSLog(@"Strength of Earth's magnetic field= %8.2f",sqrt(x*x+y*y+z*z));
    myLabel.text = [NSString stringWithFormat:@"%8.2f", sqrt(x*x+y*y+z*z)];
}];