我希望与该问题相关的链接到我自己的博客文章的规则不违反规则，但是我过去已经解决了这个问题。来自链接帖子的独立答案：
@implementation MKPolyline (MKPolyline_EnpredString)+ (MKPolyline *)polylineWithEnpredString:(NSString *)enpredString { const char *bytes = [enpredString UTF8String]; NSUInteger length = [enpredString lengthOfBytesUsingEncoding:NSUTF8StringEncoding]; NSUInteger idx = 0; NSUInteger count = length / 4; CLLocationCoordinate2D *coords = calloc(count, sizeof(CLLocationCoordinate2D)); NSUInteger coordIdx = 0; float latitude = 0; float longitude = 0; while (idx < length) { char byte = 0; int res = 0; char shift = 0; do { byte = bytes[idx++] - 63; res |= (byte & 0x1F) << shift; shift += 5; } while (byte >= 0x20); float deltaLat = ((res & 1) ? ~(res >> 1) : (res >> 1)); latitude += deltaLat; shift = 0; res = 0; do { byte = bytes[idx++] - 0x3F; res |= (byte & 0x1F) << shift; shift += 5; } while (byte >= 0x20); float deltaLon = ((res & 1) ? ~(res >> 1) : (res >> 1)); longitude += deltaLon; float finalLat = latitude * 1E-5; float finalLon = longitude * 1E-5; CLLocationCoordinate2D coord = CLLocationCoordinate2DMake(finalLat, finalLon); coords[coordIdx++] = coord; if (coordIdx == count) { NSUInteger newCount = count + 10; coords = realloc(coords, newCount * sizeof(CLLocationCoordinate2D)); count = newCount; } } MKPolyline *polyline = [MKPolyline polylineWithCoordinates:coords count:coordIdx]; free(coords); return polyline;}@end
