this refers to the current object. The keyword this identifies a special type of pointer. Suppose that you create an object named x of class A, and class A has a non-static member function f(). If you call the function x.f(), the keyword this in the body of f() stores the address of x.
When the language was first evolving, in early releases with real users, there were no references, only pointers. References were added when operator overloading was added, as it requires references to work consistently. One of the uses of this is for an object to get a pointer to itself. If it was a reference, we’d … Read more
If you want to have the this property be consistent, you should bind the functions that are being called. For example, setInterval(function() { /* code here */ }.bind(this), 500) That way, the this of the inner function will be the same as that of the outer function.
Leaking the this reference in the constructor (not controller) is dangerous, especially in a multithreaded environment. This is because the object is not fully constructed until the constructor call finishes. Leaking this from the constructor thus means that the external world gets access to an object which is not yet fully constructed. This may not … Read more
The this keyword refers to the object the function belongs to, or the window object if the function belongs to no object. It’s used in OOP code, to refer to the class/object the function belongs to For example: function foo() { this.value=”Hello, world”; this.bar = function() { alert(this.value); } } var inst = new foo(); … Read more
Javascripts .call() and .apply() methods allow you to set the context for a function. var myfunc = function(){ alert(this.name); }; var obj_a = { name: “FOO” }; var obj_b = { name: “BAR!!” }; Now you can call: myfunc.call(obj_a); Which would alert FOO. The other way around, passing obj_b would alert BAR!!. The difference between … Read more
Because this refers to the object instance. There is no object instance in a call of a static method. But of course you can access your static field (only the static ones!). Just use class Sub { static int y; public static void foo() { y = 10; } } If you want to make … Read more
Toast and Intent, both requires reference to context. And getApplication, getApplicationContext, LoginActivity.this and getBaseContext, they all offer reference to the context. Now the thing confuses is the declaration of different contexts and their specific-usage. To make things simple, you should count two types of context available in the Android framework. Application Context Activity Context Application … Read more
but Java is clever enough to know what is happening if I change the statement in the constructor to bar = bar; FALSE! It compiles but it doesn’t do what you think it does! As to when to use it, a lot of it is personal preference. I like to use this in my public … Read more
There is a difference between $(this) and event.target, and quite a significant one. While this (or event.currentTarget, see below) always refers to the DOM element the listener was attached to, event.target is the actual DOM element that was clicked. Remember that due to event bubbling, if you have <div class=”outer”> <div class=”inner”></div> </div> and attach … Read more