英文文章來源 http://www.jappit.com/blog/midmaps-google-maps-java-me-library/
中文文章來源 http://yarin.iteye.com/blog/519754
谷歌地圖api連接 http://www.jappit.com/j2me/midmaps/javadocs/
?
?
MidMaps: Google Maps Java ME library
-
MidMaps ?is a tiny? Google Maps ?library for Java ME applications .
With MidMaps you can integrate Google Maps into your J2ME applications in few, easy steps!
How to use it?
MidMaps ?is designed to be simple. You don’t need to deal with threads, connections or other boring stuff like that: all you have to do is to? create a map and display it on in your application .
Creating a simple map
To get a map object, you have to perform two steps:
-
First,?
instantiate a new?
GoogleMaps
?object
:
GoogleMaps gMaps = new GoogleMaps ( ) ; -
Then, create a new?
GoogleStaticMap
?instance by using the createMap() method:
GoogleStaticMap map = gMaps. createMap ( mapWidth, mapHeight, GoogleStaticMap. FORMAT_PNG ) ;
Once you have created a map, it is necessary to define its? handler . The handler has an important role:? it gets automatically called each time the map object is updated, or when an error occurs : this way, you can know when you need to repaint the map, or how to notify the user about what’s going on. The handler has to implement the GoogleStaticMapHandler ?interface , that defines? two methods :
public void GoogleStaticMapUpdated ( GoogleStaticMap map ) ; public void GoogleStaticMapUpdateError ( GoogleStaticMap map, int errorCode, String errorMessage ) ;The first one is called? when a map is updated , so that your MIDlet knows that it must be repainted. The second one gets called? when an error occurs ?(e.g.: when there is a network issue and the map image cannot be downloaded).
Once you’ve created your handler, you have to pass it to the GoogleStaticMap instance with the? setHandler() ?method:
map. setHandler ( mapHandler ) ;Now, how to actually load a map? First, it is necessary to? define a location for the map :
- create a? GoogleMapsCoordinates ?instance with the preferred? latitude and longitude ?values
- use the GoogleStaticMap? setCenter() ?method
map. setCenter ( new GoogleMapsCoordinates ( 41.8954656 , 12.4823243 ) ) ;and then, you have to? update() the map :
map. update ( ) ;After you’ve called update, the map image will be loaded and,? when finished (or when an error occurs) the GoogleStaticMapHandler will be called . If the map is correctly loaded, you can actually draw it by using its draw(Graphics g, int left, int top, int attach) ?method.
Complete example
Below you can see a? full example ?on how MidMaps can be used to? display a map on a Canvas .
import javax.microedition.lcdui.Canvas ; import javax.microedition.lcdui.Graphics ; ? import com.jappit.midmaps.googlemaps.GoogleMaps ; import com.jappit.midmaps.googlemaps.GoogleMapsCoordinates ; import com.jappit.midmaps.googlemaps.GoogleStaticMapHandler ; import com.jappit.midmaps.googlemaps.GoogleStaticMap ; ? public class GoogleMapsSimpleCanvas extends Canvas implements GoogleStaticMapHandler { GoogleMaps gMaps = null ; GoogleStaticMap map = null ; ? public GoogleMapsSimpleCanvas ( ) { gMaps = new GoogleMaps ( ) ; ? map = gMaps. createMap ( getWidth ( ) , getHeight ( ) , GoogleStaticMap. FORMAT_PNG ) ; ? map. setHandler ( this ) ; ? map. setCenter ( new GoogleMapsCoordinates ( 41.8954656 , 12.4823243 ) ) ; ? map. setZoom ( 15 ) ; ? map. update ( ) ; } ? protected void paint ( Graphics g ) { map. draw ( g, 0 , 0 , Graphics . TOP | Graphics . LEFT ) ; } public void GoogleStaticMapUpdateError ( GoogleStaticMap map, int errorCode, String errorMessage ) { System . out . println ( "map error: " + errorCode + ", " + errorMessage ) ; } public void GoogleStaticMapUpdated ( GoogleStaticMap map ) { repaint ( ) ; } }Markers
You can? add markers to a map ?by using the? GoogleMapsMarker ?class. You create a marker by specifying its location:
GoogleMapsMarker marker = new GoogleMapsMarker ( new GoogleMapsCoordinates ( 41.8954656 , 12.4823243 ) ) ;Optionally, you can? customize the marker ?by setting its? color, size and and label ?(must be a single character):
marker. setColor ( GoogleStaticMap. COLOR_GREEN ) ; marker. setColor ( GoogleMapsMarker. SIZE_TINY ) ; marker. setLabel ( 'P' ) ;Then, you? add the marker to your GoogleStaticMap instance ?with the addMarker() method:
map. addMarker ( marker ) ;Here’s an example of 2 different markers added to the previous map.
GoogleMapsMarker redMarker = new GoogleMapsMarker ( new GoogleMapsCoordinates ( 41.8954656 , 12.4823243 ) ) ; redMarker. setColor ( GoogleStaticMap. COLOR_RED ) ; redMarker. setSize ( GoogleMapsMarker. SIZE_MID ) ; ? GoogleMapsMarker blueMarker = new GoogleMapsMarker ( new GoogleMapsCoordinates ( 41.8964656 , 12.4843243 ) ) ; blueMarker. setColor ( GoogleStaticMap. COLOR_BLUE ) ; blueMarker. setSize ( GoogleMapsMarker. SIZE_SMALL ) ; blueMarker. setLabel ( 'R' ) ; ? map. addMarker ( redMarker ) ; map. addMarker ( blueMarker ) ;Paths
Paths can be easily defined by using the? GoogleMapsPath ?class. To create a new Path, just? istantiate a new GoogleMapsPath ?object:
GoogleMapsPath path = new GoogleMapsPath ( ) ;And then? add the path points ?with the addPoint() method:
path. addPoint ( new GoogleMapsCoordinates ( 41.8954656 , 12.4823243 ) ) ; path. addPoint ( new GoogleMapsCoordinates ( 41.8934656 , 12.4833243 ) ) ;Path? weight,? color and fill color can be customized ?with the following methods:
bluePath. setColor ( GoogleStaticMap. COLOR_BLUE ) ; bluePath. setWeight ( 5 ) ; bluePath. setFillColor ( GoogleStaticMap. COLOR_GREEN ) ;Below you can see an example of? 2 different paths ?added to the map defined above.
GoogleMapsPath path = new GoogleMapsPath ( ) ; path. addPoint ( new GoogleMapsCoordinates ( 41.8954656 , 12.4823243 ) ) ; path. addPoint ( new GoogleMapsCoordinates ( 41.8934656 , 12.4833243 ) ) ; path. addPoint ( new GoogleMapsCoordinates ( 41.8944656 , 12.4843243 ) ) ; path. setColor ( GoogleStaticMap. COLOR_RED ) ; path. setWeight ( 10 ) ; map. addPath ( path ) ; ? GoogleMapsPath bluePath = new GoogleMapsPath ( ) ; bluePath. addPoint ( new GoogleMapsCoordinates ( 41.8954656 , 12.4823243 ) ) ; bluePath. addPoint ( new GoogleMapsCoordinates ( 41.8964656 , 12.4813243 ) ) ; bluePath. addPoint ( new GoogleMapsCoordinates ( 41.8934656 , 12.4803243 ) ) ; bluePath. setColor ( GoogleStaticMap. COLOR_BLUE ) ; bluePath. setFillColor ( GoogleStaticMap. COLOR_GREEN ) ; bluePath. setWeight ( 5 ) ; map. addPath ( bluePath ) ;Geocoding
Geocoding requires a Google Maps API key , so you have to? get your own key ?to use this feature.
To start, you have to? instantiate a Google Maps object by using your own API key :
GoogleMaps gMaps = new GoogleMaps ( "<your_api_key>" ) ;Then, you have to get a? GoogleMapsGeocoder ?instance by using the createGeocoder() method:
GoogleMapsGeocoder geocoder = gMaps. createGeocoder ( ) ;Then, as done for the GoogleStaticMap objects, also the? GoogleMapsGeocoder ?objects require an handler to be defined. The? GoogleMapsGeocoderHandler ?interface defines 2 methods :
public void GoogleMapsGeocodeSuccess ( String address, GoogleMapsCoordinates coordinates, int accuracy ) ; public void GoogleMapsGeocodeError ( String address, int errorCode, String errorDescription ) ;These 2 methods are? called when a geocoding request successes or fails , respectively. Once you have implemented your GoogleMapsGeocoderHandler, you have to pass it to the GoogleMapsGeocoder instance created above:
geocoder. setHandler ( geocoderHandler ) ;Done this, all is ready to geocode an address: to do this, just call the? geocodeAddress() ?method:
geocoder. geocodeAddress ( "Rome, Italy" ) ;When the geocoding ends, your handler will be notified via the GoogleMapsGeocodeSuccess() method. A possible implementation of such method is visible below:
public void GoogleMapsGeocodeSuccess ( String address, GoogleMapsCoordinates coordinates, int accuracy ) { map. setCenter ( coordinates ) ; ? map. addMarker ( new GoogleMapsMarker ( coordinates ) ) ; ? map. setZoom ( GoogleMaps. getZoomForAccuracy ( accuracy ) ) ; ? map. update ( ) ; }Since the? geocoding operation returns an “accuracy” value , you can use this value to get a? default zoom value ?for your map. To do this, you can use the? GoogleMaps.getZoomForAccuracy() ?method, as shown above.
Below you can see the map generated by the previous code:
發表評論
-
First,?
instantiate a new?
GoogleMaps
?object
:
更多文章、技術交流、商務合作、聯系博主
微信掃碼或搜索：z360901061
微信掃一掃加我為好友
QQ號聯系： 360901061
您的支持是博主寫作最大的動力，如果您喜歡我的文章，感覺我的文章對您有幫助，請用微信掃描下面二維碼支持博主2元、5元、10元、20元等您想捐的金額吧，狠狠點擊下面給點支持吧，站長非常感激您！手機微信長按不能支付解決辦法：請將微信支付二維碼保存到相冊，切換到微信，然后點擊微信右上角掃一掃功能，選擇支付二維碼完成支付。
【本文對您有幫助就好】元
評論