Android标题栏最右边添加按钮

@Override
	public boolean onCreateOptionsMenu(Menu menu){
	    MenuInflater inflater = getMenuInflater();
	    inflater.inflate(R.menu.main, menu);
	    return true;
	}

<menu xmlns:android="http://schemas.android.com/apk/res/android" >
   <item
        android:id="@+id/action_cart"
        android:title="扫描"
        android:orderInCategory="100"
        android:showAsAction="always"/>
</menu>

@Override  
	public boolean onOptionsItemSelected(MenuItem item){
	    switch (item.getItemId()) {
	    case R.id.action_cart://监听菜单按钮
	    	
	    	break;
	    }
	    return super.onOptionsItemSelected(item);
	}