該動畫利用三角形的正余弦定理來實現(xiàn)
核心代碼
?_imageView= imageView;
? ? self.center = CGPointMake(_radius * sinf(_angle) + _imageView.center.x, _radius * cosf(_angle + M_PI) + _imageView.center.y);
? ? _timer = [NSTimer scheduledTimerWithTimeInterval:_time target:self selector:@selector(moveView) userInfo:nil repeats:YES];
