建立ExpensesResponse

用於接收從 Spring Boot 返回的支出數據類別。當發出請求期望獲得關於支出的資訊時，Spring Boot 會將數據以 JSON 格式返回，而可以使用 ExpensesResponse 類別來將對應的 JSON 數據轉換為 Java 物件。

public class ExpensesResponse {
    @SerializedName("status")
    private String status;

    @SerializedName("message")
    private String message;

    @SerializedName("expensesDataList")
    private List<ExpensesData> expensesDataList;

    public String getStatus() {
        return status;
    }

    public void setStatus(String status) {
        this.status = status;
    }

    public String getMessage() {
        return message;
    }

    public void setMessage(String message) {
        this.message = message;
    }

    public List<ExpensesData> getExpensesDataList() {
        return expensesDataList;
    }

    public void setExpensesDataList(List<ExpensesData> expensesDataList) {
        this.expensesDataList = expensesDataList;
    }
}

建立ExpensesData

用於表示每筆支出數據的詳細資訊。ExpensesResponse 物件中的expensesDataList 屬性包含多個 ExpensesData 物件，每個物件表示一筆支出記錄，可以使用 get 方法來訪問這些屬性。

public class ExpensesData {
    @SerializedName("id")
    private Long id;

    @SerializedName("expensesType")
    private String expensesType;

    @SerializedName("expensesName")
    private String expensesName;

    @SerializedName("expensesValue")
    private int expensesValue;

    public Long getId() {
        return id;
    }

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

    public String getExpensesName() {
        return expensesName;
    }

    public void setExpensesName(String expensesName) {
        this.expensesName = expensesName;
    }

    public int getExpensesValue() {
        return expensesValue;
    }

    public void setExpensesValue(int expensesValue) {
        this.expensesValue = expensesValue;
    }

    public String getExpensesType() {
        return expensesType;
    }

    public void setExpensesType(String expensesType) {
        this.expensesType = expensesType;
    }
}

使用 RxJava 與 Retrofit

建立ApiService

用於定義你的 Android 和 Spring Boot 伺服器之間的 API 請求方法。這些方法都對應了不同的 API 端點：

public interface ApiService {
    @GET("user/expenses")
    Observable<ExpensesResponse> getExpensesData(@Query("date") String date);
    @GET("user/expenses/all")
    Observable<ExpensesResponse> getAllExpensesData();
    @DELETE("user/expenses")
    Observable<StatusResponse> deleteExpensesData(@Query("id") Long id);
}    
    @POST("user/expenses")
    Observable<StatusResponse> insertExpenses(@Body ExpensesRequest expensesRequest);

建立RetrofitManager

用於管理 Retrofit 實例並提供一個全局的 ApiService 實例，以便在整個應用程式中使用 Retrofit 來發送請求。

public class RetrofitManager {
    private static RetrofitManager mInstance = new RetrofitManager();
    private ApiService apiService;
    private RetrofitManager() {
        Retrofit retrofit = new Retrofit.Builder()
                .baseUrl("http://請更改IP:8080/api/")
                .addConverterFactory(GsonConverterFactory.create())
                .addCallAdapterFactory(RxJava2CallAdapterFactory.create())
                .client(client)
                .build();

        apiService = retrofit.create(ApiService.class);
    }
    public static RetrofitManager getInstance() {
        return mInstance;
    }

    public ApiService getAPI() {
        return apiService;
    }
}

Rxjava ( 新增、讀取、刪除 操作 )

這邊以讀取方法為示範：

    @Override
    public void loadExpensesData(String date) {
        apiService.getExpensesData(date)
                .subscribeOn(Schedulers.io())
                .observeOn(AndroidSchedulers.mainThread())
                .subscribeWith(new Observer<ExpensesResponse>() {
                    @Override
                    public void onSubscribe(Disposable d) {

                    }

                    @Override
                    public void onNext(ExpensesResponse expensesResponse) {
                        //取得支出相關資料，並進行相關處理
                        presenter.showExpenses(expensesResponse.getExpensesDataList());
                    }

                    @Override
                    public void onError(Throwable e) {
                        Log.e("loadExpensesData", e.toString());

                    }

                    @Override
                    public void onComplete() {

                    }
                });
    }