Flutter Singleton Usage without late-CodePudding

I have learned the how can I use singleton class. After that, I wanted to use for my baseUrl class.

class BaseUrls {
  BaseUrls._();
  static BaseUrls get instance => BaseUrls._();
  final String baseUrl="https://pub.dev/packages/";
  late final String bloc="${baseUrl}bloc";
}

when I wants to use any variable for instance bloc, I can use it like

BaseUrls.instance.bloc

but when I wants to use baseUrl inside of the bloc variable, I'm encountering the init error. I have solved that problem thanks to late usage. But in this time, there is a performance problem of late. when I use the late, it is harmful for ram usage.

So, my question is How can I use that usage without late? I mean, I wanna use the base url and bloc variable with together.

I'm open the new usage or best practices. Many thanks.

CodePudding user response：

To use bloc variable without using late, you can define the bloc variable as a function that returns a string, and inside the function, you can use the baseUrl variable:

    class BaseUrls {
    BaseUrls._();
    static BaseUrls get instance => BaseUrls._();
    final String baseUrl="https://pub.dev/packages/";
    String get bloc => "${baseUrl}bloc";
    }

Now, you can access the bloc variable like this: BaseUrls.instance.bloc. Because bloc is a function, it will be evaluated every time it is accessed, which means the value of baseUrl will always be up-to-date.

CodePudding user response：

finally,I have found 2 ways. First one is use static for baseUrl. Second way is use get function instead of bloc variable.

Summary:

//FIRST ONE
class BaseUrls {
  BaseUrls._();
  static BaseUrls get instance => BaseUrls._();
  final String baseUrl="https://pub.dev/packages/";
  final String get bloc="${baseUrl}bloc";
}

//SECOND WAY
    class BaseUrls {
        BaseUrls._();
        static BaseUrls get instance => BaseUrls._();
        static const String baseUrl="https://pub.dev/packages/";
        final String bloc="${baseUrl}bloc";
        }

so, which one if I use ,app will be more performance? Should I use getter function or only use static to baseUrl? Thanks....