停止餅圖

Question

IM通過下面的代碼旋轉的餅圖

-(BOOL)plotSpace:(CPTPlotSpace *)space shouldHandlePointingDeviceDownEvent:(id)event atPoint:(CGPoint)point 
{ 
    CABasicAnimation *rotation = [CABasicAnimation animationWithKeyPath:@"transform.rotation"];  
    rotation.removedOnCompletion = NO; 
    rotation.fromValue = [NSNumber numberWithFloat:M_PI_4]; 
    rotation.toValue = [NSNumber numberWithFloat:M_PI_4+10]; 
    rotation.duration = 1.0f; 
    rotation.timingFunction = [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionDefault]; 
    rotation.delegate = self; 
    pieChart.startAngle = M_PI_4+10; 
    [pieChart addAnimation:rotation forKey:@"rotation"]; 
    return YES; 
} 

但是旋轉的餅圖後回到其初始position.But我想，現在餅圖應該在轉角。如何在這裏取得成功？

Answer 1

請參閱this CocoaDev article。它提供了幾個可能的解決方案。他們的示例使用position屬性，但所討論的技術適用於任何動畫屬性。