MainActivity

package com.simonic.testapp;

import android.app.Activity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;

public class MainActivity extends Activity {

	final EditText zahleneingabe = (EditText)findViewById(R.id.txtn);
    Button savebutton = (Button)findViewById(R.id.savebutton);
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        savebutton.setOnClickListener(new View.OnClickListener() {

    		@Override
    		public void onClick(View v) {
    			Toast toast = new Toast(getApplicationContext());
    			toast.setGravity(100, 100, 100);
    			Toast.makeText(MainActivity.this, zahleneingabe.getText(), Toast.LENGTH_SHORT).show();

    		}
    	});

    }

    @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);
    }
}