volley android我的代码中的列表大小返回Zero

Question

请任何人帮助我，我的代码中的列表大小返回零 注意： - 当获取大小为零返回时，列表是全局变量

15

感谢所有

Answer 1

Volley不是同步的，它接受请求并在请求完成时给你回调。如果在调用onResponse后检查大小，您将获得所需的结果

String url = "http://api.openweathermap.org/data/2.5/weather?q=" + cities + "&APPID=8072ed7ede0fc9bcb8591a2a2eb90cfd";
    StringRequest request = new StringRequest(Request.Method.GET, url, new Response.Listener<String>() {
        @Override
        public void onResponse(String response) {
            try {
                CityWeather cityWeather = new CityWeather();
                JSONObject object = new JSONObject(response);
                cityWeather.setLonitude(String.valueOf(object.getJSONObject("coord").getDouble("lon")));
                cityWeather.setLatitude(String.valueOf(object.getJSONObject("coord").getDouble("lat")));
                cityWeather.setCityName(object.getString("name"));
                cityWeather.setCurrentTemp(String.valueOf(object.getJSONObject("main").getDouble("temp")));
                cityWeather.setPressure(String.valueOf(object.getJSONObject("main").getInt("pressure")));
                cityWeather.setHumidity(String.valueOf(object.getJSONObject("main").getInt("humidity")));
                cityWeather.setMinTemp(String.valueOf(object.getJSONObject("main").getDouble("temp_min")));
                cityWeather.setMaxTemp(String.valueOf(object.getJSONObject("main").getDouble("temp_max")));
                cityWeather.setWindSpeed(String.valueOf(object.getJSONObject("wind").getDouble("speed")));
                cityWeather.setWindDegree(String.valueOf(object.getJSONObject("wind").getInt("deg")));
                list.add(cityWeather);
                //Check list size here and do whatever you want with the list
            } catch (JSONException e) {
                Toast.makeText(MainActivity.this, e.getMessage().toString(), Toast.LENGTH_LONG).show();
            }
        }
    }, new Response.ErrorListener() {
        @Override
        public void onErrorResponse(VolleyError error) {
            Toast.makeText(MainActivity.this, error.toString(), Toast.LENGTH_LONG).show();
        }

    });

    RequestQueue queue = Volley.newRequestQueue(this);
    queue.add(request);