本文介绍了使用Google地图SDK在地图上绘制错误多段线的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！
问题描述
我正在尝试使用Google地图SDK在我的地图上绘制路线。
是我调用的URL，我解析了对坐标数组的JSON响应：
id jsonResponse = [NSJSONSerialization JSONObjectWithData：responseObject options：NSJSONReadingMutableContainers error：nil];
int points_count = 0;
points_count = [[[[[[[jsonResponse objectForKey：@routes] objectAtIndex：0] objectForKey：@legs] objectAtIndex：0] objectForKey：@steps] count];
NSArray * steps = nil;
if（points_count&& [[[[jsonResponse objectForKey：@routes] objectAtIndex：0] objectForKey：@legs] count]）
{
steps = [[ [[[jsonResponse objectForKey：@routes] objectAtIndex：0] objectForKey：@legs] objectAtIndex：0] objectForKey：@steps];
}
NSMutableArray * coordinates = [[NSMutableArray alloc] initWithCapacity：points_count];
for（int i = 0; i< points_count; i ++）
{
NSDictionary * start;
NSDictionary *完成;
double st_lat = [[[[steps [objectAtIndex：i] objectForKey：@start_location] valueForKey：@lat] doubleValue];
double st_lon = [[[[steps [objectAtIndex：i] objectForKey：@start_location] valueForKey：@lng] doubleValue];
if（st_lat> 0.0f& st_lon> 0.0f）
{
start = @ {@latitude：[NSNumber numberWithDouble：st_lat]， @longitude：[NSNumber numberWithDouble：st_lon]};
}
double end_lat = [[[[steps [objectAtIndex：i] objectForKey：@end_location] valueForKey：@lat] doubleValue];
double end_lon = [[[[steps [objectAtIndex：i] objectForKey：@end_location] valueForKey：@lng] doubleValue];
if（end_lat> 0.0f&& end_lon> 0.0f）
{
finish = @ {@latitude：[NSNumber numberWithDouble：end_lat]， @longitude：[NSNumber numberWithDouble：end_lon]};
}
[坐标addObject：@ {@start：start，@finish：finish}];
}
比使用此方法绘制地图视图：
GMSMutablePath * path = [GMSMutablePath path];
for（NSDictionary * d in directions）
{
NSDictionary * start = d [@start];
NSDictionary * finish = d [@finish];
CLLocationCoordinate2D c_start = CLLocationCoordinate2DMake（[start [@latitude] doubleValue]，[start [@longitude] doubleValue]）;
CLLocationCoordinate2D c_finish = CLLocationCoordinate2DMake（[finish [@latitude] doubleValue]，[finish [@longitude] doubleValue]）;
[path addCoordinate：c_start];
[path addCoordinate：c_finish];
}
GMSPolyline * line = [GMSPolyline polylineWithPath：path];
line.strokeColor = [UIColor redColor];
line.strokeWidth = 2.0f;
line.map = self.mapView;
我在这里做错了什么？
解决方案
所以问题是我用 start_location 和 end_location 而不是 polyline - > points 。修正了我的代码：
请求URL例如： https://maps.googleapis.com/maps/api/directions/json？来源= 40.716072，-74.008836和目的地= 40.697545，-73.983892& sensor = false& waypoints = optimize：true& mode = driving
id jsonResponse = [NSJSONSerialization JSONObjectWithData：responseObject options：NSJSONReadingMutableContainers error：nil];
int points_count = 0;
points_count = [[[[[[[jsonResponse objectForKey：@routes] objectAtIndex：0] objectForKey：@legs] objectAtIndex：0] objectForKey：@steps] count];
NSArray * steps = nil;
if（points_count&& [[[[jsonResponse objectForKey：@routes] objectAtIndex：0] objectForKey：@legs] count]）
{
steps = [[ [[[jsonResponse objectForKey：@routes] objectAtIndex：0] objectForKey：@legs] objectAtIndex：0] objectForKey：@steps];
}
NSMutableArray * coordinates = [[NSMutableArray alloc] initWithCapacity：points_count];
for（int i = 0; i< points_count; i ++）
{
NSString * toDecode = [[[steps objectAtIndex：i] objectForKey：@polyline] valueForKey：@点];
NSArray * locations = [AppUtils decodePolylineWithString：toDecode];
for（int i = 0; i< locations.count; i ++）
{
if（i！= locations.count - 1）{
CLLocation * start = [locations objectAtIndex：i];
CLLocation * finish = [locations objectAtIndex：i + 1];
[坐标addObject：@ {@start：start，@finish：finish}];
}
}
}
GMSMutablePath * path = [GMSMutablePath path];
for（NSDictionary * d in directions）
{
CLLocation * start = d [@start];
CLLocation * finish = d [@finish];
[path addCoordinate：start.coordinate];
[path addCoordinate：finish.coordinate];
}
GMSPolyline * line = [GMSPolyline polylineWithPath：path];
line.strokeColor = [UIColor redColor];
line.strokeWidth = 2.0f;
line.map = self.mapView;
$ b +（NSArray *）decodePolylineWithString :( NSString *）encodedString
{
NSMutableArray * coordinates = [NSMutableArray array];
const char * bytes = [encodedString UTF8String];
NSUInteger length = [encodedString 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）<<转移;
shift + = 5;
} while（byte> = 0x20）; （res& 1）？〜（res>> 1）：（res>> 1））;
float deltaLat =
latitude + = deltaLat;
shift = 0;
res = 0;
do {
byte = bytes [idx ++] - 0x3F;
res | =（byte& 0x1F）<<转移;
shift + = 5;
} while（byte> = 0x20）; （res& 1）？〜（res>> 1）：（res>> 1））;
float deltaLon =
longitude + = deltaLon;
float finalLat =纬度* 1E-5;
float finalLon = longitude * 1E-5;
CLLocationCoordinate2D coord = CLLocationCoordinate2DMake（finalLat，finalLon）;
coords [coordIdx ++] = coord;
CLLocation * location = [[CLLocation alloc] initWithLatitude：finalLat longitude：finalLon];
[coordinates addObject：location];
if（coordIdx == count）{
NSUInteger newCount = count + 10;
coords = realloc（coords，newCount * sizeof（CLLocationCoordinate2D））;
count = newCount;
}
}
free（coords）;
返回坐标;
}
我知道这有点肮脏，但这很有效，而且效果很好。
享受。
I'm trying to draw route on my map using Google Maps SDK.This is the URL that i'm calling and I parse the JSON response to array of coordinates:
id jsonResponse = [NSJSONSerialization JSONObjectWithData:responseObject options:NSJSONReadingMutableContainers error:nil];
int points_count = 0;
points_count = [[[[[[jsonResponse objectForKey:@"routes"] objectAtIndex:0] objectForKey:@"legs"] objectAtIndex:0] objectForKey:@"steps"] count];
NSArray *steps = nil;
if (points_count && [[[[jsonResponse objectForKey:@"routes"] objectAtIndex:0] objectForKey:@"legs"] count])
{
steps = [[[[[jsonResponse objectForKey:@"routes"] objectAtIndex:0] objectForKey:@"legs"] objectAtIndex:0] objectForKey:@"steps"];
}
NSMutableArray *coordinates = [[NSMutableArray alloc] initWithCapacity:points_count];
for (int i = 0; i < points_count; i++)
{
NSDictionary *start;
NSDictionary *finish;
double st_lat = [[[[steps objectAtIndex:i] objectForKey:@"start_location"] valueForKey:@"lat"] doubleValue];
double st_lon = [[[[steps objectAtIndex:i] objectForKey:@"start_location"] valueForKey:@"lng"] doubleValue];
if (st_lat > 0.0f && st_lon > 0.0f)
{
start = @{ @"latitude" : [NSNumber numberWithDouble:st_lat], @"longitude" : [NSNumber numberWithDouble:st_lon] };
}
double end_lat = [[[[steps objectAtIndex:i] objectForKey:@"end_location"] valueForKey:@"lat"] doubleValue];
double end_lon = [[[[steps objectAtIndex:i] objectForKey:@"end_location"] valueForKey:@"lng"] doubleValue];
if (end_lat > 0.0f && end_lon > 0.0f)
{
finish = @{ @"latitude" : [NSNumber numberWithDouble:end_lat], @"longitude" : [NSNumber numberWithDouble:end_lon] };
}
[coordinates addObject:@{ @"start" : start, @"finish" : finish }];
}
And than drawing on the map view with this method:
GMSMutablePath *path = [GMSMutablePath path];
for (NSDictionary *d in directions)
{
NSDictionary *start = d[@"start"];
NSDictionary *finish = d[@"finish"];
CLLocationCoordinate2D c_start = CLLocationCoordinate2DMake([start[@"latitude"] doubleValue], [start[@"longitude"] doubleValue]);
CLLocationCoordinate2D c_finish = CLLocationCoordinate2DMake([finish[@"latitude"] doubleValue], [finish[@"longitude"] doubleValue]);
[path addCoordinate:c_start];
[path addCoordinate:c_finish];
}
GMSPolyline *line = [GMSPolyline polylineWithPath:path];
line.strokeColor = [UIColor redColor];
line.strokeWidth = 2.0f;
line.map = self.mapView;
Why it is drawing like that and not going into the street it self?
What am I doing wrong here?
解决方案
So the problem was that I used the start_location and end_location instead of the polyline -> points. Fixed my code into this:
Request URL for example: https://maps.googleapis.com/maps/api/directions/json?origin=40.716072,-74.008836&destination=40.697545,-73.983892&sensor=false&waypoints=optimize:true&mode=driving
id jsonResponse = [NSJSONSerialization JSONObjectWithData:responseObject options:NSJSONReadingMutableContainers error:nil];
int points_count = 0;
points_count = [[[[[[jsonResponse objectForKey:@"routes"] objectAtIndex:0] objectForKey:@"legs"] objectAtIndex:0] objectForKey:@"steps"] count];
NSArray *steps = nil;
if (points_count && [[[[jsonResponse objectForKey:@"routes"] objectAtIndex:0] objectForKey:@"legs"] count])
{
steps = [[[[[jsonResponse objectForKey:@"routes"] objectAtIndex:0] objectForKey:@"legs"] objectAtIndex:0] objectForKey:@"steps"];
}
NSMutableArray *coordinates = [[NSMutableArray alloc] initWithCapacity:points_count];
for (int i = 0; i < points_count; i++)
{
NSString *toDecode = [[[steps objectAtIndex:i] objectForKey:@"polyline"] valueForKey:@"points"];
NSArray *locations = [AppUtils decodePolylineWithString:toDecode];
for (int i = 0 ; i < locations.count ; i++)
{
if (i != locations.count - 1) {
CLLocation *start = [locations objectAtIndex:i];
CLLocation *finish = [locations objectAtIndex:i + 1];
[coordinates addObject:@{ @"start" : start, @"finish" : finish }];
}
}
}
GMSMutablePath *path = [GMSMutablePath path];
for (NSDictionary *d in directions)
{
CLLocation *start = d[@"start"];
CLLocation *finish = d[@"finish"];
[path addCoordinate:start.coordinate];
[path addCoordinate:finish.coordinate];
}
GMSPolyline *line = [GMSPolyline polylineWithPath:path];
line.strokeColor = [UIColor redColor];
line.strokeWidth = 2.0f;
line.map = self.mapView;
+ (NSArray*)decodePolylineWithString:(NSString *)encodedString
{
NSMutableArray *coordinates = [NSMutableArray array];
const char *bytes = [encodedString UTF8String];
NSUInteger length = [encodedString 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;
CLLocation *location = [[CLLocation alloc] initWithLatitude:finalLat longitude:finalLon];
[coordinates addObject:location];
if (coordIdx == count) {
NSUInteger newCount = count + 10;
coords = realloc(coords, newCount * sizeof(CLLocationCoordinate2D));
count = newCount;
}
}
free(coords);
return coordinates;
}
I know it's a little bit dirty, but that's work and it works great.
Enjoy.
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