Explain ExtJS 4 event handling

Let’s start by describing DOM elements’ event handling. DOM node event handling First of all you wouldn’t want to work with DOM node directly. Instead you probably would want to utilize Ext.Element interface. For the purpose of assigning event handlers, Element.addListener and Element.on (these are equivalent) were created. So, for example, if we have html: … Read more

Why does Boost.Asio not support an event-based interface?

Boost.Asio is a C++ library for network and low-level I/O programming. As such, OS-level synchronization objects, such as condition variables, are outside of the scope of the library, and a much better fit for Boost.Thread. The Boost.Asio author often presents the boost::asio::io_service as the bridge or link between the application and the OS. While this … Read more

Creating a custom event listener on an Android app

Define a callback interface public interface NewsUpdateListener { void onNewsUpdate(<News data to be passed>); } Provide a registration facility on the background thread which gets the RSS feed class <Background processing class name> { …. ArrayList<NewsUpdateListener> listeners = new ArrayList<NewsUpdateListener> (); …. public void setOnNewsUpdateListener (NewsUpdateListener listener) { // Store the listener object this.listeners.add(listener); } … Read more

How can I remove a JavaScript event listener?

You need to use named functions. Also, the click variable needs to be outside the handler to increment. var click_count = 0; function myClick(event) { click_count++; if(click_count == 50) { // to remove canvas.removeEventListener(‘click’, myClick); } } // to add canvas.addEventListener(‘click’, myClick); You could close around the click_counter variable like this: var myClick = (function( … Read more