show a Select SIM button at message sending, if multiple are available

app/src/main/AndroidManifest.xml

@@ -10,6 +10,7 @@
     <uses-permission android:name="android.permission.RECEIVE_MMS" />
     <uses-permission android:name="android.provider.Telephony.SMS_RECEIVED" />
     <uses-permission android:name="android.permission.WAKE_LOCK" />
+    <uses-permission android:name="android.permission.READ_PHONE_STATE" />
 
     <uses-permission android:name="android.permission.READ_CONTACTS" />
     <uses-permission

app/src/main/kotlin/com/simplemobiletools/smsmessenger/activities/ThreadActivity.kt

@@ -8,6 +8,7 @@ import android.media.MediaMetadataRetriever
 import android.net.Uri
 import android.os.Bundle
 import android.provider.Telephony
+import android.telephony.SubscriptionManager
 import android.text.TextUtils
 import android.view.*
 import android.view.inputmethod.EditorInfo
@@ -28,6 +29,7 @@ import com.klinker.android.send_message.Settings
 import com.klinker.android.send_message.Transaction
 import com.simplemobiletools.commons.dialogs.ConfirmationDialog
 import com.simplemobiletools.commons.extensions.*
+import com.simplemobiletools.commons.helpers.PERMISSION_READ_PHONE_STATE
 import com.simplemobiletools.commons.helpers.ensureBackgroundThread
 import com.simplemobiletools.commons.helpers.isNougatPlus
 import com.simplemobiletools.smsmessenger.R
@@ -72,7 +74,16 @@ class ThreadActivity : SimpleActivity() {
 
         bus = EventBus.getDefault()
         bus!!.register(this)
+        handlePermission(PERMISSION_READ_PHONE_STATE) {
+            if (it) {
+                setupThread()
+            } else {
+                finish()
+            }
+        }
+    }
 
+    private fun setupThread() {
         ensureBackgroundThread {
             messages = getMessages(threadId)
             participants = if (messages.isEmpty()) {
@@ -210,9 +221,10 @@ class ThreadActivity : SimpleActivity() {
 
     private fun setupButtons() {
         updateTextColors(thread_holder)
-        thread_send_message.applyColorFilter(config.textColor)
+        val textColor = config.textColor
-        confirm_manage_contacts.applyColorFilter(config.textColor)
+        thread_send_message.applyColorFilter(textColor)
-        thread_add_attachment.applyColorFilter(config.textColor)
+        confirm_manage_contacts.applyColorFilter(textColor)
+        thread_add_attachment.applyColorFilter(textColor)
 
         thread_send_message.setOnClickListener {
             sendMessage()
@@ -251,6 +263,18 @@ class ThreadActivity : SimpleActivity() {
                 addAttachment(it)
             }
         }
+
+        val availableSIMs = SubscriptionManager.from(this).activeSubscriptionInfoList
+        if (availableSIMs.size > 1) {
+            thread_select_sim_icon.applyColorFilter(textColor)
+            thread_select_sim_icon.beVisible()
+            thread_select_sim_icon.setOnClickListener {
+
+            }
+
+            thread_select_sim_number.setTextColor(textColor.getContrastColor())
+            thread_select_sim_number.text = "1"
+        }
     }
 
     private fun blockNumber() {
@@ -422,6 +446,7 @@ class ThreadActivity : SimpleActivity() {
         val numbers = participants.map { it.phoneNumber }.toTypedArray()
         val settings = Settings()
         settings.useSystemSending = true
+
         val transaction = Transaction(this, settings)
         val message = com.klinker.android.send_message.Message(msg, numbers)
 

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

@@ -0,0 +1,9 @@
+<vector xmlns:android="http://schemas.android.com/apk/res/android"
+    android:width="24dp"
+    android:height="24dp"
+    android:viewportWidth="24"
+    android:viewportHeight="24">
+    <path
+        android:fillColor="#FFFFFF"
+        android:pathData="m20.6507,3.3384c0,-1.191 -0.9636,-2.1654 -2.1546,-2.1654l-8.6616,0 -6.4962,6.4962 0,12.9923c0,1.191 0.9744,2.1654 2.1654,2.1654l13.0032,0c1.191,0 2.1546,-0.9744 2.1546,-2.1654z" />
+</vector>

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

@@ -156,13 +156,37 @@
         android:layout_height="wrap_content"
         android:layout_alignParentBottom="true"
         android:layout_marginEnd="@dimen/small_margin"
-        android:layout_toStartOf="@+id/thread_send_message"
+        android:layout_toStartOf="@+id/thread_select_sim_icon"
         android:layout_toEndOf="@+id/thread_add_attachment"
         android:background="@android:color/transparent"
         android:gravity="center_vertical"
         android:hint="@string/type_a_message"
         android:minHeight="@dimen/normal_icon_size" />
 
+    <ImageView
+        android:id="@+id/thread_select_sim_icon"
+        android:layout_width="@dimen/normal_icon_size"
+        android:layout_height="@dimen/normal_icon_size"
+        android:layout_alignParentBottom="true"
+        android:layout_marginTop="@dimen/small_margin"
+        android:layout_toStartOf="@+id/thread_send_message"
+        android:alpha="0.9"
+        android:background="?selectableItemBackgroundBorderless"
+        android:padding="@dimen/normal_margin"
+        android:src="@drawable/ic_sim_vector" />
+
+    <TextView
+        android:id="@+id/thread_select_sim_number"
+        android:layout_width="match_parent"
+        android:layout_height="match_parent"
+        android:layout_alignStart="@+id/thread_select_sim_icon"
+        android:layout_alignTop="@+id/thread_select_sim_icon"
+        android:layout_alignEnd="@+id/thread_select_sim_icon"
+        android:layout_alignBottom="@+id/thread_select_sim_icon"
+        android:gravity="center"
+        android:textSize="@dimen/normal_text_size"
+        tools:text="1" />
+
     <ImageView
         android:id="@+id/thread_send_message"
         android:layout_width="@dimen/normal_icon_size"