Unable to cast Action Provider to Share Action Provider

Below is the code for my Activity

    import android.app.Activity;
    import android.os.Bundle;
    import android.support.v7.widget.ShareActionProvider;
    import android.view.Menu;
    import android.view.MenuItem;

    public class MainActivity extends Activity {
    private ShareActionProvider shareAction;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.activity_main, menu);
        MenuItem item = menu.getItem(R.id.menu_settings);
        shareAction = (ShareActionProvider) item.getActionProvider();
        return true;
    }
}

The Problem is that there is a cast error from ActionProvider to ShareActionProvider.Why it is so below is activity_menu.xml

 <menu xmlns:android="http://schemas.android.com/apk/res/android" >

<item
    android:id="@+id/menu_settings"
    android:orderInCategory="100"
    android:showAsAction="always"
    android:title="@string/menu_settings"
    android:actionProviderClass="android.widget.ShareActionProvider"
    />

</menu>

I had the same problem and I have found the solution:

1) You have to use:

<menu xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:bwq="http://schemas.android.com/apk/res-auto" >

    <item
        android:id="@+id/menu_share"
        android:title="@string/menu_share"
        bwq:actionProviderClass="android.support.v7.widget.ShareActionProvider"
        bwq:showAsAction="always"/>
</menu>

2) and in Java

import android.support.v7.widget.ShareActionProvider;

and

// Locate MenuItem with ShareActionProvider
MenuItem item = menu.findItem(R.id.menu_share);
// Fetch and store ShareActionProvider
mShareActionProvider = (ShareActionProvider) MenuItemCompat.getActionProvider(item);