从json获取数据一次，并在3个片段中使用它 [英] Getting data from json once and use it in 3 fragment

问题描述

我正在使用截击从JSON获取数据，在Activity中有3个Fragment，我必须用从MainActivity中从JSON接收到的数据填充这些片段.我想一次从JSON获取数据，并在Activity和所有这3个Fragment中使用它.我将接收到的数据放在这样的List中:

I am getting the data from JSON using volley, there is 3 Fragment in Activity which I have to populate these fragments with the data that I have received from JSON in MainActivity. I would like to get data from JSON once and use it in Activity and in all those 3 Fragment. I put the received data in a List like this:

List<Display_Activity_Model> videoDetailList;

然后我使用以下接口将此列表从活动发送到其他片段:

and I send this list from activity to other fragments using an Interface like:

在活动中，我有这种方法:

In activity I have this method:

@Override
public List<Display_Activity_Model> getDataList() {
    return videoDetailList;
}

在其中一个片段中，我有:

In one of fragments I have:

public interface GetDataInterface {
    List<Display_Activity_Model> getDataList();
}
@Override
public void onAttach(Context context) {
    super.onAttach(context);
    try {
        sGetDataInterface= (GetDataInterface) context;
    } catch (ClassCastException e) {
        throw new ClassCastException(context.toString() + "must implement GetDataInterface Interface");
    }
}

@Override
public void onResume() {
    super.onResume();
    if(sGetDataInterface != null){
        dataListFromDispAct = sGetDataInterface.getDataList();
    }
}

当我调试代码时，我看到MainActivity中的getDataList方法在使用凌空获取json的方法之前被调用.因此，我一直都收到空白清单.

When I debug the code, I see that the method getDataList in MainActivity is called before the method for fetching json with volley. So all the time I receive empty list.

我的问题是:用齐射一次获取数据并将其用于其他片段的最佳方法是什么?

My question is that: What is the best way to fetch data with volley once and use it in other fragments?

Update1:​​

Update1:

@Keita Junichiro:

@Keita Junichiro:

我在片段中定义了更新"方法，例如:

I defined "update" method in fragment like:

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
    View view=inflater.inflate(R.layout.video_info,container,false);

    initComponents(view);

   if (dataListFromDispAct != null) {
        txt_view_count.setText(dataListFromDispAct.get(0).getView_count());
    }

    return view;
}

public void update(List<Display_Activity_Model> videoDetailList){

    dataListFromDispAct=videoDetailList;

}

并且在json加载到"getItemMenuGson"方法中后，我正在 activity 中调用"update"方法:

and I am calling "update" method in activity after json loaded in "getItemMenuGson" method:

getItemMenuGson(new CallBack() {
        @Override
        public void onSuccess(List<Display_Activity_Model> itemMenuGsonList) {
            videoDetailList=itemMenuGsonList;
            new Video_Info().update(videoDetailList);

        }

        @Override
        public void onFail(String msg) {

        }
    });

问题是在更新方法之前调用了片段中的方法"onCreateView".当我声明更新方法为静态时，它也是相同的，并且变量"dataListFromDispAct"一直为空.

The problem is method "onCreateView" in fragment is called before update method. When I declare update method static it is also the same and variable "dataListFromDispAct" is null all the time.

Update2:

更新3: @Piyush

Update 3: @Piyush

我实施了您的回复，但此问题无法解决.我得到的是空列表，因为onActivity的onCreateView方法早于Activity中的getItemMenuGson方法执行.我宣布:

I implemented your respond, but it is not working in this problem. I am getting empty list because method onCreateView executing earlier than getItemMenuGson method in Activity. I declared :

SharedApplication mapp = SharedApplication.getInstance();
ArrayList<String> myList = mapp.getArrayListData();

在onActivityCreate中的

在片段中创建，但它也在Activity中的getItemMenuGson方法之前运行.方法的调用顺序:

in onActivityCreated in fragment but it is also running before getItemMenuGson method in Activity. The order in which methods are calling:

我该怎么办?如何在Activity中调用getItemMenuGson方法以获取JSON，然后加载片段布局以将那些已加载的数据填充到片段中?

what should I do? How can I call getItemMenuGson method in Activity to fetch JSON and then load fragment layout to populate those loaded data to the fragment?

解决方案:问题的关键是首先运行的静态方法:

Solution: The key for the problem was Static method which runs first:

在片段中定义以下代码:

public class Video_Info extends Fragment {

static TextView txt_view_count;
List<Display_Activity_Model> dataListFromDispAct;


@Nullable
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) 
  {
    View view=inflater.inflate(R.layout.video_info,container,false);
    txt_view_count= (TextView) view.findViewById(R.id.txt_view_count);
    return view;
  }
public static void update(List<Display_Activity_Model> videoDetailList)
  {
    txt_view_count.setText(videoDetailList.get(0).getView_count());
  }
 }

从JSON提取数据以列出调用更新方法后，在活动中进行

In Activity after fetching data from JSON to list call update method:

 getItemMenuGson(new CallBack() {
    @Override
    public void onSuccess(List<Display_Activity_Model> itemMenuGsonList) {
        videoDetailList = itemMenuGsonList;

         //////////////////
        Video_Info.update(videoDetailList);
        ///////////////////

        Uri vidUri = Uri.parse(itemMenuGsonList.get(0).getMedia().getURL());
        vidView.setVideoURI(vidUri);

    }

推荐答案

为了在调用API之后将数据从活动发送到片段，您可以在片段中创建方法update()来接收数据并调用fragment.update()当loadData finish()处于活动状态时.

In order to send data from activity to fragment after call API, you can create a method update() in fragment to receive data and call fragment.update() in activity when loadData finish().

new Response.Listener<JSONObject>() {
    @Override
    public void onResponse(JSONObject response) {
        //Parse resonse to *videoDetailList*
        fragment.update(videoDetailList);
    }
}

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