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Singleton: How should it be used
...rface widgets
It is supposed to be a cache
In strings
In Sessions
I can go all day long
How to create the best singleton:
The smaller, the better. I am a minimalist
Make sure it is thread safe
Make sure it is never null
Make sure it is created only once
Lazy or system initialization? Up to your re...
Finding Key associated with max Value in a Java Map
...
Basically you'd need to iterate over the map's entry set, remembering both the "currently known maximum" and the key associated with it. (Or just the entry containing both, of course.)
For example:
Map.Entry<Foo, Bar> maxE...
How to make return key on iPhone make keyboard disappear?
...ate after you init the textfield in the .m:
yourTextField = [[UITextField alloc] initWithFrame:yourFrame];
//....
//....
//Setting the textField's properties
//....
//The next line is important!!
yourTextField.delegate = self; //self references the viewcontroller or view your textField is on
...
How to avoid null checking in Java?
...ts they are participating in and defensively overcheck for nulls. Additionally, when writing their own code, they tend to rely on returning nulls to indicate something thus requiring the caller to check for nulls.
To put this another way, there are two instances where null checking comes up:
Whe...
Animate the transition between fragments
...urse animate the translationX, translationY, x, and y properties, but generally slides involve animating content to and from off-screen. As far as I know there aren't any transition properties that use relative values. However, this doesn't prevent you from writing them yourself. Remember that prope...
What is recursion and when should I use it?
...sion.
To see why, walk through the steps that the above languages use to call a function:
space is carved out on the stack for the function's arguments and local variables
the function's arguments are copied into this new space
control jumps to the function
the function's code runs
the function's...
In C++, what is a virtual base class?
..." diagram is confusing, although it seems to be commonly used. This is actually a diagram showing class inheritance relationships -- not an object layout. The confusing part is that if we do use virtual, then the object layout looks like the diamond; and if we do not use virtual then the object la...
Super-simple example of C# observer/observable with delegates
...
The observer pattern is usually implemented with events.
Here's an example:
using System;
class Observable
{
public event EventHandler SomethingHappened;
public void DoSomething() =>
SomethingHappened?.Invoke(this, EventArgs.Empt...
Add only non-whitespace changes
I have my text editor to automatically trim trailing whitespace upon saving a file, and I am contributing to an open source project that has severe problems with trailing whitespace.
...
Disabling and enabling a html input button
...nt.getElementById("Button").disabled = false;
Demo Here
Using jQuery
All versions of jQuery prior to 1.6
Disabling a html button
$('#Button').attr('disabled','disabled');
Enabling a html button
$('#Button').removeAttr('disabled');
Demo Here
All versions of jQuery after 1.6
Disabling ...