我CMMotionManager
用于检索加速度计数据。问题是加速度计数据会定期打印,视图中的实例变量会更改,但视图不会重绘。我检查过hv
它不是 nil 并且一切都被钩住了。在块内调用 setNeedsDisplay 有问题吗?
-(void) viewDidAppear:(BOOL) animated
{
[super viewDidAppear: animated];
[motionManager startAccelerometerUpdatesToQueue:motionQueue withHandler:
^(CMAccelerometerData *accelerometerData, NSError *error)
{
NSLog(@"%@",accelerometerData);
HypnosisView *hv = (HypnosisView *) [self view];
hv.xShift = 10.0 * accelerometerData.acceleration.x;
hv.yShift = -10.0 * accelerometerData.acceleration.y;
[hv setNeedsDisplay];
}];
}