Android selfie App review

content/learning-paths/smartphones-and-mobile/build-android-selfie-app-using-mediapipe-multimodality/3-camera-permission.md

@@ -0,0 +1,118 @@
+---
+title: Handle camera permissions
+weight: 3
+
+### FIXED, DO NOT MODIFY
+layout: learningpathall
+---
+
+## Run the app on your device
+
+1. Connect your Android device to your computer via a USB data cable. If this is your first time running and debugging Android apps, follow [this guide](https://developer.android.com/studio/run/device#setting-up) and double check this checklist:
+
+    1. You have enabled USB debugging on your Android device following [this doc](https://developer.android.com/studio/debug/dev-options#Enable-debugging). 
+
+    2. You have confirmed by tapping "OK" on your Android device when an "Allow USB debugging" dialog pops up, and checked "Always allow from this computer".
+
+    ![Allow USB debugging dialog](https://ftc-docs.firstinspires.org/en/latest/_images/AllowUSBDebugging.jpg)
+
+
+2. Make sure your device model name and SDK version correctly show up on the top right toolbar. Click the "Run" button to build and run the app.
+
+3. After a while, you should see a success notification in Android Studio and the app showing up on your Android device. 
+
+4. However, the app shows only a black screen while printing error messages in your [Logcat](https://developer.android.com/tools/logcat) which looks like this:
+
+```
+2024-11-20 11:15:00.398 18782-18818 Camera2CameraImpl       com.example.holisticselfiedemo      E  Camera reopening attempted for 10000ms without success.
+2024-11-20 11:30:13.560   667-707   BufferQueueProducer     pid-667                              E  [SurfaceView - com.example.holisticselfiedemo/com.example.holisticselfiedemo.MainActivity#0](id:29b00000283,api:4,p:2657,c:667) queueBuffer: BufferQueue has been abandoned
+2024-11-20 11:36:13.100 20487-20499 isticselfiedem          com.example.holisticselfiedemo      E  Failed to read message from agent control socket! Retrying: Bad file descriptor
+2024-11-20 11:43:03.408  2709-3807  PackageManager          pid-2709                             E  Permission android.permission.CAMERA isn't requested by package com.example.holisticselfiedemo
+```
+
+5. Do not worry. This is expected behavior because you haven't correctly configured this app's [permissions](https://developer.android.com/guide/topics/permissions/overview) yet. Android OS restricts this app's access to camera features due to privacy reasons.
+
+## Request camera permission at runtime
+
+1. Navigate to `manifest.xml` in your `app` subproject's `src/main` path. Declare camera hardware and permission by inserting the following lines into the `<manifest>` element. Make sure it's declared outside and above `<application>` element.
+
+```xml
+    <uses-feature
+        android:name="android.hardware.camera"
+        android:required="true" />
+    <uses-permission android:name="android.permission.CAMERA" />
+```
+
+2. Navigate to `strings.xml` in your `app` subproject's `src/main/res/values` path. Insert the following lines of text resources, which will be used later.
+
+```xml
+    <string name="permission_request_camera_message">Camera permission is required to recognize face and hands</string>
+    <string name="permission_request_camera_rationale">To grant Camera permission to this app, please go to system settings</string>
+```
+
+3. Navigate to `MainActivity.kt` and add the following permission related values to companion object:
+
+```kotlin
+        // Permissions
+        private val PERMISSIONS_REQUIRED = arrayOf(Manifest.permission.CAMERA)
+        private const val REQUEST_CODE_CAMERA_PERMISSION = 233
+```
+
+4. Add a new method named `hasPermissions()` to check on runtime whether camera permission has been granted:
+
+```kotlin
+    private fun hasPermissions(context: Context) = PERMISSIONS_REQUIRED.all {
+        ContextCompat.checkSelfPermission(context, it) == PackageManager.PERMISSION_GRANTED
+    }
+```
+
+5. Add a condition check in `onCreate()` wrapping `setupCamera()` method, to request camera permission on runtime.
+
+```kotlin
+        if (!hasPermissions(baseContext)) {
+            requestPermissions(
+                arrayOf(Manifest.permission.CAMERA),
+                REQUEST_CODE_CAMERA_PERMISSION
+            )
+        } else {
+            setupCamera()
+        }
+```
+
+6. Override `onRequestPermissionsResult` method to handle permission request results:
+
+```kotlin
+    override fun onRequestPermissionsResult(
+        requestCode: Int,
+        permissions: Array<out String>,
+        grantResults: IntArray
+    ) {
+        when (requestCode) {
+            REQUEST_CODE_CAMERA_PERMISSION -> {
+                if (PackageManager.PERMISSION_GRANTED == grantResults.getOrNull(0)) {
+                    setupCamera()
+                } else {
+                    val messageResId =
+                        if (shouldShowRequestPermissionRationale(Manifest.permission.CAMERA))
+                            R.string.permission_request_camera_rationale
+                        else
+                            R.string.permission_request_camera_message
+                    Toast.makeText(baseContext, getString(messageResId), Toast.LENGTH_LONG).show()
+                }
+            }
+            else -> super.onRequestPermissionsResult(requestCode, permissions, grantResults)
+        }
+    }
+```
+
+## Verify camera permission
+
+1. Rebuild and run the app. Now you should see a dialog pop up requesting camera permissions! 
+
+2. Tap `Allow` or `While using the app` (depending on your Android OS versions). Then you should see your own face in the camera preview. Good job!  
+
+{{% notice Tip %}}
+Sometimes you might need to restart the app to observe the permission change take effect.
+{{% /notice %}}
+
+In the next section, you will learn how to integrate MediaPipe vision solutions.