Create Button with code only

package com.java2s.app;
//from w  w w  . ja v a  2s .  c o m
import android.app.Activity;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.view.ViewGroup.LayoutParams;
import android.widget.Button;
import android.widget.LinearLayout;

public class MainActivity extends Activity {
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        LinearLayout parentContainer = new LinearLayout(this);
        parentContainer.setLayoutParams(new LayoutParams(LayoutParams.MATCH_PARENT,
                LayoutParams.MATCH_PARENT));
        parentContainer.setOrientation(LinearLayout.VERTICAL);

        Button button = new Button(this);
        button.setText("OK");
        parentContainer.addView(button);
        button.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                Log.v("java2s.com","button clicked");
            }
        });

        setContentView(parentContainer);
    }
}