load fragment after one second of text change

refresh fragment after one second of text changed. And hide preview icon if fragmented as there is no point of having this option because the fragment will auto-refresh the content.

AnkiDroid/src/main/java/com/ichi2/anki/CardTemplateEditor.kt

@@ -21,6 +21,8 @@ import android.content.Context
 import android.content.Intent
 import android.os.Build
 import android.os.Bundle
+import android.os.Handler
+import android.os.Looper
 import android.text.Editable
 import android.text.TextWatcher
 import android.view.ActionMode
@@ -65,6 +67,7 @@ import com.ichi2.anki.previewer.TemplatePreviewerArguments
 import com.ichi2.anki.previewer.TemplatePreviewerFragment
 import com.ichi2.anki.snackbar.showSnackbar
 import com.ichi2.anki.utils.ext.isImageOcclusion
+import com.ichi2.anki.utils.postDelayed
 import com.ichi2.annotations.NeedsTest
 import com.ichi2.compat.CompatHelper.Companion.getSerializableCompat
 import com.ichi2.libanki.Collection
@@ -87,6 +90,7 @@ import timber.log.Timber
 import java.util.regex.Pattern
 import kotlin.math.max
 import kotlin.math.min
+import kotlin.time.Duration.Companion.seconds
 
 /**
  * Allows the user to view the template for the current note type
@@ -414,6 +418,7 @@ open class CardTemplateEditor : AnkiActivity(), DeckSelectionListener {
     }
 
     class CardTemplateFragment : Fragment() {
+        private val refreshFragmentHandler = Handler(Looper.getMainLooper())
         private var currentEditorTitle: FixedTextView? = null
         private lateinit var editorEditText: FixedEditText
 
@@ -463,14 +468,26 @@ open class CardTemplateEditor : AnkiActivity(), DeckSelectionListener {
 
             // Set text change listeners
             val templateEditorWatcher: TextWatcher = object : TextWatcher {
+                /**
+                 * Declare a nullable variable refreshFragmentRunnable of type Runnable.
+                 * This will hold a reference to the Runnable that refreshes the previewer fragment.
+                 * It is used to manage delayed fragment updates and can be null if no updates in card.
+                 */
+                private var refreshFragmentRunnable: Runnable? = null
                 override fun afterTextChanged(arg0: Editable) {
+                    refreshFragmentRunnable?.let { refreshFragmentHandler.removeCallbacks(it) }
                     templateEditor.tabToCursorPosition[cardIndex] = editorEditText.selectionStart
                     when (currentEditorViewId) {
                         R.id.styling_edit -> tempModel.updateCss(editorEditText.text.toString())
                         R.id.back_edit -> template.put("afmt", editorEditText.text)
                         else -> template.put("qfmt", editorEditText.text)
                     }
                     templateEditor.tempModel!!.updateTemplate(cardIndex, template)
+                    val updateRunnable = Runnable {
+                        templateEditor.loadTemplatePreviewerFragmentIfFragmented()
+                    }
+                    refreshFragmentRunnable = updateRunnable
+                    refreshFragmentHandler.postDelayed(updateRunnable, REFRESH_PREVIEW_DELAY)
                 }
 
                 override fun beforeTextChanged(arg0: CharSequence, arg1: Int, arg2: Int, arg3: Int) {
@@ -755,6 +772,11 @@ open class CardTemplateEditor : AnkiActivity(), DeckSelectionListener {
                 menu.findItem(R.id.action_delete).isVisible = false
             }
 
+            // Hide preview option if the view is big enough
+            if (templateEditor.fragmented) {
+                menu.findItem(R.id.action_preview).isVisible = false
+            }
+
             // marked insert field menu item invisible for style view
             val isInsertFieldItemVisible = currentEditorViewId != R.id.styling_edit
             menu.findItem(R.id.action_insert_field).isVisible = isInsertFieldItemVisible
@@ -1198,6 +1220,9 @@ open class CardTemplateEditor : AnkiActivity(), DeckSelectionListener {
         private const val EDITOR_START_ORD_ID = "ordId"
         private const val CARD_INDEX = "card_ord"
 
+        // Time to wait before refreshing the previewer
+        private val REFRESH_PREVIEW_DELAY = 1.seconds
+
         @Suppress("unused")
         private const val REQUEST_PREVIEWER = 0