Q:

AutoCompleteView crashing at cursor

My frist post only had less than half my text hence the second (complete) post.
I'm working on a test app using sqlite to populate two AutoCompleteTextView's i'm using car make and model for the test
AutoComplete's:
makeAutocomplete 
modelAutocomplete
makeAutocomplete's list is populated from a sql query and it works fine
the second is populated when the make is selected 
makeAutoComplete.setOnItemSelectedListener(new OnItemSelectedListener() {

        @Override
        public void onItemSelected(AdapterView<?> arg0, View arg1, int arg2, long arg3) {

            final String[] makeSelected = {arg0.getItemAtPosition(arg2).toString()};
            final String[] modelDeal = sqlDBModel.getAllModelFilter(makeSelected);
            ArrayAdapter<String> modelAdapter = new ArrayAdapter<String>(getApplicationContext(), android.R.layout.simple_dropdown_item_1line, modelDeal);
            initModelAutoComplete(modelAdapter);

        }

        @Override
        public void onNothingSelected(AdapterView<?> arg0) {
            // TODO Auto-generated method stub

        }
    });

initModelAutoComplete Declaration
public void initModelAutoComplete(ArrayAdapter<String> adapter){

    //adapter = new ArrayAdapter<String>(this, android.R.layout.simple_dropdown_item_1line, list);
    modelAutoComplete.setAdapter(adapter);
    modelAutoComplete.setThreshold(1);
    modelAutoComplete.setOnItemClickListener(new OnItemClickListener() {
        @Override
        public void onItemClick(AdapterView<?> arg0, View arg1, int arg2, long arg3){
            arg0.getItemAtPosition(arg2);
        }
    });
}

SQLiteModelSearch.getAllModelFilter Declaration
    public String[] getAllModelFilter(String[] vehiclemake){

    if(vehiclemake != null){

        Cursor cursor = this.sqliteDBInstance.query(DB_MAKEMODEL_TABLE,
                                                    new String[]{DB_COLUMN_MAKE, DB_COLUMN_MODEL},
                                                    DB_COLUMN_MAKE+"=?",
                                                    vehiclemake,
                                                    null,
                                                    null,
                                                    null,
                                                    null);

        if( cursor != null){
            String[] str = new String[cursor.getCount()];

            int i = 0;
            while(cursor.moveToNext()){
                str[i] = cursor.getString(cursor.getColumnIndex(DB_COLUMN_MODEL));
                i++;
            }
            return str;
        } else {
            Log.i("vehiclemake = ", "NULL");
            return new String[]{};
        }
    }

    return new String[]{};
}

LogCat 

07-31 13:00:19.631: E/AndroidRuntime(1302):   at
  android.app.ActivityThread.main(ActivityThread.java:3683)
07-31 13:00:19.631: E/AndroidRuntime(1302):   at
  java.lang.reflect.Method.invokeNative(Native Method) 07-31
  13:00:19.631: E/AndroidRuntime(1302): FATAL EXCEPTION: main
07-31 13:00:19.631: E/AndroidRuntime(1302):
  java.lang.NullPointerException
07-31 13:00:19.631: E/AndroidRuntime(1302):   at
  com.myapp.sqltest.database.SQLiteModelSearch.getAllModelFilter(SQLiteModelSearch.java:100)
07-31 13:00:19.631: E/AndroidRuntime(1302):   at
  com.myapp.sqltest.activity.addVehicleActivity$2.onItemSelected(addVehicleActivity.java:62)
07-31 13:00:19.631: E/AndroidRuntime(1302):   at
  android.widget.AdapterView.fireOnSelected(AdapterView.java:871)
07-31 13:00:19.631: E/AndroidRuntime(1302):   at
  android.widget.AdapterView.access$200(AdapterView.java:42)
07-31 13:00:19.631: E/AndroidRuntime(1302):   at
  android.widget.AdapterView$SelectionNotifier.run(AdapterView.java:837)
07-31 13:00:19.631: E/AndroidRuntime(1302):   at
  android.os.Handler.handleCallback(Handler.java:587)
07-31 13:00:19.631: E/AndroidRuntime(1302):   at
  android.os.Handler.dispatchMessage(Handler.java:92)
07-31 13:00:19.631: E/AndroidRuntime(1302):   at
  android.os.Looper.loop(Looper.java:130)
07-31 13:00:19.631: E/AndroidRuntime(1302):   at
  java.lang.reflect.Method.invoke(Method.java:507)
07-31 13:00:19.631: E/AndroidRuntime(1302):   at
  com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:839)
07-31 13:00:19.631: E/AndroidRuntime(1302):   at
  com.android.internal.os.ZygoteInit.main(ZygoteInit.java:597)
07-31 13:00:19.631: E/AndroidRuntime(1302):   at
  dalvik.system.NativeStart.main(Native Method)

I can see that the exception is being thrown at:
Cursor cursor = this.sqliteDBInstance.query(DB_MAKEMODEL_TABLE,
                                                    new String[]{DB_COLUMN_MAKE, DB_COLUMN_MODEL},
                                                    DB_COLUMN_MAKE+"=?",
                                                    vehiclemake,
                                                    null,
                                                    null,
                                                    null,
                                                    null);

but can't tell why, i've watched all the variables going into the functions and none of them are null?

A:

I've figured it out. the issue was that I had defined 
public AutoCompleteTextView modelAutoComplete;
public AutoCompleteTextView makeAutoComplete;

Then then in function onCreate
I had defined:
AutoCompleteTextView modelAutoComplete = (AutoCompleteTextView) findViewById(R.id.autoCompleteModel);
AutoCompleteTextView makeAutoComplete = (AutoCompleteTextView) findViewById(R.id.autoCompleteModel);

I overlooked variable scope since both makeAutoComplete and modelAutoComplete where defined twice, one as a global class variable, and the second as a local function variable.
since the global variable was only defined and not initialized. The function initModelAutoComplete() was referencing the global public variable modelAutoComplete causing the NPE exception.

