Image Requests

If you need an ImageRequest that consists only of a URI, you can use the helper method ImageRequest.fromURI. Loading multiple-images is a common case of this.

If you need to tell the image pipeline anything more than a simple URI, you need to use ImageRequestBuilder:

Uri uri;

ImageDecodeOptions decodeOptions = ImageDecodeOptions.newBuilder()
    .setBackgroundColor(Color.GREEN)
    .build();

ImageRequest request = ImageRequestBuilder
    .newBuilderWithSource(uri)
    .setImageDecodeOptions(decodeOptions)
    .setAutoRotateEnabled(true)
    .setLocalThumbnailPreviewsEnabled(true)
    .setLowestPermittedRequestLevel(RequestLevel.FULL_FETCH)
    .setProgressiveRenderingEnabled(false)
    .setResizeOptions(new ResizeOptions(width, height))
    .build();

Fields in ImageRequest

• uri - the only mandatory field. See Supported URIs
• autoRotateEnabled - whether to enable auto-rotation.
• progressiveEnabled - whether to enable progressive loading.
• postprocessor - component to postprocess the decoded image.
• resizeOptions - desired width and height. Use with caution. See Resizing.

Lowest Permitted Request Level

The image pipeline follows a definite sequence in where it looks for the image.

1. Check the bitmap cache. This is nearly instant. If found, return.
2. Check the encoded memory cache. If found, decode the image and return.
3. Check the "disk" (local storage) cache. If found, load from disk, decode, and return.
4. Go to the original file on network or local file. Download, resize and/or rotate if requested, decode, and return. For network images in particular, this will be the slowest by a long shot.

The setLowestPermittedRequestLevel field lets you control how far down this list the pipeline will go. Possible values are:

• BITMAP_MEMORY_CACHE
• ENCODED_MEMORY_CACHE
• DISK_CACHE
• FULL_FETCH

This is useful in situations where you need an instant, or at least relatively fast, image or none at all.