Add the share menu icon to the ReceiveTransactionFragment toolbar, verify for the storage permission required to store a temp image of the QR code when the sare icon is tapped and create a temp image of the QR code to be used later to send a share intent to the Andriod System so that it shows the user a list of options for him to select his preferred one.

app/src/main/AndroidManifest.xml

@@ -11,6 +11,8 @@
     <uses-permission android:name="android.permission.ACCESS_FINE_LOCATION"/>
     <uses-permission android:name="android.permission.INTERNET"/>
     <uses-permission android:name="android.permission.CAMERA"/>
+    <uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE"/>
+    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>
 
     <application
         android:name=".utils.BitsyApplication"

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

@@ -1,19 +1,21 @@
 package cy.agorise.bitsybitshareswallet.fragments
 
+import android.Manifest
 import android.content.ComponentName
 import android.content.Context
 import android.content.Intent
 import android.content.ServiceConnection
+import android.content.pm.PackageManager
 import android.graphics.Bitmap
 import android.graphics.Color
 import android.os.Bundle
 import android.os.IBinder
 import android.preference.PreferenceManager
 import android.util.Log
-import android.view.LayoutInflater
+import android.view.*
-import android.view.View
-import android.view.ViewGroup
 import android.widget.AdapterView
+import android.widget.Toast
+import androidx.core.content.ContextCompat
 import androidx.fragment.app.Fragment
 import androidx.lifecycle.Observer
 import androidx.lifecycle.ViewModelProviders
@@ -28,6 +30,7 @@ import cy.agorise.bitsybitshareswallet.R
 import cy.agorise.bitsybitshareswallet.adapters.AssetsAdapter
 import cy.agorise.bitsybitshareswallet.adapters.AutoSuggestAssetAdapter
 import cy.agorise.bitsybitshareswallet.utils.Constants
+import cy.agorise.bitsybitshareswallet.utils.Helper
 import cy.agorise.bitsybitshareswallet.viewmodels.AssetViewModel
 import cy.agorise.bitsybitshareswallet.viewmodels.UserAccountViewModel
 import cy.agorise.graphenej.*
@@ -51,6 +54,7 @@ class ReceiveTransactionFragment : Fragment(), ServiceConnection {
     private val TAG = this.javaClass.simpleName
 
     private val RESPONSE_LIST_ASSETS = 1
+    private val REQUEST_WRITE_EXTERNAL_STORAGE_PERMISSION = 100
 
     /** Number of assets to request from the NetworkService to show as suggestions in the AutoCompleteTextView */
     private val AUTO_SUGGEST_ASSET_LIMIT = 5
@@ -88,6 +92,8 @@ class ReceiveTransactionFragment : Fragment(), ServiceConnection {
     private var mShouldUnbindNetwork: Boolean = false
 
     override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?): View? {
+        setHasOptionsMenu(true)
+
         return inflater.inflate(R.layout.fragment_receive_transaction, container, false)
     }
 
@@ -333,6 +339,69 @@ class ReceiveTransactionFragment : Fragment(), ServiceConnection {
         tvTo.text = txtAccount
     }
 
+    override fun onCreateOptionsMenu(menu: Menu, inflater: MenuInflater) {
+        inflater.inflate(R.menu.menu_receive_transaction, menu)
+    }
+
+    override fun onOptionsItemSelected(item: MenuItem?): Boolean {
+        if (item?.itemId == R.id.menu_share) {
+            verifyStoragePermission()
+            return true
+        }
+        return super.onOptionsItemSelected(item)
+    }
+
+    private fun verifyStoragePermission() {
+        if (ContextCompat.checkSelfPermission(activity!!, Manifest.permission.WRITE_EXTERNAL_STORAGE)
+            != PackageManager.PERMISSION_GRANTED) {
+            // Permission is not already granted
+            requestPermissions(arrayOf(android.Manifest.permission.WRITE_EXTERNAL_STORAGE),
+                REQUEST_WRITE_EXTERNAL_STORAGE_PERMISSION)
+        } else {
+            // Permission is already granted
+            shareQRScreenshot()
+        }
+    }
+
+    override fun onRequestPermissionsResult(requestCode: Int, permissions: Array<out String>, grantResults: IntArray) {
+        super.onRequestPermissionsResult(requestCode, permissions, grantResults)
+
+        if (requestCode == REQUEST_WRITE_EXTERNAL_STORAGE_PERMISSION) {
+            if ((grantResults.isNotEmpty() && grantResults[0] == PackageManager.PERMISSION_GRANTED)) {
+                shareQRScreenshot()
+            } else {
+                // TODO extract string resource
+                Toast.makeText(context!!, "Storage permission is necessary to share QR codes.", Toast.LENGTH_SHORT).show()
+            }
+            return
+        }
+    }
+
+    /**
+     * This function takes a screenshot as a bitmap, saves it into a temporal cache image and then
+     * sends an intent so the user can select the desired method to share the image.
+     */
+    private fun shareQRScreenshot() {
+        // Get Screenshot
+        val screenshot = Helper.loadBitmapFromView(container)
+        val imageUri = Helper.saveTemporalBitmap(context!!, screenshot)
+
+        // Prepare information for share intent
+        val subject = getString(R.string.msg__invoice_subject, mUserAccount?.name)
+        val content = tvPleasePay.text.toString() + "\n" +
+                tvTo.text.toString()
+
+        // Create share intent and call it
+        val shareIntent = Intent()
+        shareIntent.action = Intent.ACTION_SEND
+        shareIntent.addFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION) // temp permission for receiving app to read this file
+        shareIntent.putExtra(Intent.EXTRA_STREAM, imageUri)
+        shareIntent.putExtra(Intent.EXTRA_SUBJECT, subject)
+        shareIntent.putExtra(Intent.EXTRA_TEXT, content)
+        shareIntent.type = "*/*"
+        startActivity(Intent.createChooser(shareIntent, getString(R.string.text__share_with)))
+    }
+
     override fun onResume() {
         super.onResume()
 

app/src/main/java/cy/agorise/bitsybitshareswallet/utils/Helper.kt

@@ -0,0 +1,60 @@
+package cy.agorise.bitsybitshareswallet.utils
+
+import android.content.Context
+import android.graphics.Bitmap
+import android.graphics.Canvas
+import android.net.Uri
+import android.util.Log
+import android.view.View
+import androidx.core.content.FileProvider
+import java.io.File
+import java.io.FileOutputStream
+import java.io.IOException
+
+/**
+ * Contains methods that are helpful in different parts of the app
+ */
+class Helper {
+
+    companion object {
+        private val TAG = "Helper"
+
+        /**
+         * Creates and returns a Bitmap from the contents of a View, does not matter
+         * if it is a simple view or a ViewGroup like a ConstraintLayout or a LinearLayout.
+         *
+         * @param view The view that is gonna be pictured.
+         * @return The generated image from the given view.
+         */
+        fun loadBitmapFromView(view: View): Bitmap {
+            val bitmap = Bitmap.createBitmap(view.width, view.height, Bitmap.Config.ARGB_8888)
+            val canvas = Canvas(bitmap)
+            view.draw(canvas)
+
+            return bitmap
+        }
+
+        fun saveTemporalBitmap(context: Context, bitmap: Bitmap): Uri {
+            // save bitmap to cache directory
+            try {
+                val cachePath = File(context.cacheDir, "images")
+                if (!cachePath.mkdirs())
+                // don't forget to make the directory
+                    Log.d(TAG, "shareBitmapImage creating cache images folder")
+
+                val stream = FileOutputStream(cachePath.toString() + "/image.png") // overwrites this image every time
+                bitmap.compress(Bitmap.CompressFormat.PNG, 100, stream)
+                stream.close()
+            } catch (e: IOException) {
+                Log.d(TAG, "shareBitmapImage error: " + e.message)
+            }
+
+            // Send intent to share image+text
+            val imagePath = File(context.cacheDir, "images")
+            val newFile = File(imagePath, "image.png")
+
+            // Create and return image uri
+            return FileProvider.getUriForFile(context, "cy.agorise.FileProvider", newFile)
+        }
+    }
+}

app/src/main/res/drawable/ic_share.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="M18,16.08c-0.76,0 -1.44,0.3 -1.96,0.77L8.91,12.7c0.05,-0.23 0.09,-0.46 0.09,-0.7s-0.04,-0.47 -0.09,-0.7l7.05,-4.11c0.54,0.5 1.25,0.81 2.04,0.81 1.66,0 3,-1.34 3,-3s-1.34,-3 -3,-3 -3,1.34 -3,3c0,0.24 0.04,0.47 0.09,0.7L8.04,9.81C7.5,9.31 6.79,9 6,9c-1.66,0 -3,1.34 -3,3s1.34,3 3,3c0.79,0 1.5,-0.31 2.04,-0.81l7.12,4.16c-0.05,0.21 -0.08,0.43 -0.08,0.65 0,1.61 1.31,2.92 2.92,2.92 1.61,0 2.92,-1.31 2.92,-2.92s-1.31,-2.92 -2.92,-2.92z"/>
+</vector>

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

@@ -83,6 +83,14 @@
 
     </com.google.android.material.textfield.TextInputLayout>
 
+    <androidx.constraintlayout.widget.ConstraintLayout
+        android:id="@+id/container"
+        android:layout_width="match_parent"
+        android:layout_height="0dp"
+        android:background="?android:windowBackground"
+        app:layout_constraintTop_toBottomOf="@+id/tilAsset"
+        app:layout_constraintBottom_toBottomOf="parent">
+
         <ImageView
             android:id="@+id/ivQR"
             android:layout_width="0dp"
@@ -90,7 +98,7 @@
             android:layout_marginTop="@dimen/spacing_different_topic"
             android:layout_marginBottom="@dimen/spacing_different_topic"
             app:layout_constraintDimensionRatio="1:1"
-        app:layout_constraintTop_toBottomOf="@+id/tilAsset"
+            app:layout_constraintTop_toTopOf="parent"
             app:layout_constraintBottom_toTopOf="@+id/llText"
             app:layout_constraintStart_toStartOf="parent"
             app:layout_constraintEnd_toEndOf="parent"
@@ -126,4 +134,6 @@
 
         </LinearLayout>
 
+    </androidx.constraintlayout.widget.ConstraintLayout>
+
 </androidx.constraintlayout.widget.ConstraintLayout>

app/src/main/res/menu/menu_receive_transaction.xml

@@ -0,0 +1,11 @@
+<?xml version="1.0" encoding="utf-8"?>
+<menu
+    xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:app="http://schemas.android.com/apk/res-auto">
+
+    <item android:id="@+id/menu_share"
+          android:icon="@drawable/ic_share"
+          android:title="@string/title_share"
+          app:showAsAction="always"/>
+
+</menu>

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

@@ -56,6 +56,8 @@
     <string name="text__asset">Asset</string>
     <string name="template__please_pay">Please Pay: %1$s %2$s</string>
     <string name="template__to">To: %1$s</string>
+    <string name="msg__invoice_subject">BiTSy invoice from %1$s</string>
+    <string name="text__share_with">Share with</string>
 
     <!-- Settings -->
     <string name="title_settings">Settings</string>
@@ -79,5 +81,6 @@
     <string name="title_search">Search</string>
     <string name="title_filter">Filter</string>
     <string name="title_export">Export</string>
+    <string name="title_share">Share</string>
 
 </resources>