(#) Unsafe cast of `Context` to `Activity` !!! ERROR: Unsafe cast of `Context` to `Activity` This is an error. Id : `CastingViewContextToActivity` Summary : Unsafe cast of `Context` to `Activity` Severity : Error Category : Correctness Platform : Any Vendor : slack Identifier : slack-lint Contact : https://github.com/slackhq/slack-lints Feedback : https://github.com/slackhq/slack-lints Min : Lint 8.7+ Compiled : Lint 8.7+ Artifact : [com.slack.lint:slack-lint-checks](com_slack_lint_slack-lint-checks.md.html) Since : 0.1.0 Affects : Kotlin and Java files and test sources Editing : This check runs on the fly in the IDE editor Implementation : [Source Code](https://github.com/slackhq/slack-lints/tree/main/slack-lint-checks/src/main/java/slack/lint/ViewContextDetector.kt) Tests : [Source Code](https://github.com/slackhq/slack-lints/tree/main/slack-lint-checks/src/test/java/slack/lint/ViewContextDetectorTest.kt) Copyright Year : 2021 `View.getContext()` is not guaranteed to return an `Activity` and can often return a `ContextWrapper` instead resulting in a `ClassCastException`. Instead, use `UiUtils.getActivityFromView()`. (##) Including !!! This is not a built-in check. To include it, add the below dependency to your project. This lint check is included in the lint documentation, but the Android team may or may not agree with its recommendations. ``` // build.gradle.kts lintChecks("com.slack.lint:slack-lint-checks:0.9.0") // build.gradle lintChecks 'com.slack.lint:slack-lint-checks:0.9.0' // build.gradle.kts with version catalogs: lintChecks(libs.slack.lint.checks) # libs.versions.toml [versions] slack-lint-checks = "0.9.0" [libraries] # For clarity and text wrapping purposes the following declaration is # shown split up across lines, but in TOML it needs to be on a single # line (see https://github.com/toml-lang/toml/issues/516) so adjust # when pasting into libs.versions.toml: slack-lint-checks = { module = "com.slack.lint:slack-lint-checks", version.ref = "slack-lint-checks" } ``` 0.9.0 is the version this documentation was generated from; there may be newer versions available. [Additional details about com.slack.lint:slack-lint-checks](com_slack_lint_slack-lint-checks.md.html). (##) Suppressing You can suppress false positives using one of the following mechanisms: * Using a suppression annotation like this on the enclosing element: ```kt // Kotlin @Suppress("CastingViewContextToActivity") fun method() { getContext(...) } ``` or ```java // Java @SuppressWarnings("CastingViewContextToActivity") void method() { getContext(...); } ``` * Using a suppression comment like this on the line above: ```kt //noinspection CastingViewContextToActivity problematicStatement() ``` * Using a special `lint.xml` file in the source tree which turns off the check in that folder and any sub folder. A simple file might look like this: ```xml <?xml version="1.0" encoding="UTF-8"?> <lint> <issue id="CastingViewContextToActivity" severity="ignore" /> </lint> ``` Instead of `ignore` you can also change the severity here, for example from `error` to `warning`. You can find additional documentation on how to filter issues by path, regular expression and so on [here](https://googlesamples.github.io/android-custom-lint-rules/usage/lintxml.md.html). * In Gradle projects, using the DSL syntax to configure lint. For example, you can use something like ```gradle lintOptions { disable 'CastingViewContextToActivity' } ``` In Android projects this should be nested inside an `android { }` block. * For manual invocations of `lint`, using the `--ignore` flag: ``` $ lint --ignore CastingViewContextToActivity ...` ``` * Last, but not least, using baselines, as discussed [here](https://googlesamples.github.io/android-custom-lint-rules/usage/baselines.md.html).