概念介绍：
Provder相关：
- GPS_PROVIDER：基于GNSS信号的位置信息。
- NETWORK_PROVIDER：基于第三方位置供应商的位置信息。
- PASSIVE_PROVIDER：被动定位位置信息。
- FUSED_PROVIDER: 混合定位位置信息。
LocationRequest:
| 属性 | 说明 |
|---|---|
| mProvider | 见Provider说明 |
| mQuality | 电池相关，有POWER_NONE（不主动定位），POWER_LOW（默认值，能耗低的定位模式），POWER_HIGH（允许高能耗的定位模式） |
| mInterval | 定位间隔，默认值60分钟 |
| mSmallestDisplacement | 最小位移（米） |
| mExpireAt | request过期时间 |
| mNumUpdates | 更新次数，默认值为IntMAX，相当于一直更新 |
| mHideFromAppOps | 是否从（权限）管理隐藏 |
| mWorkSource | 维护了一些调用者信息 |
Location: 返回的location对象
| 属性 | 说明 |
|---|---|
| mProvider | 见Provider说明 |
| mTime | 数据unix时间 |
| mElapsedRealtimeNanos | 数据Elapsed时间 |
| mLatitude | 纬度 |
| mLongitude | 经度 |
| mAltitude | 高度 |
| mSpeed | 速度，米/秒 |
| mBearing | 以度为单位获取方位角 |
| mHorizontalAccuracyMeters | 水平方向精度（米） |
| mVerticalAccuracyMeters | 垂直方向精度（米） |
| mSpeedAccuracyMetersPerSecond | 速度(米/秒)精度 |
| mBearingAccuracyDegrees | 方位角精度 |
| mExtras | 额外数据 |
LocationManager开启位置监听方法：
- requestLocationUpdates
源码部分：
LocationManager通过ILocationManager.aild调用到LocationManagerService类：
@Override
public void requestLocationUpdates(LocationRequest request, ILocationListener listener,
PendingIntent intent, String packageName) {
synchronized (mLock) {
...//一堆检测
try {
...
Receiver receiver;
if (intent != null) {
receiver = getReceiverLocked(intent, pid, uid, packageName, workSource,
hideFromAppOps);
} else {
receiver = getReceiverLocked(listener, pid, uid, packageName, workSource,
hideFromAppOps);
}
requestLocationUpdatesLocked(sanitizedRequest, receiver, uid, packageName);
} finally {
Binder.restoreCallingIdentity(identity);
}
}
}
对LocationRequest 里的值做了一系列判断与初始化
根据两种接收返回数据方式：intent和listener，生成内部receiver
继续走requestLocationUpdatesLocked
@GuardedBy("mLock")
private void requestLocationUpdatesLocked(LocationRequest request, Receiver receiver,
int uid, String packageName) {
...//一系列判断
LocationProvider provider = getLocationProviderLocked(name);
if (provider == null) {
throw new IllegalArgumentException("provider doesn't exist: " + name);
}
UpdateRecord record = new UpdateRecord(name, request, receiver);
...
UpdateRecord oldRecord = receiver.mUpdateRecords.put(name, record);
if (oldRecord != null) {
oldRecord.disposeLocked(false);
}
...
applyRequirementsLocked(name);
receiver.updateMonitoring(true);
}
生成一个UpdateRecord，并放在receiver对象中
applyRequirementsLocked最终走的是·applyRequirementsLocked·方法：
@GuardedBy("mLock")
private void applyRequirementsLocked(LocationProvider provider) {
...
provider.setRequestLocked(providerRequest, worksource);
}
最终是调用的provider的setReques方法
所以重点还是研究provider
回到LocationManagerService的init方法，发现会调用initializeProvidersLocked(),这里就是初始化所有provider的地方：
@GuardedBy("mLock")
private void initializeProvidersLocked() {
// create a passive location provider, which is always enabled
LocationProvider passiveProviderManager = new LocationProvider(PASSIVE_PROVIDER);
addProviderLocked(passiveProviderManager);
mPassiveProvider = new PassiveProvider(mContext, passiveProviderManager);
passiveProviderManager.attachLocked(mPassiveProvider);
if (GnssLocationProvider.isSupported()) {
// Create a gps location provider
LocationProvider gnssProviderManager = new LocationProvider(GPS_PROVIDER, true);
mRealProviders.add(gnssProviderManager);
addProviderLocked(gnssProviderManager);
GnssLocationProvider gnssProvider = new GnssLocationProvider(mContext,
gnssProviderManager,
mHandler.getLooper());
gnssProviderManager.attachLocked(gnssProvider);
...
}
...
// bind to network provider
LocationProvider networkProviderManager = new LocationProvider(NETWORK_PROVIDER, true);
LocationProviderProxy networkProvider = LocationProviderProxy.createAndBind(
mContext,
networkProviderManager,
NETWORK_LOCATION_SERVICE_ACTION,
com.android.internal.R.bool.config_enableNetworkLocationOverlay,
com.android.internal.R.string.config_networkLocationProviderPackageName,
com.android.internal.R.array.config_locationProviderPackageNames);
if (networkProvider != null) {
mRealProviders.add(networkProviderManager);
addProviderLocked(networkProviderManager);
networkProviderManager.attachLocked(networkProvider);
} else {
Slog.w(TAG, "no network location provider found");
}
// bind to fused provider
LocationProvider fusedProviderManager = new LocationProvider(FUSED_PROVIDER);
LocationProviderProxy fusedProvider = LocationProviderProxy.createAndBind(
mContext,
fusedProviderManager,
FUSED_LOCATION_SERVICE_ACTION,
com.android.internal.R.bool.config_enableFusedLocationOverlay,
com.android.internal.R.string.config_fusedLocationProviderPackageName,
com.android.internal.R.array.config_locationProviderPackageNames);
if (fusedProvider != null) {
mRealProviders.add(fusedProviderManager);
addProviderLocked(fusedProviderManager);
fusedProviderManager.attachLocked(fusedProvider);
} else {
Slog.e(TAG, "no fused location provider found",
new IllegalStateException("Location service needs a fused location provider"));
}
// bind to geocoder provider
mGeocodeProvider = GeocoderProxy.createAndBind(mContext,
com.android.internal.R.bool.config_enableGeocoderOverlay,
com.android.internal.R.string.config_geocoderProviderPackageName,
com.android.internal.R.array.config_locationProviderPackageNames);
if (mGeocodeProvider == null) {
Slog.e(TAG, "no geocoder provider found");
}
// bind to geofence provider
GeofenceProxy provider = GeofenceProxy.createAndBind(
mContext, com.android.internal.R.bool.config_enableGeofenceOverlay,
com.android.internal.R.string.config_geofenceProviderPackageName,
com.android.internal.R.array.config_locationProviderPackageNames,
mGpsGeofenceProxy,
null);
if (provider == null) {
Slog.d(TAG, "Unable to bind FLP Geofence proxy.");
}
// bind to hardware activity recognition
...
ActivityRecognitionProxy proxy = ActivityRecognitionProxy.createAndBind(
mContext,
activityRecognitionHardwareIsSupported,
activityRecognitionHardware,
com.android.internal.R.bool.config_enableActivityRecognitionHardwareOverlay,
com.android.internal.R.string.config_activityRecognitionHardwarePackageName,
com.android.internal.R.array.config_locationProviderPackageNames);
if (proxy == null) {
Slog.d(TAG, "Unable to bind ActivityRecognitionProxy.");
}
...
}
- PassiveProvider,GnssLocationProvider 都是直接new出来的
- networkProvider，fusedProvider 是由LocationProviderProxy的方法createAndBind创建的
- GeocodeProvider（地理位置反解析） 是由GeocoderProxy的方法createAndBind创建的，里面的实现和LocationProviderProxy相似
- GeofenceProvider（地理围栏） 是由GeofenceProxy 的方法createAndBind创建的，里面的实现和LocationProviderProxy相似
- ActivityRecognitionProxy 是gms的功能，不做多介绍
1. GnssLocationProvider
先拿GnssLocationProvider作分析:
GnssLocationProvider.java中setRequest的实现：
@Override
public void setRequest(ProviderRequest request, WorkSource source) {
sendMessage(SET_REQUEST, 0, new GpsRequest(request, source));
}
private final class ProviderHandler extends Handler {
@Override
public void handleMessage(Message msg) {
int message = msg.what;
switch (message) {
case SET_REQUEST:
GpsRequest gpsRequest = (GpsRequest) msg.obj;
handleSetRequest(gpsRequest.request, gpsRequest.source);
break;
...
}
}
}
private void handleSetRequest(ProviderRequest request, WorkSource source) {
mProviderRequest = request;
mWorkSource = source;
updateEnabled();
updateRequirements();
}
主要在updateRequirements中实现
// Called when the requirements for GPS may have changed
private void updateRequirements() {
...
if (mProviderRequest.reportLocation && isGpsEnabled()) {
...
if (mStarted && hasCapability(GPS_CAPABILITY_SCHEDULING)) {
...
} else if (!mStarted) {
// start GPS
startNavigating();
} else {
...
}
} else {
...
}
}
startNavigating中调用的是native方法：
private void startNavigating() {
if (!mStarted) {
...
if (!native_start()) {
setStarted(false);
Log.e(TAG, "native_start failed in startNavigating()");
return;
}
...
mFixRequestTime = SystemClock.elapsedRealtime();
if (!hasCapability(GPS_CAPABILITY_SCHEDULING)) {
// set timer to give up if we do not receive a fix within NO_FIX_TIMEOUT
// and our fix interval is not short
if (mFixInterval >= NO_FIX_TIMEOUT) {
mAlarmManager.set(AlarmManager.ELAPSED_REALTIME_WAKEUP,
SystemClock.elapsedRealtime() + NO_FIX_TIMEOUT, mTimeoutIntent);
}
}
}
}
native_start为native方法，当他成功运行后，AlarmManager会起一个timeout的计时
这就是gnss开始获取位置的过程
那么定位结果是如何上报的呢：
结果上报：
我们注意到GnssLocationProvider.java中有一个NativeEntryPoint注解
@NativeEntryPoint
private void reportLocation(boolean hasLatLong, Location location) {
sendMessage(REPORT_LOCATION, hasLatLong ? 1 : 0, location);
}
该注解的意义为JNI调用的入口，防止IDE编译警告
然后通过handler调用到handleReportLocation，handleReportLocation调用父类接口：
public abstract class AbstractLocationProvider {
public interface LocationProviderManager {
/**
* May be called to inform the location service of a change in this location provider's
* enabled/disabled state.
*/
void onSetEnabled(boolean enabled);
/**
* May be called to inform the location service of a change in this location provider's
* properties.
*/
void onSetProperties(ProviderProperties properties);
/**
* May be called to inform the location service that this provider has a new location
* available.
*/
void onReportLocation(Location location);
/**
* May be called to inform the location service that this provider has a new location
* available.
*/
void onReportLocation(List locations);
}
protected void reportLocation(Location location) {
mLocationProviderManager.onReportLocation(location);
}
}
LocationProviderManager接口的实现在LocationManagerService的内部类LocationProvider中
// called from any thread
@Override
public void onReportLocation(Location location) {
// no security check necessary because this is coming from an internal-only interface
// move calls coming from below LMS onto a different thread to avoid deadlock
mHandler.post(() -> {
synchronized (mLock) {
handleLocationChangedLocked(location, this);
}
});
}
这里只是做了层线程转换,关键在于handleLocationChangedLocked这个方法:
private void handleLocationChangedLocked(Location location, LocationProvider provider) {
...
if (provider.isUseableLocked()) {
if (!provider.isPassiveLocked()) {
mPassiveProvider.updateLocation(location);
}
}
...
if (provider.isUseableLocked()) {
updateLastLocationLocked(location, provider.getName());
}
...
for (UpdateRecord r : records) {
...
if (notifyLocation != null) {
Location lastLoc = r.mLastFixBroadcast;
if ((lastLoc == null)
|| shouldBroadcastSafeLocked(notifyLocation, lastLoc, r, now)) {
if (lastLoc == null) {
lastLoc = new Location(notifyLocation);
r.mLastFixBroadcast = lastLoc;
} else {
lastLoc.set(notifyLocation);
}
...
r.mRealRequest.decrementNumUpdates();
}
}
}
...
}
1.mPassiveProvider更新了其location数据
2.更新自己的location数据
3.更新UpdateRecord 里的location数据
2. NetworkProvider
先看下LocationProviderProxy是如何createAndBind的：
public static LocationProviderProxy createAndBind(
Context context, LocationProviderManager locationProviderManager, String action,
int overlaySwitchResId, int defaultServicePackageNameResId,
int initialPackageNamesResId) {
LocationProviderProxy proxy = new LocationProviderProxy(context, locationProviderManager,
action, overlaySwitchResId, defaultServicePackageNameResId,
initialPackageNamesResId);
if (proxy.bind()) {
return proxy;
} else {
return null;
}
}
private LocationProviderProxy(Context context, LocationProviderManager locationProviderManager,
String action, int overlaySwitchResId, int defaultServicePackageNameResId,
int initialPackageNamesResId) {
super(context, locationProviderManager);
mServiceWatcher = new ServiceWatcher(context, TAG, action, overlaySwitchResId,
defaultServicePackageNameResId, initialPackageNamesResId,
FgThread.getHandler()) {
...
};
...
}
实际上是交给ServiceWatcher这个类去生成，在proxy.bind()时调用ServiceWatcher.start()方法，start方法中最关键的是调用bindBestPackage方法，bindBestPackage最终调用的是bind方法，看下此方法的实现：
private void bind(ComponentName component, int version, int userId) {
Preconditions.checkState(Looper.myLooper() == mHandler.getLooper());
Intent intent = new Intent(mAction);
intent.setComponent(component);
mBestComponent = component;
mBestVersion = version;
mBestUserId = userId;
if (D) Log.d(mTag, "binding " + component + " (v" + version + ") (u" + userId + ")");
mContext.bindServiceAsUser(intent, this,
Context.BIND_AUTO_CREATE | Context.BIND_NOT_FOREGROUND | Context.BIND_NOT_VISIBLE,
UserHandle.of(userId));
}
可以看到此处是bind了一个Service，那么：
networkProvider的action="com.android.location.service.v3.NetworkLocationProvider"（此处OS版本不同，对应的action也可能不同）
fusedProvider的的action=com.android.location.service.FusedLocationProvider
所以system层只要定义一个Service，接收上述的action，就可以接收到系统发来的请求
以上是NetworkProvider如何生成
我们再研究下setRequest如何处理
在networkprovider生成的代码中可知：
在LocationManagerService中，networkProvider是用其代理类LocationProviderProxy交互的
所以看下LocationProviderProxy中setRequest的实现：
@Override
public void setRequest(ProviderRequest request, WorkSource source) {
synchronized (mRequestLock) {
mRequest = request;
mWorkSource = source;
}
mServiceWatcher.runOnBinder(binder -> {
ILocationProvider service = ILocationProvider.Stub.asInterface(binder);
service.setRequest(request, source);
});
}
可以看到用了 ILocationProvider这个aidl进行实现的，
ILocationProvider.aidl的实现在LocationProviderBase类的内部类Service 中：
private final class Service extends ILocationProvider.Stub {
@Override
public void setLocationProviderManager(ILocationProviderManager manager) {
synchronized (mBinder) {
...
mManager = manager;
}
onInit();
}
@Override
public void setRequest(ProviderRequest request, WorkSource ws) {
onSetRequest(new ProviderRequestUnbundled(request), ws);
}
@Override
public int getStatus(Bundle extras) {
return onGetStatus(extras);
}
@Override
public long getStatusUpdateTime() {
return onGetStatusUpdateTime();
}
@Override
public void sendExtraCommand(String command, Bundle extras) {
onSendExtraCommand(command, extras);
}
}
setLocationProviderManager方法传进来一个ILocationProviderManager ，这个ILocationProviderManager.aidl就是LocationManagerService的内部类LocationProvider，作为LocationManagerService与LocationProviderBase的交互
实现就在onSetRequest这个方法中
onSetRequest是一个抽象方法，LocationProviderBase类也是抽象类，这就提供了自定义Provider实现的可能性：
public LocationProviderBase(String tag, ProviderPropertiesUnbundled properties) {
mBinder = new Service();//此处Service为内部类
...
}
public IBinder getBinder() {
return mBinder;
}
只要在上述自定义Service中，bind自定义的provider:
class RobinProviderService : Service(){
override fun onBind(intent: Intent): IBinder? {
if (mProvider == null) {
mProvider = RobinProvide(applicationContext)
}
return mProvider?.binder
}
}
同样的我们来研究下如何上报location数据：
结果上报：
在LocationProviderBase中：
/**
* Reports a new location from this provider.
*/
public void reportLocation(Location location) {
ILocationProviderManager manager = mManager;
if (manager != null) {
try {
manager.onReportLocation(location);
} catch (RemoteException | RuntimeException e) {
Log.w(mTag, e);
}
}
}
通过aidl调用LocationManagerService的内部类LocationProvider的onReportLocation方法,此方法在GnssLocationProvider中已做过介绍
以上就是LocationManager定位的大致实现过程