title: Trying to show ProgressDialog - Gives error
body: <p>I have an activity that gets coordinates for Google maps in the background thread and i want to display a Progress dialog to show when the background thread finishes.</p>
  
  <p><em>map.class</em></p>
  
  <pre><code>package com.example.androidbasic12;
  
  public class map extends FragmentActivity{
  private static LatLng SYDNEY = new LatLng(-33.88,151.21);
  public static  LatLng sala = new LatLng(59.91602, 16.594108);
  int travel = 0;
  int MapTypeInt = 0;
  private GoogleMap mMap;
  GoogleMapOptions options = new GoogleMapOptions();
  String username;
  
  String Lat1;
  String Lng1;
  Double lat;
  Double lng;
  ProgressDialog dialog = new ProgressDialog(this);
  
  // JSON response node names
  private static String KEY_SUCCESS = "success";
  private static String KEY_ERROR = "error";
  private static String KEY_NAME = "name";
  private static String KEY_LAT = "lat";
  private static String KEY_LNG = "lng";
  
  String errorhandler = "";
  
  @Override
  protected void onCreate(Bundle savedInstanceState) {
      super.onCreate(savedInstanceState);
      setContentView(R.layout.maps);
      setUpMapIfNeeded();
  
  
      UserFunctions userFunc = new UserFunctions();
      ArrayList&lt;String&gt; cordarr = new ArrayList&lt;String&gt;();
      cordarr = userFunc.getCoords(getApplicationContext(), Lat1, Lng1);
      if(cordarr != null &amp;&amp; cordarr.size()&gt; 1 ){
          Log.d("LOG", "I got lat long");
          Lat1 = cordarr.get(0);
          Lng1 = cordarr.get(1);
          lat = goDouble(Lat1);
          lng  = goDouble(Lng1);
          LatLng sala = new LatLng(lat, lng);
          mMap.addMarker(new MarkerOptions().position(sala).title("Coords: " 
          + lat + ", "
          + lng));
          options.mapType(GoogleMap.MAP_TYPE_NORMAL)
          .compassEnabled(true)
          .rotateGesturesEnabled(true)
          .tiltGesturesEnabled(true);
      } else {
          Log.d("LOG", "no lat long found");
      }
  
      new getCord().execute();
  
  
  
      //Button that sends the user to Sala by default, and to Sydney if Sala
      Button btnSyd =  (Button) findViewById(R.id.btnSyd);
      btnSyd.setOnClickListener(new View.OnClickListener() {
          @Override
          public void onClick(View v) {
              // TODO Auto-generated method stu
  
              if (travel == 0){
                  travelToSala();
                  travel = 1;
              } else if (travel == 1) {
                  travelToSydney();
                  travel = 0;
              }
          }
      });
      //Button for setting map type to satellite if normal, to normal if satellite
      final ImageButton changeBtn =(ImageButton) findViewById(R.id.changeBtn);
      changeBtn.setOnClickListener(new View.OnClickListener() {
          @Override
          public void onClick(View v) {
              // TODO Auto-generated method stub
              changeMapType(changeBtn);
          }
      });     
  }
  //method that changes maptype
  private void changeMapType(ImageButton button){
      if(MapTypeInt == 0){
          mMap.setMapType(GoogleMap.MAP_TYPE_HYBRID);
          button.setImageResource(R.drawable.normal_map);
          MapTypeInt = 1;
      } else if (MapTypeInt == 1) {
          mMap.setMapType(GoogleMap.MAP_TYPE_NORMAL);
          button.setImageResource(R.drawable.satellite);
          MapTypeInt = 0;
      }
  }
  //Function that travels user to Sydney
  private void travelToSydney(){
      mMap.animateCamera(CameraUpdateFactory.newLatLngZoom(SYDNEY, 15));
      Button btnSyd = (Button) findViewById(R.id.btnSyd);
      btnSyd.setText("travel to Sala");
  }
  //Function that travels user to Sala
  private void travelToSala(){
      mMap.animateCamera(CameraUpdateFactory.newLatLngZoom(sala, 15));
      Button btnSyd = (Button) findViewById(R.id.btnSyd);
      btnSyd.setText("travel to Sydney!");
  }
  //Checks if map is setup, and if it isn't, set's up the map
  private void setUpMapIfNeeded() {
      if (mMap == null) {
          mMap = ((SupportMapFragment) getSupportFragmentManager().findFragmentById(R.id.map)).getMap();
          mMap.animateCamera(CameraUpdateFactory.newLatLngZoom(sala, 15));
          if(mMap != null){
              //The map is veriefied
          }
      } 
  }
  
  class getCord extends AsyncTask&lt;String, String, String&gt;{
  
      @Override
      protected String doInBackground(String... params) {
          // TODO Auto-generated method stub
          UserFunctions userFunction = new UserFunctions();
          username = userFunction.getUsername(getApplicationContext(), "uname"); 
          JSONObject json = userFunction.getCarcoord(username);
  
          try {
              if (json.getString(KEY_SUCCESS) != null){
                  String res = json.getString(KEY_SUCCESS);
                  if (Integer.parseInt(res)==1){
                      //Successfully found users car coordinates
                      DatabaseHandler db = new DatabaseHandler(getApplicationContext());
                      JSONObject json_coord = json.getJSONObject("user");
  
                      //clear previous entries in table "TABLE_COORD"
                      userFunction.resetCarcoord(getApplicationContext());
                      db.addCoord(json_coord.getString(KEY_NAME), json_coord.getString(KEY_LAT), json_coord.getString(KEY_LNG));
                      errorhandler = "2";
  
                  }
              } else if(json.getString(KEY_ERROR) != null) {
                  String res = json.getString(KEY_ERROR);
                  if(Integer.parseInt(res) == 1){
                      //Some error in getting registration, should not happen though
                      errorhandler = "1";
                  }
  
              }
  
          }catch (JSONException e) {
              e.printStackTrace();
          }
          return null;
      }
  
      @Override
      protected void onPreExecute() {
          // TODO Auto-generated method stub
          super.onPreExecute();
          dialog.setCancelable(true);
          dialog.setMessage("Loading car coordinats");
          dialog.show();
  
      }
  
      @Override
      protected void onPostExecute(String result) {
          // TODO Auto-generated method stub
          super.onPostExecute(result);
          dialog.cancel();
          if(errorhandler == "1"){
              Toast toast = Toast.makeText(getApplicationContext(),
                      "User has not got car", Toast.LENGTH_LONG);
              toast.show();
              errorhandler = "";
          } else if (errorhandler == "2" ) {
              // Error in login
              Toast toast = Toast.makeText(getApplicationContext(),
                      "Successfully got coords for car", Toast.LENGTH_LONG);
              toast.show();
              errorhandler = "";
          }
      }
  }
  public Double goDouble(String Latlng) {
      Double goDouble = Double.parseDouble(Latlng);
      return goDouble;
  }
  </code></pre>
  
  <p>}
  <em>Error msg</em></p>
  
  <pre><code>01-25 13:51:00.721: E/AndroidRuntime(7780): FATAL EXCEPTION: main
  01-25 13:51:00.721: E/AndroidRuntime(7780): java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{com.example.androidbasic12/com.example.androidbasic12.map}: java.lang.NullPointerException
  01-25 13:51:00.721: E/AndroidRuntime(7780):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1891)
  01-25 13:51:00.721: E/AndroidRuntime(7780):     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1992)
  01-25 13:51:00.721: E/AndroidRuntime(7780):     at android.app.ActivityThread.access$600(ActivityThread.java:127)
  01-25 13:51:00.721: E/AndroidRuntime(7780):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1158)
  01-25 13:51:00.721: E/AndroidRuntime(7780):     at android.os.Handler.dispatchMessage(Handler.java:99)
  01-25 13:51:00.721: E/AndroidRuntime(7780):     at android.os.Looper.loop(Looper.java:137)
  01-25 13:51:00.721: E/AndroidRuntime(7780):     at android.app.ActivityThread.main(ActivityThread.java:4511)
  01-25 13:51:00.721: E/AndroidRuntime(7780):     at java.lang.reflect.Method.invokeNative(Native Method)
  01-25 13:51:00.721: E/AndroidRuntime(7780):     at java.lang.reflect.Method.invoke(Method.java:511)
  01-25 13:51:00.721: E/AndroidRuntime(7780):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:980)
  01-25 13:51:00.721: E/AndroidRuntime(7780):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:747)
  01-25 13:51:00.721: E/AndroidRuntime(7780):     at dalvik.system.NativeStart.main(Native Method)
  01-25 13:51:00.721: E/AndroidRuntime(7780): Caused by: java.lang.NullPointerException
  01-25 13:51:00.721: E/AndroidRuntime(7780):     at android.content.ContextWrapper.getApplicationInfo(ContextWrapper.java:139)
  01-25 13:51:00.721: E/AndroidRuntime(7780):     at android.view.ContextThemeWrapper.getTheme(ContextThemeWrapper.java:65)
  01-25 13:51:00.721: E/AndroidRuntime(7780):     at android.app.AlertDialog.resolveDialogTheme(AlertDialog.java:142)
  01-25 13:51:00.721: E/AndroidRuntime(7780):     at android.app.AlertDialog.&lt;init&gt;(AlertDialog.java:98)
  01-25 13:51:00.721: E/AndroidRuntime(7780):     at android.app.ProgressDialog.&lt;init&gt;(ProgressDialog.java:77)
  01-25 13:51:00.721: E/AndroidRuntime(7780):     at com.example.androidbasic12.map.&lt;init&gt;(map.java:42)
  01-25 13:51:00.721: E/AndroidRuntime(7780):     at java.lang.Class.newInstanceImpl(Native Method)
  01-25 13:51:00.721: E/AndroidRuntime(7780):     at java.lang.Class.newInstance(Class.java:1319)
  01-25 13:51:00.721: E/AndroidRuntime(7780):     at android.app.Instrumentation.newActivity(Instrumentation.java:1026)
  01-25 13:51:00.721: E/AndroidRuntime(7780):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1882)
  01-25 13:51:00.721: E/AndroidRuntime(7780):     ... 11 more
  </code></pre>
  
  <p>Anyone that can see what the problem is?</p>