android - Android + Google Map API V2 +当前位置

我正在使用google map View 创建一个应用，并且我希望该应用检测用户的当前位置并在 map 上显示带有标记的纬度和经度，但是到目前为止，我所能做的就是显示google map和检测当前位置时未显示任何标记，也未显示任何文本以显示经纬度

直到现在我还没有添加标记，因为我不知道将其放置在代码中的什么位置以及这样做的最佳实践是什么

谁能帮我 ？？？
这是代码:

list 文件

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="in.wptrafficanalyzer.locationgooglemapv2demo"
    android:versionCode="1"
    android:versionName="1.0" >

    <uses-sdk
        android:minSdkVersion="8"
        android:targetSdkVersion="16" />

    <permission
        android:name="in.wptrafficanalyzer.LocationGoogleMapV2Demo.permission.MAPS_RECEIVE"
        android:protectionLevel="signature" />

    <uses-permission android:name="in.wptrafficanalyzer.LocationGoogleMapV2Demo.permission.MAPS_RECEIVE" />
    <uses-permission android:name="android.permission.INTERNET" />
    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
    <uses-permission android:name="com.google.android.providers.gsf.permission.READ_GSERVICES" />
    <uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" />
    <uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />

    <uses-feature
        android:glEsVersion="0x00020000"
        android:required="true" />

    <application
        android:allowBackup="true"
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name"
        android:theme="@style/AppTheme" >
        <activity
            android:name="in.wptrafficanalyzer.locationgooglemapv2demo.MainActivity"
            android:label="@string/app_name" >
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>

        <meta-data
            android:name="com.google.android.maps.v2.API_KEY"
            android:value="API KEY" />
    </application>

</manifest>

xml文件

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity" >

    <TextView
        android:id="@+id/tv_location"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content" />

    <fragment
        android:id="@+id/map"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        class="com.google.android.gms.maps.SupportMapFragment" />

</RelativeLayout>

Java文件

package in.wptrafficanalyzer.locationgooglemapv2demo;

import android.app.Dialog;
import android.location.Criteria;
import android.location.Location;
import android.location.LocationListener;
import android.location.LocationManager;
import android.os.Bundle;
import android.support.v4.app.FragmentActivity;
import android.view.Menu;
import android.widget.TextView;

import com.google.android.gms.common.ConnectionResult;
import com.google.android.gms.common.GooglePlayServicesUtil;
import com.google.android.gms.maps.CameraUpdateFactory;
import com.google.android.gms.maps.GoogleMap;
import com.google.android.gms.maps.SupportMapFragment;
import com.google.android.gms.maps.model.LatLng;

public class MainActivity extends FragmentActivity implements LocationListener {

    GoogleMap googleMap;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        // Getting Google Play availability status
        int status = GooglePlayServicesUtil.isGooglePlayServicesAvailable(getBaseContext());

        // Showing status
        if(status!=ConnectionResult.SUCCESS){ // Google Play Services are not available

            int requestCode = 10;
            Dialog dialog = GooglePlayServicesUtil.getErrorDialog(status, this, requestCode);
            dialog.show();

        }else { // Google Play Services are available

            // Getting reference to the SupportMapFragment of activity_main.xml
            SupportMapFragment fm = (SupportMapFragment) getSupportFragmentManager().findFragmentById(R.id.map);

            // Getting GoogleMap object from the fragment
            googleMap = fm.getMap();

            // Enabling MyLocation Layer of Google Map
            googleMap.setMyLocationEnabled(true);

            // Getting LocationManager object from System Service LOCATION_SERVICE
            LocationManager locationManager = (LocationManager) getSystemService(LOCATION_SERVICE);

            // Creating a criteria object to retrieve provider
            Criteria criteria = new Criteria();

            // Getting the name of the best provider
            String provider = locationManager.getBestProvider(criteria, true);

            // Getting Current Location
            Location location = locationManager.getLastKnownLocation(provider);

            if(location!=null){
                onLocationChanged(location);
            }
            locationManager.requestLocationUpdates(provider, 20000, 0, this);
        }
    }
    @Override
    public void onLocationChanged(Location location) {

        TextView tvLocation = (TextView) findViewById(R.id.tv_location);

        // Getting latitude of the current location
        double latitude = location.getLatitude();

        // Getting longitude of the current location
        double longitude = location.getLongitude();

        // Creating a LatLng object for the current location
        LatLng latLng = new LatLng(latitude, longitude);

        // Showing the current location in Google Map
        googleMap.moveCamera(CameraUpdateFactory.newLatLng(latLng));

        // Zoom in the Google Map
        googleMap.animateCamera(CameraUpdateFactory.zoomTo(15));

        // Setting latitude and longitude in the TextView tv_location
        tvLocation.setText("Latitude:" +  latitude  + ", Longitude:"+ longitude );

    }

    @Override
    public void onProviderDisabled(String provider) {
        // TODO Auto-generated method stub
    }

    @Override
    public void onProviderEnabled(String provider) {
        // TODO Auto-generated method stub
    }

    @Override
    public void onStatusChanged(String provider, int status, Bundle extras) {
        // TODO Auto-generated method stub
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.main, menu);
        return true;
    }
}

最佳答案

首先检查文档here，它很好地说明了获得用户排名的最佳策略。

就我个人而言，我通常会在 map 上以在获取的位置放置一个标记

Location lastKnownLocation = locationManager.getLastKnownLocation(locationProvider);

然后开始收听位置更新并移动标记。

这也取决于应用程序所需的精确位置，如果您不需要真正精确的位置，但是面积足够，则可以只使用lastKnownLocation。

您可以尝试这样的事情

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    // Getting Google Play availability status
    int status = GooglePlayServicesUtil.isGooglePlayServicesAvailable(getBaseContext());

    // Showing status
    if(status!=ConnectionResult.SUCCESS){ // Google Play Services are not available

        int requestCode = 10;
        Dialog dialog = GooglePlayServicesUtil.getErrorDialog(status, this, requestCode);
        dialog.show();

    }else { // Google Play Services are available

        // Getting reference to the SupportMapFragment of activity_main.xml
        SupportMapFragment fm = (SupportMapFragment) getSupportFragmentManager().findFragmentById(R.id.map);

        // Getting GoogleMap object from the fragment
        googleMap = fm.getMap();

        // Enabling MyLocation Layer of Google Map
        googleMap.setMyLocationEnabled(true);

        // Getting LocationManager object from System Service LOCATION_SERVICE
        LocationManager locationManager = (LocationManager) getSystemService(LOCATION_SERVICE);

        // Creating a criteria object to retrieve provider
        Criteria criteria = new Criteria();

        // Getting the name of the best provider
        String provider = locationManager.getBestProvider(criteria, true);

        // Getting Current Location
        Location location = locationManager.getLastKnownLocation(provider);

        LocationListener locationListener = new LocationListener() {
          void onLocationChanged(Location location) {
          // redraw the marker when get location update.
          drawMarker(location);
        }

        if(location!=null){
           //PLACE THE INITIAL MARKER
           drawMarker(location);
        }
        locationManager.requestLocationUpdates(provider, 20000, 0, locationListener);
    }
}

private void drawMarker(Location location){
    // Remove any existing markers on the map
    googleMap.clear();
    LatLng currentPosition = new LatLng(location.getLatitude(),location.getLongitude());
    googleMap.addMarker(new MarkerOptions()
    .position(currentPosition)
    .snippet("Lat:" + location.getLatitude() + "Lng:"+ location.getLongitude())
    .icon(BitmapDescriptorFactory.defaultMarker(BitmapDescriptorFactory.HUE_AZURE))
    .title("ME"));
}

另外，您不需要将Activity类添加到implements LocationListener，您只需定义一个监听器并像上面一样注册即可

P.S.我没有编辑器儿子，我的代码可能包含错字

希望这会有所帮助，欢呼