Extract and unit test MultipleTapToUnlock

features/preferences/impl/build.gradle.kts

@@ -66,6 +66,7 @@ dependencies {
     implementation(projects.libraries.permissions.api)
     implementation(projects.libraries.push.api)
     implementation(projects.libraries.pushproviders.api)
+    implementation(projects.libraries.uiUtils)
     implementation(projects.libraries.fullscreenintent.api)
     implementation(projects.features.rageshake.api)
     implementation(projects.features.lockscreen.api)

features/preferences/impl/src/main/kotlin/io/element/android/features/preferences/impl/root/PreferencesRootPresenter.kt

@@ -15,6 +15,7 @@ import androidx.compose.runtime.getValue
 import androidx.compose.runtime.mutableStateOf
 import androidx.compose.runtime.produceState
 import androidx.compose.runtime.remember
+import androidx.compose.runtime.rememberCoroutineScope
 import androidx.compose.runtime.setValue
 import io.element.android.features.logout.api.direct.DirectLogoutState
 import io.element.android.features.preferences.impl.utils.ShowDeveloperSettingsProvider
@@ -49,6 +50,7 @@ class PreferencesRootPresenter @Inject constructor(
 ) : Presenter<PreferencesRootState> {
     @Composable
     override fun present(): PreferencesRootState {
+        val coroutineScope = rememberCoroutineScope()
         val matrixUser = matrixClient.userProfile.collectAsState()
         LaunchedEffect(Unit) {
             // Force a refresh of the profile
@@ -103,7 +105,7 @@ class PreferencesRootPresenter @Inject constructor(
         fun handleEvent(event: PreferencesRootEvents) {
             when (event) {
                 is PreferencesRootEvents.OnVersionInfoClick -> {
-                    showDeveloperSettingsProvider.unlockDeveloperSettings()
+                    showDeveloperSettingsProvider.unlockDeveloperSettings(coroutineScope)
                 }
             }
         }

features/preferences/impl/src/main/kotlin/io/element/android/features/preferences/impl/utils/ShowDeveloperSettingsProvider.kt

@@ -9,6 +9,8 @@ package io.element.android.features.preferences.impl.utils
 
 import io.element.android.libraries.core.meta.BuildMeta
 import io.element.android.libraries.core.meta.BuildType
+import io.element.android.libraries.ui.utils.MultipleTapToUnlock
+import kotlinx.coroutines.CoroutineScope
 import kotlinx.coroutines.flow.MutableStateFlow
 import kotlinx.coroutines.flow.StateFlow
 import javax.inject.Inject
@@ -19,18 +21,15 @@ class ShowDeveloperSettingsProvider @Inject constructor(
     companion object {
         const val DEVELOPER_SETTINGS_COUNTER = 7
     }
-    private var counter = DEVELOPER_SETTINGS_COUNTER
+
+    private val multipleTapToUnlock = MultipleTapToUnlock(DEVELOPER_SETTINGS_COUNTER)
     private val isDeveloperBuild = buildMeta.buildType != BuildType.RELEASE
 
     private val _showDeveloperSettings = MutableStateFlow(isDeveloperBuild)
     val showDeveloperSettings: StateFlow<Boolean> = _showDeveloperSettings
 
-    fun unlockDeveloperSettings() {
-        if (counter == 0) {
-            return
-        }
-        counter--
-        if (counter == 0) {
+    fun unlockDeveloperSettings(scope: CoroutineScope) {
+        if (multipleTapToUnlock.unlock(scope)) {
             _showDeveloperSettings.value = true
         }
     }

libraries/ui-utils/build.gradle.kts

@@ -15,5 +15,7 @@ android {
     dependencies {
         testImplementation(libs.test.junit)
         testImplementation(libs.test.truth)
+        testImplementation(libs.coroutines.test)
+        testImplementation(libs.test.truth)
     }
 }

libraries/ui-utils/src/main/kotlin/io/element/android/libraries/ui/utils/MultipleTapToUnlock.kt

@@ -0,0 +1,42 @@
+/*
+ * Copyright 2025 New Vector Ltd.
+ *
+ * SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial
+ * Please see LICENSE files in the repository root for full details.
+ */
+
+package io.element.android.libraries.ui.utils
+
+import kotlinx.coroutines.CoroutineScope
+import kotlinx.coroutines.Job
+import kotlinx.coroutines.delay
+import kotlinx.coroutines.launch
+import kotlin.time.Duration.Companion.seconds
+
+/**
+ * Returns true if the user has tapped [numberOfTapToUnlock] times in a short amount of time.
+ * The counter is reset after 2 seconds of inactivity.
+ *
+ * @param numberOfTapToUnlock The number of taps required to unlock.
+ */
+class MultipleTapToUnlock(
+    private val numberOfTapToUnlock: Int = 7,
+) {
+    private var counter = numberOfTapToUnlock
+    private var currentJob: Job? = null
+
+    fun unlock(scope: CoroutineScope): Boolean {
+        counter--
+        currentJob?.cancel()
+        return if (counter > 0) {
+            currentJob = scope.launch {
+                delay(2.seconds)
+                // Reset counter if user is not fast enough
+                counter = numberOfTapToUnlock
+            }
+            false
+        } else {
+            true
+        }
+    }
+}

libraries/ui-utils/src/test/kotlin/io/element/android/libraries/ui/utils/MultipleTapToUnlockTest.kt

@@ -0,0 +1,41 @@
+/*
+ * Copyright 2025 New Vector Ltd.
+ *
+ * SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial
+ * Please see LICENSE files in the repository root for full details.
+ */
+
+@file:OptIn(ExperimentalCoroutinesApi::class)
+
+package io.element.android.libraries.ui.utils
+
+import com.google.common.truth.Truth.assertThat
+import kotlinx.coroutines.ExperimentalCoroutinesApi
+import kotlinx.coroutines.test.advanceTimeBy
+import kotlinx.coroutines.test.runTest
+import org.junit.Test
+import kotlin.time.Duration.Companion.seconds
+
+class MultipleTapToUnlockTest {
+    @Test
+    fun `test multiple tap should unlock`() = runTest {
+        val sut = MultipleTapToUnlock(3)
+        assertThat(sut.unlock(backgroundScope)).isFalse()
+        assertThat(sut.unlock(backgroundScope)).isFalse()
+        assertThat(sut.unlock(backgroundScope)).isTrue()
+        assertThat(sut.unlock(backgroundScope)).isTrue()
+        // All next call returns true
+        advanceTimeBy(3.seconds)
+        assertThat(sut.unlock(backgroundScope)).isTrue()
+    }
+    @Test
+    fun `test waiting should reset counter`() = runTest {
+        val sut = MultipleTapToUnlock(3)
+        assertThat(sut.unlock(backgroundScope)).isFalse()
+        assertThat(sut.unlock(backgroundScope)).isFalse()
+        advanceTimeBy(3.seconds)
+        assertThat(sut.unlock(backgroundScope)).isFalse()
+        assertThat(sut.unlock(backgroundScope)).isFalse()
+        assertThat(sut.unlock(backgroundScope)).isTrue()
+    }
+}