adding Settings and About sections

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

@@ -0,0 +1,59 @@
+package com.simplemobiletools.smsmessenger.activities
+
+import android.os.Bundle
+import com.simplemobiletools.commons.dialogs.ChangeDateTimeFormatDialog
+import com.simplemobiletools.commons.extensions.beVisibleIf
+import com.simplemobiletools.commons.extensions.isThankYouInstalled
+import com.simplemobiletools.commons.extensions.launchPurchaseThankYouIntent
+import com.simplemobiletools.commons.extensions.updateTextColors
+import com.simplemobiletools.smsmessenger.R
+import com.simplemobiletools.smsmessenger.extensions.config
+import kotlinx.android.synthetic.main.activity_settings.*
+import java.util.*
+
+class SettingsActivity : SimpleActivity() {
+
+    override fun onCreate(savedInstanceState: Bundle?) {
+        super.onCreate(savedInstanceState)
+        setContentView(R.layout.activity_settings)
+    }
+
+    override fun onResume() {
+        super.onResume()
+
+        setupPurchaseThankYou()
+        setupCustomizeColors()
+        setupUseEnglish()
+        setupChangeDateTimeFormat()
+        updateTextColors(settings_scrollview)
+    }
+
+    private fun setupPurchaseThankYou() {
+        settings_purchase_thank_you_holder.beVisibleIf(!isThankYouInstalled())
+        settings_purchase_thank_you_holder.setOnClickListener {
+            launchPurchaseThankYouIntent()
+        }
+    }
+
+    private fun setupCustomizeColors() {
+        settings_customize_colors_holder.setOnClickListener {
+            startCustomizationActivity()
+        }
+    }
+
+    private fun setupUseEnglish() {
+        settings_use_english_holder.beVisibleIf(config.wasUseEnglishToggled || Locale.getDefault().language != "en")
+        settings_use_english.isChecked = config.useEnglish
+        settings_use_english_holder.setOnClickListener {
+            settings_use_english.toggle()
+            config.useEnglish = settings_use_english.isChecked
+            System.exit(0)
+        }
+    }
+
+    private fun setupChangeDateTimeFormat() {
+        settings_change_date_time_format_holder.setOnClickListener {
+            ChangeDateTimeFormatDialog(this) {}
+        }
+    }
+}