Magento Admin Menu action not working gives 404 error Magento 1.9.2.4

Question

Problem Statement: I have created an adminmenu and call an action on it. For the action, I have created one controller. When click on menu it redirects to 404 page on front side.(Can't access to controller and it jump to frontarea) Code is as below:

config.xml (demo/etc/config.xml)

<?xml version="1.0"?>
<config>
    <modules>
        <Sevenbits_Demo>
            <version>1.0.0</version>
        </Sevenbits_Demo>
    </modules>
    <global>
        <models>
            <demo>
                <class>Sevenbits_Demo_Model</class>
            </demo>
        </models>
        <helpers>
            <demo>
                <class>Sevenbits_Demo_Helper</class>
            </demo>
        </helpers>
        <blocks>
            <demo>
                <class>Sevenbits_Demo_Block</class>
            </demo>
        </blocks>
    </global>
    <!-- Frontend Controller started here -->
    <frontend>
        <routers>
            <demo>
                <use>standard</use>
                <args>
                    <frontName>Demo</frontName>
                    <module>Sevenbits_Demo</module>
                </args>
            </demo>
        </routers>
        <layout>
            <updates>
                <demo>
                    <file>demo.xml</file>
                </demo>

            </updates>
        </layout>
    </frontend>
    <!-- Frontend Controller end here -->

    <!-- Frontend Controller started here -->
    <admin>
        <routers>
            <adminhtml>
                <args>
                    <module>
                        <demo before="Mage_Adminhtml">
                            Sevenbits_Demo_Adminhtml
                        </demo>

                    </module>
                </args>
            </adminhtml>
        </routers>
    </admin>
    <!-- Frontend Controller end here -->
</config>

adminhtml.xml(demo/etc/adminhtml.xml)

<?xml version="1.0"?>
<config>
    <menu>
        <demo transalte="title" module="demo">
            <title>Mage Hunter</title>
            <sort_order>1000</sort_order>
            <action>Adminhtml/demo</action>
        </demo>
    </menu>
</config>

DemoController.php (/demo/controllers/Adminhtml/DemoController.php)

<?php

class Sevenbits_Demo_Adminhtml_DemoController extends Mage_Adminhtml_Controller_Action
{

    public function indexAction()
    {
        //$this->loadLayout();
        echo "Hwll";
        return $this->renderLayout();

    }
}

After Menu click (page redirect to 404 page and display frontend layout) get this output.

Answer 1

remove the new lines in here:

<demo before="Mage_Adminhtml">
    Sevenbits_Demo_Adminhtml
</demo>

make that look like this

<demo before="Mage_Adminhtml">Sevenbits_Demo_Adminhtml</demo>

Answer 2

You need to define layout for it

Create file for it app/design/adminhtml/default/default/layout/demo.xml

add below code to it:

<?xml version="1.0"?>
<layout version="0.1.0">
    <adminhtml_demo_index>
        <reference name="content">
            <block type="demo/adminhtml_demo" name="demo" />
        </reference>
    </adminhtml_demo_index>
</layout>

Also you need to add below code in config.xml file between <adminhtml></adminhtml>

<layout>
    <updates>
        <demo>
            <file>demo.xml</file>
        </demo>
    </updates>
</layout>

Also give the link

<action>adminhtml/demo</action> instead of <action>Adminhtml/demo</action>