android开发笔记--Helloword开始

import android.app.Activity;
import android.os.Bundle;
import android.widget.TextView;

public class TestActivity extends Activity {
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
TextView tv =new TextView(this);
tv.setText("Hello World");
setContentView(tv);
}
}