在我的应用程序，我有了两个片段在动作条的标签导航模式，活动就像Android开发者网站的例子。

In my app, I have an activity that has two fragments in actionbar tabs navigation mode, just like the android developer site example.

在我的第一个片段，我有一个列表视图（其中有它自己的适配器）和列表视图中的每一项都有一个称为+1按钮。我要刷新的第二个片段，显示在第一个片段，他们的+1按钮的点击列表视图中的项目。

in my first fragment I have a listview (which has it's own adapter ) and each item of the listview has a button called +1. I want to refresh the second fragment that shows the items in listview in first fragment that their +1 button's clicked.

我知道我必须使用的接口。但我无法弄清楚如何使用它们。我在哪里有定义接口？如何使用它？以及如何从活动的访问刷新第二个片段？

I know i have to use interfaces. but I cant figure how to use them. where do I have to define the interface? how to use it? and how to access it from the activity to refresh the second fragment?

快速帮助将是巨大的。谢谢。

a quick help would be great. thanks.

推荐答案

如果你想让它在列表项单击

If you want it on List Item Click

片段A：

public class FragmentA extends ListFragment {

OnItemSelectedListener mListener;

...
// Container Activity must implement this interface
public interface OnItemSelectedListener {
    public void onItemSelected(int position);
}
...

@Override
public void onAttach(Activity activity) {
    super.onAttach(activity);
    try {
        mListener = (OnItemSelectedListener) activity;
    } catch (ClassCastException e) {
        throw new ClassCastException(activity.toString() + " must implement OnItemSelectedListener");
    }
}

@Override
public void onListItemClick(ListView l, View v, int position, long id) {

    mCallback.onItemSelected(position);

    }   
}

ContainerActivity：

ContainerActivity:

public class ContainerActivity extends FragmentActivity 
    implements FragmentA.OnItemSelectedListener
{

//...



public void onItemSelected(int Position/*pass anything which u want*/) 
    {

        SecondFragment second_fragment = (SecondFragment) getSupportFragmentManager().findFragmentById(R.id.fragmentB);

        if(second_fragment !=null)
        {
            second_fragment.UpdateUI(Position); 
        }

    }


 }

第二个片段：

Second Fragment:

public class SecondFragment extends Fragment {

    ...
    public void UpdateUI(Position)
    {

    }

}

希望这有助于。在点击每个列表项内按钮可能会有点困难，但尝试了同样的方法。可能是你写的界面声明，并在自定义的适配器调用。

Hope this helps. On click of a Button inside each listitem might be bit difficult, but try the same approach. May be you have to write the interface declaration and call in your custom adapter.