这部分是对上一个问题的扩展：Android 编程，mapview locationoverlay: how to change the default blue location dot, with another image
我一直在努力让设备位置显示在地图上（使用 enablemylocation 很容易），但我需要替换默认图标（很简单，对其进行排序）然后旋转它以对应于当前设备方位 - 从 GPS 获取，因为它需要是移动方向，而不是手机面对的方向。
我使用 'getbearing()' 的方式与我成功使用 'getlatitude()' 和 'getaltitude()' 的方式相同，但 getbearing 始终返回 0。（以确保不是旋转的代码图标是轴承的变量在发生其他任何事情之前打印在文本视图中的问题）
非常奇怪的是，它现在在 5 秒内工作了两次，然后又返回 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
主要活动：
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();
}
}
我的位置监听器
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;
}
}