[英]Android Location getBearing() always returns 0
我一直在尝试为我的Android应用程序实现一项功能,该功能无论设备指向何处都可以获取设备的速度和行进方向。 例如:如果我的Android设备指向北向,而我向南移动,则返回向南移动。
我一直在环顾四周,并且提出了使用Location的getBearing()方法的可能性(不过,我不知道这是否可以解决我的整个问题)。 当我调用getBearing()时,由于某种原因它总是返回0.0。 我不知道为什么。 这是我的代码:
LocationManager lm;
@Override
protected void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_gcm);
setUpUI(findViewById(R.id.LinearLayout1));
isRegged = false;
// GCM startup
gcm = GoogleCloudMessaging.getInstance(this);
context = getApplicationContext();
gps = new GPSTracker(context);
// gps.startListening(context);
// gps.setGpsCall(this);
/*
* Variables to indicate location and device ID
*/
TelephonyManager telephonyManager = (TelephonyManager) getSystemService(Context.TELEPHONY_SERVICE);
if (gps.getIsGPSTrackingEnabled())
{
longitude = Double.valueOf(gps.getLongitude()).toString();
latitude = Double.valueOf(gps.getLatitude()).toString();
}
deviceID = telephonyManager.getDeviceId();
mSensorManager = (SensorManager) getSystemService(SENSOR_SERVICE);
lm = (LocationManager) getSystemService(Context.LOCATION_SERVICE);
lm.requestLocationUpdates(LocationManager.GPS_PROVIDER, 0, (float) 0.0,
this);
}
这就是我要承受的地方。
@Override
public void onLocationChanged(Location currentLocation)
{
float speed = 0;
float speed_mph = 0;
if (previousLocation != null)
{
float distance = currentLocation.distanceTo(previousLocation);
// time taken (in seconds)
float timeTaken = ((currentLocation.getTime() - previousLocation
.getTime()) / 1000);
// calculate speed
if (timeTaken > 0)
{
speed = getAverageSpeed(distance, timeTaken);
speed_mph = (float) (getAverageSpeed(distance, timeTaken) / 1.6);
}
if (speed >= 0)
{
info_text.setVisibility(View.VISIBLE);
info_text_mph.setVisibility(View.VISIBLE);
DecimalFormat df = new DecimalFormat("#.#");
info_text.setText("Speed: " + df.format(speed) + " " + "km/h");
info_text_mph.setText(" Speed: " + df.format(speed_mph) + " "
+ "mph");
if (speed >= 10 && lm.getProvider(LocationManager.GPS_PROVIDER).supportsBearing())
{
float degree = currentLocation.getBearing();
direction_text.setVisibility(View.VISIBLE);
Log.i(TAG, String.valueOf(degree));
if (degree == 0 && degree < 45 || degree >= 315
&& degree == 360)
{
direction_text.setText("You are: Northbound");
}
if (degree >= 45 && degree < 90)
{
direction_text.setText("You are: NorthEastbound");
}
if (degree >= 90 && degree < 135)
{
direction_text.setText("You are: Eastbound");
}
if (degree >= 135 && degree < 180)
{
direction_text.setText("You are: SouthEastbound");
}
if (degree >= 180 && degree < 225)
{
direction_text.setText("You are: SouthWestbound");
}
if (degree >= 225 && degree < 270)
{
direction_text.setText("You are: Westbound");
}
if (degree >= 270 && degree < 315)
{
direction_text.setText("You are: NorthWestbound");
}
}
}
}
previousLocation = currentLocation;
}
非常感谢!
如果您使用LocationManager.NETWORK_PROVIDER
获取数据,则getBearing()
将返回0,因为信号/准确性太弱。 尝试将GPS提供程序设置为GPS,并确保在室外对其进行测试(由于卫星之间没有直接通讯,GPS无法在室内或在很高的建筑物中间使用)
为了确保你选择支持getBearing提供商(),您可以使用从方法LocationProvider
称为supportsBearing ()
如果提供您选择支持的返回true getBearing()
调用。
最后,确保您在AndroidManifest.xml中具有ACCESS_COARSE_LOCATION
或ACCESS_FINE_LOCATION
权限
根据我的建议,代码如下所示:
LocationManager mlocManager =
(LocationManager)getSystemService(Context.LOCATION_SERVICE);
LocationListener mlocListener = new MyLocationListener();
mlocManager.requestLocationUpdates( LocationManager.GPS_PROVIDER, 0, 0, mlocListener);
资源: http : //developer.android.com/reference/android/location/LocationManager.html http://developer.android.com/reference/android/location/LocationProvider.html http://www.firstdroid.com/ 2010/04/29 / android-development-using-gps-get-current-location-2 /
更新:答案是,用于在getBearing()中计算的两点太近了,因此得出的结果不准确。 要更正此问题,请手动获取两个GPS点,然后使用bearingTo()查看更准确的结果。
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