Apps application crashes in AVD after writing .setText method

[aandroiddevelop1]

hello guys
i need some help here

im using adt-bundle-windows-x86_64-20140321
and the latest version of eclipse
and developing for android v4.4.2

im learning android development from a site that used the older virsion of eclipse
and developed for older virsion of android
so most of the time the site's orders isnt correct
i wish you could help me on this one

this is my app main activity

package user.workingproject;

import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.support.v7.app.ActionBarActivity;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;

public class MainActivity extends ActionBarActivity {

	TextView myTextView;
	
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);

        myTextView = (TextView) findViewById(R.id.myText);
        myTextView.setText("New text in TextView");
        
        if (savedInstanceState == null) {
            getSupportFragmentManager().beginTransaction()
                    .add(R.id.container, new PlaceholderFragment())
                    .commit();
        }
        

    }


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

    /**
     * A placeholder fragment containing a simple view.
     */
    public static class PlaceholderFragment extends Fragment {

        public PlaceholderFragment() {
        }

        @Override
        public View onCreateView(LayoutInflater inflater, ViewGroup container,
                Bundle savedInstanceState) {
            View rootView = inflater.inflate(R.layout.fragment_main, container, false);
            return rootView;
        }
    }

}

the first paragraph is the importent one
this app workes just fine without the line

        myTextView.setText("New text in TextView");

because of this line the AVD crashes the application and write me an errore massege:
unfortunately, WorkingProject has stopped

what can i do??
help me plz
tnx

 

[out of ideas]

You need to study debugging and the use of logcat.

I never use the avd because it is slow and a pain the ass. but logcat should still be easy for you to figure out with an avd. it will give you a more precise idea of where things went wrong, then you can google search for specific problems, which usually have been answered before.