I have a Google Map with a bunch of markers.
I add markers to the map one-by-one and need to remove individual markers one-by-one too when required, using individual IDs.
Currently I have some horrible, verbose code, involving a global array of markers, an ID added as metadata to each marker, and a clunky method for looking up a marker's position within the array, as follows:
var markersArray = [];
function getPositionById(markerId, arr) {
for (var i = 0; i < arr.length; i++) {
if (arr[i].metadata.id === markerId) {
return i;
}
}
return null;
}
function removeMarker(markerId) {
var marker_position = getPositionById(markerId, markersArray);
if (marker_position !== null) {
markersArray[marker_position].setMap(null);
markersArray.splice(marker_position,1);
}
}
function setMarker(position, markerId) {
removeMarker(markerId);
var temp_marker = new google.maps.Marker({
position: position
});
temp_marker.setMap(map);
temp_marker.metadata = { id: markerId };
markersArray.push(temp_marker);
}
Could anyone suggest an even slightly more elegant way to do it?
Given that to remove a marker from the Map you need to use setMap(null), means that you need to have a reference to that marker.
The way you presented in your question doesn't look as horrible as you think, but another way to do it is to use a map instead of an array (not sure if map is the best term to use here since we are already working with the Google maps Map), nonetheless, using a map would rid you from the getPositionById() function, off course this assumes that all your markerIds are unique.
Your code would look something like this.
var markers = {};
function removeMarker(markerId) {
if(markers[markerId]){
markers[markerId].setMap(null);
delete markers[markerId];
}
}
function setMarker(position, markerId) {
removeMarker(markerId);
var temp_marker = new google.maps.Marker({
position: position
});
temp_marker.setMap(map);
temp_marker.metadata = { id: markerId };
markers[markerId] = temp_marker;
}
Related
I'm trying to create a straight line network in Leaflet, which at each junction has a marker, and on drag of each marker, update the position of the corresponding polyline which connects to it.
I've done some research (mostly this question) & reworked a fiddle to strip it down a bit to try & get it to do what I want. I am able to draw the network with individual polylines, however, I need to add multiple parentLines to the marker which is connected to two polylines. I can't find it in the Leaflet documentation, but punted with this:
marker_arr[1].parentLine = [polyline_a,polyline_b];
My issue is when I call the dragstart/drag/dragend handlers, it doesn't work with multiple polylines. (Edit) I have made some headway in capturing the parentLines as an array, but can only make it work for the first parentLine
function dragHandler(e) {
var polyline=[]
console.log("drag")
if(e.target.parentLine.length){
polyline.push(e.target.parentLine[0]);
} else {
polyline.push(e.target.parentLine);
}
if(polyline){
var latlngPoly = polyline[0].getLatLngs(), // Get the polyline's latlngs
latlngMarker = this.getLatLng(); // Get the marker's current latlng
latlngPoly.splice(this.polylineLatlng, 1, latlngMarker); // Replace the old latlng with the new
polyline[0].setLatLngs(latlngPoly); // Update the polyline with the new latlngs
}
}
Can anyone point me to either the documentation about parentLine, or how I might make this work? Using Leaflet v1.6.0 and cannot use more recent versions as this is to extend an already existing implementation of Leaflet based on 1.6.
Fiddle here
Here is a sample.
Add to the marker the parentLines always as array:
marker_arr[0].parentLine = [polyline_a];
marker_arr[1].parentLine = [polyline_a,polyline_b];
marker_arr[2].parentLine = [polyline_b];
and then loop through all parentLines in the dragstart handler:
// Now on dragstart you'll need to find the latlng from the polyline which corresponds
// with your marker's latlng and store it's key in your marker instance so you can use it later on:
function dragStartHandler(e) {
var marker = e.target;
marker.polylineLatlng = {};
e.target.parentLine.forEach((line)=>{
var latlngPoly = line.getLatLngs(), // Get the polyline's latlngs
latlngMarker = marker.getLatLng(); // Get the marker's current latlng
for (var i = 0; i < latlngPoly.length; i++) { // Iterate the polyline's latlngs
if (latlngMarker.equals(latlngPoly[i])) { // Compare marker's latlng ot the each polylines
marker.polylineLatlng[L.stamp(line)] = i; // If equals store key in marker instance
}
}
})
}
And in the drag handler:
// Now you know the key of the polyline's latlng you can change it
// when dragging the marker on the dragevent:
function dragHandler(e) {
var marker = e.target;
e.target.parentLine.forEach((line)=>{
var latlngPoly = line.getLatLngs(), // Get the polyline's latlngs
latlngMarker = marker.getLatLng(); // Get the marker's current latlng
latlngPoly.splice(marker.polylineLatlng[L.stamp(line)], 1, latlngMarker); // Replace the old latlng with the new
line.setLatLngs(latlngPoly); // Update the polyline with the new latlngs
})
}
And clean it in the dragend handler:
// Just to be clean and tidy remove the stored key on dragend:
function dragEndHandler(e) {
var marker = e.target;
delete marker.polylineLatlng;
console.log("end");
}
I currently have an app that creates an array of markers. But it is not useful, because I would like to see a group of markers and a custom property summed based on the distance between markers (depending on the zoom level).
I've said that maybe with MarkerClusterPlus I could accomplish something like this:
This even shows a custom icon, I don't need that, I only need the number over the cluster.
But I don't know where to start. Could someone place an example or a link?
You must define a custom property on the Marker object, so you can override the Calculator function in markercluster.js
MarkerClusterer.CALCULATOR = function (markers, numStyles) {
var index = 0;
var title = "";
var count = markers.length.toString();
var valueToSum=0;
for(var m=0;m<markers.length;m++){
//This is the custom property called MyValue
valueToSum+=Number(markers[m].MyValue);
}
var dv = val;
while (dv !== 0) {
dv = parseInt(dv / 10, 10); //you could define your own rules
index++;
}
index = Math.min(index, numStyles);
return {
text: valueToSum,
index: index,
title: title
};
};
Simply put, I am trying to dynamically create a marker and corresponding label for each property of in the loop. The label will contain the time-stamp.
However, I am fairly stuck on figuring out how to get the on-click function to remain bound to it's respective marker. The infowindow variable as well.
I have tried using a counter and creating an array of variables to reference each function. I have also tried eval and creating new variables within the global window
window["foo" + counter]
unsuccessfully. With all variations of this that I have tried the code has broken or resulted in all triggers/infowindows being bound to the same property.
Any help or direction would be greatly appreciated. I think I am just missing some depth on understanding variable/object scope. This base code results in all markers appearing and the final label (since the previous ones are overwritten) as depicted below.
variables:
prop = string representing long,lat coordinates
obj[prop] = An ISOformat timestamp
Rest of the code taken from marker Labels Google Maps API
for (var prop in obj) {
// skip loop if the property is from prototype
if(!obj.hasOwnProperty(prop)) continue;
var templocs = prop.split(",").map(Number);
console.log(templocs[0]);
var temppos = new google.maps.LatLng(templocs[0], templocs[1]);
var mark = new google.maps.Marker({
position:temppos,
map: map,
animation:google.maps.Animation.BOUNCE,
});
var infowindow = new google.maps.InfoWindow({
content: "date taken: " + obj[prop],
maxWidth: 200
});
mark.addListener('click', function() {
infowindow.open(map, mark);
});
}
var cnt = 0;
var infowindow = [];
var mark = [];
var bounds = new google.maps.LatLngBounds();
for (var prop in obj) {
// skip loop if the property is from prototype
if(!obj.hasOwnProperty(prop)) continue;
var templocs = prop.split(",").map(Number);
console.log(templocs[0]);
var temppos = new google.maps.LatLng(templocs[0], templocs[1]);
infowindow[cnt] = new google.maps.InfoWindow({
content: "date taken: " + obj[prop],
maxWidth: 200
});
mark[cnt] = new google.maps.Marker({
position: temppos,
map: map,
animation:google.maps.Animation.BOUNCE,
});
/* mark[cnt].addListener('click', function() {
infowindow[cnt].open(map, mark);
}); */
google.maps.event.addListener(mark[cnt], 'click', (function(markerrr, cnt) {
return function() {
infowindow[cnt].open(map, mark[cnt]);
}
})(mark[cnt], cnt));
bounds.extend(mark[cnt].getPosition());
cnt++;
}
Fixed. This post is a duplicate of this one
Issue had to do with closure.
Im currently working on a cross platform app that has a google map that has a whole bunch of icons on it. I use an Ajax query to get a kendo ui mobile datasource that has a list of lat/lng values and a category of the object.
From there when the user selects turn on that category, those markers appear on the map. This currently works however removing them is the issue.
When I go to remove them, I do not know how to delete all markers with a specific label. Is there a global array of markers that I can iterate through to find the appropriate markers to remove?
If there is I can simply set these particular markers map to null to remove them.
My code for adding markers is below:
var dataItem;
var facData = new kendo.data.DataSource({
........
});
facData.fetch(function() {
if (e.checked == 1) {
for (var i = 0;i < facData.view().length;i++) {
dataItem = facData.view()[i];
dataItemLatLng = new google.maps.LatLng(dataItem.lat, dataItem.lon);
createMarker(dataItemLatLng, "Toilets", toiletIcon);
}
}
else {
Code for removing all markers with label "Toilets"
}
})
}
In some outer scope :
var markers = [];
And your function that creates/removes markers :
function foo() {
var facData = new kendo.data.DataSource({
........
});
facData.fetch(function() {
if (e.checked == 1) {
for (var i = 0; i < facData.view().length; i++) {
var dataItem = facData.view()[i];
var dataItemLatLng = new google.maps.LatLng(dataItem.lat, dataItem.lon);
var marker = createMarker(dataItemLatLng, "Toilets", toiletIcon);
markers.push(marker);
}
}
else {
while(markers.length) {
markers.pop().setMap(null);
}
}
});
}
You need to ensure that createMarker() returns the created marker.
As written, the markers array is emptied as the markers are removed from the map. This seems sensible, otherwise, next time round the array would still contain references to the old markers plus references to all the new ones - much of the time, this would mean duplicate markers created from the same data as last time ... and so on, and so on.
I created a global array that each marker, when added is pushed into. Then the remove code is simply:
for(var i=0; i< markerArray.length;i++){
if(markerArray[i].getTitle()=="Toilets"){
markerArray[i].setMap(null);
}
}
I'm trying to add markers to a google maps by iterating through a list and retrieving some information. I'm using the prototype library. The code is the following:
var point = new Array();
var myMarkerOptions = new Array();
var marker = new Array();
recommendedList.each(function(item){
point[item.location.ID] = new google.maps.LatLng(item.location.lat, item.location.lng);
myMarkerOptions[item.location.ID] = {
position: point[item.location.ID],
map: map
};
marker[item.location.ID] = new google.maps.Marker(myMarkerOption[item.location.ID]);
});
where the recommendedList is a JSON response of the form:
[
{"artist":"artist1","location":{"lat":"50.952226","lng":"5.34832","ID":28}},
{"artist":"artist2","location":{"lat":"52.362287","lng":"4.883965","ID":32}},
...
]
However, this is not working.
I know that the problem is not about the JSON or the google map, because I tried a simpler version with the following code and it worked:
var myLatlng = new google.maps.LatLng(recommendedList[0].location.lat,recommendedList[0].location.lng);
var marker = new google.maps.Marker({
position: myLatlng,
map: map
});
So the problem must be in the iteration and the hash maps.
Anyone can see the problem? Thanks!
Simple enough to test without the .each
for (var i=0, item; item = recommendedList[i]; i++) {
point[item.location.ID] = new google.maps.LatLng(item.location.lat, item.location.lng);
myMarkerOptions[item.location.ID] = {
position: point[item.location.ID],
map: map
};
marker[item.location.ID] = new google.maps.Marker(myMarkerOption[item.location.ID]);
}
You can also simplify this quite a lot, unless you "need" those other arrays:
for (var i=0, item; item = recommendedList[i]; i++) {
marker[item.location.ID] = new google.maps.Marker({
new google.maps.LatLng(item.location.lat, item.location.lng),
map
});
}
I think it could be the array accessors you're using. What are you doing the point, myMarkerOptions and marker arrays once you're done with them?
Can you try declaring them as
var point = {};
var myMarkerOptions = {};
var marker = {};
That'll let you refer to them as point[item.location.ID] (etc). I think with the item.ID property being a number, JS is trying to set that numeric index of the array, rather than creating a new property in your hash.
Prototype each iterator doesn't support JSON or object data type.