Programmatically trigger shake event iOS

Question

How can I programmatically trigger the shake event in iOS?

I've tried the following but it keeps crashing...

+ (void)shake {
    NSLog(@"TEST");

    UIMotionEventProxy *m = [[NSClassFromString(@"UIMotionEvent") alloc] _init];

    m->_subtype = UIEventSubtypeMotionShake;
    m->_shakeState = 1;

    [[[UIApplication sharedApplication] keyWindow] motionBegan:UIEventSubtypeMotionShake withEvent:m];
    [[[UIApplication sharedApplication] keyWindow] motionEnded:UIEventSubtypeMotionShake withEvent:m];
}

What does apple do in the simulator under Hardware > Shake Gesture ?

Answer 1

Try to replace

UIMotionEventProxy *m = [[NSClassFromString(@"UIMotionEvent") alloc] _init];

with

UIMotionEventProxy *m = [[UIMotionEventProxy alloc] _init];

I guess it's crushing when NSClassFromString(@"UIMotionEvent") returns nil.

Answer 2

Do you want to use in Jailbreak app or Apple compliant use ?

For your question about simulator, Apple use a private function.

Here is a little explanation:

When you use "Shake Gesture", the simulator call sendButtonEvent:0x3fc

sendButtonEvent is a function in Simulator, who:

• get frontmostAppPort
• send a message via sendPurpleEvent or HIDEvent

In a jailbreak application, you can do something like (not tested, but should works):

struct UIEvent {
    int subtype;
    double timestamp;
    int type;
} * event;

bzero(event, sizeof(event));

event->type = UIEventTypeMotion;
event->subtype = UIEventSubtypeMotionShake;
event->timestamp = GSCurrentEventTimestamp();

NSString* bundle = [[NSBundle mainBundle] bundleIdentifier];
mach_port_t port = GSCopyPurpleNamedPort([bundle UTF8String]);

GSEventRecord* record = (GSEventRecord*)event;
GSSendEvent(record, port);

Answer 3

Changing the UIMotionEventProxy class (adding two setter methods) seemed to do the trick. I simply added two methods setShakeState and _setSubtype , shown below.

-(void)setShakeState:(int)fp8 {
    _shakeState = fp8;
}
-(void)_setSubtype:(int)fp8 {
    _subtype = fp8;
}

I then changed my code to the following...

UIMotionEventProxy *m = [[NSClassFromString(@"UIMotionEvent") alloc] _init];

[m setShakeState:1];
[m _setSubtype:UIEventSubtypeMotionShake];

[[UIApplication sharedApplication] sendEvent:m];
[[[UIApplication sharedApplication] keyWindow] motionBegan:UIEventSubtypeMotionShake withEvent:m];
[[[UIApplication sharedApplication] keyWindow] motionEnded:UIEventSubtypeMotionShake withEvent:m];

Seems to be working flawlessly for both simulator and physical device. Here are main and header files available for download if anyone wants to see the full UIMotionEventProxy files.