Android编程实现隐藏状态栏及测试Activity是否活动的方法

package cn.edu.pku;import android.app.Activity;import android.os.Bundle;import android.view.Window;import android.view.WindowManager;public class FrameLayoutActivity extends Activity {  @Override  public void onCreate(Bundle savedInstanceState) {    super.onCreate(savedInstanceState);   // remove title    requestWindowFeature(Window.FEATURE_NO_TITLE);   getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,    WindowManager.LayoutParams.FLAG_FULLSCREEN);    setContentView(R.layout.main);  }}

try { startActivity(new Intent(..)); }catch (ActivityNotFoundException e){ Toast.makeText(this, "Not installed.", LENGTH_SHORT).show();}