ImageLoader

ui/res.ImageLoader

Cooperative image loading for ImageView and other views (memory + disk cache, cancellation).

Table of contents

Methods

• cancel
• clearDiskCache
• clearMemoryCache
• loadImageBitmap
• loadImageDrawable
• loadImageInto
• loadImageIntoBackground

Methods

cancel

▸ cancel(view): void

Cancel any in-flight load tagged to view. If nothing is loading, this is a no-op.

Example

"nodejs";
const { imageLoader } = require("ui/res");

imageLoader.loadImageInto(imageView, "https://example.com/image.jpg");
imageLoader.cancel(imageView);

Parameters

Name	Type	Description
view	View	Target view to cancel.

Returns

void

---

clearDiskCache

▸ clearDiskCache(): void

Delete all files in the on-disk image cache.

Example

"nodejs";
const { imageLoader } = require("ui/res");

imageLoader.clearDiskCache();
console.log("Disk cache cleared");

Returns

void

---

clearMemoryCache

▸ clearMemoryCache(): void

Drop in-memory bitmaps. Does not remove disk cache entries.

Example

"nodejs";
const { imageLoader } = require("ui/res");

imageLoader.clearMemoryCache();
console.log("Memory cache cleared");

Returns

void

---

loadImageBitmap

▸ loadImageBitmap(view, uri): Promise<Bitmap>

Load uri and resolve an Android Bitmap. uri may be http(s), a filesystem path, or content://….

Example

"nodejs";
const { imageLoader } = require("ui/res");

async function main() {
  const bitmap = await imageLoader.loadImageBitmap(
    view,
    "https://example.com/image.jpg",
  );
  imageView.setImageBitmap(bitmap);
}
main();

Parameters

Name	Type	Description
view	View	Any view that supplies a Context (often an ImageView).
uri	String	Image location.

Returns

Promise<Bitmap>

---

loadImageDrawable

▸ loadImageDrawable(view, uri): Promise<Drawable>

Same as loadImageBitmap, but returns a Drawable.

Example

"nodejs";
const { imageLoader } = require("ui/res");

async function main() {
  const drawable = await imageLoader.loadImageDrawable(
    view,
    "https://example.com/image.jpg",
  );
  imageView.setImageDrawable(drawable);
}
main();

Parameters

Name	Type	Description
view	View	Context source view.
uri	String	Image location.

Returns

Promise<Drawable>

---

loadImageInto

▸ loadImageInto(imageView, uri): Promise<void>

Decode uri and assign the result directly to imageView.

Example

"nodejs";
const { imageLoader } = require("ui/res");
const { inflateXml } = require("ui/layout");

async function main() {
  const rootView = inflateXml(
    context,
    `
        <ImageView id="img" />
    `,
  );
  const imageView = rootView.findView("img");

  await imageLoader.loadImageInto(imageView, "https://example.com/image.jpg");
  await imageLoader.loadImageInto(imageView, "/sdcard/image.png");
}
main();

Parameters

Name	Type	Description
imageView	ImageView	Destination view.
uri	String	Image location.

Returns

Promise<void>

Resolves when the image has been applied.

---

loadImageIntoBackground

▸ loadImageIntoBackground(view, uri): Promise<void>

Load uri and set it as view’s background drawable.

Example

"nodejs";
const { imageLoader } = require("ui/res");
const { inflateXml } = require("ui/layout");

async function main() {
  const rootView = inflateXml(
    context,
    `
        <LinearLayout id="container" />
    `,
  );
  const container = rootView.findView("container");

  await imageLoader.loadImageIntoBackground(
    container,
    "https://example.com/background.jpg",
  );
}
main();

Parameters

Name	Type	Description
view	View	Target view.
uri	String	Image location.

Returns

Promise<void>

Resolves when the background has been applied.