refactor(app): improve permissions management

app/src/main/java/io/github/thibaultbee/streampack/example/MainActivity.kt

@@ -16,6 +16,7 @@ import io.github.thibaultbee.streampack.data.VideoConfig
 import io.github.thibaultbee.streampack.error.StreamPackError
 import io.github.thibaultbee.streampack.example.databinding.ActivityMainBinding
 import io.github.thibaultbee.streampack.example.utils.PermissionsManager
+import io.github.thibaultbee.streampack.example.utils.showDialog
 import io.github.thibaultbee.streampack.example.utils.toast
 import io.github.thibaultbee.streampack.ext.rtmp.streamers.CameraRtmpLiveStreamer
 import io.github.thibaultbee.streampack.ext.srt.streamers.CameraSrtLiveStreamer
@@ -36,13 +37,30 @@ class MainActivity : AppCompatActivity() {
     private val permissionsManager = PermissionsManager(this,
         streamerRequiredPermissions,
         onAllGranted = { inflateStreamer() },
-        onShowPermissionRationale = { true },
-        onDenied = {})
+        onShowPermissionRationale = { permissions, onRequiredPermissionLastTime ->
+            // Explain why we need permissions
+            showDialog(
+                title = "Permissions denied",
+                message = "Explain why you need to grant $permissions permissions to stream",
+                positiveButtonText = R.string.accept,
+                onPositiveButtonClick = { onRequiredPermissionLastTime() },
+                negativeButtonText = R.string.denied
+            )
+        },
+        onDenied = {
+            showDialog(
+                "Permissions denied",
+                "You need to grant all permissions to stream",
+                positiveButtonText = 0,
+                negativeButtonText = 0
+            )
+        }
+    )
 
     // Reports and manages error with [OnErrorListener]
     private val errorListener = object : OnErrorListener {
         override fun onError(error: StreamPackError) {
-            toast("An error occured: $error")
+            toast("An error occurred: $error")
         }
     }
 
@@ -114,8 +132,8 @@ class MainActivity : AppCompatActivity() {
         }
     }
 
-    override fun onResume() {
-        super.onResume()
+    override fun onStart() {
+        super.onStart()
         permissionsManager.requestPermissions()
     }
 

app/src/main/java/io/github/thibaultbee/streampack/example/utils/Extensions.kt

@@ -1,7 +1,40 @@
 package io.github.thibaultbee.streampack.example.utils
 
 import android.content.Context
+import android.content.DialogInterface
 import android.widget.Toast
+import androidx.annotation.StringRes
+import androidx.appcompat.app.AlertDialog
 
 fun Context.toast(message: String) =
     Toast.makeText(this, message, Toast.LENGTH_SHORT).show()
+
+fun Context.showDialog(
+    title: String,
+    message: String = "",
+    @StringRes
+    positiveButtonText: Int = android.R.string.ok,
+    @StringRes
+    negativeButtonText: Int = android.R.string.cancel,
+    onPositiveButtonClick: () -> Unit = {},
+    onNegativeButtonClick: () -> Unit = {}
+) {
+    AlertDialog.Builder(this)
+        .setTitle(title)
+        .setMessage(message)
+        .apply {
+            if (positiveButtonText != 0) {
+                setPositiveButton(positiveButtonText) { dialogInterface: DialogInterface, _: Int ->
+                    dialogInterface.dismiss()
+                    onPositiveButtonClick()
+                }
+            }
+            if (negativeButtonText != 0) {
+                setNegativeButton(negativeButtonText) { dialogInterface: DialogInterface, _: Int ->
+                    dialogInterface.dismiss()
+                    onNegativeButtonClick()
+                }
+            }
+        }
+        .show()
+}

app/src/main/java/io/github/thibaultbee/streampack/example/utils/PermissionsManager.kt

@@ -8,43 +8,60 @@ class PermissionsManager(
     private val activity: ComponentActivity,
     private val requiredPermissions: List<String>,
     private val onAllGranted: () -> Unit,
-    private val onShowPermissionRationale: (List<String>) -> Boolean,
+    private val onShowPermissionRationale: (List<String>, () -> Unit) -> Unit,
     private val onDenied: (List<String>) -> Unit
 ) {
-    private fun hasPermissions(): Boolean {
+    private fun hasAllPermissions(): Boolean {
         return requiredPermissions.all {
             activity.checkSelfPermission(it) == PackageManager.PERMISSION_GRANTED
         }
     }
 
+    private fun hasShownAllRationales(): Boolean {
+        return requiredPermissions.all {
+            !activity.shouldShowRequestPermissionRationale(it)
+        }
+    }
+
     fun requestPermissions() {
-        if (hasPermissions()) {
+        if (hasAllPermissions()) {
             onAllGranted()
         } else {
-            var hasShownRationale = false
-            requiredPermissions.forEach {
-                if (activity.shouldShowRequestPermissionRationale(it)) {
-                    hasShownRationale = true
-                    // Last chance to show rationale
-                    if (onShowPermissionRationale(requiredPermissions)) {
-                        requestMultiplePermissions.launch(arrayOf(it))
-                    }
-                }
-            }
-            if (!hasShownRationale) {
+            // Either we ask for rationale or we ask for all permissions
+            if (requestRationales()) {
                 requestMultiplePermissions.launch(requiredPermissions.toTypedArray())
             }
         }
     }
 
+    private fun requestRationales(): Boolean {
+        // List of permissions that have been denied once. In this case, we should explain why we need them.
+        val rationalesPermission = mutableListOf<String>()
+        requiredPermissions.filter {
+            activity.shouldShowRequestPermissionRationale(it)
+        }.forEach {
+            rationalesPermission.add(it)
+        }
+        if (rationalesPermission.isNotEmpty()) {
+            onShowPermissionRationale(rationalesPermission) {
+                requestMultiplePermissions.launch(rationalesPermission.toTypedArray())
+            }
+        }
+
+        return rationalesPermission.isEmpty()
+    }
+
     private val requestMultiplePermissions =
         activity.registerForActivityResult(ActivityResultContracts.RequestMultiplePermissions()) { permissions ->
-            permissions.filter { !it.value }.keys.toList().let {
-                if (it.isNotEmpty()) {
-                    onDenied(it)
+            val deniedPermissions = permissions.filter { !it.value }.keys.toList()
+            if (deniedPermissions.isNotEmpty()) {
+                if (!hasShownAllRationales()) {
+                    requestRationales()
                 } else {
-                    onAllGranted()
+                    onDenied(deniedPermissions)
                 }
+            } else {
+                onAllGranted()
             }
         }
 }

app/src/main/res/values/strings.xml

@@ -1,3 +1,5 @@
 <resources>
     <string name="app_name">My Streaming App</string>
+    <string name="denied">Denied</string>
+    <string name="accept">Accept</string>
 </resources>