1 /*
2 * Copyright 2021 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * https://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17 package com.google.accompanist.permissions
18
19 import android.app.Activity
20 import android.content.Context
21 import androidx.activity.compose.rememberLauncherForActivityResult
22 import androidx.activity.result.ActivityResultLauncher
23 import androidx.activity.result.contract.ActivityResultContracts
24 import androidx.compose.runtime.Composable
25 import androidx.compose.runtime.DisposableEffect
26 import androidx.compose.runtime.Stable
27 import androidx.compose.runtime.getValue
28 import androidx.compose.runtime.mutableStateOf
29 import androidx.compose.runtime.remember
30 import androidx.compose.runtime.setValue
31 import androidx.compose.ui.platform.LocalContext
32
33 /**
34 * Creates a [MutablePermissionState] that is remembered across compositions.
35 *
36 * It's recommended that apps exercise the permissions workflow as described in the
37 * [documentation](https://developer.android.com/training/permissions/requesting#workflow_for_requesting_permissions).
38 *
39 * @param permission the permission to control and observe.
40 * @param onPermissionResult will be called with whether or not the user granted the permission
41 * after [PermissionState.launchPermissionRequest] is called.
42 */
43 @ExperimentalPermissionsApi
44 @Composable
rememberMutablePermissionStatenull45 internal fun rememberMutablePermissionState(
46 permission: String,
47 onPermissionResult: (Boolean) -> Unit = {}
48 ): MutablePermissionState {
49 val context = LocalContext.current
<lambda>null50 val permissionState = remember(permission) {
51 MutablePermissionState(permission, context, context.findActivity())
52 }
53
54 // Refresh the permission status when the lifecycle is resumed
55 PermissionLifecycleCheckerEffect(permissionState)
56
57 // Remember RequestPermission launcher and assign it to permissionState
<lambda>null58 val launcher = rememberLauncherForActivityResult(ActivityResultContracts.RequestPermission()) {
59 permissionState.refreshPermissionStatus()
60 onPermissionResult(it)
61 }
<lambda>null62 DisposableEffect(permissionState, launcher) {
63 permissionState.launcher = launcher
64 onDispose {
65 permissionState.launcher = null
66 }
67 }
68
69 return permissionState
70 }
71
72 /**
73 * A mutable state object that can be used to control and observe permission status changes.
74 *
75 * In most cases, this will be created via [rememberMutablePermissionState].
76 *
77 * @param permission the permission to control and observe.
78 * @param context to check the status of the [permission].
79 * @param activity to check if the user should be presented with a rationale for [permission].
80 */
81 @ExperimentalPermissionsApi
82 @Stable
83 internal class MutablePermissionState(
84 override val permission: String,
85 private val context: Context,
86 private val activity: Activity
87 ) : PermissionState {
88
89 override var status: PermissionStatus by mutableStateOf(getPermissionStatus())
90
launchPermissionRequestnull91 override fun launchPermissionRequest() {
92 launcher?.launch(
93 permission
94 ) ?: throw IllegalStateException("ActivityResultLauncher cannot be null")
95 }
96
97 internal var launcher: ActivityResultLauncher<String>? = null
98
refreshPermissionStatusnull99 internal fun refreshPermissionStatus() {
100 status = getPermissionStatus()
101 }
102
getPermissionStatusnull103 private fun getPermissionStatus(): PermissionStatus {
104 val hasPermission = context.checkPermission(permission)
105 return if (hasPermission) {
106 PermissionStatus.Granted
107 } else {
108 PermissionStatus.Denied(activity.shouldShowRationale(permission))
109 }
110 }
111 }
112