如何将数据从 Android 后台服务传递到 activity
How to pass data from an Android background service to an activity
我有一个 Android 应用程序，有两个组件
- 一个 activity，它在网络视图中创建、显示 javascript 代码 运行 并与之通信。
- 创建并绑定到上述 activity 的后台服务，即使 activity 对用户不可见，它也会捕获位置数据。
谁能告诉我将位置数据从服务传回 activity 的最简单方法，无论 activity 是否显示给用户，该方法都有效。
我应该使用 EventBus 吗？广播接收器、本地广播管理器或什么？
理想情况下，我希望有人指出 GitHub（或类似）上的示例应用程序的方向，我可以下载并检查它是如何工作的，如果失败，一些代码会很好。
这是您的服务：
<service
android:name=".Services.Service.GPSTracker"
android:exported="false" />
和java class：
import android.Manifest;
import android.app.Service;
import android.content.Context;
import android.content.Intent;
import android.content.pm.PackageManager;
import android.location.Criteria;
import android.location.GpsSatellite;
import android.location.GpsStatus;
import android.location.Location;
import android.location.LocationListener;
import android.location.LocationManager;
import android.os.IBinder;
import android.provider.Settings;
import android.support.v4.app.ActivityCompat;
import android.util.Log;
import static android.location.GpsStatus.GPS_EVENT_SATELLITE_STATUS;
public class GPSTracker extends Service {
private Context mContext;
// flag for GPS status
boolean isGPSEnabled = false;
// flag for network status
boolean isNetworkEnabled = false;
// flag for GPS status
boolean canGetLocation = false;
Location location; // location
double latitude; // latitude
double longitude; // longitude
float bearing; // bearing
// The minimum distance to change Updates in meters
private static final long MIN_DISTANCE_CHANGE_FOR_UPDATES = 1; // 10 meters
// The minimum time between updates in milliseconds
private static final long MIN_TIME_BW_UPDATES = 1000; // 5 sec
// Declaring a Location Manager
protected LocationManager locationManager;
protected LocationListener locationListenerNetwork;
protected LocationListener locationListenerGPS;
protected GpsStatus.Listener gpsStatusListener;
protected GpsListener gpsListener;
public GPSTracker(Context context, LocationListener listenerNetwork, LocationListener listenerGPS, GpsListener gpsListener) {
locationListenerGPS = listenerGPS;
locationListenerNetwork = listenerNetwork;
this.mContext = context;
this.gpsListener = gpsListener;
getLocation();
}
public GPSTracker() {
}
private GPSTracker(Context mContext) {
this.mContext = mContext;
}
public Location getLocation() {
try {
locationManager = (LocationManager) mContext
.getSystemService(LOCATION_SERVICE);
// getting GPS status
isGPSEnabled = locationManager
.isProviderEnabled(LocationManager.GPS_PROVIDER);
// getting network status
isNetworkEnabled = locationManager
.isProviderEnabled(LocationManager.NETWORK_PROVIDER);
if (!isGPSEnabled && !isNetworkEnabled) {
// no network provider is enabled
} else {
this.canGetLocation = true;
// if GPS Enabled get lat/long using GPS Services
if (isGPSEnabled) {
if (location == null) {
if (ActivityCompat.checkSelfPermission(mContext, Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED && ActivityCompat.checkSelfPermission(mContext, Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
// TODO: Consider calling
// ActivityCompat#requestPermissions
// here to request the missing permissions, and then overriding
// public void onRequestPermissionsResult(int requestCode, String[] permissions,
// int[] grantResults)
// to handle the case where the user grants the permission. See the documentation
// for ActivityCompat#requestPermissions for more details.
return null;
}
final Criteria criteria = new Criteria();
criteria.setCostAllowed(true);
criteria.setPowerRequirement(Criteria.POWER_HIGH);
criteria.setAccuracy(Criteria.ACCURACY_FINE);
final String p = locationManager.getBestProvider(criteria, true);
locationManager.requestLocationUpdates(
LocationManager.GPS_PROVIDER,
MIN_TIME_BW_UPDATES,
MIN_DISTANCE_CHANGE_FOR_UPDATES, locationListenerGPS);
gpsStatusListener = new GpsStatus.Listener() {
@Override
public void onGpsStatusChanged(int event) {
if (event == GPS_EVENT_SATELLITE_STATUS) {
if (ActivityCompat.checkSelfPermission(mContext, Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
// TODO: Consider calling
// ActivityCompat#requestPermissions
// here to request the missing permissions, and then overriding
// public void onRequestPermissionsResult(int requestCode, String[] permissions,
// int[] grantResults)
// to handle the case where the user grants the permission. See the documentation
// for ActivityCompat#requestPermissions for more details.
return;
}
GpsStatus status = locationManager.getGpsStatus(null);
Iterable<GpsSatellite> sats = status.getSatellites();
gpsListener.OnGpsSatelliteChanged(sats);
// Check number of satellites in list to determine fix state
}
}
};
locationManager.addGpsStatusListener(gpsStatusListener);
Log.d("GPS Enabled", "GPS Enabled");
if (locationManager != null) {
location = locationManager
.getLastKnownLocation(LocationManager.GPS_PROVIDER);
if (location != null) {
latitude = location.getLatitude();
longitude = location.getLongitude();
bearing = location.getBearing();
}
}
}
}
if (isNetworkEnabled) {
if (ActivityCompat.checkSelfPermission(mContext, Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED && ActivityCompat.checkSelfPermission(mContext, Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
// TODO: Consider calling
// ActivityCompat#requestPermissions
// here to request the missing permissions, and then overriding
// public void onRequestPermissionsResult(int requestCode, String[] permissions,
// int[] grantResults)
// to handle the case where the user grants the permission. See the documentation
// for ActivityCompat#requestPermissions for more details.
return null;
}
locationManager.requestLocationUpdates(
LocationManager.NETWORK_PROVIDER,
MIN_TIME_BW_UPDATES,
MIN_DISTANCE_CHANGE_FOR_UPDATES, locationListenerNetwork);
Log.d("Network", "Network");
if (locationManager != null) {
location = locationManager
.getLastKnownLocation(LocationManager.NETWORK_PROVIDER);
if (location != null) {
latitude = location.getLatitude();
longitude = location.getLongitude();
bearing = location.getBearing();
}
}
}
}
} catch (Exception e) {
e.printStackTrace();
}
return location;
}
/**
* Stop using GPS listener
* Calling this function will stop using GPS in your app
*/
public void stopUsingGPSProvider() {
if (locationManager != null) {
locationManager.removeUpdates(locationListenerGPS);
}
}
public void stopUsingNetworkProvider() {
if (locationManager != null) {
locationManager.removeUpdates(locationListenerNetwork);
}
}
/**
* 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;
}
public float getBearing() {
if (location != null) {
bearing = location.getBearing();
}
return bearing;
}
/**
* 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 IBinder onBind(Intent arg0) {
return null;
}
public interface GpsListener {
void OnGpsSatelliteChanged(Iterable<GpsSatellite> gpsSatellites);
}
}
在 activity 中：
GPSTracker gps;
LocationListener locationListenerNetwork = new LocationListener() {
@Override
public void onLocationChanged(Location location) {
}
@Override
public void onStatusChanged(String provider, int status, Bundle extras) {
}
@Override
public void onProviderEnabled(String provider) {
}
@Override
public void onProviderDisabled(String provider) {
}
};
LocationListener locationListenerGPS = new LocationListener() {
@Override
public void onLocationChanged(Location location) {
}
@Override
public void onStatusChanged(String provider, int status, Bundle extras) {
}
@Override
public void onProviderEnabled(String provider) {
}
@Override
public void onProviderDisabled(String provider) {
}
};
GPSTracker.GpsListener gpsListener = new GPSTracker.GpsListener() {
@Override
public void OnGpsSatelliteChanged(Iterable<GpsSatellite> gpsSatellites) {
}
};
void start(){
gps = new GPSTracker(this, locationListenerNetwork, locationListenerGPS, gpsListener);
}
void stop(){
if (gps != null) {
gps.stopUsingGPSProvider();
gps.stopUsingNetworkProvider();
}
}
@Override
protected void onPause() {
super.onPause();
stop();
}
@Override
protected void onResume() {
super.onResume();
start();
}
只要你的 activity 打开并开始向你的 activity 发送 gps 数据，如果 activity 进入后台或停止，上面的代码将 运行 gps 并且等等... gps 也会停止（您也需要处理许可）。另外，如果你想在 activity 未打开时也有 gps 数据，你可以制作一个 List<location> 并将其保存在服务中，并且当 activity 被重置时通过接口将其发回（希望你知道如何创建接口和传递数据）；
由于您使用的是 Bound service，最简单的方法是在 Activity 绑定到 Service 时 return 一个合适的 Binder 对象.
相关文档在 here。
此外，这是绑定的示例代码 service and the corresponding actvitiy。
请注意，Activity 一旦连接，就可以调用添加到相应 Binder 对象的 public 方法。如果您希望 Service 自行决定向 Activity 提供信息，只需注册一个服务可以调用的侦听器即可。
我发现最简单的解决方案实际上是使用 EventBus。他们的 website 入门页面说明了四个简单的步骤
- 在我的 gradle 文件中添加 "implementation 'org.greenrobot:eventbus:3.1.1'"
- 在我的 MainActivity 中注册和取消注册接收器。我在 onCreate 和 onDestroy 中做了这个，但他们推荐 onStart 和 onStop
- 添加一个新的 JavaClass MessageEvent - 来自上面 link 的 4 行代码
- 在我的服务中，使用 EventBus post 可用的新位置数据
- 在我的 MainActivity 中使用 onMessageEvent
对这些 post 做出反应
即使主 activity 暂停（在后台）也能正常工作
有两件额外的事情要做，上面的 link 中没有记录。
- 我必须将 "import org.greenrobot.eventbus.EventBus;" 添加到我的 MainActivity class 文件和我的 BackgroundService class 文件。
- 必须将 mavenCentral() 添加到顶级构建文件的所有项目部分。
我有一个 Android 应用程序，有两个组件
- 一个 activity，它在网络视图中创建、显示 javascript 代码 运行 并与之通信。
- 创建并绑定到上述 activity 的后台服务，即使 activity 对用户不可见，它也会捕获位置数据。
谁能告诉我将位置数据从服务传回 activity 的最简单方法，无论 activity 是否显示给用户，该方法都有效。
我应该使用 EventBus 吗？广播接收器、本地广播管理器或什么？
理想情况下，我希望有人指出 GitHub（或类似）上的示例应用程序的方向，我可以下载并检查它是如何工作的，如果失败，一些代码会很好。
这是您的服务：
<service
android:name=".Services.Service.GPSTracker"
android:exported="false" />
和java class：
import android.Manifest;
import android.app.Service;
import android.content.Context;
import android.content.Intent;
import android.content.pm.PackageManager;
import android.location.Criteria;
import android.location.GpsSatellite;
import android.location.GpsStatus;
import android.location.Location;
import android.location.LocationListener;
import android.location.LocationManager;
import android.os.IBinder;
import android.provider.Settings;
import android.support.v4.app.ActivityCompat;
import android.util.Log;
import static android.location.GpsStatus.GPS_EVENT_SATELLITE_STATUS;
public class GPSTracker extends Service {
private Context mContext;
// flag for GPS status
boolean isGPSEnabled = false;
// flag for network status
boolean isNetworkEnabled = false;
// flag for GPS status
boolean canGetLocation = false;
Location location; // location
double latitude; // latitude
double longitude; // longitude
float bearing; // bearing
// The minimum distance to change Updates in meters
private static final long MIN_DISTANCE_CHANGE_FOR_UPDATES = 1; // 10 meters
// The minimum time between updates in milliseconds
private static final long MIN_TIME_BW_UPDATES = 1000; // 5 sec
// Declaring a Location Manager
protected LocationManager locationManager;
protected LocationListener locationListenerNetwork;
protected LocationListener locationListenerGPS;
protected GpsStatus.Listener gpsStatusListener;
protected GpsListener gpsListener;
public GPSTracker(Context context, LocationListener listenerNetwork, LocationListener listenerGPS, GpsListener gpsListener) {
locationListenerGPS = listenerGPS;
locationListenerNetwork = listenerNetwork;
this.mContext = context;
this.gpsListener = gpsListener;
getLocation();
}
public GPSTracker() {
}
private GPSTracker(Context mContext) {
this.mContext = mContext;
}
public Location getLocation() {
try {
locationManager = (LocationManager) mContext
.getSystemService(LOCATION_SERVICE);
// getting GPS status
isGPSEnabled = locationManager
.isProviderEnabled(LocationManager.GPS_PROVIDER);
// getting network status
isNetworkEnabled = locationManager
.isProviderEnabled(LocationManager.NETWORK_PROVIDER);
if (!isGPSEnabled && !isNetworkEnabled) {
// no network provider is enabled
} else {
this.canGetLocation = true;
// if GPS Enabled get lat/long using GPS Services
if (isGPSEnabled) {
if (location == null) {
if (ActivityCompat.checkSelfPermission(mContext, Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED && ActivityCompat.checkSelfPermission(mContext, Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
// TODO: Consider calling
// ActivityCompat#requestPermissions
// here to request the missing permissions, and then overriding
// public void onRequestPermissionsResult(int requestCode, String[] permissions,
// int[] grantResults)
// to handle the case where the user grants the permission. See the documentation
// for ActivityCompat#requestPermissions for more details.
return null;
}
final Criteria criteria = new Criteria();
criteria.setCostAllowed(true);
criteria.setPowerRequirement(Criteria.POWER_HIGH);
criteria.setAccuracy(Criteria.ACCURACY_FINE);
final String p = locationManager.getBestProvider(criteria, true);
locationManager.requestLocationUpdates(
LocationManager.GPS_PROVIDER,
MIN_TIME_BW_UPDATES,
MIN_DISTANCE_CHANGE_FOR_UPDATES, locationListenerGPS);
gpsStatusListener = new GpsStatus.Listener() {
@Override
public void onGpsStatusChanged(int event) {
if (event == GPS_EVENT_SATELLITE_STATUS) {
if (ActivityCompat.checkSelfPermission(mContext, Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
// TODO: Consider calling
// ActivityCompat#requestPermissions
// here to request the missing permissions, and then overriding
// public void onRequestPermissionsResult(int requestCode, String[] permissions,
// int[] grantResults)
// to handle the case where the user grants the permission. See the documentation
// for ActivityCompat#requestPermissions for more details.
return;
}
GpsStatus status = locationManager.getGpsStatus(null);
Iterable<GpsSatellite> sats = status.getSatellites();
gpsListener.OnGpsSatelliteChanged(sats);
// Check number of satellites in list to determine fix state
}
}
};
locationManager.addGpsStatusListener(gpsStatusListener);
Log.d("GPS Enabled", "GPS Enabled");
if (locationManager != null) {
location = locationManager
.getLastKnownLocation(LocationManager.GPS_PROVIDER);
if (location != null) {
latitude = location.getLatitude();
longitude = location.getLongitude();
bearing = location.getBearing();
}
}
}
}
if (isNetworkEnabled) {
if (ActivityCompat.checkSelfPermission(mContext, Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED && ActivityCompat.checkSelfPermission(mContext, Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
// TODO: Consider calling
// ActivityCompat#requestPermissions
// here to request the missing permissions, and then overriding
// public void onRequestPermissionsResult(int requestCode, String[] permissions,
// int[] grantResults)
// to handle the case where the user grants the permission. See the documentation
// for ActivityCompat#requestPermissions for more details.
return null;
}
locationManager.requestLocationUpdates(
LocationManager.NETWORK_PROVIDER,
MIN_TIME_BW_UPDATES,
MIN_DISTANCE_CHANGE_FOR_UPDATES, locationListenerNetwork);
Log.d("Network", "Network");
if (locationManager != null) {
location = locationManager
.getLastKnownLocation(LocationManager.NETWORK_PROVIDER);
if (location != null) {
latitude = location.getLatitude();
longitude = location.getLongitude();
bearing = location.getBearing();
}
}
}
}
} catch (Exception e) {
e.printStackTrace();
}
return location;
}
/**
* Stop using GPS listener
* Calling this function will stop using GPS in your app
*/
public void stopUsingGPSProvider() {
if (locationManager != null) {
locationManager.removeUpdates(locationListenerGPS);
}
}
public void stopUsingNetworkProvider() {
if (locationManager != null) {
locationManager.removeUpdates(locationListenerNetwork);
}
}
/**
* 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;
}
public float getBearing() {
if (location != null) {
bearing = location.getBearing();
}
return bearing;
}
/**
* 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 IBinder onBind(Intent arg0) {
return null;
}
public interface GpsListener {
void OnGpsSatelliteChanged(Iterable<GpsSatellite> gpsSatellites);
}
}
在 activity 中：
GPSTracker gps;
LocationListener locationListenerNetwork = new LocationListener() {
@Override
public void onLocationChanged(Location location) {
}
@Override
public void onStatusChanged(String provider, int status, Bundle extras) {
}
@Override
public void onProviderEnabled(String provider) {
}
@Override
public void onProviderDisabled(String provider) {
}
};
LocationListener locationListenerGPS = new LocationListener() {
@Override
public void onLocationChanged(Location location) {
}
@Override
public void onStatusChanged(String provider, int status, Bundle extras) {
}
@Override
public void onProviderEnabled(String provider) {
}
@Override
public void onProviderDisabled(String provider) {
}
};
GPSTracker.GpsListener gpsListener = new GPSTracker.GpsListener() {
@Override
public void OnGpsSatelliteChanged(Iterable<GpsSatellite> gpsSatellites) {
}
};
void start(){
gps = new GPSTracker(this, locationListenerNetwork, locationListenerGPS, gpsListener);
}
void stop(){
if (gps != null) {
gps.stopUsingGPSProvider();
gps.stopUsingNetworkProvider();
}
}
@Override
protected void onPause() {
super.onPause();
stop();
}
@Override
protected void onResume() {
super.onResume();
start();
}
只要你的 activity 打开并开始向你的 activity 发送 gps 数据，如果 activity 进入后台或停止，上面的代码将 运行 gps 并且等等... gps 也会停止（您也需要处理许可）。另外，如果你想在 activity 未打开时也有 gps 数据，你可以制作一个 List<location> 并将其保存在服务中，并且当 activity 被重置时通过接口将其发回（希望你知道如何创建接口和传递数据）；
由于您使用的是 Bound service，最简单的方法是在 Activity 绑定到 Service 时 return 一个合适的 Binder 对象.
相关文档在 here。
此外，这是绑定的示例代码 service and the corresponding actvitiy。
请注意，Activity 一旦连接，就可以调用添加到相应 Binder 对象的 public 方法。如果您希望 Service 自行决定向 Activity 提供信息，只需注册一个服务可以调用的侦听器即可。
我发现最简单的解决方案实际上是使用 EventBus。他们的 website 入门页面说明了四个简单的步骤
- 在我的 gradle 文件中添加 "implementation 'org.greenrobot:eventbus:3.1.1'"
- 在我的 MainActivity 中注册和取消注册接收器。我在 onCreate 和 onDestroy 中做了这个，但他们推荐 onStart 和 onStop
- 添加一个新的 JavaClass MessageEvent - 来自上面 link 的 4 行代码
- 在我的服务中，使用 EventBus post 可用的新位置数据
- 在我的 MainActivity 中使用 onMessageEvent 对这些 post 做出反应
即使主 activity 暂停（在后台）也能正常工作
有两件额外的事情要做，上面的 link 中没有记录。
- 我必须将 "import org.greenrobot.eventbus.EventBus;" 添加到我的 MainActivity class 文件和我的 BackgroundService class 文件。
- 必须将 mavenCentral() 添加到顶级构建文件的所有项目部分。