当有人摇晃iPhone时,我想做出反应。我并不特别在意他们是如何摇晃它的,只在意它在一瞬间被使劲地挥舞着。有人知道怎么检测吗?


当前回答

为了在整个应用范围内启用这个功能,我在UIWindow上创建了一个类别:

@implementation UIWindow (Utils)

- (BOOL)canBecomeFirstResponder
{
    return YES;
}

- (void)motionBegan:(UIEventSubtype)motion withEvent:(UIEvent *)event
{
    if (motion == UIEventSubtypeMotionShake) {
        // Do whatever you want here...
    }
}

@end

其他回答

查看GLPaint示例。

http://developer.apple.com/library/ios/#samplecode/GLPaint/Introduction/Intro.html

你需要通过accelerometer:didAccelerate: method检查加速度计,这是UIAccelerometerDelegate协议的一部分,检查这些值是否超过了震动所需的移动量的阈值。

在AppController底部的accelerometer:didAccelerate:方法中有一些不错的示例代码。m在GLPaint例子中,这个例子可以在iPhone开发者网站上找到。

最简单的解决方案是为你的应用程序派生一个新的根窗口:

@implementation OMGWindow : UIWindow

- (void)motionEnded:(UIEventSubtype)motion withEvent:(UIEvent *)event {
    if (event.type == UIEventTypeMotion && motion == UIEventSubtypeMotionShake) {
        // via notification or something   
    }
}
@end

然后在你的应用委托中:

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
    self.window = [[OMGWindow alloc] initWithFrame:[UIScreen mainScreen].bounds];
    //…
}

如果你使用的是故事板,这可能会更棘手,我不知道你在应用委托中需要精确的代码。

只要用这三种方法就可以了

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

要了解详细信息,您可以在那里查看完整的示例代码

在我的Diceshaker应用中:

// Ensures the shake is strong enough on at least two axes before declaring it a shake.
// "Strong enough" means "greater than a client-supplied threshold" in G's.
static BOOL L0AccelerationIsShaking(UIAcceleration* last, UIAcceleration* current, double threshold) {
    double
        deltaX = fabs(last.x - current.x),
        deltaY = fabs(last.y - current.y),
        deltaZ = fabs(last.z - current.z);

    return
        (deltaX > threshold && deltaY > threshold) ||
        (deltaX > threshold && deltaZ > threshold) ||
        (deltaY > threshold && deltaZ > threshold);
}

@interface L0AppDelegate : NSObject <UIApplicationDelegate> {
    BOOL histeresisExcited;
    UIAcceleration* lastAcceleration;
}

@property(retain) UIAcceleration* lastAcceleration;

@end

@implementation L0AppDelegate

- (void)applicationDidFinishLaunching:(UIApplication *)application {
    [UIAccelerometer sharedAccelerometer].delegate = self;
}

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

    if (self.lastAcceleration) {
        if (!histeresisExcited && L0AccelerationIsShaking(self.lastAcceleration, acceleration, 0.7)) {
            histeresisExcited = YES;

            /* SHAKE DETECTED. DO HERE WHAT YOU WANT. */

        } else if (histeresisExcited && !L0AccelerationIsShaking(self.lastAcceleration, acceleration, 0.2)) {
            histeresisExcited = NO;
        }
    }

    self.lastAcceleration = acceleration;
}

// and proper @synthesize and -dealloc boilerplate code

@end

组织性可以防止震动事件多次触发,直到用户停止震动。