I think copy-paste of next code:
View close = searchView.findViewById(R.id.search_close_btn);
close.setBackgroundResource(R.drawable.desired_icon);
Is not good solution. Please, use styles for this.
First solution. Add close icon as default android:searchViewCloseIcon
in your primary theme:
<style name="Theme" parent="AppBaseTheme">
<item name="android:searchViewCloseIcon">@drawable/ic_your_search_close_icon</item>
</style>
Second solution(Better). Style your action bar
<style name="CustomActionBarTheme" parent="@style/Theme.AppCompat.Light.DarkActionBar">
<item name="android:actionBarStyle">@style/MyActionBar</item>
<!-- Support library compatibility -->
<item name="actionBarStyle">@style/MyActionBar</item>
</style>
<!-- ActionBar styles -->
<style name="MyActionBar"
parent="@style/Theme.AppCompat.Light.DarkActionBar">
<item name="searchViewCloseIcon">@android:drawable/ic_your_search_close_icon</item>
</style>
Other SearchView attributes(from appcompat-v7 source code(UPDATED LINK)):
<attr name="searchResultListItemHeight" format="dimension" />
<attr name="searchViewAutoCompleteTextView" format="reference" />
<attr name="searchViewCloseIcon" format="reference" />
<attr name="searchViewEditQuery" format="reference" />
<attr name="searchViewEditQueryBackground" format="reference" />
<attr name="searchViewGoIcon" format="reference" />
<attr name="searchViewSearchIcon" format="reference" />
<attr name="searchViewTextField" format="reference" />
<attr name="searchViewTextFieldRight" format="reference" />
<attr name="searchViewVoiceIcon" format="reference" />
Exaple usage:
<item name="searchDropdownBackground">@android:drawable/spinner_dropdown_background</item>
<item name="searchViewTextField">@drawable/textfield_searchview_holo_dark</item>
<item name="searchViewTextFieldRight">@drawable/textfield_searchview_right_holo_dark</item>
<item name="searchViewCloseIcon">@android:drawable/ic_clear</item>
<item name="searchViewSearchIcon">@android:drawable/ic_search</item>
<item name="searchViewGoIcon">@android:drawable/ic_go</item>
<item name="searchViewVoiceIcon">@android:drawable/ic_voice_search</item>
<item name="searchViewEditQuery">@android:drawable/ic_commit_search_api_holo_dark</item>
<item name="searchViewEditQueryBackground">?attr/selectableItemBackground</item>
<item name="searchDialogTheme">@style/Theme.SearchBar</item>
More about styling:
Android – Theming ActionBar and the SearchView within it by Andreas Nilsson
Styling the Action Bar by Android official documentation