求解！！！！！！！！！！！！！！！

package hutai.namespace; import android.app.Activity;
import android.os.Bundle;
import android.widget.Button; public class Activity01 extends Activity {
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
TextView myTextView = (TextView)findViewById(R.id.myTextView); 它说这里有问题："Cannot cast from View to TextView"
Button myButton = (Button)findViewById(R.id.myButton);
myTextView.setText("我的第一个TextView");
myButton.setText("我的第一个Button");
}
}