Why is NPE occurred in SearchView only in API level 21 with the following attributes?

Question

I'm using android.support.v7.widget.SearchView like the following code.

    <android.support.v7.widget.SearchView 
        android:id="@+id/search_view"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginTop="3dp"
        android:layout_toRightOf="@id/img_search"
        android:closeIcon="@null"
        android:searchIcon="@null"
        android:iconifiedByDefault="false"
        android:queryBackground="@android:color/transparent"/>

NPE occurred only in api level 21 with the fatal log.

    Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'boolean android.graphics.drawable.Drawable.setState(int[])' on a null object reference
        at android.widget.SearchView.updateCloseButton(SearchView.java:849)
        at android.widget.SearchView.updateViewsVisibility(SearchView.java:798)

I figure it happened 'cause I set attribute is null of closeIcon and searchIcon.

How can I solve this problem wisely?

SUGGESTION:: modify your gradle.properties, build.gradle, *.java source and *.xml layouts to use androidx instead of android.support. — paulsm4, Nov 07 '19 at 02:31
It's quite hard to change it quickly. I'll try it later. Is there another solution? — libliboom, Nov 07 '19 at 02:32
android studio has a menu to do that for you. see https://stackoverflow.com/questions/51280090/what-is-androidx — njzk2, Nov 07 '19 at 03:01

score 0 · Answer 1 · answered Nov 07 '19 at 09:08

I solved it with the following code.

    <android.support.v7.widget.SearchView 
        android:id="@+id/search_view"
        style="@style/LanguageSearchView"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginTop="3dp"
        android:layout_toRightOf="@id/img_search"
        android:iconifiedByDefault="false"
        android:queryBackground="@android:color/transparent"/>

Actually I made style for api level 21 in value-v21/styles.xml.

    <style name="LanguageSearchView">
        <item name="closeIcon">@null</item>
        <item name="searchIcon">@null</item>
    </style>

All api level except for 21, they will use the following style in value/styles.xml.

    <style name="LanguageSearchView">
        <item name="android:closeIcon">@null</item>
        <item name="android:searchIcon">@null</item>
    </style>

I just know with prefix of android is framework attribute,
otherwise it's own application attribute.

But I'm still confusing about this solution.
Anyone who can explain it clearly?

Got the same crash here. Do you have any reference to your solution? And does it really work? Thanks. — iForests, Aug 13 '21 at 16:43

Why is NPE occurred in SearchView only in API level 21 with the following attributes?

1 Answers1