使用Volley＆amp ;;从JSON获取的数据填充ListView。在SearchView上触发提交

Question

目前，我正在制作我的第一个Android应用程序，并遇到了一些我似乎无法解决的问题。
我目前正在为我的应用程序的1页开发搜索片段，
它包含一个SearchView，一个Spinner和一个ListView。 Spinner和SearchView用于过滤ListView中的先前搜索结果（尚未实现），此过滤适用于硬编码值。

但是，当我使用JSON获取数据（Logs显示它已成功获取）并尝试使用适配器填充listview时，它不会被填充。我假设在ListViewAdapter创建/实例化之前，ListView中显示的硬编码值的原因是它们被提供。但是对于JSONAdapter，这实际上是不可能的，因为它仅在提交搜索时从服务器获取，因此当给ListViewAdapter时ArrayList为null，但更新ArrayList不会导致填充ListView。

在我的项目中，我将User类用于硬编码值，因为它只有2个字段，平台和用户名，而GeneralObject类用于JSONAdapter来存储所有JSON数据。

搜索片段（Search.java）

SearchView searchView;
ListView listView;
ListViewAdapter listViewAdapter;
String[] platformList;
String[] userNameList;
ArrayList<User> userList = new ArrayList<User>();
ArrayList<GeneralObject> searchResults = new ArrayList<>();
ArrayList<GeneralObject> filteredSearchResults = new ArrayList<>();
ArrayAdapter<CharSequence> spinnerAdapter;

private RequestQueue mQueue;

String currPlatformSelected = "";
String currUserNameSelected = "";
public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, Bundle savedInstanceState) {
    View view = inflater.inflate(R.layout.search_fragment, container, false);

    Spinner spinner = (Spinner) view.findViewById(R.id.spinner);
    spinnerAdapter = ArrayAdapter.createFromResource(getContext(), R.array.platform_array, android.R.layout.simple_spinner_item);
    spinnerAdapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
    //spinner.setPrompt("Platform");
    spinner.setAdapter(spinnerAdapter);
    spinner.setOnItemSelectedListener(this);

    SearchManager searchManager = (SearchManager) getActivity().getSystemService(Context.SEARCH_SERVICE);
    searchView = (SearchView) view.findViewById(R.id.searchView);
    searchView.setSearchableInfo(searchManager.getSearchableInfo(getActivity().getComponentName()));
    setupSearchView();

    userNameList = new String[]{"sallad_", "fork__", "KonoAma", "Darksubi_", "XboxTest", "PlaystationTest"};
    platformList = new String[]{"PC", "PC", "PC", "PC", "Xbox", "PS4"};

    listView = (ListView) view.findViewById(R.id.listview);
    mQueue = Volley.newRequestQueue(getContext());

    // just for populating the arrays before implementing previous history
    if (userNameList.length == 0 || platformList.length == 0)  // if no hardcoded values given
    {
        User previousSearches = new User("No Results", "Please Search Usernames to populate");
        userList.add(previousSearches);
        currUserNameSelected = "Please Search Usernames to populate";
        currPlatformSelected = "No Results";
    }
    else if (userNameList.length == platformList.length) // if there are equal matching pairs in the hardcoded string arrays
    {
        for (int i = 0; i < userNameList.length; i++) {
            User user = new User(platformList[i], userNameList[i]);
            userList.add(user);
        }
    }

    //if i replace the below userList with searchResults it doesn't work as it isnt populated yet
    listViewAdapter = new ListViewAdapter(getContext(), userList);
    listView.setAdapter(listViewAdapter);

    return view;
}

private void setupSearchView()
{
    searchView.setIconified(false);
    searchView.setIconifiedByDefault(false);
    searchView.setOnQueryTextListener(this);
    searchView.setOnSearchClickListener(this);
    searchView.setOnCloseListener(this);
    searchView.setQueryHint("Enter Username...");
}

@Override
public void onItemSelected(AdapterView<?> adapterView, View view, int i, long l) // Spinner Select
{
    currPlatformSelected = (String) adapterView.getItemAtPosition(i);
    listViewAdapter.filter(currUserNameSelected, currPlatformSelected);
    Log.v("item", (String) currPlatformSelected);
}

@Override
public boolean onQueryTextSubmit(String query) // on SearchView text submit
{
    //searchView.setIconified(true);
    currUserNameSelected = query;

    Log.v("JSON", "starting json import with username = " + currUserNameSelected + " and platform = " + currPlatformSelected);
    //R6StatsJSONAdapter r6StatsJsonAdapter = new R6StatsJSONAdapter(currUserNameSelected, currPlatformSelected, mQueue);
    R6DBJSONAdapter r6DBJsonAdapter = new R6DBJSONAdapter(currUserNameSelected, currPlatformSelected, mQueue);
    r6DBJsonAdapter.ParseGeneral();
    searchResults = r6DBJsonAdapter.getSearchResults();
    Log.v("JSON", "finished json import");
    return true;
}

@Override
public boolean onQueryTextChange(String newText) // on SearchView text change
{
    //searchView.setIconified(false);
    //searchView.setIconifiedByDefault(false);
    currUserNameSelected = newText;
    listViewAdapter.filter(currUserNameSelected, currPlatformSelected);
    return false;
}

ListViewAdapter

public class ListViewAdapter extends BaseAdapter {

// Declare Variables

Context mContext;
LayoutInflater inflater;
private List<User> userList = null;
private ArrayList<User> arraylist;

public ListViewAdapter(Context context, List<User> userList) {
    mContext = context;
    this.userList = userList;
    inflater = LayoutInflater.from(mContext);
    this.arraylist = new ArrayList<User>();
    this.arraylist.addAll(userList);
}

public class ViewHolder {
    TextView userName;
    TextView platformName;
}

@Override
public int getCount() {
    return userList.size();
}

@Override
public User getItem(int position) {
    return userList.get(position);
}

@Override
public long getItemId(int position) {
    return position;
}

public View getView(final int position, View view, ViewGroup parent) {
    final ViewHolder holder;
    if (view == null) {
        holder = new ViewHolder();
        view = inflater.inflate(R.layout.list_view_items, null);

        holder.userName = (TextView) view.findViewById(R.id.userName);
        holder.platformName = (TextView) view.findViewById(R.id.platformName);
        view.setTag(holder);
    }
    else
    {
        holder = (ViewHolder) view.getTag();
    }
    holder.userName.setText(userList.get(position).getPlayerName());
    holder.platformName.setText(userList.get(position).getPlatform());
    return view;
}

// Filter Class
public void filter(String userName, String platformName)
{
    userName = userName.toLowerCase(Locale.getDefault());
    platformName = platformName.toLowerCase(Locale.getDefault());
    userList.clear();
    for (User currPrevSearch : arraylist)
    {
        if (userName.length() == 0 && currPrevSearch.getPlatform().toLowerCase(Locale.getDefault()).contains(platformName))
        {
            userList.add(currPrevSearch);
        }
        else if (currPrevSearch.getPlayerName().toLowerCase(Locale.getDefault()).contains(userName) && currPrevSearch.getPlatform().toLowerCase(Locale.getDefault()).contains(platformName))
        {
            userList.add(currPrevSearch);
        }
    }
    notifyDataSetChanged();
}

}

任何帮助将不胜感激，我可以清除任何困惑。

Answer 1

修正了它，使用适配器onDataSetChanged()方法，它更新了数据但没有立即显示它，这是因为onSubmit数据是使用Volley异步获取的，所以它不是可以显示（虽然关闭键盘使其显示）。

仅在JSONAdapter完成解析时才更新数据。