kotlin.TypeCastException: null cannot be cast to non-null type

Question

I am trying to initialize custom search tool (3d library ) on menu but I got error.

Here is my code

 override fun onCreateOptionsMenu(menu: Menu?): Boolean {
        menuInflater.inflate(R.menu.base_nav_drawer,menu)
      searchItem= menu?.findItem(R.id.srchbar_menu)!!
            global_search= searchItem.actionView as MaterialSearchBar
       lastsuggestions=ArrayList<String>()
        loadSuggest()
global_search.lastSuggestions=lastsuggestions
        return true
    }

Logcat message

kotlin.TypeCastException: null cannot be cast to non-null type com.mancj.materialsearchbar.MaterialSearchBar
        at com.example.sg772.foodorder.BaseNavDrawerActivity.onCreateOptionsMenu(BaseNavDrawerActivity.kt:136)

I tried this

 global_search= searchItem.actionView as? MaterialSearchBar

But it doesnt help line 136 corresponds to global_search= searchItem.actionView as MaterialSearchBar

xml of menu

<?xml version="1.0" encoding="utf-8"?>
<menu xmlns:android="http://schemas.android.com/apk/res/android"
      xmlns:app="http://schemas.android.com/apk/res-auto">
    <item android:id="@+id/srchbar_menu"
          android:title="search"
          android:icon="@drawable/ic_search_black_24dp"
          app:showAsAction="ifRoom|collapseActionView"
          app:actionViewClass="com.mancj.materialsearchbar.MaterialSearchBar"/>
</menu>

Son Truong Son Truong · Accepted Answer · 2019-03-08T03:18:01

This line make your app crash

global_search = searchItem.actionView as MaterialSearchBar

Because searchItem.actionView always returns null and global_search type is MaterialSearchBar (non-null type). You assign null to a non-null type, that why your app crash.

You can change your code to

var global_search: MaterialSearchBar? = null

override fun onCreateOptionsMenu(menu: Menu?): Boolean {
    menuInflater.inflate(R.menu.base_nav_drawer,menu)
    searchItem= menu?.findItem(R.id.srchbar_menu)!!
    global_search = searchItem.actionView as MaterialSearchBar?
    lastsuggestions=ArrayList<String>()
    loadSuggest()
    global_search.lastSuggestions=lastsuggestions
    return true
}

But the search view does not show on your app, it seems 3rd party does not support to integrate into a menu item by using app:actionViewClass.

Here is a workaround solution that you can try.

https://github.com/mancj/MaterialSearchBar/issues/107

kotlin.TypeCastException: null cannot be cast to non-null type

3 Answers