在我的 iOS 应用程序中,我有一个使用加速度计移动 UIImageView 的视图。当我退出视图回到主屏幕时,应用程序崩溃。我不知道为什么。在 viewDidUnload 方法中,我有这个:
[ball removeFromSuperview];
在 .h 文件中:
@interface PlayShotguniPad : UIViewController <UIAccelerometerDelegate> {
// Declare IBOutlets for the moving fly
IBOutlet UIImageView *ball;
// Floats for the movement data
float valueX;
float valueY;
}
在.m中,我有这个代码来移动苍蝇:
-(void)awakeFromNib {
[[UIAccelerometer sharedAccelerometer] setUpdateInterval:1.0/100.0];
[[UIAccelerometer sharedAccelerometer] setDelegate:self];
}
// Get accelerometer movement data, move fly with device tilt
- (void)accelerometer:(UIAccelerometer *)accelerometer didAccelerate:(UIAcceleration *)acceleration {
valueX = acceleration.x*60.0;
valueY = acceleration.y*60.0;
int newX = (int)(ball.center.x +valueY);
if (newX > 1000-BALL_RADIUS)
newX = 1000-BALL_RADIUS;
if (newX < 0+BALL_RADIUS)
newX = 0+BALL_RADIUS;
int newY = (int)(ball.center.y +valueX);
if (newY > 740-BALL_RADIUS)
newY = 740-BALL_RADIUS;
if (newY < 0+BALL_RADIUS)
newY = 0+BALL_RADIUS;
CGPoint newCenter = CGPointMake(newX, newY);
ball.center = newCenter ;
}
viewDidLoad 方法:
[self awakeFromNib];
有什么我必须做的,比如在离开视图时释放任何东西,以防止崩溃?