Jak używać AutoCompleteTextView i zapełniać go danymi z internetowego interfejsu API?

Chcę użyć AutoCompleteTextVieww mojej aktywności i wypełnić dane w miarę wpisywania przez użytkownika, wysyłając zapytanie do internetowego interfejsu API. Jak mam to zrobić?

Czy mogę utworzyć nową klasę i przesłonić AutoCompleteTextView.performFiltering, czy też użyć niestandardowego adaptera listy i udostępnić niestandardowy, android.widget.Filterktóry przesłania performFiltering?

A może jest lepszy sposób na osiągnięcie celu końcowego?

Zrobiłem coś podobnego, ale dotyczyło to okna szybkiego wyszukiwania i wymagało wdrożenia usługi, ale uważam, że nie to chcę tutaj robić.

Wymyśliłem rozwiązanie, nie wiem, czy jest to najlepsze rozwiązanie, ale wydaje się, że działa bardzo dobrze. To, co zrobiłem, to stworzenie niestandardowego adaptera, który rozszerza ArrayAdapter. W adapterze niestandardowym nadpisałem getFilter i utworzyłem własną klasę Filter, która przesłania performFiltering. To rozpoczyna nowy wątek, więc nie przerywa interfejsu użytkownika. Poniżej znajduje się przykład szkieletu.

MyActivity.java

public class MyActivity extends Activity {
    private AutoCompleteTextView style;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        ...
        style = (AutoCompleteTextView) findViewById(R.id.style);
        adapter = new AutoCompleteAdapter(this, android.R.layout.simple_dropdown_item_1line); 
        style.setAdapter(adapter);
    }
}

AutoCompleteAdapter.java

public class AutoCompleteAdapter extends ArrayAdapter<Style> implements Filterable {
    private ArrayList<Style> mData;

    public AutoCompleteAdapter(Context context, int textViewResourceId) {
        super(context, textViewResourceId);
        mData = new ArrayList<Style>();
    }

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

    @Override
    public Style getItem(int index) {
        return mData.get(index);
    }

    @Override
    public Filter getFilter() {
        Filter myFilter = new Filter() {
            @Override
            protected FilterResults performFiltering(CharSequence constraint) {
                FilterResults filterResults = new FilterResults();
                if(constraint != null) {
                    // A class that queries a web API, parses the data and returns an ArrayList<Style>
                    StyleFetcher fetcher = new StyleFetcher();
                    try {
                        mData = fetcher.retrieveResults(constraint.toString());
                    }
                    catch(Exception e) {
                        Log.e("myException", e.getMessage());
                    }
                    // Now assign the values and count to the FilterResults object
                    filterResults.values = mData;
                    filterResults.count = mData.size();
                }
                return filterResults;
            }

            @Override
            protected void publishResults(CharSequence contraint, FilterResults results) {
                if(results != null && results.count > 0) {
                notifyDataSetChanged();
                }
                else {
                    notifyDataSetInvalidated();
                }
            }
        };
        return myFilter;
    }
}

Rozszerzanie na AJ. Odpowiedzi powyżej, następujący adapter niestandardowy obejmuje również obsługę żądań serwera i analizę json:

class AutoCompleteAdapter extends ArrayAdapter<String> implements Filterable
{
    private ArrayList<String> data;
    private final String server = "http://myserver/script.php?query=";

    AutoCompleteAdapter (@NonNull Context context, @LayoutRes int resource)
    {
        super (context, resource);
        this.data = new ArrayList<>();
    }

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

    @Nullable
    @Override
    public String getItem (int position)
    {
        return data.get (position);
    }

    @NonNull
    @Override
    public Filter getFilter()
    {
        return new Filter()
        {
            @Override
            protected FilterResults performFiltering (CharSequence constraint)
            {
                FilterResults results = new FilterResults();
                if (constraint != null)
                {
                    HttpURLConnection conn = null;
                    InputStream input = null;
                    try
                    {
                        URL url = new URL (server + constraint.toString());
                        conn = (HttpURLConnection) url.openConnection();
                        input = conn.getInputStream();
                        InputStreamReader reader = new InputStreamReader (input, "UTF-8");
                        BufferedReader buffer = new BufferedReader (reader, 8192);
                        StringBuilder builder = new StringBuilder();
                        String line;
                        while ((line = buffer.readLine()) != null)
                        {
                            builder.append (line);
                        }
                        JSONArray terms = new JSONArray (builder.toString());
                        ArrayList<String> suggestions = new ArrayList<>();
                        for (int ind = 0; ind < terms.length(); ind++)
                        {
                            String term = terms.getString (ind);
                            suggestions.add (term);
                        }
                        results.values = suggestions;
                        results.count = suggestions.size();
                        data = suggestions;
                    }
                    catch (Exception ex)
                    {
                        ex.printStackTrace();
                    }
                    finally
                    {
                        if (input != null)
                        {
                            try
                            {
                                input.close();
                            }
                            catch (Exception ex)
                            {
                                ex.printStackTrace();
                            }
                        }
                        if (conn != null) conn.disconnect();
                    }
                }
                return results;
            }

            @Override
            protected void publishResults (CharSequence constraint, FilterResults results)
            {
                if (results != null && results.count > 0)
                {
                    notifyDataSetChanged();
                }
                else notifyDataSetInvalidated();
            }
        };
    }

i używaj go w ten sam sposób:

public class MyActivity extends Activity
{
    @Override
    public void onCreate(Bundle savedInstanceState) {
        ...
        AutoCompleteTextView textView = (AutoCompleteTextView) findViewById (R.id.style);
        int layout = android.R.layout.simple_list_item_1;
        AutoCompleteAdapter adapter = new AutoCompleteAdapter (this, layout); 
        textView.setAdapter (adapter);
    }
}

Chu: Aby dostosować wygląd widoku i uzyskać większą kontrolę nad rozpakowywaniem obiektu, wykonaj następujące czynności ...

    @Override
    public View getView (int position, View convertView, ViewGroup parent) {
        TextView originalView = (TextView) super.getView(position, convertView, parent); // Get the original view

        final LayoutInflater inflater = LayoutInflater.from(getContext());
        final TextView view = (TextView) inflater.inflate(android.R.layout.simple_dropdown_item_1line, parent, false);

        // Start tweaking
        view.setText(originalView.getText());
        view.setTextColor(R.color.black);  // also useful if you have a color scheme that makes the text show up white
        view.setTextSize(TypedValue.COMPLEX_UNIT_SP, 10); // override the text size
        return view;
    }

private AutoCompleteUserAdapter userAdapter;
private AutoCompleteTextView actvName;
private ArrayList<SearchUserItem> arrayList;

actvName = findViewById(R.id.actvName);

actvName.setOnItemClickListener(new AdapterView.OnItemClickListener() {
    @Override
    public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
        actvName.setText(userAdapter.getItemNameAtPosition(position));
        actvName.setSelection(actvName.getText().toString().trim().length());
    }
});

actvName.addTextChangedListener(new TextWatcher() {
    @Override
    public void beforeTextChanged(CharSequence s, int start, int count, int after) {

    }

    @Override
    public void onTextChanged(final CharSequence s, int start, int before, int count) {
        if (actvName.isPerformingCompletion()) {
            // An item has been selected from the list. Ignore.
        } else {
            if (s.toString().toLowerCase().trim().length() >= 2) {
                getUserList(s.toString().toLowerCase().trim());
            }
        }
    }

    @Override
    public void afterTextChanged(Editable s) {

    }
});

private void getUserList(String searchText) {
    //Add data to your list after success of API call
    arrayList = new ArrayList<>();
    arrayList.addAll(YOUR_LIST);
    userAdapter = new AutoCompleteUserAdapter(context, R.layout.row_user, arrayList);
    getActivity().runOnUiThread(new Runnable() {
        @Override
        public void run() {
            actvName.setAdapter(userAdapter);
            userAdapter.notifyDataSetChanged();
            actvName.showDropDown();
        }
    });        
}

AutoCompleteUserAdapter

/**
 * Created by Ketan Ramani on 11/07/2019.
 */
public class AutoCompleteUserAdapter extends ArrayAdapter<SearchUserItem> {

    private Context context;
    private int layoutResourceId;
    private ArrayList<SearchUserItem> arrayList;

    public AutoCompleteUserAdapter(Context context, int layoutResourceId, ArrayList<SearchUserItem> arrayList) {
        super(context, layoutResourceId, arrayList);
        this.context = context;
        this.layoutResourceId = layoutResourceId;
        this.arrayList = arrayList;
    }

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        try {
            if (convertView == null) {
                convertView = LayoutInflater.from(parent.getContext()).inflate(layoutResourceId, parent, false);
            }

            SearchUserItem model = arrayList.get(position);

            AppCompatTextView tvUserName = convertView.findViewById(R.id.tvUserName);
            tvUserName.setText(model.getFullname());
        } catch (NullPointerException e) {
            e.printStackTrace();
        } catch (Exception e) {
            e.printStackTrace();
        }

        return convertView;
    }

    public String getItemNameAtPosition(int position) {
        return arrayList.get(position).getName();
    }

    public String getItemIDAtPosition(int position) {
        return arrayList.get(position).getId();
    }
}

Oto wersja klasy adaptera Kotlin, która ładuje dane z lokalnej bazy danych za pośrednictwem Room:

import android.content.Context
import android.view.LayoutInflater
import android.view.View
import android.view.ViewGroup
import android.widget.ArrayAdapter
import android.widget.Filter
import android.widget.Filterable
import android.widget.TextView
import ...MyFinderDatabase
import ...R
import ...model.SearchResult

class SearchCompleteAdapter(context: Context, val resourceId: Int): ArrayAdapter<SearchResult>(context, resourceId), Filterable {
    private val results = mutableListOf<SearchResult>()

    override fun getCount() = results.size

    override fun getItem(position: Int) = results[position]

    override fun getView(position: Int, convertView: View?, parent: ViewGroup): View {
        val view = convertView ?: LayoutInflater.from(context).inflate(resourceId, parent, false)
        val textView = view.findViewById<TextView>(R.id.autocomplete_name)
        textView.text = getItem(position).fullName
        return view
    }

    override fun getFilter() = object : Filter(){
        override fun performFiltering(constraint: CharSequence?): FilterResults {
            val filterResults = FilterResults()
            val db = MyRoomDatabase.getDatabase(context.applicationContext)
            val dbResults = db.resultDao().findWithNameLike(String.format("%%%s%%", constraint.toString()))
            filterResults.values = dbResults
            filterResults.count = dbResults.size
            results.clear()
            results.addAll(dbResults)
            return filterResults
        }

        override fun publishResults(constraint: CharSequence?, results: FilterResults?) {
            if((results != null) && (results.count > 0)){
                notifyDataSetChanged()
            }
            else{
                notifyDataSetInvalidated()
            }
        }

        override fun convertResultToString(resultValue: Any?): CharSequence {
            val searchResult = resultValue as SearchResult
            return searchResult.fullName
        }
    }
}

Definicja metody DAO:

    @Query("select * from SearchResult where full_name like :name and type = 'USER_TYPE'")
fun findWithNameLike(name: String): List<SearchResult>