Remove magic number

src/main/java/com/kdanmobile/reader/screen/view/SearchView.kt

@@ -36,6 +36,7 @@ class SearchView: RelativeLayout, View.OnClickListener, LeftToolbarView {
     companion object {
         private const val SEARCH_RESULT_INIT_NUMBER = 200
         private const val SEARCH_RESULT_ADD_NUMBER = 50
+        private const val SEARCH_RESULT_PRE_LOAD_BUFFER = 1
     }
 
     private var pdfInfoHandler: PdfInfoHandler? = null
@@ -186,7 +187,7 @@ class SearchView: RelativeLayout, View.OnClickListener, LeftToolbarView {
 
         listView.setOnScrollListener(object : AbsListView.OnScrollListener {
             override fun onScroll(view: AbsListView?, firstVisibleItem: Int, visibleItemCount: Int, totalItemCount: Int) {
-                val shouldLoadMore = firstVisibleItem + visibleItemCount >= totalItemCount - 1
+                val shouldLoadMore = firstVisibleItem + visibleItemCount >= totalItemCount - SEARCH_RESULT_PRE_LOAD_BUFFER
                 if (shouldLoadMore) {
                     search(searchStartPage)
                 }