Add support for .txt files for importing

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

@@ -627,7 +627,7 @@ class MainActivity : SimpleActivity() {
             Intent(Intent.ACTION_GET_CONTENT).apply {
                 addCategory(Intent.CATEGORY_OPENABLE)
                 type = JSON_MIME_TYPE
-                putExtra(Intent.EXTRA_MIME_TYPES, arrayOf(JSON_MIME_TYPE, XML_MIME_TYPE))
+                putExtra(Intent.EXTRA_MIME_TYPES, arrayOf(JSON_MIME_TYPE, XML_MIME_TYPE, TXT_MIME_TYPE))
 
                 try {
                     startActivityForResult(this, PICK_IMPORT_SOURCE_INTENT)

app/src/main/kotlin/com/simplemobiletools/smsmessenger/helpers/Constants.kt

@@ -31,6 +31,7 @@ const val EXPORT_MMS = "export_mms"
 const val JSON_FILE_EXT = ".json"
 const val JSON_MIME_TYPE = "application/json"
 const val XML_MIME_TYPE = "text/xml"
+const val TXT_MIME_TYPE = "text/plain"
 const val IMPORT_SMS = "import_sms"
 const val IMPORT_MMS = "import_mms"
 const val WAS_DB_CLEARED = "was_db_cleared_2"

app/src/main/kotlin/com/simplemobiletools/smsmessenger/helpers/MessagesImporter.kt

@@ -32,13 +32,19 @@ class MessagesImporter(private val context: Context) {
     fun importMessages(path: String, onProgress: (total: Int, current: Int) -> Unit = { _, _ -> }, callback: (result: ImportResult) -> Unit) {
         ensureBackgroundThread {
             try {
-                val inputStream = if (path.contains("/")) {
+                val isXml = if (path.endsWith("txt")) {
-                    File(path).inputStream()
+                    // Need to read the first line to determine if it is xml
+                    val tempStream = getInputStreamForPath(path)
+                    tempStream.bufferedReader().use {
+                        it.readLine().startsWith("<?xml")
+                    }
                 } else {
-                    context.assets.open(path)
+                    path.endsWith("xml")
                 }
 
-                if (path.endsWith("xml")) {
+                val inputStream = getInputStreamForPath(path)
+
+                if (isXml) {
                     inputStream.importXml()
                 } else {
                     inputStream.importJson()
@@ -60,6 +66,14 @@ class MessagesImporter(private val context: Context) {
         }
     }
 
+    private fun getInputStreamForPath(path: String): InputStream {
+        return if (path.contains("/")) {
+            File(path).inputStream()
+        } else {
+            context.assets.open(path)
+        }
+    }
+
     private fun InputStream.importJson() {
         bufferedReader().use { reader ->
             val jsonReader = gson.newJsonReader(reader)