全局响应MotionEvent

遇到这样一个需求：应用无论处于哪个view controller，摇动手机，都能够出发某一方法。

能够想到的思路就是用苹果封装好的“MotionEvent”，但是如果简单的把一下代码加到某一view controller中，那么只有在该view controller展示在前端时，摇动手机才会出发方法。

- (BOOL)canBecomeFirstResponder {//默认是NO，所以得重写此方法，设成YES
     return YES;
}

然后实现下列方法://很像TouchEvent事件
 
- (void)motionBegan:(UIEventSubtype)motion withEvent:(UIEvent *)event
{
}
 
- (void)motionEnded:(UIEventSubtype)motion withEvent:(UIEvent *)event
{
    NSLog(@"shake");
}
 
- (void)motionCancelled:(UIEventSubtype)motion withEvent:(UIEvent *)event
{
}

解决方法：用Category扩展UIWindow，代码如下：

UIWindow+.h

#import <UIKit/UIKit.h>


#define UIEventSubtypeMotionShakeNotification @"UIEventSubtypeMotionShakeNotification"


@interface UIWindow (Motion)

// @override
- (BOOL)canBecomeFirstResponder;
- (void)motionEnded:(UIEventSubtype)motion withEvent:(UIEvent *)event;

@end

UIWindow+.m

#import "UIWindow+.h"


@implementation UIWindow (Motion)
- (BOOL)canBecomeFirstResponder {//默认是NO，所以得重写此方法，设成YES
     return YES;
}

然后实现下列方法://很像TouchEvent事件
 
- (void)motionBegan:(UIEventSubtype)motion withEvent:(UIEvent *)event
{
}
 
- (void)motionEnded:(UIEventSubtype)motion withEvent:(UIEvent *)event
{
    NSLog(@"shake");
}
 
- (void)motionCancelled:(UIEventSubtype)motion withEvent:(UIEvent *)event
{
}

@end