如何判断touch移动或离开视图

- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event{
UITouch *touch=[touches anyObject];
if (![self pointInside:[touch locationInView:self] withEvent:nil]) {
NSLog(@"touches moved outside the view");
}else {
UIView *hitView=[self hitTest:[[touches anyObject] locationInView:self] withEvent:nil];
if (hitView==self) {
NSLog(@"touches moved in the view");
}else{
NSLog(@"touches moved in the subview");
}
}
}