我需要通过GPS程序获得我的当前位置。 我怎样才能做到呢?
当前回答
自2020年9月23日起,play-services-location版本17.1.0包含了FusedLocationProviderClient.getCurrentLocation()方法,这是获得当前位置的推荐和直接的方法:
返回设备上的单个当前位置固定。与返回缓存位置的getLastLocation()不同,此方法可能导致设备上的活动位置计算。如果能在合理的时间内(几十秒)确定设备位置,将返回一个新的位置,否则将返回null。
关于详细的例子,看看codingjeremy的回答和GitHub上的官方Android位置示例- Current location (Kotlin)。
其他回答
如果你正在为Android创建新的位置项目,你应该使用新的谷歌Play位置服务。它更准确,使用起来更简单。
几年来,我一直致力于一个开源的GPS跟踪器项目,GpsTracker。我最近更新了它,以处理来自Android、iOS、Windows Phone和Java ME手机的定期更新。它功能齐全,可以满足您的需要,并且拥有MIT许可证。
GpsTracker中的Android项目使用了新的谷歌播放服务,还有两个服务器堆栈(ASP。NET和PHP)来让你追踪这些手机。
简单的找到写代码在位置方法
public void onLocationChanged(Location location) {
if (mCurrLocationMarker != null) {
mCurrLocationMarker.remove();
}
//Place current location marker
LatLng latLng = new LatLng(location.getLatitude(), location.getLongitude());
MarkerOptions markerOptions = new MarkerOptions();
markerOptions.position(latLng);
markerOptions.title("Current Position");
markerOptions.icon(BitmapDescriptorFactory.defaultMarker(BitmapDescriptorFactory.HUE_RED));
mCurrLocationMarker = mMap.addMarker(markerOptions);
//move map camera
mMap.moveCamera(CameraUpdateFactory.newLatLng(latLng));
mMap.animateCamera(CameraUpdateFactory.zoomTo(18));
PolylineOptions pOptions = new PolylineOptions()
.width(5)
.color(Color.GREEN)
.geodesic(true);
for (int z = 0; z < routePoints.size(); z++) {
LatLng point = routePoints.get(z);
pOptions.add(point);
}
line = mMap.addPolyline(pOptions);
routePoints.add(latLng);
}
到2020年下半年,有一种更简单的方法来做到这一点。
不包括请求权限(我将在底部包含更新的开发人员),下面是代码。
记住,你至少需要在你的依赖项中包含这个版本的库(在应用程序的build.gradle中):
implementation 'com.google.android.gms:play-services-location:17.1.0'
... 当然还有你清单上的准许
<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />
Kotlin(首先是设置):
private val fusedLocationClient: FusedLocationProviderClient by lazy {
LocationServices.getFusedLocationProviderClient(applicationContext)
}
private var cancellationTokenSource = CancellationTokenSource()
然后是主代码(FINE_LOCATION):
private fun requestCurrentLocation() {
// Check Fine permission
if (ActivityCompat.checkSelfPermission(
this,
Manifest.permission.ACCESS_FINE_LOCATION) ==
PackageManager.PERMISSION_GRANTED) {
// Main code
val currentLocationTask: Task<Location> = fusedLocationClient.getCurrentLocation(
PRIORITY_HIGH_ACCURACY,
cancellationTokenSource.token
)
currentLocationTask.addOnCompleteListener { task: Task<Location> ->
val result = if (task.isSuccessful) {
val result: Location = task.result
"Location (success): ${result.latitude}, ${result.longitude}"
} else {
val exception = task.exception
"Location (failure): $exception"
}
Log.d(TAG, "getCurrentLocation() result: $result")
}
} else {
// Request fine location permission (full code below).
}
如果你更喜欢Java,它看起来像这样:
public class JavaVersion extends AppCompatActivity {
private final String TAG = "MainActivity";
// The Fused Location Provider provides access to location APIs.
private FusedLocationProviderClient fusedLocationClient;
// Allows class to cancel the location request if it exits the activity.
// Typically, you use one cancellation source per lifecycle.
private final CancellationTokenSource cancellationTokenSource = new CancellationTokenSource();
@Override
protected void onCreate(@Nullable Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
fusedLocationClient = LocationServices.getFusedLocationProviderClient(this);
}
...
private void requestCurrentLocation() {
Log.d(TAG, "requestCurrentLocation()");
// Request permission
if (ActivityCompat.checkSelfPermission(
this,
Manifest.permission.ACCESS_FINE_LOCATION) ==
PackageManager.PERMISSION_GRANTED) {
// Main code
Task<Location> currentLocationTask = fusedLocationClient.getCurrentLocation(
PRIORITY_HIGH_ACCURACY,
cancellationTokenSource.getToken()
);
currentLocationTask.addOnCompleteListener((new OnCompleteListener<Location>() {
@Override
public void onComplete(@NonNull Task<Location> task) {
String result = "";
if (task.isSuccessful()) {
// Task completed successfully
Location location = task.getResult();
result = "Location (success): " +
location.getLatitude() +
", " +
location.getLongitude();
} else {
// Task failed with an exception
Exception exception = task.getException();
result = "Exception thrown: " + exception;
}
Log.d(TAG, "getCurrentLocation() result: " + result);
}
}));
} else {
// TODO: Request fine location permission
Log.d(TAG, "Request fine location permission.");
}
}
...
}
的参数:
PRIORITY类型是自解释的。(其他选项是PRIORITY_BALANCED_POWER_ACCURACY, PRIORITY_LOW_POWER和PRIORITY_NO_POWER。) CancellationToken——如果用户导航离开Activity,这个token允许你取消请求。
操作(Kotlin):
override fun onStop() {
super.onStop()
// Cancels location request (if in flight).
cancellationTokenSource.cancel()
}
就是这样。
现在,这使用FusedLocationProviderClient,这是一个谷歌播放服务api。
这意味着这适用于所有带有谷歌Play Store的Android设备(数量很多)。然而,对于在中国没有Play Store的设备来说,这是行不通的,所以要考虑到这一点。
对于这方面的开发人员来说,如果用户还没有批准,则需要请求精细(或粗略)位置权限,因此在上面的代码中,我将请求位置权限。
下面是完整的代码(在Kotlin中)。
我希望这对你有所帮助(让你的生活更轻松一点)!
/**
* Demonstrates how to easily get the current location via the [FusedLocationProviderClient.getCurrentLocation].
* The main code is in this class's requestCurrentLocation() method.
*/
class MainActivity : AppCompatActivity() {
private lateinit var binding: ActivityMainBinding
// The Fused Location Provider provides access to location APIs.
private val fusedLocationClient: FusedLocationProviderClient by lazy {
LocationServices.getFusedLocationProviderClient(applicationContext)
}
// Allows class to cancel the location request if it exits the activity.
// Typically, you use one cancellation source per lifecycle.
private var cancellationTokenSource = CancellationTokenSource()
// If the user denied a previous permission request, but didn't check "Don't ask again", this
// Snackbar provides an explanation for why user should approve, i.e., the additional rationale.
private val fineLocationRationalSnackbar by lazy {
Snackbar.make(
binding.container,
R.string.fine_location_permission_rationale,
Snackbar.LENGTH_LONG
).setAction(R.string.ok) {
requestPermissions(
arrayOf(Manifest.permission.ACCESS_FINE_LOCATION),
REQUEST_FINE_LOCATION_PERMISSIONS_REQUEST_CODE
)
}
}
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
binding = ActivityMainBinding.inflate(layoutInflater)
val view = binding.root
setContentView(view)
}
override fun onStop() {
super.onStop()
// Cancels location request (if in flight).
cancellationTokenSource.cancel()
}
override fun onRequestPermissionsResult(
requestCode: Int,
permissions: Array<String>,
grantResults: IntArray
) {
Log.d(TAG, "onRequestPermissionResult()")
if (requestCode == REQUEST_FINE_LOCATION_PERMISSIONS_REQUEST_CODE) {
when {
grantResults.isEmpty() ->
// If user interaction was interrupted, the permission request
// is cancelled and you receive an empty array.
Log.d(TAG, "User interaction was cancelled.")
grantResults[0] == PackageManager.PERMISSION_GRANTED ->
Snackbar.make(
binding.container,
R.string.permission_approved_explanation,
Snackbar.LENGTH_LONG
)
.show()
else -> {
Snackbar.make(
binding.container,
R.string.fine_permission_denied_explanation,
Snackbar.LENGTH_LONG
)
.setAction(R.string.settings) {
// Build intent that displays the App settings screen.
val intent = Intent()
intent.action = Settings.ACTION_APPLICATION_DETAILS_SETTINGS
val uri = Uri.fromParts(
"package",
BuildConfig.APPLICATION_ID,
null
)
intent.data = uri
intent.flags = Intent.FLAG_ACTIVITY_NEW_TASK
startActivity(intent)
}
.show()
}
}
}
}
fun locationRequestOnClick(view: View) {
Log.d(TAG, "locationRequestOnClick()")
requestCurrentLocation()
}
/**
* Gets current location.
* Note: The code checks for permission before calling this method, that is, it's never called
* from a method with a missing permission. Also, I include a second check with my extension
* function in case devs just copy/paste this code.
*/
private fun requestCurrentLocation() {
Log.d(TAG, "requestCurrentLocation()")
if (ActivityCompat.checkSelfPermission(
this,
Manifest.permission.ACCESS_FINE_LOCATION) ==
PackageManager.PERMISSION_GRANTED) {
// Returns a single current location fix on the device. Unlike getLastLocation() that
// returns a cached location, this method could cause active location computation on the
// device. A single fresh location will be returned if the device location can be
// determined within reasonable time (tens of seconds), otherwise null will be returned.
//
// Both arguments are required.
// PRIORITY type is self-explanatory. (Other options are PRIORITY_BALANCED_POWER_ACCURACY,
// PRIORITY_LOW_POWER, and PRIORITY_NO_POWER.)
// The second parameter, [CancellationToken] allows the activity to cancel the request
// before completion.
val currentLocationTask: Task<Location> = fusedLocationClient.getCurrentLocation(
PRIORITY_HIGH_ACCURACY,
cancellationTokenSource.token
)
currentLocationTask.addOnCompleteListener { task: Task<Location> ->
val result = if (task.isSuccessful) {
val result: Location = task.result
"Location (success): ${result.latitude}, ${result.longitude}"
} else {
val exception = task.exception
"Location (failure): $exception"
}
Log.d(TAG, "getCurrentLocation() result: $result")
logOutputToScreen(result)
}
} else {
val provideRationale = shouldShowRequestPermissionRationale(Manifest.permission.ACCESS_FINE_LOCATION)
if (provideRationale) {
fineLocationRationalSnackbar.show()
} else {
requestPermissions(arrayOf(Manifest.permission.ACCESS_FINE_LOCATION), REQUEST_FINE_LOCATION_PERMISSIONS_REQUEST_CODE)
}
}
}
private fun logOutputToScreen(outputString: String) {
val finalOutput = binding.outputTextView.text.toString() + "\n" + outputString
binding.outputTextView.text = finalOutput
}
companion object {
private const val TAG = "MainActivity"
private const val REQUEST_FINE_LOCATION_PERMISSIONS_REQUEST_CODE = 34
}
}
Edit 2022:不要使用这个库,因为该库有内存泄漏,不再支持/更新。
我将推荐使用智能位置库 使用起来非常简单,它很好地包装了位置逻辑。
启动位置服务:
SmartLocation.with(context).location()
.start(new OnLocationUpdatedListener() { ... });
如果你只想获得一个单一的位置(不是周期性的),你可以使用oneFix修饰符。例子:
SmartLocation.with(context).location()
.oneFix()
.start(new OnLocationUpdatedListener() { ... });
既然谷歌Play位置服务已经推出,我建议开发者开始使用新的融合位置提供商。你会发现它更容易使用和更准确。请观看谷歌I/O视频《超越蓝点:Android位置的新功能》,由两位创建了新的谷歌Play位置服务API的人制作。
I've been working with location APIs on a number of mobile platforms, and I think what these two guys have done is really revolutionary. It's gotten rid of a huge amount of the complexities of using the various providers. Stack Overflow is littered with questions about which provider to use, whether to use last known location, how to set other properties on the LocationManager, etc. This new API that they have built removes most of those uncertainties and makes the location services a pleasure to use.
I've written an Android app that periodically gets the location using Google Play location services and sends the location to a web server where it is stored in a database and can be viewed on Google Maps. I've written both the client software (for Android, iOS, Windows Phone and Java ME) and the server software (for ASP.NET and SQL Server or PHP and MySQL). The software is written in the native language on each platform and works properly in the background on each. Lastly, the software has the MIT License. You can find the Android client here:
https://github.com/nickfox/GpsTracker/tree/master/phoneClients/android
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