如何为改造2制作单件？

如果存在多个改装调用,我如何进行改造的单例,以便在类中不会重复代码,从而摆脱不必要的代码.

这是一个例子,但是!虽然这可能是闪亮的,易于使用,但单身人士是邪恶的.尽可能避免使用它们.解决它的一种方法是使用依赖注入.

无论如何.

public class Api {
    private static Api instance = null;
    public static final String BASE_URL = "your_base_url";

    // Keep your services here, build them in buildRetrofit method later
    private UserService userService;

    public static Api getInstance() {
        if (instance == null) {
            instance = new Api();
        }

        return instance;
    }

    // Build retrofit once when creating a single instance
    private Api() {
        // Implement a method to build your retrofit
        buildRetrofit(BASE_URL);
    }

    private void buildRetrofit() {
        Retrofit retrofit = ...

        // Build your services once
        this.userService = retrofit.create(UserService.class);
        ...
    }

    public UserService getUserService() {
        return this.userService;
    }
    ...
}

现在你把所有东西放在一个地方.用它.

UserService userService = Api.getInstance().getUserService();