iphone - CGMotion move UIImageView in Landscape Mode - iphone

Question

My app is simple: I want to move a small uiimageview around a view of an iPad with the accelerometer (now Core Motion). So, I can move the uiimageview around with the accelerometer, but I am having trouble establishing working borders in landscape mode. So, here is my code. The problem is that the uiimageview tends to stick to the borders and some of the borders are not perfectly on the edge of the view. Here is my code, any help is greatly appreciated:
- (void)startMyMotionDetect
{
__block float stepMoveFactor = 15;
[self.motionManager
startAccelerometerUpdatesToQueue:[[NSOperationQueue alloc] init]
withHandler:^(CMAccelerometerData *data, NSError *error)
{
dispatch_async(dispatch_get_main_queue(),
^{
CGRect rect = self.sumbarine.frame;
float movetoY = rect.origin.x + (data.acceleration.x * stepMoveFactor);
float maxY = self.view.frame.size.width-rect.size.width;
float movetoX = (rect.origin.y + rect.size.height)
- (data.acceleration.y * stepMoveFactor);
float maxX = self.view.frame.size.height;
if ( movetoX >0 && movetoX < maxX ) {
rect.origin.x += (data.acceleration.y * stepMoveFactor);
};
if ( movetoY > 0 && movetoY < maxY ) {
rect.origin.y += (data.acceleration.x * stepMoveFactor);
};
[UIView animateWithDuration:0 delay:0
options:UIViewAnimationOptionCurveEaseIn
animations:
^{
self.sumbarine.frame = rect;
}
completion:nil
];
}
);
}
];
}

Answer 1

The sticking issue comes from your conditions for moving. Right now, you say, if "moveToX/Y" is > 0, and less than the width/height, then add Acceleration X/Y.
What happens if origin is == or >greater than "maxX/Y"? Answer: Nothing. And thus, the submarine image acts like it's stuck to a board. Probably it can move on the alternate axis, until it's finally stuck at a condition where it no longer can move.
You'll want to play around with your conditional rules. I do not know what type of actions/input you're trying to implement for gameplay, so I can't tell you what to do next. I'm assuming the sub is supposed to go up/down depending on some user gesture/action.
One last piece of advice. Accelerometers are based on G-Force... What this means for you is even though acceleration on some axis is positive when you move say left... There's also an inverse curve when you need apply the force needed to stop. Try looking at the motiongraphs app (available in documentation) to help you get a better feel/sense of this stuff.
And remember, have fun!