Android的getbearing只返回0.0。尝试使用旋转当前位置图标(Android g

这部分的扩展，以前的问题： Android的编程，MapView的locationoverlay：如何更改默认蓝色位置点，与其它图像

我一直在努力来获得设备的位置显示在地图上（容易enablemylocation），但我需要更换默认图标（很容易，排序时），然后将其旋转至对应于当前设备轴承 - 从GPS获取，因为它需要的运动方向，没有方向的手机面对的问题。

我现在用同样的方式“getbearing（）”，因为我已经成功地使用了“getlatitude（）”和“getaltitude（）”，但始终getbearing返回0（以确保它是不是旋转代码图标是用于轴承的变量在一个TextView印刷别的发生之前）的问题

非常奇怪的是，它已经两次工作了所有的5秒钟，然后回到了返回0， - 所以理论上代码似乎是正确的？

代码如下。

亲切的问候

缺口

Mainactivity：

package com.nick.kestrel;

import android.content.Context;
import android.location.LocationListener;
import android.location.LocationManager;
import android.os.Bundle;
import android.widget.TextView;

import com.google.android.maps.MapActivity;
import com.google.android.maps.MapView;


public class KestrelActivity extends MapActivity {
/** Called when the activity is first created. */

static TextView LocationText;
MapView mapView;


@Override
protected boolean isRouteDisplayed() {
        return false;
}

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);

  //Identifies the textview 'locationtext' as the variable LocationText. Planned usage just for debugging
    LocationText = (TextView)findViewById(R.id.locationtext);

  //defines the mapview as variable 'mapView' and enables zoom controls
    mapView = (MapView) findViewById(R.id.mapview);
    mapView.setBuiltInZoomControls(true);

    /**
     * Code required to receive gps location. Activates GPS provider, and is set to update only after
     * at least 10 seconds and a position change of at least 10 metres
     */
    LocationListener locationListener = new MyLocationListener();

    //setting up the location manager
    LocationManager locman = (LocationManager) getSystemService(Context.LOCATION_SERVICE);

    locman.requestLocationUpdates(LocationManager.GPS_PROVIDER, 500, (float) 0.01, locationListener); 

    //Adds a current location overlay to the map 'mapView' and turns on the map's compass

    MyLocation myLocationOverlay = new MyLocation(this, mapView);
    myLocationOverlay.enableMyLocation();
    myLocationOverlay.enableCompass();

    mapView.getOverlays().add(myLocationOverlay);
    mapView.postInvalidate();
}

}

mylocationlistener

package com.nick.kestrel;

import android.location.Location;
import android.location.LocationListener;
import android.os.Bundle;


public class MyLocationListener implements LocationListener {

private boolean hasbearing;

/**
 * Code to run when the listener receives a new location
 */



@Override
public void onLocationChanged(Location locFromGps) {



    //Toast.makeText(getApplicationContext(), "Location changed, Lat: "+locFromGps.getLatitude()+" Long: "+ locFromGps.getLongitude(), Toast.LENGTH_SHORT).show();

    //LocationText.setText("Your Location: Latitude " +locFromGps.getLatitude() + " Longitude: " +locFromGps.getLongitude());

    double dbllatitude = locFromGps.getLatitude();
    double dbllongitude = locFromGps.getLongitude();
    double dblaltitude = locFromGps.getAltitude();
    float bearing = locFromGps.getBearing(); 

    KestrelActivity.LocationText.setText("Your Location: Latitude " + dbllatitude + " Longitude: " +dbllongitude + " Altitude " + dblaltitude + " Bearing: " + bearing);



    hasbearing = locFromGps.hasBearing();


    if (hasbearing =  false) {

        //Toast.makeText(getApplicationContext(), "No bearing", Toast.LENGTH_SHORT).show();

    }
    else
    {
        //Toast.makeText(getApplicationContext(), "I HAZ bearing: " + locFromGps.getBearing(), Toast.LENGTH_SHORT).show();
    }


}

@Override
public void onProviderDisabled(String provider) {
   // called when the GPS provider is turned off (user turning off the GPS on the phone)
}

@Override
public void onProviderEnabled(String provider) {
   // called when the GPS provider is turned on (user turning on the GPS on the phone)
}

@Override
public void onStatusChanged(String provider, int status, Bundle extras) {
   // called when the status of the GPS provider changes

}

}

我的位置

package com.nick.kestrel;

import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.graphics.Matrix;
import android.graphics.Point;
import android.location.Location;

import com.google.android.maps.GeoPoint;
import com.google.android.maps.MapView;
import com.google.android.maps.MyLocationOverlay;



public class MyLocation extends MyLocationOverlay {
private Context mContext;
static float   mOrientation;

public MyLocation(Context context, MapView mapView) {
    super(context, mapView);
    mContext = context;
}

@Override 
protected void drawMyLocation(Canvas canvas, MapView mapView, Location lastFix, GeoPoint myLocation, long when) {
    // translate the GeoPoint to screen pixels
    Point screenPts = mapView.getProjection().toPixels(myLocation, null);

    // create a rotated copy of the marker
    Bitmap arrowBitmap = BitmapFactory.decodeResource( mContext.getResources(), R.drawable.pin_icon);
    Matrix matrix = new Matrix();
    matrix.postRotate(mOrientation);
    Bitmap rotatedBmp = Bitmap.createBitmap(
        arrowBitmap, 
        0, 0, 
        arrowBitmap.getWidth(), 
        arrowBitmap.getHeight(), 
        matrix, 
        true
    );
    // add the rotated marker to the canvas
    canvas.drawBitmap(
        rotatedBmp, 
        screenPts.x - (rotatedBmp.getWidth()  / 2), 
        screenPts.y - (rotatedBmp.getHeight() / 2), 

        null

    );
    mapView.postInvalidate();

}

public void setOrientation(float newOrientation) {
     mOrientation = newOrientation;
}

}

Answer 1:

什么是地点的供应商？如果NETWORK_PROVIDER ，那么您将无法获得轴承，因为其精度低，检测轴承。

试试你的应用程序外，并与GPS_PROVIDER ？

Answer 2:

问题解决了！感谢Aleksejs你的努力 - 原来这是野餐的情况。

我已经设定的GPS在最小的移动进行更新，并作为定位中跳来跳去，我认为它应该能够制定出轴承和上算。

当检测出从结果“getSpeed（）”我注意到轴承的工作-原来你必须移动远一点花园周围，而不是给它时间来解决您的轴承。

问候

缺口