Select value from dropdown with selenium webdriver - selenium

Question

I am trying to select a value from a dropdown with selenium webdriver but it just opens the dropdown and immediately closes it.
Here is the code for webdriver:
driver.findElement(By.cssSelector("span.k-select ")).click();
Thread.sleep(3000);
driver.findElement(By.xpath("//li[#class='k-item'][.='Revenue per click']")).click();
And this is the html code from the browser for the dropdown:
<div class="controls">
<span class="k-widget k-dropdown k-header kendo-input span8 ddFix" unselectable="on">
<span unselectable="on" class="k-dropdown-wrap k-state-default">
<span unselectable="on" class="k-input">Select revenue type...
</span>
<span unselectable="on" class="k-select">
<span unselectable="on" class="k-icon k-i-arrow-s">select</span>
</span>
</span>
<input name="revenueType" id="revenueType" class="kendo-input span8 ddFix" data-role="dropdownlist" style="display: none;">
</span>
</div>
<div class="k-animation-container km-popup">
<div class="k-list-container k-popup k-group k-reset" id="revenueType-list" data-role="popup">
<ul unselectable="on" class="k-list k-reset" tabindex="-1" role="listbox" aria-hidden="true" id="revenueType_listbox" aria-live="off" style="overflow: auto;">
<li tabindex="-1" role="option" unselectable="on" class="k-item">Select revenue type...</li>
<li tabindex="-1" role="option" unselectable="on" class="k-item">Revenue per action</li>
<li tabindex="-1" role="option" unselectable="on" class="k-item">Revenue per click</li>
<li tabindex="-1" role="option" unselectable="on" class="k-item">Revenue per sale</li>
<li tabindex="-1" role="option" unselectable="on" class="k-item">Revenue per action + Revenue per sale</li>
<li tabindex="-1" role="option" unselectable="on" class="k-item">Revenue per mile</li>
</ul>
</div>
</div>

Answer 1

It's hard to debug without the context but:
Your locator is invalid, instead try using:
By.xpath("//li[text()='Revenue per click']")
Since only one item has that text, it should be sufficient. If you still want to include #class in selector, use
By.xpath("//li[#class='k-item' and text()='Revenue per click']")
Try using javascript change the unselectable to off using javascript executor.

Answer 2

Get the dropdown text value after perform click action
subdropdown_child = navigationDriver.findElements(By.cssSelector("select#ctl00_SPWebPartManager1_g_c873566a_540c_4681 option");
for (Element subchild : subdropdown_child)
{
dropdown_value = subchild.text();
new Select(navigationDriver.findElementByCssSelector("select#ctl00_SPWebPartManager1_g_c873566a_540c_4681_")).selectByVisibleText(dropdown_value);
}