From a4b0228720f271ed145721ea8335dbd6fcd1ffc2 Mon Sep 17 00:00:00 2001
From: liubihao <liubihao1@huawei.com>
Date: Thu, 7 Aug 2025 16:33:13 +0800
Subject: [PATCH] add arkts_1.2 spec for prefetcher.

Signed-off-by: liubihao <liubihao1@huawei.com>
---
 api/@ohos.arkui.Prefetcher.static.d.ets | 121 ++++++++++++++++++++++++
 1 file changed, 121 insertions(+)
 create mode 100644 api/@ohos.arkui.Prefetcher.static.d.ets

diff --git a/api/@ohos.arkui.Prefetcher.static.d.ets b/api/@ohos.arkui.Prefetcher.static.d.ets
new file mode 100644
index 00000000000..c174af04541
--- /dev/null
+++ b/api/@ohos.arkui.Prefetcher.static.d.ets
@@ -0,0 +1,121 @@
+/*
+ * Copyright (c) 2025 Huawei Device Co., Ltd.
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/**
+ * @file
+ * @kit ArkUI
+ * @arkts 1.2
+ */
+
+/**
+ * Implement this interface to provide data prefetching for the LazyForEach component.
+ *
+ * @extends IDataSource
+ * @interface IDataSourcePrefetching
+ * @syscap SystemCapability.ArkUI.ArkUI.Full
+ * @since 20
+ */
+export interface IDataSourcePrefetching extends IDataSource {
+  /**
+   * Prefetches data for the specified element in the data collection.
+   * This method can be either synchronous or asynchronous.
+   *
+   * @param { int } index - Index of the item in the collection.
+   * @returns { Promise<void> | void }
+   * @syscap SystemCapability.ArkUI.ArkUI.Full
+   * @since 20
+   */
+  prefetch(index: int): Promise<void> | void;
+
+  /**
+   * Cancels prefetching data for the specified element in the data collection.
+   * This method can be either synchronous or asynchronous.
+   *
+   * @param { int } index - Index of the item in the collection.
+   * @returns { Promise<void> | void }
+   * @syscap SystemCapability.ArkUI.ArkUI.Full
+   * @since 20
+   */
+  cancel?(index: int): Promise<void> | void;
+}
+
+/**
+ * Implement this interface to provide prefetcher logic.
+ *
+ * @interface IPrefetcher
+ * @syscap SystemCapability.ArkUI.ArkUI.Full
+ * @since 20
+ */
+export interface IPrefetcher {
+  /**
+   * Sets the data source to bind to this prefetcher.
+   *
+   * @param { IDataSourcePrefetching } dataSource - Data source that supports prefetching.
+   * @syscap SystemCapability.ArkUI.ArkUI.Full
+   * @since 20
+   */
+  setDataSource(dataSource: IDataSourcePrefetching): void;
+
+  /**
+   * Call this method when the visible area boundaries were changed.
+   *
+   * @param { int } minVisible - Index of the first visible data item.
+   * @param { int } maxVisible - Index of the last visible data item.
+   * @syscap SystemCapability.ArkUI.ArkUI.Full
+   * @since 20
+   */
+  visibleAreaChanged(minVisible: int, maxVisible: int): void;
+}
+
+/**
+ * Basic implementation of {@link IPrefetcher}.
+ * It provides an intelligent data prefetching algorithm to make decisions about which data
+ * items should be prefetched in response to the real-time changes of visible on-screen area
+ * and changes in the duration of the prefetching. It also determines which prefetch requests
+ * should be canceled based on user scrolling actions.
+ *
+ * @implements IPrefetcher
+ * @syscap SystemCapability.ArkUI.ArkUI.Full
+ * @since 20
+ */
+export class BasicPrefetcher implements IPrefetcher {
+  /**
+   * Constructs a basic prefetcher instance and optionally sets the data source.
+   *
+   * @param { IDataSourcePrefetching } [dataSource] - Data source that supports prefetching.
+   * @syscap SystemCapability.ArkUI.ArkUI.Full
+   * @since 20
+   */
+  constructor(dataSource?: IDataSourcePrefetching);
+
+  /**
+   * Sets the data source to bind to this prefetcher.
+   *
+   * @param { IDataSourcePrefetching } dataSource - Data source that supports prefetching.
+   * @syscap SystemCapability.ArkUI.ArkUI.Full
+   * @since 20
+   */
+  setDataSource(dataSource: IDataSourcePrefetching): void;
+
+  /**
+   * Call this method when the visible area changed.
+   *
+   * @param { int } minVisible - Index of the first visible data item.
+   * @param { int } maxVisible - Index of the last visible data item.
+   * @syscap SystemCapability.ArkUI.ArkUI.Full
+   * @since 20
+   */
+  visibleAreaChanged(minVisible: int, maxVisible: int): void;
+}
-- 
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