RxJava + Retrofit2 基本使用實例詳解（附源碼 效果圖）

• 效果圖：控制檯輸出
  
  源碼：https://github.com/StephaineWYT/Translation

• 步驟一
  Android Studio 新建 Empty Activity項目，在 build.gradle(Module:app) 中導入依賴與設置編譯版本：
  

      compileOptions {
          sourceCompatibility JavaVersion.VERSION_1_8
          targetCompatibility JavaVersion.VERSION_1_8
      }
  

      implementation 'io.reactivex.rxjava2:rxjava:2.2.0'
      implementation 'io.reactivex.rxjava2:rxandroid:2.0.2'
      implementation 'com.squareup.retrofit2:retrofit:2.8.1'
      implementation 'com.jakewharton.retrofit:retrofit2-rxjava2-adapter:1.0.0'
      implementation 'com.squareup.retrofit2:converter-gson:2.8.1'
  

• 步驟二
  項目的 res 目錄新建 xml 文件夾，並新建 network_security_config.xml
  

  <?xml version="1.0" encoding="utf-8"?>
  <network-security-config>
      <base-config cleartextTrafficPermitted="true" />
  </network-security-config>
  

  在AndroidManifext.xml 兩個地方設置權限

• 步驟三 File – Settings – Plugins – 右側 MarketPlace 搜索安裝 GsonFormat 插件
  如果你網絡不太順暢，先訪問網址自己下載：官網GsonFormat插件下載
  下載好 Jar 包之後 在原來Android Studio 的 Plugins頁面上選擇 Install Plugins From Disk , 再選擇你下載好的jar包即可

  
  
  

• 步驟四：項目結構，較簡單，下面逐一介紹各個文件
  
  Transalation.java
  ① 先訪問項目用到的翻譯 api 它返回了翻譯的JSON字符串

  {"status":1,"content":{"from":"zh","to":"en","out":"simple","vendor":"ciba","err_no":0}}
  

  // 參數說明：
  // a：固定值 fy
  // f：原文內容類型，日語取 ja，中文取 zh，英語取 en，韓語取 ko，德語取 de，西班牙語取 es，法語取 fr，自動則取 auto
  // t：譯文內容類型，日語取 ja，中文取 zh，英語取 en，韓語取 ko，德語取 de，西班牙語取 es，法語取 fr，自動則取 auto
  // w：查詢內容
  

  ② 新建Translation.java，在 Translation.java 同時按 Alt + S 鍵，並將上文中提到的json字符串複製進去，生成實體類及屬性，並添加 toString() 方法用於打印
  

  package wen.translation;
  
  import androidx.annotation.NonNull;
  
  public class Translation {
      /**
       * sample url : http://fy.iciba.com/ajax.php?a=fy&f=zh&t=en&w=%E7%AE%80%E5%8D%95
       * status : 1
       * content : {"from":"zh","to":"en","out":"simple","vendor":"ciba","err_no":0}
       */
  
      private int status;
      private ContentBean content;
  
      public int getStatus() {
          return status;
      }
  
      public void setStatus(int status) {
          this.status = status;
      }
  
      public ContentBean getContent() {
          return content;
      }
  
      public void setContent(ContentBean content) {
          this.content = content;
      }
  
      public static class ContentBean {
          /**
           * from : zh
           * to : en
           * out : simple
           * vendor : ciba
           * err_no : 0
           */
  
          private String from;
          private String to;
          private String out;
          private String vendor;
          private int err_no;
  
          public String getFrom() {
              return from;
          }
  
          public void setFrom(String from) {
              this.from = from;
          }
  
          public String getTo() {
              return to;
          }
  
          public void setTo(String to) {
              this.to = to;
          }
  
          public String getOut() {
              return out;
          }
  
          public void setOut(String out) {
              this.out = out;
          }
  
          public String getVendor() {
              return vendor;
          }
  
          public void setVendor(String vendor) {
              this.vendor = vendor;
          }
  
          public int getErr_no() {
              return err_no;
          }
  
          public void setErr_no(int err_no) {
              this.err_no = err_no;
          }
  
          @NonNull
          @Override
          public String toString() {
              return "ContentBean{" +
                      "from='" + from + '\'' +
                      ", to='" + to + '\'' +
                      ", out='" + out + '\'' +
                      ", vendor='" + vendor + '\'' +
                      ", err_no=" + err_no +
                      '}';
          }
      }
  
      @NonNull
      @Override
      public String toString() {
          return "Translation{" +
                  "status=" + status +
                  ", content=" + content +
                  '}';
      }
  }
  
  

  ApiService.java 設置接口服務，這裏設置參數的 url 即可，訪問的 BaseUrl 在 MainActivity 中實現

  package wen.translation;
  
  import io.reactivex.Observable;
  import retrofit2.http.GET;
  import retrofit2.http.Query;
  
  public interface ApiService {
  
      @GET("ajax.php?a=fy&f=zh&t=en")
      Observable<Translation> getCall(@Query("w") String w);
  
  }
  
  

  MainActivity.java ，使用 RxJava 與 Retrofit2 進行解析

  package wen.translation;
  
  import androidx.appcompat.app.AppCompatActivity;
  
  import android.os.Bundle;
  import android.util.Log;
  
  import com.jakewharton.retrofit2.adapter.rxjava2.RxJava2CallAdapterFactory;
  
  import io.reactivex.Observable;
  import io.reactivex.Observer;
  import io.reactivex.android.schedulers.AndroidSchedulers;
  import io.reactivex.disposables.Disposable;
  import io.reactivex.schedulers.Schedulers;
  import retrofit2.Retrofit;
  import retrofit2.converter.gson.GsonConverterFactory;
  
  public class MainActivity extends AppCompatActivity {
  
      private static final String TAG = "RxJava";
  
      @Override
      protected void onCreate(Bundle savedInstanceState) {
          super.onCreate(savedInstanceState);
          setContentView(R.layout.activity_main);
  
          Retrofit retrofit = new Retrofit.Builder()
                  .baseUrl("http://fy.iciba.com/")
                  .addConverterFactory(GsonConverterFactory.create())
                  .addCallAdapterFactory(RxJava2CallAdapterFactory.create())
                  .build();
  
          ApiService apiService = retrofit.create(ApiService.class);
  
          Observable<Translation> observable = apiService.getCall("可靠");
  
          assert observable != null;
          observable.subscribeOn(Schedulers.io())
                  .observeOn(AndroidSchedulers.mainThread())
                  .subscribe(new Observer<Translation>() {
                      @Override
                      public void onSubscribe(Disposable d) {
                          Log.d(TAG, "開始採用subscribe連接");
                      }
  
                      @Override
                      public void onNext(Translation translation) {
                          Log.i("===translation===", translation.toString());
                      }
  
                      @Override
                      public void onError(Throwable e) {
                          e.printStackTrace();
                          Log.d(TAG, "請求失敗");
                      }
  
                      @Override
                      public void onComplete() {
                          Log.d(TAG, "請求成功");
                      }
                  });
      }
  }
  
  

  效果如開頭所示，至此完成最基本的 RxJava + Retrofit2 使用
  感謝博主 https://blog.csdn.net/carson_ho/article/details/79125101