Add camera permission to Manifest to be able to use camera in the app to read QR codes.

- Add methods to SendTransactionFragment to request camera permission and start/stop the camera preview accordingly.

app/src/main/AndroidManifest.xml

@@ -3,6 +3,8 @@
       xmlns:tools="http://schemas.android.com/tools"
       package="cy.agorise.bitsybitshareswallet">
 
+    <uses-permission android:name="android.permission.CAMERA" />
+
     <application
         android:name=".utils.BitsyApplication"
         android:allowBackup="true"

app/src/main/java/cy/agorise/bitsybitshareswallet/fragments/SendTransactionFragment.kt

@@ -1,19 +1,99 @@
 package cy.agorise.bitsybitshareswallet.fragments
 
+import android.Manifest
+import android.content.pm.PackageManager
 import android.os.Bundle
 import android.view.LayoutInflater
 import android.view.View
 import android.view.ViewGroup
+import android.widget.Toast
+import androidx.core.content.ContextCompat
 import androidx.fragment.app.Fragment
+import com.google.zxing.BarcodeFormat
+import com.google.zxing.Result
 import cy.agorise.bitsybitshareswallet.R
+import kotlinx.android.synthetic.main.fragment_send_transaction.*
+import me.dm7.barcodescanner.zxing.ZXingScannerView
 
-class SendTransactionFragment : Fragment() {
+class SendTransactionFragment : Fragment(), ZXingScannerView.ResultHandler {
 
-    override fun onCreateView(
-        inflater: LayoutInflater, container: ViewGroup?,
-        savedInstanceState: Bundle?
-    ): View? {
+    // Camera Permission
+    private val REQUEST_CAMERA_PERMISSION = 1
+
+    private var isCameraPreviewVisible = false
+
+    override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?): View? {
         return inflater.inflate(R.layout.fragment_send_transaction, container, false)
     }
 
+    override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
+        super.onViewCreated(view, savedInstanceState)
+
+        verifyCameraPermission()
+
+        fabOpenCamera.setOnClickListener { if (isCameraPreviewVisible) stopCameraPreview() else verifyCameraPermission() }
+    }
+
+    private fun verifyCameraPermission() {
+        if (ContextCompat.checkSelfPermission(activity!!, Manifest.permission.CAMERA)
+            != PackageManager.PERMISSION_GRANTED) {
+            // Permission is not already granted
+            requestPermissions(arrayOf(android.Manifest.permission.CAMERA), REQUEST_CAMERA_PERMISSION)
+        } else {
+            // Permission is already granted
+            startCameraPreview()
+        }
+    }
+
+    override fun onRequestPermissionsResult(requestCode: Int, permissions: Array<out String>, grantResults: IntArray) {
+        super.onRequestPermissionsResult(requestCode, permissions, grantResults)
+
+        if (requestCode == REQUEST_CAMERA_PERMISSION) {
+            if ((grantResults.isNotEmpty() && grantResults[0] == PackageManager.PERMISSION_GRANTED)) {
+                startCameraPreview()
+            } else {
+                // TODO extract string resource
+                Toast.makeText(context!!, "Camera permission is necessary to read QR codes.", Toast.LENGTH_SHORT).show()
+            }
+            return
+        }
+    }
+
+    private fun startCameraPreview() {
+        cameraPreview.visibility = View.VISIBLE
+        fabOpenCamera.setImageResource(R.drawable.ic_close)
+        isCameraPreviewVisible = true
+
+        // Configure QR scanner
+        cameraPreview.setFormats(listOf(BarcodeFormat.QR_CODE))
+        cameraPreview.setAspectTolerance(0.5f)
+        cameraPreview.setAutoFocus(true)
+        cameraPreview.setLaserColor(R.color.colorAccent)
+        cameraPreview.setMaskColor(R.color.colorAccent)
+        cameraPreview.setResultHandler(this)
+        cameraPreview.startCamera()
+    }
+
+    private fun stopCameraPreview() {
+        cameraPreview.visibility = View.INVISIBLE
+        fabOpenCamera.setImageResource(R.drawable.ic_camera)
+        isCameraPreviewVisible = false
+        cameraPreview.stopCamera()
+    }
+
+    override fun handleResult(result: Result?) {
+        Toast.makeText(context!!, result!!.text, Toast.LENGTH_SHORT).show()
+    }
+
+    override fun onResume() {
+        super.onResume()
+        if (isCameraPreviewVisible)
+            startCameraPreview()
+    }
+
+    override fun onPause() {
+        super.onPause()
+        if (!isCameraPreviewVisible)
+            stopCameraPreview()
+    }
 }

app/src/main/res/drawable/ic_close.xml

@@ -0,0 +1,5 @@
+<vector android:height="24dp" android:tint="#FFFFFF"
+    android:viewportHeight="24.0" android:viewportWidth="24.0"
+    android:width="24dp" xmlns:android="http://schemas.android.com/apk/res/android">
+    <path android:fillColor="#FF000000" android:pathData="M19,6.41L17.59,5 12,10.59 6.41,5 5,6.41 10.59,12 5,17.59 6.41,19 12,13.41 17.59,19 19,17.59 13.41,12z"/>
+</vector>

app/src/main/res/layout/fragment_send_transaction.xml

@@ -42,6 +42,7 @@
                 android:id="@+id/tietTo"
                 android:layout_width="match_parent"
                 android:layout_height="wrap_content"
+                android:digits="abcdefghijklmnopqrstuvwxyz-0123456789"
                 android:maxLines="1"/>
 
         </com.google.android.material.textfield.TextInputLayout>
@@ -135,7 +136,7 @@
             app:layout_constraintEnd_toStartOf="@id/cameraVerticalGuideline"/>
 
         <com.google.android.material.floatingactionbutton.FloatingActionButton
-            android:id="@+id/fabCloseCamera"
+            android:id="@+id/fabOpenCamera"
             android:layout_width="wrap_content"
             android:layout_height="wrap_content"
             app:fabCustomSize="32dp"
@@ -145,7 +146,7 @@
             app:srcCompat="@drawable/ic_camera" />
 
         <me.dm7.barcodescanner.zxing.ZXingScannerView
-            android:id="@+id/ivCamera"
+            android:id="@+id/cameraPreview"
             android:layout_width="0dp"
             android:layout_height="0dp"
             app:layout_constraintDimensionRatio="w,3:4"