Android Context作用

public class MainActivity extends Activity {

    String TAG = "CARLOZ";

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        
        //Activity 本身就是一个 Context
        TextView tv = new TextView(MainActivity.this);
        tv.setText("hello carloz");
        tv.setText(R.string.hello_world);
        setContentView(tv);
        
        String str = (String) getApplicationContext().getResources().getText(R.string.hello_world);
        Log.d(TAG, str);
        // 输出 08-16 11:59:27.402: D/CARLOZ(13255): Hello world!

        ImageView iv = new ImageView(MainActivity.this);
        iv.setImageResource(R.drawable.ic_launcher);
        setContentView(iv);
    }
}