ImageButton in ActionBar for GoBack in WebView

I'm using Fragments and one of my Fragment I have a webview. I want to add a image button that will let user to go back.

I have 4 Fragments and their names are Fragment1,Fragment2,Fragment3,Fragment4.

Also I have 4 layouts tab1.xml tab2.xml tab3.xml tab4.xml and there is 4 webview objects in all layouts.

When I click Fragment1, it opens tab1.xml and tab1.xml's webview1 opens www.site.com and user starts surfing inside webview1.

If user visits 2 or more pages in webview1 I want this user let can go back with a button.

How can I do this?

In your decalarations:

WebView web = null;

In your onCreateView;

// Prepare WebView.
web = (WebView) v.findViewById(R.id.htmlDisplay);
// Set WebView.
final WebSettings webSettings = web.getSettings();

// Enable JavaScript.
webSettings.setJavaScriptEnabled(true);
webSettings.setJavaScriptCanOpenWindowsAutomatically(true);

In your back button (not the physical one):

web.goBack()

If you want to use your physical back button:

@Override
public boolean onKeyDown(int keyCode, KeyEvent event)
{
    if(event.getAction() == KeyEvent.ACTION_DOWN)
    {
        switch(keyCode)
        {
        case KeyEvent.KEYCODE_BACK:
            if(web.canGoBack() == true)
            {
                web.goBack();
            }
            else
            {
                finish();
            }
            return true;
        }
    }
    return super.onKeyDown(keyCode, event);
}