66 lines
2.8 KiB
Dart
66 lines
2.8 KiB
Dart
// Copyright 2014 The Flutter Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file.
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// Flutter imports:
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import 'package:flutter/foundation.dart';
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// Project imports:
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import 'package:invoiceninja_flutter/ui/app/tables/app_data_table.dart';
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/// A data source for obtaining row data for [PaginatedDataTable] objects.
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///
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/// A data table source provides two main pieces of information:
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///
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/// * The number of rows in the data table ([rowCount]).
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/// * The data for each row (indexed from `0` to `rowCount - 1`).
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///
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/// It also provides a listener API ([addListener]/[removeListener]) so that
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/// consumers of the data can be notified when it changes. When the data
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/// changes, call [notifyListeners] to send the notifications.
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///
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/// DataTableSource objects are expected to be long-lived, not recreated with
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/// each build.
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abstract class AppDataTableSource extends ChangeNotifier {
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/// Called to obtain the data about a particular row.
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///
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/// The [new DataRow.byIndex] constructor provides a convenient way to construct
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/// [DataRow] objects for this callback's purposes without having to worry about
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/// independently keying each row.
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///
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/// If the given index does not correspond to a row, or if no data is yet
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/// available for a row, then return null. The row will be left blank and a
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/// loading indicator will be displayed over the table. Once data is available
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/// or once it is firmly established that the row index in question is beyond
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/// the end of the table, call [notifyListeners].
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///
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/// Data returned from this method must be consistent for the lifetime of the
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/// object. If the row count changes, then a new delegate must be provided.
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DataRow getRow(int index);
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/// Called to obtain the number of rows to tell the user are available.
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///
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/// If [isRowCountApproximate] is false, then this must be an accurate number,
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/// and [getRow] must return a non-null value for all indices in the range 0
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/// to one less than the row count.
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///
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/// If [isRowCountApproximate] is true, then the user will be allowed to
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/// attempt to display rows up to this [rowCount], and the display will
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/// indicate that the count is approximate. The row count should therefore be
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/// greater than the actual number of rows if at all possible.
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///
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/// If the row count changes, call [notifyListeners].
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int get rowCount;
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/// Called to establish if [rowCount] is a precise number or might be an
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/// over-estimate. If this returns true (i.e. the count is approximate), and
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/// then later the exact number becomes available, then call
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/// [notifyListeners].
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bool get isRowCountApproximate;
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/// Called to obtain the number of rows that are currently selected.
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///
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/// If the selected row count changes, call [notifyListeners].
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int get selectedRowCount;
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}
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