title: Attempt to invoke virtual method 'void android.widget.RadioGroup.check(int)' on a null object reference
body: <p>i trying to store of session of  four  radio  buttons in  public class 
      SharedPrefManager  and acess to home activity that is  not work for me</p>
  
  <blockquote>
    <p>java.lang.NullPointerException: Attempt to invoke virtual method
    'void android.widget.RadioGroup.check(int)' on a null object reference
            at themedicall.com.Home.onCreate(Home.java:257)</p>
  </blockquote>
  
  <pre><code> public class SharedPrefManager {
  
   private static SharedPrefManager mInstance;
  SharedPreferences.Editor editor;
  SharedPreferences sharedPrefs;
  
  public static synchronized SharedPrefManager getLoginInstance(Context context) {
      if (mInstance == null) {
          mInstance = new SharedPrefManager(context);
      }
      return mInstance;
  }
  
  private SharedPrefManager(Context context) {
      sharedPrefs = context.getSharedPreferences("shared_pref", Context.MODE_PRIVATE);
  }
  
  public void saveData(String hospital) {
      editor = sharedPrefs.edit();
      if (!hospital.equalsIgnoreCase("")) editor.putString("hospital", hospital);
  
      editor.apply();
  }
  public boolean isradioChecked() {
      String hospital = sharedPrefs.getString("hospital", "");
      if (hospital.equals("")) {
          return false;
      } else {
          return true;
      }
  }
  public boolean isDrugLogin() {
      String Drugs = sharedPrefs.getString("Drugs", "");
      if (Drugs.equals("")) {
          return false;
      } else {
          return true;
      }
  }
  public void logout() {
      editor = sharedPrefs.edit();
      editor.clear();
      editor.apply();
  }
  </code></pre>
  
  <p><strong>Home Activity</strong></p>
  
  <pre><code>    public class Home extends NavigationDrawer implements
      GoogleApiClient.ConnectionCallbacks, 
      GoogleApiClient.OnConnectionFailedListener, LocationListener, 
      SearchView.OnQueryTextListener {
  
  
  EditText mainSearchView;
  public static final int REQUEST_PERMISSION_CODE = 30;
  ProgressDialog progressDialog;
  private static final String TAG = "Home";
  String cancel_req_tag = "Home";
  Boolean locationApiHasRun = false;
  
  public static Double lat, lang;
  public static LatLng userCurrentLocation;
  
  GoogleApiClient mGoogleApiClient;
  Location mLastLocation;
  LocationRequest mLocationRequest;
  public static String city, state, country, postalCode, knownName;
  SharedPreferences sharedPreferencesCityAndLatLng, sharedPreferencesForBloodCurrentCity;
  public static SharedPreferences.Editor cityAndLatLngEditor, bloodCurrentCity;
  
  JSONObject jsonObject;
  JSONArray jsonArray;
  Button locationFilter;
  CircleImageView userIcon;
  ImageView searchViewImg;
  ImageView doctorFilterImage;
  ImageView WhatsappBtn;
  ImageView WebBtn;
  ImageView AccountBtn;
  RelativeLayout.LayoutParams params;
  ImageView iv_crosee;
  RelativeLayout rl_for_drawer_icon;
  ImageView im_up_arrow, iv_touch;
  RelativeLayout rl_full_screen_view;
  
  
  
  SearchView search_view;
  
  
  
  int radioSelectedId;
  RadioButton radioButton;
  private Timer timer;
  JSONObject object;
  JSONArray hospitalArray;
  
  
  
  AutoCompleteTextView autoCompleteSearch;
  
  Handler mHandler;
  String radioButtonText = "Doctors";
  private String textToSearch;
  private String filter;
  ProgressBar advanceSearchBar;
  
  Dialog networkDialog;
  
  RelativeLayout homeMainLayout;
  MyReceiverForImageUploaded myReceiverForImageUploaded;
  SharedPreferences sharedPreferencesFirstTimeGuied;
  
  Button drugBookBtn;
  Button studyRoomBtn;
  
  RadioGroup mainSearchRadioGroup, mainSearchRadioGroup2;
  
  String generic = "Generic";
  String brand = "Brand";
  String company = "Company";
  Boolean genericBool;
  Boolean brandBool;
  Boolean companyBool;
  String company_id;
  String company_name;
  String brand_name;
  String generics_id;
  String generics_name;
  String potency;
  String potencymajor;
  String brand_detail_id;
  String packing;
  String drug_form;
  String price;
  String generic_name;
  String drugId;
  JSONObject company_jsonObject;
  JSONObject form_jsonObject;
  JSONArray drugs_JsonArray;
  JSONArray brand_details;
  Boolean companyloaded = false;
  Boolean genericsloaded = false;
  Boolean brandloaded = false;
  String type = "Brand";
  private ProgressBar bar;
  private int requestCount = 1;
  int last_page = 0;
  
  BroadcastReceiver checkConectivity;
  
  DataBaseAccess db;
  RadioButton hospital_radio;
  
  RadioGroup radio_group;
   @Override
     protected void onCreate(Bundle savedInstanceState) {
      super.onCreate(savedInstanceState);
      if (SharedPrefManager.getLoginInstance(Home.this).isradioChecked()) {
  
              radio_group.check(R.id.hospital_radio);
              radioButtonText="Hospitals";
              mainSearchRadioGroup.clearCheck();
              openSearchViewDialog();
  
  
      }else if 
  (SharedPrefManager.getLoginInstance(Home.this).isDrugLogin())
      {
  
              radio_group.check(R.id.brand_radio);
              radioButtonText="Drugs";
              openSearchViewDialog();
              mainSearchRadioGroup.clearCheck();
          }
  
  getSupportActionBar().setDisplayOptions(ActionBar.DISPLAY_SHOW_CUSTOM);
   getSupportActionBar().setCustomView
  (R.layout.custom_actionbar_navigation_drawer);
      customActionBarView=getSupportActionBar().getCustomView();
      getSupportActionBar().setElevation(0);
  
      getSupportActionBar().setBackgroundDrawable(new 
  
   ColorDrawable(getResources()
   .getColor(R.color.landingScreenBackgroundColor)));
  
      LayoutInflater layoutInflater=(LayoutInflater) 
      this.getSystemService(LAYOUT_INFLATER_SERVICE);
      View view=layoutInflater.inflate(R.layout.activity_home, null, 
     false);
      drawer.addView(view, 0);
  
     radio_group = (RadioGroup) findViewById(R.id.radio_group);
      hospital_radio= (RadioButton) findViewById(R.id.hospital_radio);
      //radio_group.check(R.id.doctor_radio);
      radio_group.setOnCheckedChangeListener(listener1);
       mainSearchRadioGroup.setOnCheckedChangeListener(listener1);
     }
     private RadioGroup.OnCheckedChangeListener listener1 = new 
     RadioGroup.OnCheckedChangeListener() {
  
      @Override
      public void onCheckedChanged(RadioGroup group, int checkedId) {
  
  
          if (group.getCheckedRadioButtonId() == R.id.doctor_radio) {
  
              radioButtonText = "Doctors";
  
  
          } else if (group.getCheckedRadioButtonId() == 
   R.id.hospital_radio) {
  
              radioButtonText = "Hospitals";
  
  
          } else if (group.getCheckedRadioButtonId() == R.id.brand_radio) {
  
              radioButtonText = "Drugs";
          } else if (group.getCheckedRadioButtonId() == R.id.generic_radio) 
     {
  
              radioButtonText = "Generics";
  
              //saveData(radioButtonText);
  
         }else {
  
  
   SharedPrefManager.getLoginInstance(Home.this).saveData(radioButtonText);
              Log.e("tag", "radio button in text in main search : " + 
   radioButtonText);
          }
  
  
      }
     };
             public void openSearchViewDialog() {
      autoCompleteSearch.addTextChangedListener(new TextWatcher() {
  
          @Override
          public void afterTextChanged(final Editable editable) {
  
  
              if (radioButtonText.equals("Doctors")) {
  
                  if (editable.toString().length() &gt;= 3) {
  
                      Log.e("tag", "auto complete text : " + 
   editable.toString());
                      Log.e("tag", "doctor radio button selected: ");
                      doctorNameFilter.clear();
                      useHandler(editable.toString(), "Doctors");
  
                  } else {
                      Log.e("tag", "web service not call " + 
   editable.toString());
                  }
              } else if (radioButtonText.equals("Hospitals")) {
                  if (editable.toString().length() &gt;= 3) {
                      Log.e("tag", "auto complete text : " + 
    editable.toString());
                      Log.e("tag", "radio button in text in main search : " 
   + radioButtonText);
  
                      HospitalNameFilter.clear();
                      useHandler(editable.toString(), "Hospitals");
                  } else {
                      Log.e("tag", "web service not call " + 
    editable.toString());
                  }
  
              } else if (radioButtonText.equals("Drugs")) {
  
                  if (editable.toString().length() &gt;= 3) {
                      Log.e("tag", "auto complete text : " + 
   editable.toString());
                      Log.e("tag", "radio button in text in main search : " 
    + radioButtonText);
  
                      brandNamesFilter.clear();
                      useHandler(editable.toString(), "Drugs");
                  } else {
                      Log.e("tag", "web service not call " + 
      editable.toString());
                  }
  
              } else if (radioButtonText.equals("Generics")) {
  
                  if (editable.toString().length() &gt;= 3) {
                      Log.e("tag", "auto complete text : " + 
     editable.toString());
                      Log.e("tag", "radio button in text in main search : " 
    + radioButtonText);
  
                      genericNamesFilter.clear();
                      useHandler(editable.toString(), "Generics");
                  } else {
                      Log.e("tag", "web service not call " + 
    editable.toString());
                  }
  
              }
  
          }
  
          @Override
          public void onTextChanged(CharSequence charSequence, int i, int 
    i1, int i2) {
  
  
          }
  
          @Override
          public void beforeTextChanged(CharSequence charSequence, int i, 
      int i1, int i2) {
              //  Toast.makeText(Hospitals.this, "text in beforeTextChanged 
    "+charSequence.toString(), Toast.LENGTH_SHORT).show();
  
          }
  
  
      });
  </code></pre>