Question

我有一个用于使用此代码找到用户位置的应用程序

public static Location getCurrentLocation(Context context) {
    LocationManager lm = (LocationManager) context.getSystemService(Context.LOCATION_SERVICE);
    Criteria c = new Criteria();
    String provider = lm.getBestProvider(c, true);
    Location location;
    if (provider == null) {
        location = new Location("gps");
        location.setLatitude(U.LATITUDE);
        location.setLongitude(U.LONGITUDE);
    } else {
        location = lm.getLastKnownLocation(provider);
        if (location == null) {
            location = new Location("gps");
            location.setLatitude(U.LATITUDE);
            location.setLongitude(U.LONGITUDE);
        }
    }
    return location;
}

此代码似乎仅在provider为null或location为null时返回行为。我的猜测是这段代码发生了一些变化。

String provider = lm.getBestProvider(c, true);

Answer 1

我有一些非常类似于你的代码，它在升级到Android 4.4后停止在我的设备上工作（即getBestProvider返回null，以前从未做过）。

我发现原因，当我看到另一个App显示NetworkProvider不可用时（尽管我与wifi和3G完美连接）并且它无法获得GPS信号（显然，因为我在室内）。然后我切换了Android的位置快速设置并弹出了一个对话框，要求我同意Android 4.4的新位置管理（参见https://support.google.com/nexus/answer/3467281）。之后，我的代码像以前一样工作。

Answer 2

这里拿我的代码来获取经度和纬度。这是整个项目。看一看。它工作得很好。但是你必须自己打开GPS，因为4.0以上版本无法以编程方式打开gps

使用我的代码获取位置。打开你的GPS和wifi之前： -

使用我的代码。我已经使用坐标成功找到了我当前的地址，但是你必须启用wifi和gps。首先在Android清单文件中添加所有这些权限

<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
<uses-permission android:name="android.permission.CHANGE_NETWORK_STATE" />
<uses-permission android:name="android.permission.ACCESS_WIFI_STATE" />
<uses-permission android:name="android.permission.CHANGE_WIFI_STATE" />
<uses-permission android:name="android.permission.WAKE_LOCK" />
<uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" />
<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />

<强> AndroidGPSTrackingActivity.java *

package com.example.gpstracking;

import java.io.IOException;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.util.List;
import java.util.Locale;

import android.app.Activity;
import android.content.Context;
import android.content.Intent;
import android.location.Address;
import android.location.Geocoder;
import android.location.LocationManager;
import android.net.ConnectivityManager;
import android.net.Uri;
import android.net.wifi.WifiManager;
import android.os.Bundle;
import android.view.View;
import android.webkit.WebView;
import android.widget.Button;
import android.widget.CompoundButton;
import android.widget.CompoundButton.OnCheckedChangeListener;
import android.widget.Toast;
import android.widget.ToggleButton;

public class AndroidGPSTrackingActivity extends Activity {

    Button btnShowLocation;

    // GPSTracker class
    GPSTracker gps;
    ToggleButton gpstoggle,wifitoggle,datatoggle;
    static WifiManager wifiManager;
    LocationManager lm;
    WebView web;
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);

        btnShowLocation = (Button) findViewById(R.id.btnShowLocation);

        gpstoggle = (ToggleButton) findViewById(R.id.gps);
        wifitoggle = (ToggleButton) findViewById(R.id.wifi);

        wifiManager = (WifiManager) this.getSystemService(Context.WIFI_SERVICE); 

        lm = (LocationManager) getSystemService(LOCATION_SERVICE);

        //gps toggle
        gpstoggle.setOnCheckedChangeListener(new OnCheckedChangeListener() {

            @Override
            public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
                if(isChecked){
                    final Intent poke = new Intent();
                    poke.setClassName("com.android.settings", "com.android.settings.widget.SettingsAppWidgetProvider"); 
                    poke.addCategory(Intent.CATEGORY_ALTERNATIVE);
                    poke.setData(Uri.parse("3")); 
                    getApplicationContext().sendBroadcast(poke);
                }
                else{
                    final Intent poke = new Intent();
                    poke.setClassName("com.android.settings", "com.android.settings.widget.SettingsAppWidgetProvider"); 
                    poke.addCategory(Intent.CATEGORY_ALTERNATIVE);
                    poke.setData(Uri.parse("3")); 
                    getApplicationContext().sendBroadcast(poke);
                }
            }
        });
        //wifi toggle
        wifitoggle.setOnCheckedChangeListener(new OnCheckedChangeListener() {

            @Override
            public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
                if(isChecked){
                    wifiManager.setWifiEnabled(true);
                }
                else{
                    wifiManager.setWifiEnabled(false);
                }
            }
        });

        //data toggle
        datatoggle.setOnCheckedChangeListener(new OnCheckedChangeListener() {

            @Override
            public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
                if(isChecked){
                    ConnectivityManager dataManager;
                    dataManager  = (ConnectivityManager)getSystemService(Context.CONNECTIVITY_SERVICE);
                    Method dataMtd = null;

                    try {
                        dataMtd = ConnectivityManager.class.getDeclaredMethod("setMobileDataEnabled", boolean.class);
                        dataMtd.setAccessible(true);
                        dataMtd.invoke(dataManager, true);

                    } catch (NoSuchMethodException e1) {
                        e1.printStackTrace();
                    }
                    catch (IllegalArgumentException e) {
                        e.printStackTrace();
                    } catch (IllegalAccessException e) {
                        e.printStackTrace();
                    } catch (InvocationTargetException e) {
                        e.printStackTrace();
                    }  
                    catch (SecurityException e) {
                        e.printStackTrace();
                    } 

                }
                else{
                    ConnectivityManager dataManager;
                    dataManager  = (ConnectivityManager)getSystemService(Context.CONNECTIVITY_SERVICE);
                    Method dataMtd = null;

                    try {
                        dataMtd = ConnectivityManager.class.getDeclaredMethod("setMobileDataEnabled", boolean.class);
                        dataMtd.setAccessible(false);
                        dataMtd.invoke(dataManager, false);


                    } catch (NoSuchMethodException e1) {
                        e1.printStackTrace();
                    }
                    catch (IllegalArgumentException e) {
                        e.printStackTrace();
                    } catch (IllegalAccessException e) {
                        e.printStackTrace();
                    } catch (InvocationTargetException e) {
                        e.printStackTrace();
                    }  
                    catch (SecurityException e) {
                        e.printStackTrace();
                    } 

                }
            }
        });

        // show location button click event
        btnShowLocation.setOnClickListener(new View.OnClickListener() {

            @Override
            public void onClick(View arg0) {        
                // create class object
                gps = new GPSTracker(AndroidGPSTrackingActivity.this);

                // check if GPS enabled     
                if(gps.canGetLocation()){

                    double latitude = gps.getLatitude();
                    double longitude = gps.getLongitude();

                    Geocoder gcd = new Geocoder(getApplicationContext(), Locale.getDefault());
                    List<Address> addresses = null;
                    try {
                        addresses = gcd.getFromLocation(latitude, longitude, 1);
                    } catch (IOException e) {
                        // TODO Auto-generated catch block
                        e.printStackTrace();
                    }
                    if(!(addresses == null)){
                        if (!addresses.isEmpty() ){
                            System.out.println(addresses.get(0).getLocality());

                            Address address = addresses.get(0);

                            String addressText = String.format("%s, %s, %s, %s, %s, %s",
                                    address.getAddressLine(0),
                                    address.getAddressLine(1),
                                    address.getAddressLine(2),
                                    address.getAddressLine(3),
                                    address.getPhone(),
                                    address.getPremises());

                            System.out.println(addressText);

                            // \n is for new line
                            Toast.makeText(getApplicationContext(), "Your Location is - \nLat: " + latitude + "\nLong: " + longitude, Toast.LENGTH_LONG).show();
                        }else{
                            // can't get location
                            // GPS or Network is not enabled
                            // Ask user to enable GPS/network in settings
                            gps.showSettingsAlert();
                        }
                    }else{
                        // can't get location
                        // GPS or Network is not enabled
                        // Ask user to enable GPS/network in settings
                        gps.showSettingsAlert();
                    }

                }

            }
        });
    }

}

<强> GPSTracker.java

package com.example.gpstracking;

import android.app.AlertDialog;
import android.app.Service;
import android.content.Context;
import android.content.DialogInterface;
import android.content.Intent;
import android.location.Location;
import android.location.LocationListener;
import android.location.LocationManager;
import android.net.ConnectivityManager;
import android.net.NetworkInfo;
import android.net.wifi.WifiManager;
import android.os.Bundle;
import android.os.IBinder;
import android.provider.Settings;
import android.util.Log;
import android.widget.Toast;

public class GPSTracker extends Service implements LocationListener {

    private final Context mContext;

    // flag for GPS status
    boolean isGPSEnabled = false;

    // flag for GPS status
    boolean canGetLocation = false;

    Location location; // location
    double latitude; // latitude
    double longitude; // longitude

    // The minimum distance to change Updates in meters
    private static final long MIN_DISTANCE_CHANGE_FOR_UPDATES = 10; // 10 meters

    // The minimum time between updates in milliseconds
    private static final long MIN_TIME_BW_UPDATES = 1000 * 60 * 1; // 1 minute

    // Declaring a Location Manager
    protected LocationManager locationManager;

    public GPSTracker(Context context) {
        this.mContext = context;
        getLocation();
    }

    public Location getLocation() {
        try {
            locationManager = (LocationManager) mContext.getSystemService(LOCATION_SERVICE);

            // getting GPS status
            isGPSEnabled = locationManager.isProviderEnabled(LocationManager.GPS_PROVIDER);

            // getting network status
            boolean wifiEnabled = AndroidGPSTrackingActivity.wifiManager.isWifiEnabled();

            ConnectivityManager cm = (ConnectivityManager) mContext.getSystemService(Context.CONNECTIVITY_SERVICE);
            NetworkInfo activeNetwork = cm.getActiveNetworkInfo();

            this.canGetLocation = true;

            // if DATA Enabled get lat/long using WIFI Services
            if (activeNetwork.isConnected()) {
                locationManager.requestLocationUpdates(
                        LocationManager.NETWORK_PROVIDER,
                        MIN_TIME_BW_UPDATES,
                        MIN_DISTANCE_CHANGE_FOR_UPDATES, this);
                Log.d("Network", "Network");
                if (locationManager != null) {
                    location = locationManager
                            .getLastKnownLocation(LocationManager.NETWORK_PROVIDER);

                }
            }
            // if WIFI Enabled get lat/long using WIFI Services
            if (wifiEnabled) {
                locationManager.requestLocationUpdates(
                        LocationManager.NETWORK_PROVIDER,
                        MIN_TIME_BW_UPDATES,
                        MIN_DISTANCE_CHANGE_FOR_UPDATES, this);
                Log.d("Network", "Network");
                if (locationManager != null) {
                    location = locationManager
                            .getLastKnownLocation(LocationManager.NETWORK_PROVIDER);

                }
            }
            // if GPS Enabled get lat/long using GPS Services
            if (isGPSEnabled) {
                if (location == null) {
                    locationManager.requestLocationUpdates(
                            LocationManager.GPS_PROVIDER,
                            MIN_TIME_BW_UPDATES,
                            MIN_DISTANCE_CHANGE_FOR_UPDATES, this);
                    Log.d("GPS Enabled", "GPS Enabled");
                    if (locationManager != null) {
                        location = locationManager
                                .getLastKnownLocation(LocationManager.GPS_PROVIDER);

                    }
                }
            }
            if (location != null) {
                latitude = location.getLatitude();
                longitude = location.getLongitude();
            }

        } catch (Exception e) {
            e.printStackTrace();
        }

        return location;
    }

    /**
     * Stop using GPS listener
     * Calling this function will stop using GPS in your app
     * */
    public void stopUsingGPS(){
        if(locationManager != null){
            locationManager.removeUpdates(GPSTracker.this);
        }       
    }

    /**
     * Function to get latitude
     * */
    public double getLatitude(){
        if(location != null){
            latitude = location.getLatitude();
        }

        // return latitude
        return latitude;
    }

    /**
     * Function to get longitude
     * */
    public double getLongitude(){
        if(location != null){
            longitude = location.getLongitude();
        }

        // return longitude
        return longitude;
    }

    /**
     * Function to check GPS/wifi enabled
     * @return boolean
     * */
    public boolean canGetLocation() {
        return this.canGetLocation;
    }

    /**
     * Function to show settings alert dialog
     * On pressing Settings button will lauch Settings Options
     * */
    public void showSettingsAlert(){
        AlertDialog.Builder alertDialog = new AlertDialog.Builder(mContext);

        // Setting Dialog Title
        alertDialog.setTitle("GPS is settings");

        // Setting Dialog Message
        alertDialog.setMessage("GPS is not enabled. Do you want to go to settings menu?");

        // On pressing Settings button
        alertDialog.setPositiveButton("Settings", new DialogInterface.OnClickListener() {
            public void onClick(DialogInterface dialog,int which) {
                Intent intent = new Intent(Settings.ACTION_LOCATION_SOURCE_SETTINGS);
                mContext.startActivity(intent);
            }
        });

        // on pressing cancel button
        alertDialog.setNegativeButton("Cancel", new DialogInterface.OnClickListener() {
            public void onClick(DialogInterface dialog, int which) {
                dialog.cancel();
            }
        });

        // Showing Alert Message
        alertDialog.show();
    }

    @Override
    public void onLocationChanged(Location location) {
    }

    @Override
    public void onProviderDisabled(String provider) {
    }

    @Override
    public void onProviderEnabled(String provider) {
    }

    @Override
    public void onStatusChanged(String provider, int status, Bundle extras) {
    }

    @Override
    public IBinder onBind(Intent arg0) {
        return null;
    }

}

<强> main.xml中

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:orientation="vertical" >

    <Button android:id="@+id/btnShowLocation" 
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Show Location"
        android:layout_centerVertical="true"
        android:layout_centerHorizontal="true"/>

    <ToggleButton
        android:id="@+id/gps"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_above="@+id/btnShowLocation"
        android:layout_alignRight="@+id/btnShowLocation"
        android:layout_marginBottom="49dp"
        android:layout_marginRight="72dp"
        android:text="GPS"
         />

    <ToggleButton
        android:id="@+id/wifi"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignBaseline="@+id/gps"
        android:layout_alignBottom="@+id/gps"
        android:layout_alignLeft="@+id/btnShowLocation"
        android:layout_marginLeft="79dp"
        android:text="WIFI" />

    <TextView
        android:id="@+id/textView1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_above="@+id/gps"
        android:layout_alignLeft="@+id/btnShowLocation"
        android:text="GPS"
        android:textSize="15sp" />

    <TextView
        android:id="@+id/textView2"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignBaseline="@+id/textView1"
        android:layout_alignBottom="@+id/textView1"
        android:layout_marginLeft="61dp"
        android:layout_toRightOf="@+id/textView1"
        android:text="WIFI"
        android:textSize="15sp" />

</RelativeLayout>

的AndroidManifest.xml

<?xml version="1.0" encoding="utf-8"?>

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

<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
<uses-permission android:name="android.permission.CHANGE_NETWORK_STATE" />
<uses-permission android:name="android.permission.ACCESS_WIFI_STATE" />
<uses-permission android:name="android.permission.CHANGE_WIFI_STATE" />
<uses-permission android:name="android.permission.WAKE_LOCK" />
<uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" />
<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />

<application
    android:icon="@drawable/ic_launcher"
    android:label="@string/app_name" >
    <activity
        android:name=".AndroidGPSTrackingActivity"
        android:label="@string/app_name" >
        <intent-filter>
            <action android:name="android.intent.action.MAIN" />

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

<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />
<uses-permission android:name="android.permission.INTERNET" />

</manifest>

Android GoogleMaps v1 LocationManager在4.4 kitkat上运行奇怪

2 个答案: