Add show QR code button to settings

src/org/thoughtcrime/securesms/loki/QRCodeFragment.kt

@@ -0,0 +1,32 @@
+package org.thoughtcrime.securesms.loki
+
+import android.os.Bundle
+import android.support.v4.app.Fragment
+import android.view.LayoutInflater
+import android.view.View
+import android.view.ViewGroup
+import kotlinx.android.synthetic.main.fragment_qr_code.*
+import network.loki.messenger.R
+import org.thoughtcrime.securesms.ApplicationPreferencesActivity
+import org.thoughtcrime.securesms.qr.QrCode
+import org.thoughtcrime.securesms.util.TextSecurePreferences
+
+class QRCodeFragment : Fragment() {
+
+    override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?): View? {
+        return inflater.inflate(R.layout.fragment_qr_code, container, false)
+    }
+
+    override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
+        super.onViewCreated(view, savedInstanceState)
+        val hexEncodedPublicKey = TextSecurePreferences.getLocalNumber(context)
+        val qrCode = QrCode.create(hexEncodedPublicKey)
+        qrCodeImageView.setImageBitmap(qrCode)
+    }
+
+    override fun onResume() {
+        super.onResume()
+        val activity = activity as ApplicationPreferencesActivity
+        activity.supportActionBar!!.setTitle(R.string.fragment_qr_code_title)
+    }
+}