ExactAssetImage class Null safety

Fetches an image from an AssetBundle, associating it with the given scale.

This implementation requires an explicit final assetName and scale on construction, and ignores the device pixel ratio and size in the configuration passed into resolve. For a resolution-aware variant that uses the configuration to pick an appropriate image based on the device pixel ratio and size, see AssetImage.

Fetching assets

When fetching an image provided by the app itself, use the assetName argument to name the asset to choose. For instance, consider a directory icons with an image heart.png. First, the pubspec.yaml of the project should specify its assets in the flutter section:

flutter:
  assets:
    - icons/heart.png

Then, to fetch the image and associate it with scale 1.5, use:

const ExactAssetImage('icons/heart.png', scale: 1.5)

Assets in packages

To fetch an asset from a package, the package argument must be provided. For instance, suppose the structure above is inside a package called my_icons. Then to fetch the image, use:

const ExactAssetImage('icons/heart.png', scale: 1.5, package: 'my_icons')

Assets used by the package itself should also be fetched using the package argument as above.

If the desired asset is specified in the pubspec.yaml of the package, it is bundled automatically with the app. In particular, assets used by the package itself must be specified in its pubspec.yaml.

A package can also choose to have assets in its 'lib/' folder that are not specified in its pubspec.yaml. In this case for those images to be bundled, the app has to specify which ones to include. For instance a package named fancy_backgrounds could have:

lib/backgrounds/background1.png
lib/backgrounds/background2.png
lib/backgrounds/background3.png

To include, say the first image, the pubspec.yaml of the app should specify it in the assets section:

  assets:
    - packages/fancy_backgrounds/backgrounds/background1.png

The lib/ is implied, so it should not be included in the asset path.

See also:

• Image.asset for a shorthand of an Image widget backed by ExactAssetImage when using a scale.