(#) Missing `registerReceiver()` exported flag !!! ERROR: Missing `registerReceiver()` exported flag This is an error. Id : `UnspecifiedRegisterReceiverFlag` Summary : Missing `registerReceiver()` exported flag Severity : Error Category : Correctness Platform : Android Vendor : Android Open Source Project Feedback : https://issuetracker.google.com/issues/new?component=192708 Since : 8.1.0 (July 2023) Affects : Kotlin and Java files and test sources Editing : This check runs on the fly in the IDE editor See : https://developer.android.com/reference/androidx/core/content/ContextCompat#registerReceiver(android.content.Context,android.content.BroadcastReceiver,android.content.IntentFilter,int) Implementation : [Source Code](https://cs.android.com/android-studio/platform/tools/base/+/mirror-goog-studio-main:lint/libs/lint-checks/src/main/java/com/android/tools/lint/checks/RegisterReceiverFlagDetector.kt) Tests : [Source Code](https://cs.android.com/android-studio/platform/tools/base/+/mirror-goog-studio-main:lint/libs/lint-tests/src/test/java/com/android/tools/lint/checks/RegisterReceiverFlagDetectorTest.kt) In Android U, all receivers registering for non-system broadcasts are required to include a flag indicating the receiver's exported state. Apps registering for non-system broadcasts should use the `ContextCompat#registerReceiver` APIs with flags set to either `RECEIVER_EXPORTED` or `RECEIVER_NOT_EXPORTED`. If you are not expecting broadcasts from other apps on the device, register your receiver with `RECEIVER_NOT_EXPORTED` to protect your receiver on all platform releases. !!! Tip This lint check has an associated quickfix available in the IDE. (##) Example Here is an example of lint warnings produced by this check: ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~text src/test/pkg/TestClass1.java:17:Warning: receiver is missing RECEIVER_EXPORTED or RECEIVER_NOT_EXPORTED flag for unprotected broadcasts registered for an IntentFilter that cannot be inspected by lint [UnspecifiedRegisterReceiverFlag] mContext.registerReceiver(receiver, myIntentFilter); --------------------------------------------------- ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Here is the source file referenced above: `src/test/pkg/TestClass1.java`: ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~java linenumbers package test.pkg; import android.content.BroadcastReceiver; import android.content.Context; import android.content.Intent; import android.content.IntentFilter; public class TestClass1 { private Context mContext; IntentFilter myIntentFilter; private TestClass1(Context context) { mContext = context; myIntentFilter = new IntentFilter(); myIntentFilter.addAction(Intent.ACTION_BATTERY_LOW); myIntentFilter.addAction(Intent.ACTION_BATTERY_OKAY); } public void testMethod(BroadcastReceiver receiver) { mContext.registerReceiver(receiver, myIntentFilter); } } ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ You can also visit the [source code](https://cs.android.com/android-studio/platform/tools/base/+/mirror-goog-studio-main:lint/libs/lint-tests/src/test/java/com/android/tools/lint/checks/RegisterReceiverFlagDetectorTest.kt) for the unit tests for this check to see additional scenarios. The above example was automatically extracted from the first unit test found for this lint check, `RegisterReceiverFlagDetector.testIntentFilterIsFieldWithProtectedActions_nonPrivate`. To report a problem with this extracted sample, visit https://issuetracker.google.com/issues/new?component=192708. (##) 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("UnspecifiedRegisterReceiverFlag") fun method() { registerReceiver(...) } ``` or ```java // Java @SuppressWarnings("UnspecifiedRegisterReceiverFlag") void method() { registerReceiver(...); } ``` * Using a suppression comment like this on the line above: ```kt //noinspection UnspecifiedRegisterReceiverFlag 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="UnspecifiedRegisterReceiverFlag" 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 'UnspecifiedRegisterReceiverFlag' } ``` In Android projects this should be nested inside an `android { }` block. * For manual invocations of `lint`, using the `--ignore` flag: ``` $ lint --ignore UnspecifiedRegisterReceiverFlag ...` ``` * Last, but not least, using baselines, as discussed [here](https://googlesamples.github.io/android-custom-lint-rules/usage/baselines.md.html).