如何创建CLLocationCoordinate2d对象

Question

我正在尝试调用MKPolylines的+ polylineWithCoordinates:count:方法。

在这种情况下，如何创建CLLocationCoordinate2D *对象。我已经在CLLocationCoordinate2D without knowing how many will be in the array?中看过了这个特殊的答案

// unpacking an array of NSValues into memory
CLLocationCoordinate2D *points = malloc([mutablePoints count] * sizeof(CLLocationCoordinate2D));
for(int i = 0; i < [mutablePoints count]; i++) {
[[mutablePoints objectAtIndex:i] getValue:(points + i)];
}

MKPolyline *myPolyline = [MKPolyline polylineWithCoordinates:points count:[mutablePoints count]];
free(points);

在上面的例子中，数组mutablePoints中是什么类型的条目？

Answer 1

如果您的问题仅仅是数组中是哪种类型的条目，那么答案非常简单：NSValue条目。您可以查看此guide以了解有关如何使用NSValues的更多信息。

Answer 2

CLLocationCoordinate2D coordinate;
    for (int i = 0; i < arr.count; i++)
    {
        float t1 = [[arr objectAtIndex:1] floatValue];
        float t2 = [[arr objectAtIndex:0] floatValue];

        coordinate.latitude = t1;
        coordinate.longitude = t2;

    }