Rewrite the set method and load it lazily

1. Check whether the array is empty. If it is null, it indicates that it has been loaded. If it is not empty, it is not loaded.

-(NSArray *) questions

{

If (_ questions = nil ){

        

// 1. Load plist

NSArray * dictArray = [NSArray arrayWithContentsOfFile: [[NSBundle mainBundle] pathForResource: @ "questions. plist" ofType: nil];

        

        

// 2. Dictionary-to-model

NSMutableArray * questionArray = [NSMutableArray array];

    

For (NSDictionary * dict in dictArray ){

            

WNHQuestion * question = [WNHQuestion questionWithDict: dict];

[QuestionArray addObject: question];

        }

        

// 3. Assign a value

_ Questions = questionArray;

    }

Return _ questions;

}

Rewrite the set method and load it lazily