21.0~21.5 加速器与陀螺仪 Core Motion

来源：互联网发布：mod jk 源码编译编辑：程序博客网时间：2024/04/30 21:21

21.0. Introduction（Core Motion）

在使用加速器和陀螺仪之前，你应该先判断设备是否可用。

加速器可以获得在x,y,z轴上的移动数据，陀螺仪可以知到这些方向上与地面的关系

the developers need to know not only whether the device is moving on the x-,y-, andz-axes (information they can get from the accelerometer), but also whether it is changing in relation to the Earth along these directions, which requires a gyroscope.

使用时需要引入Core Motion framework

模拟器上没有加速器和陀螺仪。只能使用Hardware->Shake Gesture

21.1. Detecting the Availability of an Accelerometer

检测加速器

-(void)testAccelerometerAvailable

{

CMMotionManager *motionManager = [[CMMotionManageralloc]init];

if ([motionManagerisAccelerometerAvailable]){

NSLog(@"Accelerometer is available.");

}else{

NSLog(@"Accelerometer is not available.");

}

if ([motionManagerisAccelerometerActive]){

NSLog(@"Accelerometer is active.");

}else {

NSLog(@"Accelerometer is not active.");

}

模拟器：

2014-08-07 16:51:01.358 cookbook21[662:a0b] Accelerometer is not available.

2014-08-07 16:51:01.359 cookbook21[662:a0b] Accelerometer is not active.

真机：

2014-08-07 17:13:54.686 cookbook21[136:907] Accelerometer is available.

2014-08-07 17:13:54.688 cookbook21[136:907] Accelerometer is not active.

21.2. Detecting the Availability of a Gyroscope

检测陀螺仪

-(void)testGyroscrope

{

CMMotionManager *motionManager = [[CMMotionManageralloc]init];

if ([motionManagerisGyroAvailable]){

NSLog(@"Gryro is available.");

}else {

NSLog(@"Gyro is not available.");

}

if ([motionManagerisGyroActive]){

NSLog(@"Gryo is active.");

}else {

NSLog(@"Gryo is not active.");

}

模拟器：

2014-08-07 16:59:22.412 cookbook21[690:a0b] Gyro is not available.

2014-08-07 16:59:22.412 cookbook21[690:a0b] Gryo is not active.

真机：

2014-08-07 17:14:28.801 cookbook21[151:907] Gryro is available.

2014-08-07 17:14:28.803 cookbook21[151:907] Gryo is not active.

21.3. Retrieving Accelerometer Data

让iOS发加速器的数据给应用

iOS发送加速器的三维数据给应用，其封装在数据结构里

typedef struct {doublex;doubley;doublez; }CMAcceleration;

x轴：设备的水平中心从左至右，值范围-1~+1

y轴：设备的垂直中心从下至上，值范围-1~+1

z轴：设备由后至前，值范围-1~+1

不懂怎么翻译，下面是原文：

The x-axis runs from left to right at the horizontal center of the device,with values ranging from‒1 to +1 from left to right.
They-axis runs from bottom to top at the vertical center of the device,with values ranging from‒1 to +1 from bottom to top.
The z-axis runs from the back of the device, through the device toward you, with values ranging from‒1 to +1 from back to front.

通过后面的实验，我的理解是，有这么个三维空间，x轴正方向为向右方向，y轴正方向为向下方向，z轴正方向为指向自己的方向。

实验一：绕着Z轴旋转

1，手机垂直向上（top point to the sky），这时（x：0.0，y：-1.0，z：0.0）

2，顺时针旋转90度，这时（x：+1.0，y：0.0，z：0.0）

3，再顺时针旋转90度（top point to the ground），这时（x：0.0，y：1.0，z：0.0）

4，再顺时针旋转90度，这时（x：-1.0，y：0.0，z：0.0）

5，再顺时针旋转90度（top point to the sky），这时（x：0.0，y：-1.0，z：0.0）

实验二：绕着X轴旋转

1，手机垂直向上（top point to the sky），这时（x：0.0，y：-1.0，z：0.0）

2，从前往后旋转90度，这时（x：0.0，y：0.0，z：-1.0）

3，再旋转90度（top point to the ground），这时（x：0.0，y：1.0，z：0.0）

4，再旋转90度，这时（x：0.0，y：0.0，z：1.0）

5，再旋转90度（top point to the sky），这时（x：0.0，y：-1.0，z：0.0）

实验三：绕着Y轴旋转

额。。。这个貌似比较难，书上鼓励我们自己动手。我就自以为的这么做了：

1，让手机面向我们趴倒在桌上，这时（x：0.0，y：0.0，z：1.0）

2，让手机右侧躺着（landscape left），这时（x：1.0，y：0.0，z：0.0）

3，让手机向后躺在桌上，这时（x：0.0，y：0.0，z：-1.0）

4，让手机左侧躺着（landscape left），这时（x：-1.0，y：0.0，z：0.0）

5，回到第一步了

-(void)testAccelerometerUpdate

{

self.motionManager = [[CMMotionManageralloc]init];

if ([self.motionManagerisAccelerometerAvailable]){

NSOperationQueue *queue = [[NSOperationQueuealloc]init];

[self.motionManager

startAccelerometerUpdatesToQueue:queue

withHandler:^(CMAccelerometerData *accelerometerData,NSError *error) {

NSLog(@"X = %.04f, Y = %.04f, Z = %.04f",

accelerometerData.acceleration.x,

accelerometerData.acceleration.y,

accelerometerData.acceleration.z);

}];

}else {

NSLog(@"Accelerometer is not available.");

}

打印（竖直的时候）：

2014-08-08 11:31:37.761 cookbook21[273:1603] X = 0.0906, Y = -0.9679, Z = -0.1973

2014-08-08 11:31:37.761 cookbook21[273:4707] X = 0.0906, Y = -0.9727, Z = -0.2069

2014-08-08 11:31:37.770 cookbook21[273:1103] X = 0.0896, Y = -0.9679, Z = -0.1906

2014-08-08 11:31:37.777 cookbook21[273:1103] X = 0.0885, Y = -0.9660, Z = -0.1801

2014-08-08 11:31:37.858 cookbook21[273:1603] X = 0.0985, Y = -0.9658, Z = -0.1828

2014-08-08 11:31:37.861 cookbook21[273:1603] X = 0.0982, Y = -0.9840, Z = -0.1915

2014-08-08 11:31:37.862 cookbook21[273:1103] X = 0.1094, Y = -0.9791, Z = -0.2163

2014-08-08 11:31:37.862 cookbook21[273:1603] X = 0.1122, Y = -0.9838, Z = -0.2057

。。。。。。

21.4. Detecting Shakes on an iOS Device

摇一摇

- (BOOL)canBecomeFirstResponder

{

returnYES;// default is NO

}

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

{

if (motion ==UIEventSubtypeMotionShake){

NSLog(@"%@ %s",NSStringFromClass([selfclass]),__FUNCTION__);

}

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

if (motion ==UIEventSubtypeMotionShake){

NSLog(@"%@ %s",NSStringFromClass([self class]),__FUNCTION__);

}

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

if (motion ==UIEventSubtypeMotionShake){

NSLog(@"%@ %s",NSStringFromClass([self class]),__FUNCTION__);

}

打印：

2014-08-08 11:54:26.162 cookbook21[398:907] ViewController -[ViewController motionBegan:withEvent:]

2014-08-08 11:54:28.526 cookbook21[398:907] ViewController -[ViewController motionEnded:withEvent:]

2014-08-08 11:54:30.897 cookbook21[398:907] ViewController -[ViewController motionBegan:withEvent:]

2014-08-08 11:54:31.520 cookbook21[398:907] ViewController -[ViewController motionEnded:withEvent:]

2014-08-08 11:54:33.277 cookbook21[398:907] ViewController -[ViewController motionBegan:withEvent:]

2014-08-08 11:54:34.976 cookbook21[398:907] ViewController -[ViewController motionCancelled:withEvent:]

2014-08-08 11:54:41.767 cookbook21[398:907] ViewController -[ViewController motionBegan:withEvent:]

2014-08-08 11:54:49.834 cookbook21[398:907] ViewController -[ViewController motionEnded:withEvent:]

2014-08-08 11:54:51.071 cookbook21[398:907] ViewController -[ViewController motionBegan:withEvent:]

2014-08-08 11:54:51.681 cookbook21[398:907] ViewController -[ViewController motionEnded:withEvent:]

2014-08-08 11:54:57.766 cookbook21[398:907] ViewController -[ViewController motionBegan:withEvent:]

2014-08-08 11:55:02.295 cookbook21[398:907] ViewController -[ViewController motionEnded:withEvent:]

2014-08-08 11:55:03.735 cookbook21[398:907] ViewController -[ViewController motionBegan:withEvent:]

2014-08-08 11:55:07.353 cookbook21[398:907] ViewController -[ViewController motionEnded:withEvent:]

2014-08-08 11:55:08.156 cookbook21[398:907] ViewController -[ViewController motionBegan:withEvent:]

2014-08-08 11:55:08.795 cookbook21[398:907] ViewController -[ViewController motionEnded:withEvent:]

2014-08-08 11:55:12.677 cookbook21[398:907] ViewController -[ViewController motionBegan:withEvent:]

2014-08-08 11:55:18.639 cookbook21[398:907] ViewController -[ViewController motionCancelled:withEvent:]

21.5. Retrieving Gyroscope Data

-(void)testRetrieveGyroscopeData

{

CMMotionManager *manager = [[CMMotionManageralloc]init];

if ([managerisGyroAvailable]){

if ([managerisGyroActive] ==NO){

[managersetGyroUpdateInterval:1.0f /40.0f];

NSOperationQueue *queue = [[NSOperationQueuealloc]init];

NSLog(@"startGyroUpdatesToQueue");

[manager

startGyroUpdatesToQueue:queue

withHandler:^(CMGyroData *gyroData,NSError *error) {

NSLog(@"Gyro Rotation x = %.04f", gyroData.rotationRate.x);

NSLog(@"Gyro Rotation y = %.04f", gyroData.rotationRate.y);

NSLog(@"Gyro Rotation z = %.04f", gyroData.rotationRate.z);

}];

}else {

NSLog(@"Gyro is already active.");

}

}else {

NSLog(@"Gyro isn't available.");

}

打印：

2014-08-12 14:54:20.713 cookbook21[828:907] startGyroUpdatesToQueue

很失败，愣是收不到数据

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