添加CGPoint对象到一个NSArray

NSArray *points = [NSArray arrayWithObjects: [NSValue valueWithCGPoint:CGPointMake(0, 0)], [NSValue valueWithCGPoint:CGPointMake(0, 1)], nil];
NSValue *value = [points objectAtIndex:0]; //例如取出第一项
CGPoint point = [value CGPointValue];