Dynamic Linear Layout in Android

package com.example.dynamiclayout;

import android.annotation.SuppressLint;
import android.app.ActionBar.LayoutParams;
import android.app.Activity;
import android.graphics.Color;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.widget.Button;
import android.widget.EditText;
import android.widget.LinearLayout;

public class MainActivity extends Activity {

LinearLayout ll;
EditText et;
Button bt;

    @SuppressLint("NewApi") @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
       // setContentView(R.layout.activity_main);
       
        ll=new LinearLayout(this);    
        ll.setLayoutParams(new LayoutParams(LayoutParams.FILL_PARENT,LayoutParams.FILL_PARENT));
        ll.setOrientation(LinearLayout.VERTICAL);
       
        et=new EditText(this);
        et.setLayoutParams(new LayoutParams(LayoutParams.FILL_PARENT,LayoutParams.WRAP_CONTENT));
        ll.addView(et);
       
        bt=new Button(this);
        bt.setLayoutParams(new LayoutParams(LayoutParams.FILL_PARENT,LayoutParams.WRAP_CONTENT));
        bt.setText("DDDD");
        bt.setTextColor(Color.BLACK);
        ll.addView(bt);
       
       
       
        setContentView(ll);
       
       
    }
}