使用我的位置纬度经度和 DB 纬度经度计算距离。但总是错误“应用程序 AndroidGoogleMaps（进程 com.androidhive.googlemaps）已意外停止。请重试。”
public class AndroidGoogleMapsActivity extends MapActivity {
public int mm[][]= new int[100][100];
double[][] rtdist= new double[50][2];
double[][] okdist= new double[50][2];
public GeoPoint[] endpp = new GeoPoint[100];
private static String KEY_SUCCESS = "success";
private MyLocationOverlay mylayer;
private MapController mapController;
private MapView mapView;
protected GeoPoint geoPoint;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
findViews();
setupMap();
}
private void findViews() {
mapView = (MapView) findViewById(R.id.mapView);
mapController = mapView.getController();
mapView.setBuiltInZoomControls(true);
}
private void setupMap() {
List<Overlay> overlays = mapView.getOverlays();
mylayer = new MyLocationOverlay(this, mapView);
mylayer.runOnFirstFix(new Runnable() {
public void run() {
// Zoom in to current location
mapView.setTraffic(true);
mapController.setZoom(17);
mapController.animateTo(mylayer.getMyLocation());
}
});
overlays.add(mylayer);
GeoPoint startpp = mylayer.getMyLocation();
String b="SELECT lat,lng FROM markers";
UserFunctions userFunction = new UserFunctions();
JSONObject json = userFunction.execqlcmd(b);
try {
if (json.getString(KEY_SUCCESS) != null)
{
String res = json.getString(KEY_SUCCESS);
if(Integer.parseInt(res) == 1)
{
for(int i=0 ; i<100 ; i++) {
JSONObject json_row = json.getJSONObject("r"+i);
mm[i][0]=(int)(Double.parseDouble(json_row.getString("c0")) * 1E6) ;
mm[i][1]=(int)(Double.parseDouble(json_row.getString("c1")) * 1E6) ;
endpp[i] =new GeoPoint(mm[i][0], mm[i][1] );
MapController mc = mapView.getController();
DistanceCalculator caldist= new DistanceCalculator(6371);
for(int j = 0; j < 2; j++)
{
rtdist[j][0]=1;
rtdist[j][1]=caldist.CalculationByDistance(startpp, endpp[j]);
//startpp The location of the phone is
//endpp DB's lat lng
//To judge the results of this array is in line with the distance required by the user
if(rtdist[j][1]<=50)
{
okdist[j][0]=rtdist[j][0]; //The amount of store
okdist[j][0]=rtdist[j][1]; //Store the distance
}
}
mc.animateTo(geoPoint);
mc.setZoom(15);
mapView.invalidate();
List<Overlay> mapOverlays = mapView.getOverlays();
Drawable drawable = this.getResources().getDrawable(R.drawable.mark_red);
AddItemizedOverlay itemizedOverlay =
new AddItemizedOverlay(drawable, this);
OverlayItem overlayitem = new OverlayItem(geoPoint, "Hello", "Sample Overlay item");
itemizedOverlay.addOverlay(overlayitem);
mapOverlays.add(itemizedOverlay);
}}}}
catch (JSONException e) {
e.printStackTrace();
}
}
@Override
protected void onResume() {
// TODO Auto-generated method stub
super.onResume();
mylayer.enableMyLocation();
}
@Override
protected void onPause() {
// TODO Auto-generated method stub
super.onPause();
mylayer.disableMyLocation();
}
@Override
protected boolean isRouteDisplayed() {
return false;
}
public class DistanceCalculator {
private double Radius;
// R = earth's radius (mean radius = 6,371km)
// Constructor
DistanceCalculator(double R) {
Radius = R;
}
public double CalculationByDistance(GeoPoint startpp, GeoPoint endpp) {
double lat1 = startpp.getLatitudeE6()/1E6;
double lat2 = endpp.getLatitudeE6()/1E6;
double lon1 = startpp.getLongitudeE6()/1E6;
double lon2 = endpp.getLongitudeE6()/1E6;
double dLat = Math.toRadians(lat2-lat1);
double dLon = Math.toRadians(lon2-lon1);
double a = Math.sin(dLat/2) * Math.sin(dLat/2) +
Math.cos(Math.toRadians(lat1)) * Math.cos(Math.toRadians(lat2)) *
Math.sin(dLon/2) * Math.sin(dLon/2);
double c = 2 * Math.asin(Math.sqrt(a));
return Radius * c;
}
}
}
日志猫：
05-13 14:49:44.703: D/dalvikvm(303): GC_FOR_MALLOC freed 4358 objects / 275032 bytes in 316ms
05-13 14:49:44.903: D/dalvikvm(303): GC_FOR_MALLOC freed 10567 objects / 641664 bytes in 58ms
05-13 14:49:45.063: D/dalvikvm(303): GC_FOR_MALLOC freed 4727 objects / 310440 bytes in 45ms
05-13 14:49:45.243: D/dalvikvm(303): GC_FOR_MALLOC freed 6480 objects / 394584 bytes in 48ms
05-13 14:49:45.443: D/dalvikvm(303): GC_FOR_MALLOC freed 7949 objects / 616640 bytes in 51ms
05-13 14:49:45.623: D/dalvikvm(303): GC_FOR_MALLOC freed 6072 objects / 370040 bytes in 51ms
05-13 14:49:45.813: D/dalvikvm(303): GC_FOR_MALLOC freed 4449 objects / 354128 bytes in 62ms
05-13 14:49:45.823: I/dalvikvm-heap(303): Grow heap (frag case) to 3.048MB for 87396-byte allocation
05-13 14:49:45.884: D/dalvikvm(303): GC_FOR_MALLOC freed 45 objects / 2392 bytes in 66ms
05-13 14:49:45.953: D/dalvikvm(303): GC_FOR_MALLOC freed 2 objects / 80 bytes in 67ms
05-13 14:49:45.953: I/dalvikvm-heap(303): Grow heap (frag case) to 3.129MB for 87396-byte allocation
05-13 14:49:46.013: D/dalvikvm(303): GC_FOR_MALLOC freed 0 objects / 0 bytes in 58ms
05-13 14:49:46.273: E/JSON(303): {"tag":"exesqlcmd","success":1,"error":0,"rownum":2,"colnum":2,"r0":{"c0":"23.973728","c1":"121.583641"},"r1":{"c0":"23.973827","c1":"121.585625"}}
05-13 14:49:46.293: D/AndroidRuntime(303): Shutting down VM
05-13 14:49:46.293: W/dalvikvm(303): threadid=1: thread exiting with uncaught exception (group=0x4001d800)
05-13 14:49:46.313: E/AndroidRuntime(303): FATAL EXCEPTION: main
05-13 14:49:46.313: E/AndroidRuntime(303): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.androidhive.googlemaps/com.androidhive.googlemaps.AndroidGoogleMapsActivity}: java.lang.NullPointerException
05-13 14:49:46.313: E/AndroidRuntime(303): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2663)
05-13 14:49:46.313: E/AndroidRuntime(303): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2679)
05-13 14:49:46.313: E/AndroidRuntime(303): at android.app.ActivityThread.access$2300(ActivityThread.java:125)
05-13 14:49:46.313: E/AndroidRuntime(303): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2033)
05-13 14:49:46.313: E/AndroidRuntime(303): at android.os.Handler.dispatchMessage(Handler.java:99)
05-13 14:49:46.313: E/AndroidRuntime(303): at android.os.Looper.loop(Looper.java:123)
05-13 14:49:46.313: E/AndroidRuntime(303): at android.app.ActivityThread.main(ActivityThread.java:4627)
05-13 14:49:46.313: E/AndroidRuntime(303): at java.lang.reflect.Method.invokeNative(Native Method)
05-13 14:49:46.313: E/AndroidRuntime(303): at java.lang.reflect.Method.invoke(Method.java:521)
05-13 14:49:46.313: E/AndroidRuntime(303): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868)
05-13 14:49:46.313: E/AndroidRuntime(303): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626)
05-13 14:49:46.313: E/AndroidRuntime(303): at dalvik.system.NativeStart.main(Native Method)
05-13 14:49:46.313: E/AndroidRuntime(303): Caused by: java.lang.NullPointerException
05-13 14:49:46.313: E/AndroidRuntime(303): at com.androidhive.googlemaps.AndroidGoogleMapsActivity$DistanceCalculator.CalculationByDistance(AndroidGoogleMapsActivity.java:178)
05-13 14:49:46.313: E/AndroidRuntime(303): at com.androidhive.googlemaps.AndroidGoogleMapsActivity.setupMap(AndroidGoogleMapsActivity.java:106)
05-13 14:49:46.313: E/AndroidRuntime(303): at com.androidhive.googlemaps.AndroidGoogleMapsActivity.onCreate(AndroidGoogleMapsActivity.java:41)
05-13 14:49:46.313: E/AndroidRuntime(303): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)
05-13 14:49:46.313: E/AndroidRuntime(303): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2627)
05-13 14:49:46.313: E/AndroidRuntime(303): ... 11 more