Android 基于微调器值更新贴图

我成功地做了一个展示附近地方的活动。现在，我必须根据微调器值检索贴图，如果没有从微调器中选择值，则显示默认的世界贴图。假设我在活动的操作栏中有一个微调器，它由各种城市名称组成，如果我从微调器中选择纽约，纽约地图将显示在地图屏幕区域中。如果可能的话，有人能告诉我怎么做吗？如果可能的话，告诉我如何展示该城市著名的旅游景点。我还没有找到任何有益的教程。任何帮助都将不胜感激

My NearbyPlacesActivity.java

public class NearbyPlacesActivity extends Activity implements LocationListener {

    //instance variables for Marker icon drawable resources
    private int userIcon, foodIcon, drinkIcon, shopIcon, otherIcon;

    //the map
    private GoogleMap theMap;

    //location manager
    private LocationManager locMan;

    //gps tracker and connnection detect to be included

    //user marker
    private Marker userMarker;

    //places of interest
    private Marker[] placeMarkers;
    //max
    private final int MAX_PLACES = 20;//most returned from google
    //marker options
    private MarkerOptions[] places;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_nearby_places);

        //get drawable IDs
        userIcon = R.drawable.yellow_point;
        foodIcon = R.drawable.red_point;
        drinkIcon = R.drawable.blue_point;
        shopIcon = R.drawable.green_point;
        otherIcon = R.drawable.purple_point;

        //find out if we already have it
        if(theMap==null){
            //get the map
            theMap = ((MapFragment)getFragmentManager().findFragmentById(R.id.the_map)).getMap();
            //check in case map/ Google Play services not available
            if(theMap!=null){
                //ok - proceed
                theMap.setMapType(GoogleMap.MAP_TYPE_NORMAL);
                //create marker array
                placeMarkers = new Marker[MAX_PLACES];

            }

        }
    }

    //location listener functions

    @Override
    public void onLocationChanged(Location location) {
        Log.v("MyMapActivity", "location changed");
        updatePlaces(location);
    }
    @Override
    public void onProviderDisabled(String provider){
        Log.v("MyMapActivity", "provider disabled");
    }
    @Override
    public void onProviderEnabled(String provider) {
        Log.v("MyMapActivity", "provider enabled");
    }
    @Override
    public void onStatusChanged(String provider, int status, Bundle extras) {
        Log.v("MyMapActivity", "status changed");
    }

    /*
     * update the place markers
     */
    private void updatePlaces(Location givenlocation){
        //get location manager
        double lat = givenlocation.getLatitude();
        double lng = givenlocation.getLongitude();
        //create LatLng
        LatLng lastLatLng = new LatLng(lat, lng);

        //remove any existing marker
        if(userMarker!=null) userMarker.remove();
        //create and set marker properties
        userMarker = theMap.addMarker(new MarkerOptions()
        .position(lastLatLng)
        .title("You are here")
        .icon(BitmapDescriptorFactory.fromResource(userIcon))
        .snippet("Your last recorded location"));
        //move to location
        theMap.animateCamera(CameraUpdateFactory.newLatLng(lastLatLng), 3000, null);

        //build places query string
        @SuppressWarnings("deprecation")
        String encodedstr = URLEncoder.encode("food|bar|movie_theater|museum|bank");
        String placesSearchStr = "https://maps.googleapis.com/maps/api/place/nearbysearch/" +
                "json?location="+lat+","+lng+
                "&radius=7000&sensor=true"+
                "&types="+encodedstr+
                "&key=AIzaSyBqDgqbxFenOtooTivY5YSsJ2JrwBK42hw";//ADD KEY

        //execute query
        new GetPlaces().execute(placesSearchStr);       
        locMan.requestLocationUpdates(LocationManager.NETWORK_PROVIDER, 30000, 100, this);
    }

    private class GetPlaces extends AsyncTask<String, Void, String> {
        @Override
        protected String doInBackground(String... placesURL) {
            //fetch places

            //build result as string
            StringBuilder placesBuilder = new StringBuilder();
            //process search parameter string(s)
            for (String placeSearchURL : placesURL) {
                HttpClient placesClient = new DefaultHttpClient();
                try {
                    //try to fetch the data

                    //HTTP Get receives URL string
                    HttpGet placesGet = new HttpGet(placeSearchURL);
                    //execute GET with Client - return response
                    HttpResponse placesResponse = placesClient.execute(placesGet);
                    //check response status
                    StatusLine placeSearchStatus = placesResponse.getStatusLine();
                    //only carry on if response is OK
                    if (placeSearchStatus.getStatusCode() == 200) {
                        //get response entity
                        HttpEntity placesEntity = placesResponse.getEntity();
                        //get input stream setup
                        InputStream placesContent = placesEntity.getContent();
                        //create reader
                        InputStreamReader placesInput = new InputStreamReader(placesContent);
                        //use buffered reader to process
                        BufferedReader placesReader = new BufferedReader(placesInput);
                        //read a line at a time, append to string builder
                        String lineIn;
                        while ((lineIn = placesReader.readLine()) != null) {
                            placesBuilder.append(lineIn);
                        }
                    }
                }
                catch(Exception e){ 
                    e.printStackTrace(); 
                }
            }
            return placesBuilder.toString();
        }
        //process data retrieved from doInBackground
        protected void onPostExecute(String result) {
            //parse place data returned from Google Places
            //remove existing markers
            if(placeMarkers!=null){
                for(int pm=0; pm<placeMarkers.length; pm++){
                    if(placeMarkers[pm]!=null)
                        placeMarkers[pm].remove();
                }
            }
            try {
                //parse JSON

                //create JSONObject, pass stinrg returned from doInBackground
                JSONObject resultObject = new JSONObject(result);
                //get "results" array
                JSONArray placesArray = resultObject.getJSONArray("results");
                //marker options for each place returned
                places = new MarkerOptions[placesArray.length()];
                //loop through places
                for (int p=0; p<placesArray.length(); p++) {
                    //parse each place
                    //if any values are missing we won't show the marker
                    boolean missingValue=false;
                    LatLng placeLL=null;
                    String placeName="";
                    String vicinity="";
                    int currIcon = otherIcon;
                    try{
                        //attempt to retrieve place data values
                        missingValue=false;
                        //get place at this index
                        JSONObject placeObject = placesArray.getJSONObject(p);
                        //get location section
                        JSONObject loc = placeObject.getJSONObject("geometry")
                                .getJSONObject("location");
                        //read lat lng
                        placeLL = new LatLng(Double.valueOf(loc.getString("lat")), 
                                Double.valueOf(loc.getString("lng")));  
                        //get types
                        JSONArray types = placeObject.getJSONArray("types");
                        //loop through types
                        for(int t=0; t<types.length(); t++){
                            //what type is it
                            String thisType=types.get(t).toString();
                            //check for particular types - set icons
                            if(thisType.contains("food")){
                                currIcon = foodIcon;
                                break;
                            }
                            else if(thisType.contains("bar")){
                                currIcon = drinkIcon;
                                break;
                            }
                            else if(thisType.contains("movie_theater")){
                                currIcon = shopIcon;
                                break;
                            }
                        }
                        //vicinity
                        vicinity = placeObject.getString("vicinity");
                        //name
                        placeName = placeObject.getString("name");
                    }
                    catch(JSONException jse){
                        Log.v("PLACES", "missing value");
                        missingValue=true;
                        jse.printStackTrace();
                    }
                    //if values missing we don't display
                    if(missingValue)    places[p]=null;
                    else
                        places[p]=new MarkerOptions()
                    .position(placeLL)
                    .title(placeName)
                    .icon(BitmapDescriptorFactory.fromResource(currIcon))
                    .snippet(vicinity);
                }
            }
            catch (Exception e) {
                e.printStackTrace();
            }
            if(places!=null && placeMarkers!=null){
                for(int p=0; p<places.length && p<placeMarkers.length; p++){
                    //will be null if a value was missing
                    if(places[p]!=null)
                        placeMarkers[p]=theMap.addMarker(places[p]);

            }

        }
    }   
}
    @Override
    protected void onResume() {
        super.onResume();
        if(theMap!=null){
            //get location manager
        locMan = (LocationManager)getSystemService(Context.LOCATION_SERVICE);
        //get last location
        Location lastLoc = locMan.getLastKnownLocation(LocationManager.NETWORK_PROVIDER);
        locMan.requestLocationUpdates(LocationManager.NETWORK_PROVIDER, 30000, 100, this);
        updatePlaces(lastLoc);
        }
    }

    @Override
    protected void onPause() {
        super.onPause();
        if(theMap!=null){
            locMan.removeUpdates(this);
        }
    }
}

公共类nearbyplaceActivity扩展活动实现LocationListener{
//标记图标可绘制资源的实例变量
私有int userIcon、foodIcon、drinkIcon、shopIcon、otherIcon；
//地图
私人谷歌地图；
//位置管理器
私人场所经理洛克曼；
//包括gps跟踪器和连接检测
//用户标记
专用标记用户标记；
//名胜古迹
专用标记[]位置标记；
//马克斯
private final int MAX_PLACES=20；//大部分从google返回
//标记选项
私人市场选择[]个地点；
@凌驾
创建时受保护的void（Bundle savedInstanceState）{
super.onCreate（savedInstanceState）；
setContentView（R.layout.activity\u附近的位置）；
//获取可提取ID
userIcon=R.drawable.yellow\u点；
foodIcon=R.可绘制的红色点；
drinkIcon=R.可绘制.蓝色\u点；
shopIcon=R.drawable.green\u point；
otherIcon=R.drawable.purple_点；
//看看我们是否已经有了它
if（theMap==null）{
//去拿地图
theMap=（（MapFragment）getFragmentManager（）.findFragmentById（R.id.the_map））.getMap（）；
//签入案例地图/谷歌播放服务不可用
如果（theMap！=null）{
//好-继续
setMapType（GoogleMap.MAP\u TYPE\u NORMAL）；
//创建标记数组
placeMarkers=新标记[最大位置]；
}
}
}
//位置侦听器函数
@凌驾
已更改位置上的公共无效（位置）{
Log.v（“MyMapActivity”，“位置更改”）；
更新位置（位置）；
}
@凌驾
公共无效onProviderDisabled（字符串提供程序）{
Log.v（“MyMapActivity”、“提供程序已禁用”）；
}
@凌驾
公共无效onProviderEnabled（字符串提供程序）{
Log.v（“MyMapActivity”，“已启用提供程序”）；
}
@凌驾
public void onStatusChanged（字符串提供程序、int状态、Bundle extra）{
Log.v（“MyMapActivity”，“状态更改”）；
}
/*
*更新位置标记
*/
私有void updatePlaces（位置给定位置）{
//获取位置管理器
双lat=givenlocation.getLatitude（）；
double lng=givenlocation.getLongitude（）；
//创建板条
LatLng lastLatLng=新LatLng（lat，lng）；
//删除任何现有标记
如果（userMarker！=null）userMarker.remove（）；
//创建和设置标记属性
userMarker=theMap.addMarker（新标记选项（）
.位置（最后一个）
.title（“您在这里”）
.icon（BitmapDescriptorFactory.fromResource（userIcon））
.snippet（“您上次录制的位置”）；
//移动到位置
theMap.animateCamera（CameraUpdateFactory.newLatLng（lastLatLng），3000，空）；
//生成位置查询字符串
@抑制警告（“弃用”）
String encodedstr=URLEncoder.encode（“食品|酒吧|电影院|博物馆|银行”）；
字符串placesSearchStr=”https://maps.googleapis.com/maps/api/place/nearbysearch/" +
“json”位置=“+lat+”，“+lng+
“&radius=7000&sensor=true”+
“&types=“+编码器”+
“&key=aizasybqdgqbxfenototivity5yssj2jrwbk42hw”；//添加密钥
//执行查询
新建GetPlaces（）.execute（placesSearchStr）；
locMan.requestLocationUpdates（LocationManager.NETWORK_PROVIDER，30000100，this）；
}
私有类GetPlaces扩展异步任务{
@凌驾
受保护的字符串背景（字符串…placesURL）{
//找地方
//将结果生成为字符串
StringBuilder placesBuilder=新StringBuilder（）；
//进程搜索参数字符串
for（字符串placeSearchURL:placesURL）{
HttpClient placesClient=new DefaultHttpClient（）；
试一试{
//尝试获取数据
//HTTP Get接收URL字符串
HttpGet placesGet=新的HttpGet（placeSearchURL）；
//使用客户端返回响应执行GET
HttpResponse placesResponse=placesClient.execute（placesGet）；
//检查响应状态
StatusLine placeSearchStatus=placesResponse.getStatusLine（）；
//只有在响应正常时才能继续
if（placeSearchStatus.getStatusCode（）==200）{
//获取响应实体
HttpEntity placesEntity=placesResponse.getEntity（）；
//获取输入流设置
InputStream placesContent=placesEntity.getContent（）；
//创建阅读器
InputStreamReader placesInput=新的InputStreamReader（placesContent）；
//使用缓冲读取器来处理
BufferedReader placesReader=新的BufferedReader（placesInput）；
//一次读取一行，附加到字符串生成器
弦线；
而（（lineIn=placesReader.readLine（））！=null）{
placesBuilder.append（lineIn）；
yourpinner.setOnItemClickListener(new OnItemClickListener() {

        @Override
        public void onItemClick(AdapterView<?> arg0, View arg1, int arg2,
                long arg3) {
            // TODO Auto-generated method stub

        }
    });