Android Hello world demo

package com.example.testapk;
import android.app.Activity;
import android.os.Bundle;
import android.widget.TextView;


public class MainActivity extends Activity {   /** 活动第一次被创建后调用 */
     @Override   
     public void onCreate(Bundle savedInstanceState) {
      super.onCreate(savedInstanceState);
      TextView tv = new TextView(this);
      tv.setText("Hello, Android");
      setContentView(tv);
      }
     }