FAQ¶

Have a question that isn't part of the FAQ? Check StackOverflow with the tag #coil or search Github discussions.

Can Coil be used with Java projects or mixed Kotlin/Java projects?¶

How do I preload an image?¶

Launch an image request with no target:

val request = ImageRequest.Builder(context)
    .data("https://example.com/image.jpg")
    .build()
imageLoader.enqueue(request)

That will preload the image and save it to the disk and memory caches.

If you only want to preload to the disk cache you can skip decoding and saving to the memory cache like so:

val request = ImageRequest.Builder(context)
    .data("https://example.com/image.jpg")
    // Disables writing to the memory cache.
    .memoryCachePolicy(CachePolicy.DISABLED)
    // Skips the decode step so we don't waste time/memory decoding the image into memory.
    .decoderFactory(BlackholeDecoder.Factory())
    .build()
imageLoader.enqueue(request)

How do I enable logging?¶

Set logger(DebugLogger()) when constructing your ImageLoader.

Note

DebugLogger should only be used in debug builds.

How do I target Java 8?¶

Coil requires Java 8 bytecode. This is enabled by default on the Android Gradle Plugin 4.2.0 and later and the Kotlin Gradle Plugin 1.5.0 and later. If you're using older versions of those plugins add the following to your Gradle build script:

Gradle (.gradle):

android {
    compileOptions {
        sourceCompatibility JavaVersion.VERSION_1_8
        targetCompatibility JavaVersion.VERSION_1_8
    }
    kotlinOptions {
        jvmTarget = "1.8"
    }
}

Gradle Kotlin DSL (.gradle.kts):

android {
    compileOptions {
        sourceCompatibility = JavaVersion.VERSION_1_8
        targetCompatibility = JavaVersion.VERSION_1_8
    }
    kotlinOptions {
        jvmTarget = "1.8"
    }
}

How do I get development snapshots?¶

Add the snapshots repository to your list of repositories:

Gradle (.gradle):

allprojects {
    repositories {
        maven { url 'https://oss.sonatype.org/content/repositories/snapshots' }
    }
}

Gradle Kotlin DSL (.gradle.kts):

allprojects {
    repositories {
        maven("https://oss.sonatype.org/content/repositories/snapshots")
    }
}

Then depend on the same artifacts with the latest snapshot version.

Note

Snapshots are deployed for each new commit on main that passes CI. They can potentially contain breaking changes or may be unstable. Use at your own risk.