CLLocationCoordinate2D不知道数组中有多少个? [英] CLLocationCoordinate2D without knowing how many will be in the array?
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问题描述
我需要使用以下内容构建数组:
I need to build an array using something like the following:
CLLocationCoordinate2D points[4];
points[0] = CLLocationCoordinate2DMake(41.000512, -109.050116);
points[1] = CLLocationCoordinate2DMake(41.002371, -102.052066);
points[2] = CLLocationCoordinate2DMake(36.993076, -102.041981);
points[3] = CLLocationCoordinate2DMake(36.99892, -109.045267);
问题是,我永远不会知道阵列中有多少项,所以我可以指定计数。有没有办法创建一个CLLocationCoordinate2D数组,只是插入新坐标而不知道最终总数是多少?
Problem is, I will never know how many items are going to be in the array, so I can specify the count. Is there a way to create a CLLocationCoordinate2D array, and just insert new coordinates without knowing what the final total will be?
编辑:我的最终目标是使用坐标来使用需要CLLocationCoordinate2D数组的polylineWithCoordinates方法制作MKPolyline。
My final goal is to use the coordinates to make an MKPolyline, using the polylineWithCoordinates method which needs a CLLocationCoordinate2D array.
推荐答案
// 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);
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