Aclassforhandlinggeocodingandreversegeocoding.Geocodingistheprocessoftransformingastreetaddressorotherdescriptionofalocationintoa（latitude,longitude）coordinate.
Geocoder（Contextcontext,Localelocale）ConstructsaGeocoderwhoseresponseswillbelocalizedforthegivenLocale.
Geocoder（Contextcontext）ConstructsaGeocoderwhoseresponseswillbelocalizedforthedefaultsystemLocale.
getFromLocationName（StringlocationName,intmaxResults）Since:
APILevel1
ReturnsanarrayofAddressesthatareknowntodescribethenamedlocation,whichmaybeaplacename
suchas"Dalvik,Iceland",anaddresssuchas"1600AmphitheatreParkway,MountainView,CA",anairport
codesuchas"SFO",etc..Thereturnedaddresseswillbelocalizedforthelocaleprovidedtothisclass's
constructor.
Thequerywillblockandreturnedvalueswillbeobtainedbymeansofanetworklookup.Theresultsareabest
guessandarenotguaranteedtobemeaningfulorcorrect.Itmaybeusefultocallthismethodfromathread
separatefromyourprimaryUIthread.
Parameters
locationName
auser-supplieddescriptionofalocation
maxResults
maxnumberofresultstoreturn.Smallernumbers（1to5）arerecommended
Returns
alistofAddressobjects.Returnsnulloremptylistifnomatcheswerefoundorthereisnobackend
serviceavailable.
Throws
IllegalArgumentException
iflocationNameisnull
IOException
ifthenetworkisunavailableoranyotherI/Oproblemoccurs
说了半天还只是个定位，地图还没出来。
下面要用到com.google.android.maps包了
下面的代码我们让地图移到指定点
GeoPointp=newGeoPoint（（int）（latitude*1E6）,（int）（longitude*1E6））;
MapViewmapview=（MapView）findViewById（R.id.mv）;
MapControllermapContr=mapview.getController（）;
mapview.displayZoomControls（true）;//显示地图缩放的按钮
mapContr.animateTo（p）;//带动画移到p点
mapContr.setZoom（7）;
setZoom
publicintsetZoom（intzoomLevel）
Setsthezoomlevelofthemap.Thevaluewillbeclampedtobebetween1and21inclusive,though
notallareashavetilesathigherzoomlevels.Thisjustsetsthelevelofthezoomdirectly;fora
step-by-stepzoomwithfancyinterstitialanimations,usezoomIn（）orzoomOut（）.
Parameters:
zoomLevel-AtzoomLevel1,theequatoroftheearthis256pixelslong.Eachsuccessivezoom
levelismagnifiedbyafactorof2.
Returns:
thenewzoomlevel,between1and21inclusive.
在地图上指定一点给出经纬值
@Override
publicbooleanonTouchEvent（MotionEventev）{
intactionType=ev.getAction（）;
switch（actionType）{
caseMotionEvent.ACTION_UP:
Projectionprojection=mapview.getProjection（）;
GeoPointloc=projection.fromPixels（（int）arg0.getX（）,（int）arg0.getY（））;
StringlngStr=Double.toString（loc.getLongitudeE6（）/1E6）;
StringlatStr=Double.toString（loc.getLatitudeE6（）/1E6）;
}
returnfalse;
}
publicinterfaceProjection
AProjectionservestotranslatebetweenthecoordinatesystemofx/yon-screenpixelcoordinatesandthat
oflatitude/longitudepointsonthesurfaceoftheearth.YouobtainaProjectionfromMapView.getProjection（）.
如果需要我们还可以把经纬值转换成手机的屏幕坐标值PointscreenCoords=newPoint（）;//android.graphics.Point;GeoPointgeopoint=newGeoPoint（（int）（latitude*1E6）,（int）（longitude*1E6））;mapview.getProjection（）.toPixels（geopoint,screenCoords）;intx=screenCoords.x;inty=screenCoords.y;放大缩小地图主要就是用setZoom（intZoomLevel）函数,让ZoomLevel不停往上涨（或往下降）就可以了下面给出一个com.google.android.maps.Overlay的使用例子importcom.google.android.maps.GeoPoint;importcom.google.android.maps.MapActivity;importcom.google.android.maps.MapController;importcom.google.android.maps.MapView;importcom.google.android.maps.Overlay;importandroid.graphics.Bitmap;importandroid.graphics.BitmapFactory;importandroid.graphics.Canvas;importandroid.graphics.Point;importandroid.os.Bundle;importandroid.view.View;
publicclassMapsActivityextendsMapActivity{MapViewmapView;MapControllermc;GeoPointp;classMapOverlayextendscom.google.android.maps.Overlay{@Overridepublicbooleandraw（Canvascanvas,MapViewmapView,booleanshadow,longwhen）{super.draw（canvas,mapView,shadow）;//---translatetheGeoPointtoscreenpixels---PointscreenPts=newPoint（）;mapView.getProjection（）.toPixels（p,screenPts）;//---addthemarker---Bitmapbmp=BitmapFactory.decodeResource（getResources（）,R.drawable.pushpin）;canvas.drawBitmap（bmp,screenPts.x,screenPts.y-50,null）;returntrue;}}/**Calledwhentheactivityisfirstcreated.*/@OverridepublicvoidonCreate（BundlesavedInstanceState）{//...}@OverrideprotectedbooleanisRouteDisplayed（）{//TODOAuto-generatedmethodstubreturnfalse;}}publicvoiddraw（android.graphics.Canvascanvas,
MapViewmapView,
booleanshadow）
Drawtheoverlayoverthemap.Thiswillbecalledonallactiveoverlayswithshadow=true,tolaydown
theshadowlayer,andthenagainonalloverlayswithshadow=false.Bydefault,drawsnothing.
Parameters:
canvas-TheCanvasuponwhichtodraw.Notethatthismayalreadyhaveatransformationapplied,sobesure
toleaveitthewayyoufoundit.
mapView-theMapViewthatrequestedthedraw.UseMapView.getProjection（）toconvertbetween
on-screenpixelsandlatitude/longitudepairs.
shadow-Iftrue,drawtheshadowlayer.Iffalse,drawtheoverlaycontents.publicbooleand
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