onbackpressed() method crash
<p>I am using authentication to enter into a page, after authenticated only the user enters into the page. i wrote a code for onbackpressed(), but it is not working. Here DatabaseDemo and Login are the two classes. when i press the back button the login class with username and password is displaying. </p>

<pre><code>public class DatabaseDemo extends TabActivity {
    DatabaseHelper dbHelper;
    GridView grid;
    TextView txtTest;
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        SetupTabs();
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu)
    {
        menu.add(1, 1, 1, "Add Employee");
        return true;
    }
    public boolean onOptionsItemSelected(MenuItem item)
    {
        switch (item.getItemId())
        {
        //Add employee
        case 1:
            Intent addIntent=new Intent(this,AddEmployee.class);
            startActivity(addIntent);
            break;
        }
        super.onOptionsItemSelected(item);
        return false;
    }
    void SetupTabs()
    {
        TabHost host=getTabHost();
        TabHost.TabSpec spec=host.newTabSpec("tag1");
        Intent in1=new Intent(this, AddEmployee.class);
        spec.setIndicator("Add Employee");
        spec.setContent(in1);

        TabHost.TabSpec spec2=host.newTabSpec("tag2");
        Intent in2=new Intent(this, GridList.class);

        spec2.setIndicator("Employees");
        spec2.setContent(in2);

        host.addTab(spec);
        host.addTab(spec2);
    }
    @Override
    public void onBackPressed() 
    {
        Intent i = new Intent(DatabaseDemo.this, Login.class);
        startActivity(i);
    }
}
</code></pre>
