API 数据未转换为 java 对象

Question

我正在使用一个 openweathermap API，这是一个电话 API，来获取当前和未来 7 天的天气详细信息。我能够检索所有非嵌套的静态数据，但对于嵌套的数据（当前、每日等），它表示空指针异常。我已经为嵌套数据定义了所有 classes，它仍然没有将嵌套数据存储在 pojo class

中

这就是数据在 API 响应中的样子

{
    "lat": 55.25,
    "lon": 23.99,
    "timezone": "Europe/Vilnius",
    "timezone_offset": 10800,
    "current": {
        "dt": 1652008177,
        "sunrise": 1651976922,
        "sunset": 1652033543,
        "temp": 11.67,
        "feels_like": 10.62,
        "pressure": 1023,
        "humidity": 66,
        "dew_point": 5.54,
        "uvi": 1.26,
        "clouds": 100,
        "visibility": 10000,
        "wind_speed": 3.06,
        "wind_deg": 34,
        "wind_gust": 4.8,
        "weather": [
            {
                "id": 500,
                "main": "Rain",
                "description": "light rain",
                "icon": "10d"
            }
        ],
        "rain": {
            "1h": 0.12
        }
    },
    "daily": [
        {
            "dt": 1652004000,
            "sunrise": 1651976922,
            "sunset": 1652033543,
            "moonrise": 1651996080,
            "moonset": 1651970160,
            "moon_phase": 0.23,
            "temp": {
                "day": 11.56,
                "min": 4.9,
                "max": 12.65,
                "night": 4.9,
                "eve": 11.07,
                "morn": 8.06
            },
            "feels_like": {
                "day": 10.49,
                "night": 1.15,
                "eve": 9.75,
                "morn": 6.91
            },
            "pressure": 1023,
            "humidity": 66,
            "dew_point": 5.43,
            "wind_speed": 6.67,
            "wind_deg": 17,
            "wind_gust": 12.61,
            "weather": [
                {
                    "id": 804,
                    "main": "Clouds",
                    "description": "overcast clouds",
                    "icon": "04d"
                }
            ],
            "clouds": 100,
            "pop": 0.2,
            "uvi": 2.88
        },
      ......
         {
            "dt": 1652608800,
            "sunrise": 1652580930,
            "sunset": 1652639127,
            "moonrise": 1652636520,
            "moonset": 1652580000,
            "moon_phase": 0.47,
            "temp": {
                "day": 13.65,
                "min": 6.22,
                "max": 13.65,
                "night": 10.34,
                "eve": 13.3,
                "morn": 6.24
            },
            "feels_like": {
                "day": 12.69,
                "night": 9.44,
                "eve": 12.38,
                "morn": 4.12
            },
            "pressure": 1007,
            "humidity": 62,
            "dew_point": 6.58,
            "wind_speed": 4.15,
            "wind_deg": 280,
            "wind_gust": 5.23,
            "weather": [
                {
                    "id": 500,
                    "main": "Rain",
                    "description": "light rain",
                    "icon": "10d"
                }
            ],
            "clouds": 100,
            "pop": 0.2,
            "rain": 0.12,
            "uvi": 5
        }
    ]
}

这是我主 activity(FetchOutfitInputDetails.java) 中的代码，我从那里调用 API

WeatherAPIInterface weatherAPIInterface= RetrofitInstance.getRetrofit().create(WeatherAPIInterface.class);
            weatherAPIInterface.getWeather(lat,lon,"minutely,hourly","metric","en",apiKey).enqueue(new Callback<WeatherPojo>() {
                @Override
                public void onResponse(Call<WeatherPojo> call, Response<WeatherPojo> response) {
                    if(response.code()!=404){
                        Toast.makeText(getContext(),"list present",Toast.LENGTH_SHORT).show();
                        WeatherPojo pojo=response.body();
                        Log.v("Aaaaaa",pojo.getCurrent().toString());
                    }else{
                        Toast.makeText(getContext(),"LIst Empty",Toast.LENGTH_SHORT).show();
                    }
                }

                @Override
                public void onFailure(Call<WeatherPojo> call, Throwable t) {

                }
            }

这是我的改造实例class

import retrofit2.Retrofit;
import retrofit2.converter.gson.GsonConverterFactory;

public class RetrofitInstance {
    private static Retrofit retrofit;
    private static final String BASEURL ="https://api.openweathermap.org/data/2.5/";

    public static Retrofit getRetrofit() {
        if(retrofit==null ){
            retrofit=new Retrofit.Builder().
                    baseUrl(BASEURL).
                    addConverterFactory(GsonConverterFactory.create()).
                    build();
        }return retrofit;
    }
}

天气预报class

import java.util.ArrayList;

public class WeatherPojo {
        private float lat;
        private float lon;
        private String timezone;
        private float timezone_offset;
        CurrentWeatherPojo CurrentObject;
        ArrayList<DailyPojo> daily = new ArrayList<DailyPojo>();


        // Getter Methods

        public float getLat() {
            return lat;
        }

        public float getLon() {
            return lon;
        }

        public String getTimezone() {
            return timezone;
        }

        public float getTimezone_offset() {
            return timezone_offset;
        }

        public CurrentWeatherPojo getCurrent() {
            return CurrentObject;
        }

        // Setter Methods

        public void setLat(float lat) {
            this.lat = lat;
        }

        public void setLon(float lon) {
            this.lon = lon;
        }

        public void setTimezone(String timezone) {
            this.timezone = timezone;
        }

        public void setTimezone_offset(float timezone_offset) {
            this.timezone_offset = timezone_offset;
        }

    public ArrayList<DailyPojo> getDaily() {
        return daily;
    }

    public void setDaily(ArrayList<DailyPojo> daily) {
        this.daily = daily;
    }

    public void setCurrent(CurrentWeatherPojo currentObject) {
            this.CurrentObject = currentObject;
        }
}

当前天气 pojo class，用于 api 数据中嵌套的当前天气

package com.example.clothme.WeatherAPI;

import java.util.ArrayList;

public class CurrentWeatherPojo {
    private float dt;
    private float sunrise;
    private float sunset;
    private float temp;
    private float feels_like;
    private float pressure;
    private float humidity;
    private float dew_point;
    private float uvi;
    private float clouds;
    private float visibility;
    private float wind_speed;
    private float wind_deg;
    private float wind_gust;
    ArrayList< DailyPojo.weath > weather = new ArrayList < DailyPojo.weath>();


    // Getter Methods

    public CurrentWeatherPojo(float dt, float sunrise, float sunset, float temp, float feels_like, float pressure, float humidity, float dew_point, float uvi, float clouds, float visibility, float wind_speed, float wind_deg, float wind_gust, ArrayList<DailyPojo.weath> weather) {
        this.dt = dt;
        this.sunrise = sunrise;
        this.sunset = sunset;
        this.temp = temp;
        this.feels_like = feels_like;
        this.pressure = pressure;
        this.humidity = humidity;
        this.dew_point = dew_point;
        this.uvi = uvi;
        this.clouds = clouds;
        this.visibility = visibility;
        this.wind_speed = wind_speed;
        this.wind_deg = wind_deg;
        this.wind_gust = wind_gust;
        this.weather = weather;
    }

    public float getDt() {
        return dt;
    }

    public float getSunrise() {
        return sunrise;
    }

    public float getSunset() {
        return sunset;
    }

    public float getTemp() {
        return temp;
    }

    public float getFeels_like() {
        return feels_like;
    }

    public float getPressure() {
        return pressure;
    }

    public float getHumidity() {
        return humidity;
    }

    public float getDew_point() {
        return dew_point;
    }

    public float getUvi() {
        return uvi;
    }

    public float getClouds() {
        return clouds;
    }

    public float getVisibility() {
        return visibility;
    }

    public float getWind_speed() {
        return wind_speed;
    }

    public float getWind_deg() {
        return wind_deg;
    }

    public float getWind_gust() {
        return wind_gust;
    }

    // Setter Methods

    public void setDt(float dt) {
        this.dt = dt;
    }

    public void setSunrise(float sunrise) {
        this.sunrise = sunrise;
    }

    public void setSunset(float sunset) {
        this.sunset = sunset;
    }

    public void setTemp(float temp) {
        this.temp = temp;
    }

    public void setFeels_like(float feels_like) {
        this.feels_like = feels_like;
    }

    public void setPressure(float pressure) {
        this.pressure = pressure;
    }

    public void setHumidity(float humidity) {
        this.humidity = humidity;
    }

    public void setDew_point(float dew_point) {
        this.dew_point = dew_point;
    }

    public void setUvi(float uvi) {
        this.uvi = uvi;
    }

    public void setClouds(float clouds) {
        this.clouds = clouds;
    }

    public void setVisibility(float visibility) {
        this.visibility = visibility;
    }

    public void setWind_speed(float wind_speed) {
        this.wind_speed = wind_speed;
    }

    public void setWind_deg(float wind_deg) {
        this.wind_deg = wind_deg;
    }

    public void setWind_gust(float wind_gust) {
        this.wind_gust = wind_gust;
    }
}

另一个 class 用于更多嵌套数据

package com.example.clothme.WeatherAPI;

import java.util.ArrayList;

public class DailyPojo {
    private float dt;
    private float sunrise;
    private float sunset;
    private float moonrise;
    private float moonset;
    private float moon_phase;
    Temp TempObject;
    Feels_like Feels_likeObject;
    private float pressure;
    private float humidity;
    private float dew_point;
    private float wind_speed;
    private float wind_deg;
    private float wind_gust;
    ArrayList< weath > weather = new ArrayList < weath > ();
    private float clouds;
    private float pop;
    private float uvi;

    public DailyPojo(float dt, float sunrise, float sunset, float moonrise, float moonset, float moon_phase, Temp tempObject, Feels_like feels_likeObject, float pressure, float humidity, float dew_point, float wind_speed, float wind_deg, float wind_gust, ArrayList<weath> weather, float clouds, float pop, float uvi) {
        this.dt = dt;
        this.sunrise = sunrise;
        this.sunset = sunset;
        this.moonrise = moonrise;
        this.moonset = moonset;
        this.moon_phase = moon_phase;
        TempObject = tempObject;
        Feels_likeObject = feels_likeObject;
        this.pressure = pressure;
        this.humidity = humidity;
        this.dew_point = dew_point;
        this.wind_speed = wind_speed;
        this.wind_deg = wind_deg;
        this.wind_gust = wind_gust;
        this.weather = weather;
        this.clouds = clouds;
        this.pop = pop;
        this.uvi = uvi;
    }
// Getter Methods

    public float getDt() {
        return dt;
    }

    public float getSunrise() {
        return sunrise;
    }

    public float getSunset() {
        return sunset;
    }

    public float getMoonrise() {
        return moonrise;
    }

    public float getMoonset() {
        return moonset;
    }

    public float getMoon_phase() {
        return moon_phase;
    }

    public Temp getTemp() {
        return TempObject;
    }

    public Feels_like getFeels_like() {
        return Feels_likeObject;
    }

    public float getPressure() {
        return pressure;
    }

    public float getHumidity() {
        return humidity;
    }

    public float getDew_point() {
        return dew_point;
    }

    public float getWind_speed() {
        return wind_speed;
    }

    public float getWind_deg() {
        return wind_deg;
    }

    public float getWind_gust() {
        return wind_gust;
    }

    public float getClouds() {
        return clouds;
    }

    public float getPop() {
        return pop;
    }

    public float getUvi() {
        return uvi;
    }

    // Setter Methods

    public void setDt(float dt) {
        this.dt = dt;
    }

    public void setSunrise(float sunrise) {
        this.sunrise = sunrise;
    }

    public void setSunset(float sunset) {
        this.sunset = sunset;
    }

    public void setMoonrise(float moonrise) {
        this.moonrise = moonrise;
    }

    public void setMoonset(float moonset) {
        this.moonset = moonset;
    }

    public void setMoon_phase(float moon_phase) {
        this.moon_phase = moon_phase;
    }

    public void setTemp(Temp tempObject) {
        this.TempObject = tempObject;
    }

    public void setFeels_like(Feels_like feels_likeObject) {
        this.Feels_likeObject = feels_likeObject;
    }

    public void setPressure(float pressure) {
        this.pressure = pressure;
    }

    public void setHumidity(float humidity) {
        this.humidity = humidity;
    }

    public void setDew_point(float dew_point) {
        this.dew_point = dew_point;
    }

    public void setWind_speed(float wind_speed) {
        this.wind_speed = wind_speed;
    }

    public void setWind_deg(float wind_deg) {
        this.wind_deg = wind_deg;
    }

    public void setWind_gust(float wind_gust) {
        this.wind_gust = wind_gust;
    }

    public void setClouds(float clouds) {
        this.clouds = clouds;
    }

    public void setPop(float pop) {
        this.pop = pop;
    }

    public void setUvi(float uvi) {
        this.uvi = uvi;
    }
    public static class Feels_like {
        private float day;
        private float night;
        private float eve;
        private float morn;

        public Feels_like(float day, float night, float eve, float morn) {
            this.day = day;
            this.night = night;
            this.eve = eve;
            this.morn = morn;
        }


        // Getter Methods

        public float getDay() {
            return day;
        }

        public float getNight() {
            return night;
        }

        public float getEve() {
            return eve;
        }

        public float getMorn() {
            return morn;
        }

        // Setter Methods

        public void setDay(float day) {
            this.day = day;
        }

        public void setNight(float night) {
            this.night = night;
        }

        public void setEve(float eve) {
            this.eve = eve;
        }

        public void setMorn(float morn) {
            this.morn = morn;
        }
    }
    public static class Temp {
        private float day;
        private float min;
        private float max;
        private float night;
        private float eve;
        private float morn;

        public Temp(float day, float min, float max, float night, float eve, float morn) {
            this.day = day;
            this.min = min;
            this.max = max;
            this.night = night;
            this.eve = eve;
            this.morn = morn;
        }


        // Getter Methods

        public float getDay() {
            return day;
        }

        public float getMin() {
            return min;
        }

        public float getMax() {
            return max;
        }

        public float getNight() {
            return night;
        }

        public float getEve() {
            return eve;
        }

        public float getMorn() {
            return morn;
        }

        // Setter Methods

        public void setDay(float day) {
            this.day = day;
        }

        public void setMin(float min) {
            this.min = min;
        }

        public void setMax(float max) {
            this.max = max;
        }

        public void setNight(float night) {
            this.night = night;
        }

        public void setEve(float eve) {
            this.eve = eve;
        }

        public void setMorn(float morn) {
            this.morn = morn;
        }
    }

    public static class weath{
        private float id;
        private String main;
        private String description;
        private String icon;

        public weath(float id, String main, String description, String icon) {
            this.id = id;
            this.main = main;
            this.description = description;
            this.icon = icon;
        }


        // Getter Methods

        public float getId() {
            return id;
        }

        public String getMain() {
            return main;
        }

        public String getDescription() {
            return description;
        }

        public String getIcon() {
            return icon;
        }

        // Setter Methods

        public void setId(float id) {
            this.id = id;
        }

        public void setMain(String main) {
            this.main = main;
        }

        public void setDescription(String description) {
            this.description = description;
        }

        public void setIcon(String icon) {
            this.icon = icon;
        }
    }
}

显示的错误消息

E/AndroidRuntime: FATAL EXCEPTION: main
    Process: com.example.clothme, PID: 25632
    java.lang.NullPointerException: Attempt to invoke virtual method 'java.lang.String java.lang.Object.toString()' on a null object reference
        at com.example.clothme.Fragments.FetchOutfitInputDetails.onResponse(FetchOutfitInputDetails.java:193)
        at retrofit2.DefaultCallAdapterFactory$ExecutorCallbackCall.lambda$onResponse[=18=]$retrofit2-DefaultCallAdapterFactory$ExecutorCallbackCall(DefaultCallAdapterFactory.java:89)
        at retrofit2.DefaultCallAdapterFactory$ExecutorCallbackCall$$ExternalSyntheticLambda1.run(Unknown Source:6)
        at android.os.Handler.handleCallback(Handler.java:938)
        at android.os.Handler.dispatchMessage(Handler.java:99)
        at android.os.Looper.loop(Looper.java:233)
        at android.app.ActivityThread.main(ActivityThread.java:8030)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:631)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:978)

这是main中的错误行activity(FetchOutfitInputDetails.java)

Log.v("Aaaaaa",pojo.getCurrent().toString());

Answer 1

尝试将您的字段名称 CurrentObject 更改为 current，使其与 json 字段的名称匹配

public class WeatherPojo {
    // CurrentWeatherPojo CurrentObject;
    CurrentWeatherPojo current;
}

API 数据未转换为 java 对象

API data not getting converted to java object

java

android

android-studio

retrofit