[Permissions] Support calling rememberPermissionState in a Compose preview

permissions/api/current.api

@@ -18,6 +18,7 @@ package com.google.accompanist.permissions {
 
   public final class MultiplePermissionsStateKt {
     method @androidx.compose.runtime.Composable @com.google.accompanist.permissions.ExperimentalPermissionsApi public static com.google.accompanist.permissions.MultiplePermissionsState rememberMultiplePermissionsState(java.util.List<java.lang.String> permissions, optional kotlin.jvm.functions.Function1<? super java.util.Map<java.lang.String,java.lang.Boolean>,kotlin.Unit> onPermissionsResult);
+    method @androidx.compose.runtime.Composable @com.google.accompanist.permissions.ExperimentalPermissionsApi public static com.google.accompanist.permissions.MultiplePermissionsState rememberMultiplePermissionsState(java.util.List<java.lang.String> permissions, optional kotlin.jvm.functions.Function1<? super java.util.Map<java.lang.String,java.lang.Boolean>,kotlin.Unit> onPermissionsResult, optional java.util.Map<java.lang.String,? extends com.google.accompanist.permissions.PermissionStatus> previewPermissionStatuses);
   }
 
   public final class MutableMultiplePermissionsStateKt {
@@ -36,6 +37,7 @@ package com.google.accompanist.permissions {
 
   public final class PermissionStateKt {
     method @androidx.compose.runtime.Composable @com.google.accompanist.permissions.ExperimentalPermissionsApi public static com.google.accompanist.permissions.PermissionState rememberPermissionState(String permission, optional kotlin.jvm.functions.Function1<? super java.lang.Boolean,kotlin.Unit> onPermissionResult);
+    method @androidx.compose.runtime.Composable @com.google.accompanist.permissions.ExperimentalPermissionsApi public static com.google.accompanist.permissions.PermissionState rememberPermissionState(String permission, optional kotlin.jvm.functions.Function1<? super java.lang.Boolean,kotlin.Unit> onPermissionResult, optional com.google.accompanist.permissions.PermissionStatus previewPermissionStatus);
   }
 
   @androidx.compose.runtime.Stable @com.google.accompanist.permissions.ExperimentalPermissionsApi public sealed interface PermissionStatus {

permissions/src/main/java/com/google/accompanist/permissions/MultiplePermissionsState.kt

@@ -17,7 +17,10 @@
 package com.google.accompanist.permissions
 
 import androidx.compose.runtime.Composable
+import androidx.compose.runtime.Immutable
 import androidx.compose.runtime.Stable
+import androidx.compose.ui.platform.LocalInspectionMode
+import androidx.compose.ui.util.fastMap
 
 /**
  * Creates a [MultiplePermissionsState] that is remembered across compositions.
@@ -35,7 +38,33 @@ public fun rememberMultiplePermissionsState(
     permissions: List<String>,
     onPermissionsResult: (Map<String, Boolean>) -> Unit = {}
 ): MultiplePermissionsState {
-    return rememberMutableMultiplePermissionsState(permissions, onPermissionsResult)
+    return rememberMultiplePermissionsState(permissions, onPermissionsResult, emptyMap())
+}
+
+/**
+ * Creates a [MultiplePermissionsState] that is remembered across compositions.
+ *
+ * It's recommended that apps exercise the permissions workflow as described in the
+ * [documentation](https://developer.android.com/training/permissions/requesting#workflow_for_requesting_permissions).
+ *
+ * @param permissions the permissions to control and observe.
+ * @param onPermissionsResult will be called with whether or not the user granted the permissions
+ *  after [MultiplePermissionsState.launchMultiplePermissionRequest] is called.
+ * @param previewPermissionStatuses provides a [PermissionStatus] for a given permission when running
+ *  in a preview.
+ */
+@ExperimentalPermissionsApi
+@Composable
+public fun rememberMultiplePermissionsState(
+    permissions: List<String>,
+    onPermissionsResult: (Map<String, Boolean>) -> Unit = {},
+    previewPermissionStatuses: Map<String, PermissionStatus> = emptyMap()
+): MultiplePermissionsState {
+    return when {
+        LocalInspectionMode.current ->
+            PreviewMultiplePermissionsState(permissions, previewPermissionStatuses)
+        else -> rememberMutableMultiplePermissionsState(permissions, onPermissionsResult)
+    }
 }
 
 /**
@@ -83,3 +112,23 @@ public interface MultiplePermissionsState {
      */
     public fun launchMultiplePermissionRequest(): Unit
 }
+
+@OptIn(ExperimentalPermissionsApi::class)
+@Immutable
+private class PreviewMultiplePermissionsState(
+    permissions: List<String>,
+    permissionStatuses: Map<String, PermissionStatus>
+) : MultiplePermissionsState {
+    override val permissions: List<PermissionState> = permissions.fastMap { permission ->
+        PreviewPermissionState(
+            permission = permission,
+            status = permissionStatuses[permission] ?: PermissionStatus.Granted,
+        )
+    }
+
+    override val revokedPermissions: List<PermissionState> = emptyList()
+    override val allPermissionsGranted: Boolean = false
+    override val shouldShowRationale: Boolean = false
+
+    override fun launchMultiplePermissionRequest() {}
+}

permissions/src/main/java/com/google/accompanist/permissions/PermissionState.kt

@@ -17,7 +17,9 @@
 package com.google.accompanist.permissions
 
 import androidx.compose.runtime.Composable
+import androidx.compose.runtime.Immutable
 import androidx.compose.runtime.Stable
+import androidx.compose.ui.platform.LocalInspectionMode
 
 /**
  * Creates a [PermissionState] that is remembered across compositions.
@@ -35,7 +37,31 @@ public fun rememberPermissionState(
     permission: String,
     onPermissionResult: (Boolean) -> Unit = {}
 ): PermissionState {
-    return rememberMutablePermissionState(permission, onPermissionResult)
+    return rememberPermissionState(permission, onPermissionResult, PermissionStatus.Granted)
+}
+
+/**
+ * Creates a [PermissionState] that is remembered across compositions.
+ *
+ * It's recommended that apps exercise the permissions workflow as described in the
+ * [documentation](https://developer.android.com/training/permissions/requesting#workflow_for_requesting_permissions).
+ *
+ * @param permission the permission to control and observe.
+ * @param onPermissionResult will be called with whether or not the user granted the permission
+ *  after [PermissionState.launchPermissionRequest] is called.
+ * @param previewPermissionStatus provides a [PermissionStatus] when running in a preview.
+ */
+@ExperimentalPermissionsApi
+@Composable
+public fun rememberPermissionState(
+    permission: String,
+    onPermissionResult: (Boolean) -> Unit = {},
+    previewPermissionStatus: PermissionStatus = PermissionStatus.Granted
+): PermissionState {
+    return when {
+        LocalInspectionMode.current -> PreviewPermissionState(permission, previewPermissionStatus)
+        else -> rememberMutablePermissionState(permission, onPermissionResult)
+    }
 }
 
 /**
@@ -73,3 +99,12 @@ public interface PermissionState {
      */
     public fun launchPermissionRequest(): Unit
 }
+
+@OptIn(ExperimentalPermissionsApi::class)
+@Immutable
+internal class PreviewPermissionState(
+    override val permission: String,
+    override val status: PermissionStatus
+) : PermissionState {
+    override fun launchPermissionRequest() {}
+}