问题
I want to add multiple markers in my map, but I don't know the way.
At the moment, I'm using this, and it works correctly:
Marker m1 = googleMap.addMarker(new MarkerOptions()
.position(new LatLng(38.609556, -1.139637))
.anchor(0.5f, 0.5f)
.title("Title1")
.snippet("Snippet1")
.icon(BitmapDescriptorFactory.fromResource(R.drawable.logo1)));
Marker m2 = googleMap.addMarker(new MarkerOptions()
.position(new LatLng(40.4272414,-3.7020037))
.anchor(0.5f, 0.5f)
.title("Title2")
.snippet("Snippet2")
.icon(BitmapDescriptorFactory.fromResource(R.drawable.logo2)));
Marker m3 = googleMap.addMarker(new MarkerOptions()
.position(new LatLng(43.2568193,-2.9225534))
.anchor(0.5f, 0.5f)
.title("Title3")
.snippet("Snippet3")
.icon(BitmapDescriptorFactory.fromResource(R.drawable.logo3)));
But the problem comes when I want to add 300 markers in my map. And doing it one by one is very annoying.
Is there any way to read markers from array or anything?
Another question: could I read markers from external file, so I can add or update markers without touching app code?
回答1:
ArrayList<MarkerData> markersArray = new ArrayList<MarkerData>();
for(int i = 0 ; i < markersArray.size() ; i++) {
createMarker(markersArray.get(i).getLatitude(), markersArray.get(i).getLongitude(), markersArray.get(i).getTitle(), markersArray.get(i).getSnippet(), markersArray.get(i).getIconResID());
}
protected Marker createMarker(double latitude, double longitude, String title, String snippet, int iconResID) {
return googleMap.addMarker(new MarkerOptions()
.position(new LatLng(latitude, longitude))
.anchor(0.5f, 0.5f)
.title(title)
.snippet(snippet)
.icon(BitmapDescriptorFactory.fromResource(iconResID)));
}
回答2:
Use MarkerOptions
private GoogleMap googleMap;
private MarkerOptions options = new MarkerOptions();
private ArrayList<LatLng> latlngs = new ArrayList<>();
You can add to the list of latlngs by,
latlngs.add(new LatLng(12.334343, 33.43434)); //some latitude and logitude value
And then, use for loop to set them on the map.
for (LatLng point : latlngs) {
options.position(point);
options.title("someTitle");
options.snippet("someDesc");
googleMap.addMarker(options);
}
回答3:
So, if you get coordinates from txt file you could read them like this:
BufferedReader reader = null;
try {
reader = new BufferedReader(
new InputStreamReader(getAssets().open("filename.txt"), "UTF-8"));
// do reading, usually loop until end of file reading
String mLine = reader.readLine();
while (mLine != null) {
//process line
...
mLine = reader.readLine();
}
} catch (IOException e) {
//log the exception
} finally {
if (reader != null) {
try {
reader.close();
} catch (IOException e) {
//log the exception
}
}
}
if your txt file looks like this
23.45 43.23
23.41 43.65
.
.
.
Than you could modify string to LatLng objects:
String[] coord = mLine.split("\\r?\\n");
ArrayList<LatLng> coordinates = new ArrayList<LatLng>;
for(int i = 0; i < coord.lenght(); ++i){
String[] latlng = coord.split(" ");
coordinates.add(new LatLng(latlng[0], latlng[1]);
}
And than:
for(LatLng cor : coordinates){
map.addMarker(new MarkerOptions()
.position(cor.getLat(), cor.getLng())
.title("Hello"));
}
回答4:
It depends on the source of your data. The better way is to make your custom object to store data. For example:
public class MyMarkerData {
LatLng latLng;
String title;
Bitmap bitmap;
public LatLng getLatLng() {
return latLng;
}
public void setLatLng(LatLng latLng) {
this.latLng = latLng;
}
public String getTitle() {
return title;
}
public void setTitle(String title) {
this.title = title;
}
public Bitmap getBitmap() {
return bitmap;
}
public void setBitmap(Bitmap bitmap) {
this.bitmap = bitmap;
}
}
Then, you can write some method to convert data from your external file to list of your custom data objects (but I think it is out of scope of this question).
Then just pass this data to your marker-drawing method and loop through it. It's a good practice thought to save your markers in some arraylist or map(object, marker) too, then you can easily access it.
Something like that:
HashMap<Marker, MyMarkerData> mDataMap = new HashMap<>();
public void drawMarkers(ArrayList<MyMarkerData> data) {
Marker m;
for (MyMarkerData object: data) {
m = googleMap.addMarker(new MarkerOptions()
.position(object.getLatLng())
.title(object.getTitle())
.icon(BitmapDescriptorFactory.fromBitmap(object.getBitmap()));
mDataMap.put(m, object);
}
}
回答5:
Yes , you can use the ArrayList for storing all the marker in that list and after that use the for-loop for adding markers on map.
For example:
googleMap.clear();
Now get all the marker in the Markers
//seachModelsList is the list of all markers
Marker[] allMarkers = new Marker[seachModelsList.size()];
for (int i = 0; i < seachModelsList.size(); i++)
{
LatLng latLng = new LatLng(seachModelsList.get(i).getCoordinates()[1], seachModelsList.get(i)
.getCoordinates()[0]);
if (googleMap != null) {
googleMap.setOnMarkerClickListener(this);
allMarkers[i] = googleMap.addMarker(new MarkerOptions().position(latLng);
googleMap.animateCamera(CameraUpdateFactory.newLatLngZoom(latLng, 17.0f));
googleMap.moveCamera(CameraUpdateFactory.newLatLngZoom(latLng, 17));
}
}
回答6:
In Kotlin you can do as :-
Let you have list of markerData as markerList
val markerList = ArrayList<MarkerData>()
and then you can iterate list through forEach loop and add Marker in GoogleMap as :-
markerList.forEach{ markerData ->
googleMap.addMarker(MarkerOptions()
.position(LatLng(markerData.latitutde, markerData.longitude))
.anchor(0.5f, 0.5f)
.title(markerData.title)
.snippet(markerData.snippet)
.icon(BitmapDescriptorFactory.fromResource(markerData.iconResID)))
}
Suppose your MarkerData is :-
class MarkerData(val latitutde : Double, val longitude : Double, val title : String, val snippets: String, @DrawableRes val iconResID: Int)
And you are adding MarkerData as -:
MarkerData(
35.61049,
139.63007,
"Tokyo",
"hello Tokyo",
R.drawable.ic_icon_user_review
)
then you have to create a custom method for vector assets icon like this :-
private fun bitmapDescriptorFromVector(context: Context, vectorResId: Int): BitmapDescriptor? {
return ContextCompat.getDrawable(context, vectorResId)?.run {
setBounds(0, 0, intrinsicWidth, intrinsicHeight)
val bitmap = Bitmap.createBitmap(intrinsicWidth, intrinsicHeight, Bitmap.Config.ARGB_8888)
draw(Canvas(bitmap))
BitmapDescriptorFactory.fromBitmap(bitmap)
}
}
and then for Marker your method would be as :
markerList.forEach{ markerData ->
googleMap.addMarker(MarkerOptions()
.position(LatLng(markerData.latitutde, markerData.longitude))
.anchor(0.5f, 0.5f)
.title(markerData.title)
.snippet(markerData.snippet)
.icon(bitmapDescriptorFromVector(context!!, R.drawable.ic_icon_marker)))
}
来源：https://stackoverflow.com/questions/30569854/adding-multiple-markers-in-google-maps-api-v2-android