获取在api天气（kotlin）中使用的当前位置

Question

我如何获取currnet位置并获取纬度，经度，并在api天气中使用它们？在此方法内部，当我想在方法lat和lon中使用该方法时，我得到了纬度和经度，因此在我壶0.0之前返回我们的默认值，但在方法内部返回lat和lon的位置导致api中的lat和lon无法正常工作]

@SuppressLint("MissingPermission")
private fun getLastLocation() {
    if (checkPermissions()) {
        if (isLocationEnabled()) {


            mFusedLocationClient.lastLocation.addOnCompleteListener(this) { task ->

                var location: Location? = task.result
                if (location == null) {
                    requestNewLocationData()
                } else {
                  lat=location.latitude
                  lon=location.longitude

                    Log.i("getLOc","lat is : $lat")
                    Log.i("getLOc","lat is : $lon")

                }
            }
        } else {
            Toast.makeText(this, "Turn on location", Toast.LENGTH_LONG).show()
            val intent = Intent(Settings.ACTION_LOCATION_SOURCE_SETTINGS)
            startActivity(intent)
        }
    } else {
        requestPermissions()
    }

}

Answer 1

根据official documentation，在以下情况下，最新已知位置可能是空：

• 在设备设置中关闭了位置信息。因为它清除了缓存。
• 该设备从未记录其位置。 （新设备）
• 设备上的Google Play服务已重新启动。

在这种情况下，您应该requestLocationUpdates

并在LocationCallback上接收新位置。

通过以下步骤您的最后一个已知位置永不为空。

---

前提条件：EasyPermission library

---

步骤1：在清单文件中添加此权限

<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />
步骤2：

    override fun onCreate(savedInstanceState: Bundle?) {
    super.onCreate(savedInstanceState)
    setContentView(R.layout.activity_main)

    //Create location callback when it's ready.
    createLocationCallback()

    //createing location request, how mant request would be requested.
    createLocationRequest()

    //Build check request location setting request
    buildLocationSettingsRequest()

    //FusedLocationApiClient which includes location 
    mFusedLocationClient = LocationServices.getFusedLocationProviderClient(this)
    //Location setting client
    mSettingsClient = LocationServices.getSettingsClient(this)

    //Check if you have ACCESS_FINE_LOCATION permission
    if (!EasyPermissions.hasPermissions(
            this@MainActivity,
            Manifest.permission.ACCESS_FINE_LOCATION)) {
        requestPermissionsRequired()
    }
    else{
        //If you have the permission we should check location is opened or not
        checkLocationIsTurnedOn()
    }

}
步骤3：创建要在onCreate（）

中调用的必需函数

private fun requestPermissionsRequired() {
    EasyPermissions.requestPermissions(
        this,
        getString(R.string.location_is_required_msg),
        LOCATION_REQUEST,
        Manifest.permission.ACCESS_FINE_LOCATION
    )
}

private fun createLocationCallback() {
    //Here the location will be updated, when we could access the location we got result on this callback.
    mLocationCallback = object : LocationCallback() {
        override fun onLocationResult(locationResult: LocationResult) {
            super.onLocationResult(locationResult)
            mCurrentLocation = locationResult.lastLocation
        }
    }
}

private fun buildLocationSettingsRequest() {
    val builder = LocationSettingsRequest.Builder()
    builder.addLocationRequest(mLocationRequest!!)
    mLocationSettingsRequest = builder.build()
    builder.setAlwaysShow(true)
}

private fun createLocationRequest() {
    mLocationRequest = LocationRequest.create()
    mLocationRequest!!.interval = 0
    mLocationRequest!!.fastestInterval = 0
    mLocationRequest!!.numUpdates = 1
    mLocationRequest!!.priority = LocationRequest.PRIORITY_HIGH_ACCURACY
}

public fun checkLocationIsTurnedOn() { // Begin by checking if the device has the necessary location settings.
    mSettingsClient!!.checkLocationSettings(mLocationSettingsRequest)
        .addOnSuccessListener(this) {
            Log.i(TAG, "All location settings are satisfied.")
            startLocationUpdates()
        }
        .addOnFailureListener(this) { e ->
            val statusCode = (e as ApiException).statusCode
            when (statusCode) {
                LocationSettingsStatusCodes.RESOLUTION_REQUIRED -> {
                    try {
                        val rae = e as ResolvableApiException
                        rae.startResolutionForResult(this@MainActivity, LOCATION_IS_OPENED_CODE)
                    } catch (sie: IntentSender.SendIntentException) {
                    }
                }
                LocationSettingsStatusCodes.SETTINGS_CHANGE_UNAVAILABLE -> {
                    mRequestingLocationUpdates = false
                }
            }
        }
}

private fun startLocationUpdates() {
    mFusedLocationClient!!.requestLocationUpdates(
        mLocationRequest,
        mLocationCallback, null
    )
}
步骤4：

确保位置已打开或用户接受打开后，在onActivityResult（）

中处理回调。

override fun onActivityResult(requestCode: Int, resultCode: Int, data: Intent?) {
    super.onActivityResult(requestCode, resultCode, data)
    when (requestCode) {
        LOCATION_IS_OPENED_CODE -> {
            if (resultCode == AppCompatActivity.RESULT_OK) {
                Log.d(TAG, "Location result is OK")
            } else {
                activity?.finish()
            }
        }
}
第5步：从FusedClientApi获取最近的已知位置

override fun onMapReady(map: GoogleMap) {
    mMap = map
    mFusedLocationClient.lastLocation.addOnSuccessListener {
        if(it!=null){
            locateUserInMap(it)
        }
    }

}
   private fun locateUserInMap(location: Location) {
    showLocationSafetyInformation()
    if(mMap!=null){
        val currentLocation = LatLng(location.latitude,location.longitude )
        addMarker(currentLocation)
    }
}


private fun addMarker(currentLocation: LatLng) {
    val cameraUpdate = CameraUpdateFactory.newLatLng(currentLocation)
    mMap?.clear()
    mMap?.addMarker(
        MarkerOptions().position(currentLocation)
            .title("Current Location")
    )
    mMap?.moveCamera(cameraUpdate)
    mMap?.animateCamera(cameraUpdate)
    mMap?.setMinZoomPreference(14.0f);
}
我希望这会有所帮助。

快乐编码🤓