Android 在NativeScript的StackLayout或ListView中使用ImageCache

我有一个项目列表，每个项目都有一个图像。我想缓存图像

因此，我在XML中大致有如下内容：

        <StackLayout>
        <GridLayout>
          <gv:GridView items="{{ kats }}" verticalSpacing="0" horizontalSpacing="0"
                       colWidth="{{ colWidth }}"  rowHeight="100" padding="0"
                       itemTap="openKat" itemLoading="mainLoading">
            <gv:GridView.itemTemplate>
                <GridLayout columns="*" rows="80,20">
                    <Image row="0" src="{{ Image, Image | mkThumbLink() }}" />
                    <Label row="1" text="{{ description }}" />
                </GridLayout>
            </gv:GridView.itemTemplate>
          </gv:GridView>
        </GridLayout>
    </StackLayout>

---

页面加载中的每个图像都会调用toView方法，但我不知道如何在图像到达时将其推回到页面。在“cache.push.completed”部分，我想？

我把这个留给那些仍在寻找答案的人。 这就是我的工作。我用打字稿

public get itemImage() : imageSource.ImageSource {
    if (constants.IS_DEBUG) console.log("Attempting to fetch image for: " + this.key);

    var cache = new imageCacheModule.Cache();
    cache.placeholder = imageSource.fromResource("background");
    cache.maxRequests = 2;

    var imgSource: imageSource.ImageSource = cache.placeholder;

    if (this.imageExists && this.itemImageUrl !== '') {
        // Try to read the image from the cache
        var image = cache.get(this.itemImageUrl);
        if (image) {
            // If present -- use it.
            if (constants.IS_DEBUG) console.log("Image found in cache");
            imgSource = imageSource.fromNativeSource(image);
        }
        else {
            // If not present -- request its download.
            if (constants.IS_DEBUG) console.log("Image not cached, downloading...");
            cache.enableDownload();
            cache.enqueue({
                key: this.itemImageUrl,
                url: this.itemImageUrl,
                completed: (image: any, key: string) => {
                    if (constants.IS_DEBUG) console.log("Image downloaded");
                    cache.disableDownload();
                    if (this.itemImageUrl === key) {
                        imgSource = imageSource.fromNativeSource(image);
                        this.set('itemImage', imgSource);
                    }
                }
            });
        }
    }

    return imgSource;
}

---

做这项工作的行是this.set（'itemImage'，imgSource）

我把这个留给那些仍在寻找答案的人。 这就是我的工作。我用打字稿

public get itemImage() : imageSource.ImageSource {
    if (constants.IS_DEBUG) console.log("Attempting to fetch image for: " + this.key);

    var cache = new imageCacheModule.Cache();
    cache.placeholder = imageSource.fromResource("background");
    cache.maxRequests = 2;

    var imgSource: imageSource.ImageSource = cache.placeholder;

    if (this.imageExists && this.itemImageUrl !== '') {
        // Try to read the image from the cache
        var image = cache.get(this.itemImageUrl);
        if (image) {
            // If present -- use it.
            if (constants.IS_DEBUG) console.log("Image found in cache");
            imgSource = imageSource.fromNativeSource(image);
        }
        else {
            // If not present -- request its download.
            if (constants.IS_DEBUG) console.log("Image not cached, downloading...");
            cache.enableDownload();
            cache.enqueue({
                key: this.itemImageUrl,
                url: this.itemImageUrl,
                completed: (image: any, key: string) => {
                    if (constants.IS_DEBUG) console.log("Image downloaded");
                    cache.disableDownload();
                    if (this.itemImageUrl === key) {
                        imgSource = imageSource.fromNativeSource(image);
                        this.set('itemImage', imgSource);
                    }
                }
            });
        }
    }

    return imgSource;
}

---

做这项工作的行是this.set（'itemImage'，imgSource）

嘿，问题有进展吗？嘿，问题有进展吗？