objective-c - 任何对象到 CGPoint

Question

我似乎无法弄清楚这一点，我有一个返回 NSArray 的 Objective-C 函数，我确信 NSArray 内的数据包含 CGPoint 对象我到底如何将其转换为数组

这是函数

+(NSArray *)translatePoints:(NSArray *)points fromView:(UIView *)fromView toView:(UIView *)toView
{
    NSMutableArray *translatedPoints = [NSMutableArray new];

    // The points are provided in a dictionary with keys X and Y
    for (NSDictionary *point in points) {
        // Let's turn them into CGPoints
        CGPoint pointValue = CGPointMake([point[@"X"] floatValue], [point[@"Y"] floatValue]);
        // Now translate from one view to the other
        CGPoint translatedPoint = [fromView convertPoint:pointValue toView:toView];
        // Box them up and add to the array
        [translatedPoints addObject:[NSValue valueWithCGPoint:translatedPoint]];
    }

    return [translatedPoints copy];
}

Answer 1

您的 translatesPoints 方法返回一个 NSArray，其中包含包装 CGPoint 的 NSValue。让我们创建一个这样的数组:

let arr:NSArray = [NSValue(CGPoint: CGPointMake(1,2)), NSValue(CGPoint: CGPointMake(3,4))]

您可以从此数组中获取值并对它们调用CGPointValue():

for val in arr as [NSValue] {
    let point = val.CGPointValue()
    println("CGPoint = (\(point.x), \(point.y))")
}

如果需要，您可以将整个 NSArray 转换为 CGPoint 的 Swift 数组，如下所示:

let points = (arr as [NSValue]).map({$0.CGPointValue()})

现在 points 的类型为 [CGPoint]。