Why am I getting Android RunTime Exception on SimpleAdapter?

Question

I am trying to use a SimpleAdapter along with a ListView from an instanced class but every time I try to run the program, I get an instant crash with a runtime error. I am unsure what is exactly wrong here but if I comment out the SimpleAdapter I no longer get the error so I'm not entirely sure if its written correctly or what is happening. The entire code is below.

import java.util.ArrayList;
import java.util.HashMap;

import android.os.Bundle;
import android.support.v7.app.ActionBarActivity;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.EditText;
import android.widget.SimpleAdapter;
import android.widget.Spinner;

public class Add_Item extends ActionBarActivity {
//variables
    EditText TaskNameET;
    Spinner SpinType;
    Button SaveTodo;
    String SpinnerOptions[] = {"OptionOne", "OptionTwo", "OptionThree"};

//call mainactivity class
    MainActivity Main;

//array list and hashmap for the listview data storage
    ArrayList<HashMap<String, String>> mylist = new ArrayList<HashMap<String, String>>();
    HashMap<String, String> map = new HashMap<String, String>();
    //SimpleAdapter Causing RunTime exception
    SimpleAdapter ListAdapt = new SimpleAdapter(this, mylist, R.layout.row, new String[] {"columnone", "columntwo", "columnthree"}, new int[] {R.id.columnone, R.id.columntwo, R.id.columnthree});


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_add__item);

//define vars
        TaskNameET = (EditText) findViewById(R.id.TaskNameET);
        SpinType = (Spinner) findViewById(R.id.spinner1);
        SaveTodo = (Button) findViewById(R.id.button1);

//adapter for spinner
        ArrayAdapter<String> ard=new ArrayAdapter<String>(this,android.R.layout.simple_dropdown_item_1line, SpinnerOptions);
        SpinType.setAdapter(ard);

//Arraylist for listview
       // ListAdapt = new SimpleAdapter(this, mylist, R.layout.row, new String[] {"columnone", "columntwo", "columnthree"}, new int[] {R.id.columnone, R.id.columntwo, R.id.columnthree});


//onclick todobutton
        SaveTodo.setOnClickListener(new View.OnClickListener() {

            @Override
            public void onClick(View v) {
                map.put("columnone", Add_Item.this.TaskNameET.getText().toString());
                map.put("columntwo", Add_Item.this.TaskNameET.getText().toString());
                map.put("columnthree", Add_Item.this.TaskNameET.getText().toString());
                mylist.add(map);
               Main.MainList.setAdapter(ListAdapt);
            }
        });
    }


    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.add__item, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();
        if (id == R.id.action_settings) {
            return true;
        }
        return super.onOptionsItemSelected(item);
    }
}

Answer 1

 SimpleAdapter ListAdapt = new SimpleAdapter(this, mylist, R.layout.row, new String[] {"columnone", "columntwo", "columnthree"}, new int[] {R.id.columnone, R.id.columntwo, R.id.columnthree});

this can't be before your onCreate();

So just make it

SimpleAdapter ListAdapt; outside onCreate() and then in your onCreate()

ListAdapt = new SimpleAdapter(this, mylist, R.layout.row, new String[] {"columnone", "columntwo", "columnthree"}, new int[] {R.id.columnone, R.id.columntwo, R.id.columnthree});