Android 微调器 setOnItemSelectedListener 不会触发，但它显示来自 API 的正确值

Question

我对 Spinner 有疑问。我使用 Volley 从 API 下载数据并将其放入 Spinner。我可以看到我从 API 获得的所有物品。但是我不能 select 它，微调器 setOnItemSelectedListener 也不会触发（没有日志，没有祝酒词）。来自 getDataFromAPI() 的日志效果很好，所有数据都是从源正确下载的。

你可以看下面的代码。

感谢您的帮助。

import android.util.Log;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.Spinner;
import android.widget.TextView;
import android.widget.Toast;

import androidx.appcompat.app.AppCompatActivity;

import com.android.volley.Request;
import com.android.volley.RequestQueue;
import com.android.volley.Response;
import com.android.volley.VolleyError;
import com.android.volley.toolbox.JsonArrayRequest;
import com.android.volley.toolbox.Volley;
import com.example.plantapp.Model.WeatherStation;

import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;

import java.util.ArrayList;
import java.util.List;

public class StationUser extends AppCompatActivity {

    private Spinner stationUserSpinnerStation, stationUserSpinnerConfirm;

    private String IMGW_URL = "https://danepubliczne.imgw.pl/api/data/synop";
    private ArrayList<WeatherStation> WeatherList = new ArrayList<>();
    private List<String> StationList = new ArrayList<>();
    private RequestQueue mQueue;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_station_user);

        stationUserSpinnerStation = findViewById(R.id.stationUserSpinnerStation);

        mQueue = Volley.newRequestQueue(this);
        getDataFromAPI();

        ArrayAdapter<String> arrayAdapter = new ArrayAdapter<>(this, android.R.layout.simple_spinner_item, StationList);
        arrayAdapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
        stationUserSpinnerStation.setAdapter(arrayAdapter);
        arrayAdapter.notifyDataSetChanged();

        stationUserSpinnerStation.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
            @Override
            public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
                String spinnerValue = parent.getItemAtPosition(position).toString();
                stationUserSpinnerStation.setSelection(position);
                Log.d("saodjawduiaw", spinnerValue + " " + position + " " + id + "\n\n");
                Toast.makeText(StationUser.this,
                        "Selected item" + spinnerValue,
                        Toast.LENGTH_SHORT).show();
                arrayAdapter.notifyDataSetChanged();
            }

            @Override
            public void onNothingSelected(AdapterView<?> parent) {
                Toast.makeText(StationUser.this,
                        "Selected item",
                        Toast.LENGTH_SHORT).show();
            }
        });

    }

    private void getDataFromAPI() {
        JsonArrayRequest request = new JsonArrayRequest(Request.Method.GET, IMGW_URL, null,
                new Response.Listener<JSONArray>() {
                    @Override
                    public void onResponse(JSONArray response) {
                        try {
                            for (int i = 0; i < response.length(); i++) {
                                JSONObject station = response.getJSONObject(i);
                                String stacja = station.getString("stacja");
                                double temperatura = station.getDouble("temperatura");
                                double suma_opadu = station.getDouble("suma_opadu");
                                WeatherStation tempstation = new WeatherStation(stacja, temperatura, suma_opadu);
                                WeatherList.add(tempstation);
                                StationList.add(stacja);
                                Log.d("info", stacja + " " + temperatura + " " + suma_opadu + "\n\n");
                                Log.d("stacja", tempstation.getStation() + tempstation.getTemperature() + tempstation.getRainfall());
                            }
                        } catch (JSONException e) {
                            e.printStackTrace();
                        }
                    }
                }, new Response.ErrorListener() {
            @Override
            public void onErrorResponse(VolleyError error) {
                error.printStackTrace();
            }
        });
        mQueue.add(request);
    }
}

Answer 1

像这样尝试，将 arrayadapter 定义为全局变量，然后在 onCreate 中初始化 arrayadapter方法，然后在 onResponse 方法

中调用 arrayAdapter.notifyDataSetChanged();

public class StationUser extends AppCompatActivity {
    private Spinner stationUserSpinnerStation, stationUserSpinnerConfirm;
    private String IMGW_URL = "https://danepubliczne.imgw.pl/api/data/synop";
    private ArrayList<WeatherStation> WeatherList = new ArrayList<>();
    private List<String> StationList = new ArrayList<>();
    private RequestQueue mQueue;
    ArrayAdapter<String> arrayAdapter;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
          setContentView(R.layout.activity_test);
        stationUserSpinnerStation = findViewById(R.id.stationUserSpinnerStation);

        mQueue = Volley.newRequestQueue(this);
        getDataFromAPI();

        arrayAdapter = new ArrayAdapter<>(this, android.R.layout.simple_spinner_item, StationList);
        arrayAdapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
        stationUserSpinnerStation.setAdapter(arrayAdapter);
        arrayAdapter.notifyDataSetChanged();
        stationUserSpinnerStation.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
            @Override
            public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
                String spinnerValue = parent.getItemAtPosition(position).toString();
                stationUserSpinnerStation.setSelection(position);
                Log.d("saodjawduiaw", spinnerValue + " " + position + " " + id + "\n\n");
                Toast.makeText(getApplicationContext(),
                        "Selected item" + spinnerValue,
                        Toast.LENGTH_SHORT).show();
                arrayAdapter.notifyDataSetChanged();
            }

            @Override
            public void onNothingSelected(AdapterView<?> parent) {
                Toast.makeText(getApplicationContext(),
                        "Selected item",
                        Toast.LENGTH_SHORT).show();
            }
        });

    }

    private void getDataFromAPI() {
        JsonArrayRequest request = new JsonArrayRequest(Request.Method.GET, IMGW_URL, null,
                new Response.Listener<JSONArray>() {
                    @Override
                    public void onResponse(JSONArray response) {
                        try {
                            for (int i = 0; i < response.length(); i++) {
                                JSONObject station = response.getJSONObject(i);
                                String stacja = station.getString("stacja");
                                double temperatura = station.getDouble("temperatura");
                                double suma_opadu = station.getDouble("suma_opadu");
                                WeatherStation tempstation = new WeatherStation(stacja, temperatura, suma_opadu);
                                WeatherList.add(tempstation);
                                StationList.add(stacja);
                                Log.d("info", stacja + " " + temperatura + " " + suma_opadu + "\n\n");
                                Log.d("stacja", tempstation.getData1() + tempstation.getData2() + tempstation.getData3());

                                arrayAdapter.notifyDataSetChanged();

                            }
                        } catch (JSONException e) {
                            e.printStackTrace();
                        }
                    }
                }, new Response.ErrorListener() {
            @Override
            public void onErrorResponse(VolleyError error) {
                error.printStackTrace();
            }
        });
        mQueue.add(request);
    }

}

Android 微调器 setOnItemSelectedListener 不会触发，但它显示来自 API 的正确值

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