Dynamic visual display of IOS map lines

Before you have encountered this problem, is to draw a distance between two points, and then display the line in the visual range, the following are some of the main code:

#pragma mark-Drive route Search-(void) Ongetdrivingrouteresult: (bmkroutesearch*) Searcher Result: (bmkdrivingrouteresult*)  Result ErrorCode: (Bmksearcherrorcode) error{if (Error = = Bmk_search_no_error) {//This handles normal results nsarray* array        = [Nsarray arraywitharray:_mapview.annotations];        [_mapview Removeannotations:array];        Array = [Nsarray arraywitharray:_mapview.overlays];        [_mapview Removeoverlays:array]; if (Error = = bmk_search_no_error) {bmkdrivingrouteline* plan = (bmkdrivingrouteline*) [Result.routes objectatin            DEX:0];            Calculates the number of road segments in the route scheme int size = [Plan.steps count];            int planpointcounts = 0;                for (int i = 0; i < size; i++) {bmkdrivingstep* transitstep = [Plan.steps objectatindex:i];                    if (i==0) {routeannotation* item = [[Routeannotation alloc]init];                    Item.coordinate = plan.starting.location;              Item.title = @ "starting point";      Item.type = 0; [_mapview Addannotation:item]; Add Start Callout}else if (i==size-1) {routeannotation* item = [[Routeannota                    tion Alloc]init];                    Item.coordinate = plan.terminal.location;                    Item.title = @ "End point";                    Item.type = 1; [_mapview Addannotation:item]; Add a start callout}//Add annotation node routeannotation* item = [[Routeannotation alloc]                INIT];                Item.coordinate = transitStep.entrace.location;                Item.title = transitstep.entraceinstruction;                Item.degree = transitstep.direction * 30;                Item.type = 4;                [_mapview Addannotation:item];                                Total number of locus points cumulative planpointcounts + = Transitstep.pointscount; -----------------------------------------------------------if (i==0) {                The initial value of the first sitting punctuation Minlat = plan.starting.location.latitude;                    Maxlat = Plan.starting.location.latitude;                    Minlon = Plan.starting.location.longitude;                Maxlon = Plan.starting.location.longitude; }else{//Contrast filters out minimum latitude, maximum latitude, minimum longitude, maximum longitude Minlat = min (Minlat, transitStep.entrace.location.la                    Titude);                    Maxlat = MAX (Maxlat, transitStep.entrace.location.latitude);                    Minlon = MIN (Minlon, transitStep.entrace.location.longitude);                Maxlon = MAX (Maxlon, transitStep.entrace.location.longitude);                        }                                //-----------------------------------------------------------            }                        [Self setvisibleregin];                    Add via point if (plan.waypoints) {for (bmkplannode* Tempnode in plan.waypoints) { routeannotation* itEM = [[Routeannotation alloc]init];                    item = [[Routeannotation alloc]init];                    Item.coordinate = tempnode.pt;                    Item.type = 5;                    Item.title = Tempnode.name;                [_mapview Addannotation:item];            }}//Locus point bmkmappoint * temppoints = new bmkmappoint[planpointcounts];            int i = 0;                for (int j = 0; J < size; J + +) {bmkdrivingstep* transitstep = [Plan.steps objectatindex:j];                int k=0;                    for (k=0;k<transitstep.pointscount;k++) {temppoints[i].x = transitstep.points[k].x;                    Temppoints[i].y = TRANSITSTEP.POINTS[K].Y;                i++; }}//Build Bmkpolyline bmkpolyline* polyLine by points = [Bmkpoly            Line Polylinewithpoints:temppoints count:planpointcounts]; [_mapview Addoverlay:polyLine];                                Add route overlay Delete []temppoints;    }} else {NSLog (@ "Sorry, no results found"); }}

-(void) setvisibleregin{    //center point    cllocationcoordinate2d Centcoor;    Centcoor.latitude = (cllocationdegrees) ((maxlat+minlat) * 0.5f);    Centcoor.longitude = (cllocationdegrees) ((maxlon+minlon) * 0.5f);    Bmkcoordinatespan span;    Calculates the span of a geographic location    Span.latitudedelta = Maxlat-minlat;    Span.longitudedelta = Maxlon-minlon;    The coordinates of the data are derived    bmkcoordinateregion region = Bmkcoordinateregionmake (Centcoor, span);        The coordinate range of the Baidu map is converted to the relative view of the location    cgrect fitrect = [_mapview convertregion:region torecttoview:_mapview];    Converts the location of the map view to the location of the map,    bmkmaprect fitmaprect = [_mapview convertrect:fitrect tomaprectfromview:_mapview];    Set the map visual range to the map location where the data resides    [_mapview setvisiblemaprect:fitmaprect animated:yes];}

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Dynamic visual display of IOS map lines