Samsung keyboard backspace not working with SearchView

When using SearchView in my android app, Samsung devices users with samsung keyboard only can't use the backspace button.
Backspace button in samsung keyboard is working fine with EditText and any other input view, except SearchView.
I have tried to detect when the user press the backspace key code and remove one letter manualy, but not working also.
Is it a problem with Samsung keyboard? How can I overcome this problem?

I know this is old post, but I just had the same issue,so I will post my solution. The issue is caused by SearchView using an extended EditText that overrides onKeyPreIme, and does not pass KeyEvent.KEYCODE_BACK events.<br>
The solution I used, is not entirely safe, as I have to overide a RestrictedAPI, but it shouldn't be an issue.<br>
The solution uses the androidx library version, but can be edited for the older appcompat library.<p>
First we create a class MySearchViewSearchAutoComplete that overrides the internal static androidx.appcompat.widget.SearchView.SearchAutoComplete class. This class overrides onKeyPreIme, and when needed, intercepts KeyEvent.KEYCODE_BACK events, swaps them for KeyEvent.KEYCODE_DEL events, and dispatches them directly to the EditBox. </p>
Here is the code;

package com.example.widget.search;

import android.annotation.SuppressLint;
import android.content.Context;
import android.util.AttributeSet;
import android.view.KeyEvent;

@SuppressLint("RestrictedApi")
public class MySearchViewSearchAutoComplete extends androidx.appcompat.widget.SearchView.SearchAutoComplete
{
	boolean _isNonTouch;
	boolean _isIgnore;

	public MySearchViewSearchAutoComplete(Context context)
	{
		super(context);
		init(context);
	}

	public MySearchViewSearchAutoComplete(Context context, AttributeSet attrs)
	{
		super(context, attrs);
		init(context);
	}

	public MySearchViewSearchAutoComplete(Context context, AttributeSet attrs, int defStyle)
	{
		super(context, attrs, defStyle);
		init(context);
	}

	private void init(Context context)
	{
		_isNonTouch = context.getResources().getConfiguration().touchscreen == android.content.res.Configuration.TOUCHSCREEN_NOTOUCH;
	}

	@Override
	public boolean onKeyPreIme(int keyCode, KeyEvent event)
	{
		if (_isNonTouch && keyCode == KeyEvent.KEYCODE_BACK)
		{
			if (event.getAction() == KeyEvent.ACTION_DOWN) // on ActionUp it may already be empty, but we should treat it as not empty
			{
				_isIgnore = getSelectionStart() == 0 && getSelectionEnd() == 0;
			}
			if (!_isIgnore)
			{
				event = new KeyEvent(event.getDownTime(), event.getEventTime(), event.getAction(), KeyEvent.KEYCODE_DEL, event.getRepeatCount(), event.getMetaState(), event.getDeviceId(), event.getScanCode(), event.getFlags(), event.getSource());
				dispatchKeyEvent(event);
				return true;
			}
		}
		return super.onKeyPreIme(keyCode, event);
	}
}

Then we override the abc_search_view layout to use this above class. We use the original source code, only changing the EditText class to our above-extended class. Create a layout file called abc_search_view.xml Here is the code;

<?xml version="1.0" encoding="utf-8"?><!--
    /*
     * Copyright (C) 2014 The Android Open Source Project
     *
     * Licensed under the Apache License, Version 2.0 (the "License");
     * you may not use this file except in compliance with the License.
     * You may obtain a copy of the License at
     *
     *      http://www.apache.org/licenses/LICENSE-2.0
     *
     * Unless required by applicable law or agreed to in writing, software
     * distributed under the License is distributed on an "AS IS" BASIS,
     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     * See the License for the specific language governing permissions and
     * limitations under the License.
     */
    -->
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/search_bar"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="horizontal">

    <!-- This is actually used for the badge icon *or* the badge label (or neither) -->
    <TextView
        android:id="@+id/search_badge"
        android:layout_width="wrap_content"
        android:layout_height="match_parent"
        android:layout_marginBottom="2dip"
        android:drawablePadding="0dip"
        android:gravity="center_vertical"
        android:textAppearance="?android:attr/textAppearanceMedium"
        android:textColor="?android:attr/textColorPrimary"
        android:visibility="gone" />

    <ImageView
        android:id="@+id/search_button"
        style="?attr/actionButtonStyle"
        android:layout_width="wrap_content"
        android:layout_height="match_parent"
        android:layout_gravity="center_vertical"
        android:contentDescription="@string/abc_searchview_description_search"
        android:focusable="true" />

    <LinearLayout
        android:id="@+id/search_edit_frame"
        android:layout_width="wrap_content"
        android:layout_height="match_parent"
        android:layout_marginLeft="8dip"
        android:layout_marginRight="8dip"
        android:layout_weight="1"
        android:layoutDirection="locale"
        android:orientation="horizontal">

        <ImageView
            android:id="@+id/search_mag_icon"
            style="@style/RtlOverlay.Widget.AppCompat.SearchView.MagIcon"
            android:layout_width="@dimen/abc_dropdownitem_icon_width"
            android:layout_height="wrap_content"
            android:layout_gravity="center_vertical"
            android:scaleType="centerInside"
            android:visibility="gone" />

        <!-- Inner layout contains the app icon, button(s) and EditText -->
        <LinearLayout
            android:id="@+id/search_plate"
            android:layout_width="wrap_content"
            android:layout_height="match_parent"
            android:layout_gravity="center_vertical"
            android:layout_weight="1"
            android:orientation="horizontal">

            <view
                android:id="@+id/search_src_text"
                class="com.example.widget.search.MySearchViewSearchAutoComplete"
                android:layout_width="0dp"
                android:layout_height="36dip"
                android:layout_gravity="center_vertical"
                android:layout_weight="1"
                android:background="@null"
                android:dropDownAnchor="@id/search_edit_frame"
                android:dropDownHeight="wrap_content"
                android:dropDownHorizontalOffset="0dip"
                android:dropDownVerticalOffset="0dip"
                android:ellipsize="end"
                android:imeOptions="actionSearch"
                android:inputType="text|textAutoComplete|textNoSuggestions"
                android:paddingLeft="@dimen/abc_dropdownitem_text_padding_left"
                android:paddingRight="@dimen/abc_dropdownitem_text_padding_right"
                android:singleLine="true" />

            <ImageView
                android:id="@+id/search_close_btn"
                android:layout_width="wrap_content"
                android:layout_height="match_parent"
                android:layout_gravity="center_vertical"
                android:background="?attr/selectableItemBackgroundBorderless"
                android:contentDescription="@string/abc_searchview_description_clear"
                android:focusable="true"
                android:paddingLeft="8dip"
                android:paddingRight="8dip" />

        </LinearLayout>

        <LinearLayout
            android:id="@+id/submit_area"
            android:layout_width="wrap_content"
            android:layout_height="match_parent"
            android:orientation="horizontal">

            <ImageView
                android:id="@+id/search_go_btn"
                android:layout_width="wrap_content"
                android:layout_height="match_parent"
                android:layout_gravity="center_vertical"
                android:background="?attr/selectableItemBackgroundBorderless"
                android:contentDescription="@string/abc_searchview_description_submit"
                android:focusable="true"
                android:paddingLeft="16dip"
                android:paddingRight="16dip"
                android:visibility="gone" />

            <ImageView
                android:id="@+id/search_voice_btn"
                android:layout_width="wrap_content"
                android:layout_height="match_parent"
                android:layout_gravity="center_vertical"
                android:background="?attr/selectableItemBackgroundBorderless"
                android:contentDescription="@string/abc_searchview_description_voice"
                android:focusable="true"
                android:paddingLeft="16dip"
                android:paddingRight="16dip"
                android:visibility="gone" />
        </LinearLayout>
    </LinearLayout>
</LinearLayout>

And that's it, it should work.