42.Android LocationManager

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LocationManager 介绍

LocationManager 提供了访问系统位置服务，这些服务允许应用程序能够获得定期更新设备的地理位置。

由于 LocationManager 属于一种系统服务类型，所以还是需要通过：Context.getSystemService(Context.LOCATION_SERVICE)

于此同时，还要在AndroidManifest.xml里配置如下权限：

• 精确位置权限
  <uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />
• 粗糙位置权限
  <uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" />

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LocationManager 获取

LocationManager locationManager = (LocationManager) this.getSystemService(Context.LOCATION_SERVICE);

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LocationListener 初始化

LocationListener locationListener = new LocationListener() {    @Override    public void onLocationChanged(Location location) {        /**         * 经度         * 纬度         * 海拔         */        Log.i(TAG, "Longitude:" + Double.toString(location.getLongitude()));        Log.i(TAG, "Latitude:" + Double.toString(location.getLatitude()));        Log.i(TAG, "getAltitude:" + Double.toString(location.getAltitude()));    }    @Override    public void onStatusChanged(String provider, int status, Bundle extras) {    }    @Override    public void onProviderEnabled(String provider) {    }    @Override    public void onProviderDisabled(String provider) {    }};

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LocationManager 添加监听

在LocationManager的源码中有这段：

    /**     * Name of the network location provider.     * <p>This provider determines location based on     * availability of cell tower and WiFi access points. Results are retrieved     * by means of a network lookup.     */    public static final String NETWORK_PROVIDER = "network";    /**     * Name of the GPS location provider.     *     * <p>This provider determines location using     * satellites. Depending on conditions, this provider may take a while to return     * a location fix. Requires the permission     * {@link android.Manifest.permission#ACCESS_FINE_LOCATION}.     *     * <p> The extras Bundle for the GPS location provider can contain the     * following key/value pairs:     * <ul>     * <li> satellites - the number of satellites used to derive the fix     * </ul>     */    public static final String GPS_PROVIDER = "gps";    /**     * A special location provider for receiving locations without actually initiating     * a location fix.     *     * <p>This provider can be used to passively receive location updates     * when other applications or services request them without actually requesting     * the locations yourself.  This provider will return locations generated by other     * providers.  You can query the {@link Location#getProvider()} method to determine     * the origin of the location update. Requires the permission     * {@link android.Manifest.permission#ACCESS_FINE_LOCATION}, although if the GPS is     * not enabled this provider might only return coarse fixes.     */    public static final String PASSIVE_PROVIDER = "passive";

有这三种Provider：

• NETWORK_PROVIDER

• GPS_PROVIDER

• PASSIVE_PROVIDER

LocationManager.requestLocationUpdates
public void requestLocationUpdates(String provider, long minTime, float minDistance, LocationListener listener)

provider：LocationManager的类型（上述的三种填写一个）
minTime：两次定位的最小时间间隔（最少多少秒更新一次）
minDistance：两次定位的最小距离（最少走多远就更新一次）
listener：LocationListener 实例

this.locationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER, 1000, 0, locationListener);

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LocationManager 取得所有Provider

LocationManager.getAllProviders
public List<String> getAllProviders()

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LocationManager 匹配合适Provider

这里要用到一个类 - Criteria。

/** * 获取以下条件下，最合适的provider */private void getBestProvider() {    Criteria criteria = new Criteria();    // 精度高    criteria.setAccuracy(Criteria.ACCURACY_FINE);    // 低消耗    criteria.setPowerRequirement(Criteria.POWER_LOW);    // 海拔    criteria.setAltitudeRequired(true);    // 速度    criteria.setSpeedRequired(true);    // 费用    criteria.setCostAllowed(false);    String provider = locationManager.getBestProvider(criteria, false); //false是指不管当前适配器是否可用    this.bestProviderTV.setText(provider);}

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LocationManager 测试代码

LocationManagerActivity

public class LocationManagerActivity extends AppCompatActivity {    private static final String TAG = "LocationManagerActivity";    private LocationManager locationManager;    private TextView longitudeTV;    private TextView latitudeTV;    private TextView altitudeTV;    private TextView providersTV;    private TextView bestProviderTV;    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        this.setContentView(R.layout.activity_location_manager);        this.initViews();        this.locationManager = (LocationManager) this.getSystemService(Context.LOCATION_SERVICE);        LocationListener locationListener = new LocationListener() {            @Override            public void onLocationChanged(Location location) {                /**                 * 经度                 * 纬度                 * 海拔                 */                Log.i(TAG, "Longitude:" + Double.toString(location.getLongitude()));                Log.i(TAG, "Latitude:" + Double.toString(location.getLatitude()));                Log.i(TAG, "getAltitude:" + Double.toString(location.getAltitude()));            }            @Override            public void onStatusChanged(String provider, int status, Bundle extras) {            }            @Override            public void onProviderEnabled(String provider) {            }            @Override            public void onProviderDisabled(String provider) {            }        };        this.locationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER, 1000, 0, locationListener);        Location location = locationManager.getLastKnownLocation(LocationManager.GPS_PROVIDER);        this.longitudeTV.setText(location.getLongitude() + "");        this.latitudeTV.setText(location.getLatitude() + "");        this.altitudeTV.setText(location.getAltitude() + "");        this.getProviders();        this.getBestProvider();    }    /**     * 获取全部的provider     */    private void getProviders() {        String providers = "";        for (String provider : this.locationManager.getAllProviders()) {            providers += provider + " ";        }        this.providersTV.setText(providers);    }    /**     * 获取以下条件下，最合适的provider     */    private void getBestProvider() {        Criteria criteria = new Criteria();        // 精度高        criteria.setAccuracy(Criteria.ACCURACY_FINE);        // 低消耗        criteria.setPowerRequirement(Criteria.POWER_LOW);        // 海拔        criteria.setAltitudeRequired(true);        // 速度        criteria.setSpeedRequired(true);        // 费用        criteria.setCostAllowed(false);        String provider = locationManager.getBestProvider(criteria, false); //false是指不管当前适配器是否可用        this.bestProviderTV.setText(provider);    }    private void initViews() {        this.longitudeTV = (TextView) this.findViewById(R.id.location_longitude_tv);        this.latitudeTV = (TextView) this.findViewById(R.id.location_latitude_tv);        this.altitudeTV = (TextView) this.findViewById(R.id.location_altitude_tv);        this.providersTV = (TextView) this.findViewById(R.id.location_providers_tv);        this.bestProviderTV = (TextView) this.findViewById(R.id.location_best_provider_tv);    }}