Android requestWindowFeature崩溃

之前代码如下：

public class PlayerActivity extends ActionBarActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
requestWindowFeature(Window.FEATURE_NO_TITLE);
setContentView(R.layout.activity_player);
}

}

运行后提示： java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.down.musicdemo/

com.example.down.musicdemo.PlayerActivity}: android.util.AndroidRuntimeException: requestFeature() musts be called before adding content

最终发现继承的是ActionBarActivity 而不是 Activity；

class PlayerActivity extends ActionBarActivity {}

所以这个时候的写法应该是：

ActionBar actionBar = getSupportActionBar();

actionBar.hide();