使用Retrofit2和rxJava2解析来自OpenWeatherMap的数据

Question

我已经开始学习Retrofit和RxJava，并且决定创建weatherApp。 现在我的目标是从OpenWeatherMap Api检索天气数据。 这是我的代码：对于api：

package com.example.aldres.workingwithapis.Api;

import com.example.aldres.workingwithapis.models.WeatherData;

import retrofit2.http.GET;
import retrofit2.http.Query;
import rx.Observable;

public interface Api {
    @GET("weather?")
    Observable<WeatherData> getWeatherData(@Query("q") String city);
}

还要为我的WeatherData模型编码：

package com.example.aldres.workingwithapis.models;

import java.util.List;
import com.google.gson.annotations.Expose;
import com.google.gson.annotations.SerializedName;

public class WeatherData {

    @SerializedName("coord")
    @Expose
    private Coord coord;
    @SerializedName("weather")
    @Expose
    private List<Weather> weather = null;
    @SerializedName("base")
    @Expose
    private String base;
    @SerializedName("main")
    @Expose
    private Main main;
    @SerializedName("visibility")
    @Expose
    private Integer visibility;
    @SerializedName("wind")
    @Expose
    private Wind wind;
    @SerializedName("clouds")
    @Expose
    private Clouds clouds;
    @SerializedName("dt")
    @Expose
    private Integer dt;
    @SerializedName("sys")
    @Expose
    private Sys sys;
    @SerializedName("id")
    @Expose
    private Integer id;
    @SerializedName("name")
    @Expose
    private String name;
    @SerializedName("cod")
    @Expose
    private Integer cod;

    public Coord getCoord() {
        return coord;
    }

    public void setCoord(Coord coord) {
        this.coord = coord;
    }

    public List<Weather> getWeather() {
        return weather;
    }

    public void setWeather(List<Weather> weather) {
        this.weather = weather;
    }

    public String getBase() {
        return base;
    }

    public void setBase(String base) {
        this.base = base;
    }

    public Main getMain() {
        return main;
    }

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

    public Integer getVisibility() {
        return visibility;
    }

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

    public Wind getWind() {
        return wind;
    }

    public void setWind(Wind wind) {
        this.wind = wind;
    }

    public Clouds getClouds() {
        return clouds;
    }

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

    public Integer getDt() {
        return dt;
    }

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

    public Sys getSys() {
        return sys;
    }

    public void setSys(Sys sys) {
        this.sys = sys;
    }

    public Integer getId() {
        return id;
    }

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

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public Integer getCod() {
        return cod;
    }

    public void setCod(Integer cod) {
        this.cod = cod;
    }

}

还有我的mainActivity：

package com.example.aldres.workingwithapis;

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.widget.TextView;
import com.example.aldres.workingwithapis.Api.Api;
import com.example.aldres.workingwithapis.models.WeatherData;
import retrofit2.Retrofit;
import retrofit2.adapter.rxjava.RxJavaCallAdapterFactory;
import retrofit2.converter.gson.GsonConverterFactory;
import rx.Observable;
import rx.Subscriber;
import rx.android.schedulers.AndroidSchedulers;
import rx.schedulers.Schedulers;

public class MainActivity extends AppCompatActivity {
    private TextView middleText;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        middleText = findViewById(R.id.middleText);

        Retrofit retrofit = new Retrofit.Builder()
                .addCallAdapterFactory(RxJavaCallAdapterFactory.create())
                .addConverterFactory(GsonConverterFactory.create())
                .baseUrl("http://api.openweathermap.org/data/2.5/")
                .build();
        Api apiService = retrofit.create(Api.class);

        Observable<WeatherData> observable = apiService.getWeatherData("London");

                observable
                .subscribeOn(Schedulers.newThread())
                .observeOn(AndroidSchedulers.mainThread())
                .subscribe(new Subscriber<WeatherData>() {
                    @Override
                    public void onCompleted() {

                    }

                    @Override
                    public void onError(Throwable e) {

                    }

                    @Override
                    public void onNext(WeatherData weatherData) {
                        middleText.setText(weatherData.getWind());
                    }
                });
    }
}

此时，我的应用程序应该在我的TextView middleText中显示带有wind参数的字符串，但是当我启动我的应用程序时，它的启动没有任何错误，但是TextView中没有我的文本。 我做错了什么？

Answer 1

您的请求可能会出错，而您会忽略onError方法而一无所知。 将e.printStackTrace()添加到该方法以查看是否存在这种情况。