I'm developing an application that has the following goal:
Using the google maps android API 2 I get my current position, and as I start walking the application starts drawing the route I take
The twist is that the map is a "blind" map. Meaning the map is hidden, only the Marker of my current position and a dotted line of my route is shown.
Keep in mind I'm a novice developing to Android, so please be specific. (Thank you)
I managed to create the map, get my current position and zoom in to it (Had no sens to see the whole planet while i want only my current position). And it's pretty accurate so far.
The thing is I don't know what should I do from this point on.
Basicly I need a white View between the Marker and the real map. Also as I advance that View should always be on, over the MapFragment/MapView. Also I wish to keep the zoom and drag functionality's of the MapFragment.
How can I achieve this?
At this point I'm opened to any solutions.
(Been browsing for a few days now the developers site, I have seen that with the ViewOverlay class I can put messages over the map, but I'm not sure what would the correct aproach be in my case...)
To hide the whole map behind the white view I would use Polygon class Polygon Even if you specify Polygon to cover the whole map Markers will be still displayed in front of it and as so user's current position marker will be visible. You also will be able to zoom and drag.
To draw line on map use Polyline class Polyline It will draw users path as a polyline. If you want to stick with dotted line you can use Circle objects to create it. Circle
Related
I am building an application which uses Google Maps. When displaying the map, I'm also adding markers. Is there a way to see if there are 2 markers that touch each other, meaning if a part of a marker is on top of another marker? My goal is to be able to find that out and then make them a single bigger marker instead of 2 different markers.
The answer should depend somehow on the marker's icon size and the current map zoom since if I zoom out, there's a bigger chance they might overlap.
There seem to be a library made by Google which clusters a set of markers together automatically when they are close to one another.
The library is the marker clustering utility and instruction can be found here:
https://developers.google.com/maps/documentation/android-api/utility/marker-clustering
I have multiple markers set around on the map. What I want to know is how can I show only a few markers depending on the zoom level. For example: I have a zoom on the map with radius: the length between the center of the map and the bounds of the screen (lets say this is like 2km in real life not sure if this is true) so I want to show only the markers that are inside the radius. And of course if the user zooms out the radius will be recalculated again from the center point of the map to the bound of the screen. And again include markers that are inside the new radius. How can I achieve this?
I have thought about this problem and here could be an approach.
you can loop through your available markers and find distance from the center of your given circle (since we're talking about a radius) to the marker; this can be done using computeDistanceBetween(); for more info see link
If the marker lies within your radius, show, otherwise, hide using the setVisible() method. For more information, see link
Hope this gives you some idea.
I am developing an android application using Google maps with clustering of markers. The application works fine however once you zoom into a specific area and all the clusters expand to individual markers I would like to also show a small view that represents the entire map, where you are, and where all the markers are, to enable the user to navigate round the map while zoomed in. Ive Googled and searched SO, but not found anything. Is there any "off the shelf" solution? Or am I going to have to code this all myself? The type of solution I am looking for is the type of small window that many games use to show an overview of where the player is and all the points of interest are within the current level.
I haven't seen any "off the shelf" solutions, but here is what I would do here:
1) Create an additional fragment of the map. Place it in one of corners like games do
2) Here is where all the magic should happen. You need to synchronize these 2 maps. Map's Projection lets you to translate geo coordinates into XY coordinates within the view. That's being said you can get lat/lng of your top-left and bottom-right corners on the main map and translate these 2 corners into top-left and bottom-right XY coordinates of the mini-map's view. Now, when you have XY coordinates, the only thing you need to do - is to draw a rect on top of the mini map.
There is even easier and more native solution - since you have top-left and bottom-right lat/lng coordinates - you can draw a set of polylines on a minimap to get a rect. But in this case it will be hard to move it around (with your finger) in case you want to change current main map location using mini-map
I'm trying to write an Android app that will allow a user to search for a generic destination (e.g., "gas station") and be presented with up to ~5 nearby locations to choose from. The screen results would display the user location in the center, and possible destination options would be indicated by markers.
The trick is that I don't want to rescale the map from its starting scale, and so some of the possible destinations may not be visible on the screen. I want to dynamically draw a clickable direction indicator (such as an arrow) that emanates from the user location and points to any off-screen destination. If there are multiple off-screen destinations, I'd probably want to scale the arrow lengths to indicate relative distances. If the user clicks on the arrow, they should be "teleported" to the off-screen location.
Any thoughts on how to best implement this? The only information I've found on overlays uses static files (Most overlays seem to be just .PNG files for markers; one example had a route that was drawn from an XML file). I'd need to calculate the arrow based on direction
to the destination (direction the arrow points) and the relative distance to that location (arrow length), so the overlay is something I'd have to come up with at run time.
I think the main challenge is drawing the clickable arrows, but another question that comes to mind is, should I search using the Google Maps API, or is this job more suited to the Google Places API?
Thanks!
I guess we should put the teleportation on hold until the problem of a dynamically-drawn, clickable overlay is solved then!
A dynamically-drawn, clickable overlay is merely a subclass of Overlay. You will override one or both of the draw() methods to render your arrows using the Canvas 2D drawing API. You will override onTap() to be notified of taps on the map, to see if they tapped on an arrow. You add the overlay to the MapView via addOverlays().add().
Most overlays seem to be just .PNG files for markers
Those are usually ItemizedOverlay classes. That's much simpler to implement, particularly if you are one of those developers (like me) who is all thumbs when it comes to Canvas. However, you cannot achieve what you want with an ItemizedOverlay, in all likelihood.
I'd need to calculate the arrow based on direction to the destination (direction the arrow points) and the relative distance to that location (arrow length), so the overlay is something I'd have to come up with at run time.
Correct. You can use a Projection to help convert between pixel space and geo-space (latitude and longitude), if needed.
Note that this all assumes you are trying to use MapActivity and MapView. You are also welcome to use WebView or a plain browser to bring up your own JavaScript-based maps, if you prefer.
I have faced some problems with the Android MapView API. I get OverlayItems from a database which I want to display in a MapView. If I'm displaying 100 Icons, I have no issues, but if it gets more - like 500 Items in one City - it first looks really bad, while second it slows down a lot. Unfortunately my goal is to display 10000 of them. I think one solution can be to register a listener to ZoomLevels to make them appear/dissapear, but I couldn't find that functionality. Second, I couldn't find a function to scale my Overlays with the Zoom of the Map.
Any Ideas are very welcome
There is a very strange behavior in ItemizedOverlay draw method. When you say: Draw line from (x,y) to (x1,y1) the draw method is called about 20-30-40 times - i don't know why. It is acceptable when you draw one line, but when you draw a thousands of lines,icons and so on...it is very very bad! To solve this problem you should create a cached overlay. This is overlay that catches the first draw, creates the object and then prevents the future draws that do the same draw.
A cluster is a dozen of icons behind one icon. For example if you have 1000 markers on the map, in a specific minimal zoom level you can not see each marker separately - it becomes a mess of icons and colors and so on. And instead of 100 markers that are very very close one by one you place a cluster marker. And on zoom in remove this cluster and create another clusters...do this until the markers became far enough away and you can seen them divided.
Check this: Cluster markers
Take the following approaches:
Create a cached overlay to prevent multiple drawing of same clusters;
Draw in thread;
Cluster your markers depending on zoom level and marker proximity.
Each time you draw in the overlay, check for sure is the current marker inside of the visible part of the screen. If it is not, do no draw it!
I had a similar problem with the icon size and zoom level in my application. What I ended up doing was having 2 sets of overlays containing the markers, one with a "zoomed in" icon and one with a "zoomed out" icon. Then just changed the overlay at a certain zoom level (using a zoom poller - On zoom event for google maps on android)