adding some search boilerplate code

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

@@ -1,11 +1,20 @@
 package com.simplemobiletools.smsmessenger.activities
 
 import android.annotation.SuppressLint
+import android.app.SearchManager
+import android.content.Context
 import android.os.Bundle
 import android.view.Menu
+import android.view.MenuItem
+import androidx.appcompat.widget.SearchView
+import androidx.core.view.MenuItemCompat
+import com.simplemobiletools.commons.helpers.ensureBackgroundThread
 import com.simplemobiletools.smsmessenger.R
 
 class SearchActivity : SimpleActivity() {
+    private var mIsSearchOpen = false
+    private var mLastSearchedText = ""
+    private var mSearchMenuItem: MenuItem? = null
 
     @SuppressLint("InlinedApi")
     override fun onCreate(savedInstanceState: Bundle?) {
@@ -15,7 +24,51 @@ class SearchActivity : SimpleActivity() {
 
     override fun onCreateOptionsMenu(menu: Menu): Boolean {
         menuInflater.inflate(R.menu.menu_search, menu)
+        setupSearch(menu)
         updateMenuItemColors(menu)
         return true
     }
+
+    private fun setupSearch(menu: Menu) {
+        val searchManager = getSystemService(Context.SEARCH_SERVICE) as SearchManager
+        mSearchMenuItem = menu.findItem(R.id.search)
+        (mSearchMenuItem?.actionView as? SearchView)?.apply {
+            setSearchableInfo(searchManager.getSearchableInfo(componentName))
+            isSubmitButtonEnabled = false
+            setOnQueryTextListener(object : SearchView.OnQueryTextListener {
+                override fun onQueryTextSubmit(query: String) = false
+
+                override fun onQueryTextChange(newText: String): Boolean {
+                    if (mIsSearchOpen) {
+                        mLastSearchedText = newText
+                        textChanged(newText)
+                    }
+                    return true
+                }
+            })
+        }
+
+        MenuItemCompat.setOnActionExpandListener(mSearchMenuItem, object : MenuItemCompat.OnActionExpandListener {
+            override fun onMenuItemActionExpand(item: MenuItem?): Boolean {
+                mIsSearchOpen = true
+                return true
+            }
+
+            // this triggers on device rotation too, avoid doing anything
+            override fun onMenuItemActionCollapse(item: MenuItem?): Boolean {
+                if (mIsSearchOpen) {
+                    mIsSearchOpen = false
+                    mLastSearchedText = ""
+                }
+                return true
+            }
+        })
+        mSearchMenuItem?.expandActionView()
+    }
+
+    private fun textChanged(text: String) {
+        ensureBackgroundThread {
+
+        }
+    }
 }