Support custom data source like VirtualizedList does

[punksta]

Thanks for cool library.
DataProvider supports only array as data source. I want to use it with Immutable.js data structures

[naqvitalha]

It is already possible. DataProvider can be extended into something custom. Check the following file: https://github.com/Flipkart/recyclerlistview/blob/master/src/core/dependencies/DataProvider.ts

Inherit DataProvider and override getDataForIndex(). Start using immutable collection instead of array. Let me know if you need further help.

[punksta]

Worked, thanks.
this data: any[] stopped me. Maybe better to have an interface and then make existing DataProvider basic implementation.

[black7375]

@naqvitalha have one question.

I looked at the source to override.

recyclerlistview/src/core/dependencies/DataProvider.ts

Lines 30 to 32 in b7c23d2

	public getDataForIndex(index: number): any {
	return this._data[index];
	}

To redefine the function, need to access the _data, but it is private.

recyclerlistview/src/core/dependencies/DataProvider.ts

Line 14 in b7c23d2

private _data: any[] = [];

What about creating any[], any types to interfaces in generics, abstract functions?

[wxsms]

@black7375 Use getAllData instead.

[black7375]

@wxsms
I asked because I couldn't write a data type like List<T> because of the type of _data(any[]), but I solved the problem by creating it again exclude interface.

Like this.

export abstract class GenericDataProvider<T, K = keyof T> extends BaseDataProvider{
  public rowHasChanged: (r1: T | any, r2: T | any) => boolean;

  // In JS context make sure stable id is a string
  public getStableId: (index: number) => string;
  protected m_firstIndexToProcess: number = 0;
  protected m_size: number = 0;
  protected m_data: K | any = List<T>([]);
  protected m_hasStableIds = false;
  protected m_requiresDataChangeHandling = false;

  constructor(rowHasChanged: (r1: T | any, r2: T | any) => boolean,
              getStableId?:  (index: number) => string) {
    super(rowHasChanged, getStableId);
    this.rowHasChanged = rowHasChanged;
    if (getStableId) {
      this.getStableId = getStableId;
      this.m_hasStableIds = true;
    } else {
      this.getStableId = (index) => index.toString();
    }
  }

  public abstract newInstance(
    rowHasChanged: (r1: T, r2: T) => boolean,
    getStableId?: (index: number) => string    ): GenericDataProvider<T, K>;
  public abstract getDataForIndex(index: number): T | undefined;
  public abstract cloneWithRows(newData: K | any,
                    firstModifiedIndex?: number): DataProvider;

  public getAllData(): K | any {
    return this.m_data;
  }
...

[wxsms]

@punksta Hi, could you pls show your solution here? I've tried the solution provided by @naqvitalha , by it doesn't work. It just show a blank screen without any errors. Thank you in advance!

[wxsms]

Never mind. found out that I have to override not only getDataForIndex , but also newInstance and cloneWithRows. and should extends BaseDataProvider, not DataProvider. This is not frinedly enough 😢 . But anyway, works now.