问动作按钮没有显示在动作栏上吗？

EN

main_activity_actions.xml
<?xml version="1.0" encoding="utf-8"?>
<menu xmlns:android="http://schemas.android.com/apk/res/android" >
<!-- Search, should appear as action button -->
<item android:id="@+id/action_search"
    android:icon="@drawable/ic_action_search"
    android:title="@string/action_search"
    android:showAsAction="ifRoom" />
<!-- Settings, should always be in the overflow -->
<item android:id="@+id/action_settings"
    android:title="@string/action_settings"
    android:showAsAction="never" />
</menu>

 @Override
    public boolean onCreateOptionsMenu(Menu menu) {

        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.main_activity_actions, menu);
        return super.onCreateOptionsMenu(menu);
    }