Questions

Which websocket library to use with Node.js?

Currently there is a [plethora of websocket libraries](http://npmjs.org/keyword/websocket) for node.js, the most popular seem to be: - [https://github.com/Worlize/WebSocket-Node](https://github.com/W...

Android activity life cycle - what are all these methods for?

What is the life cycle of an Android activity? Why are so many similar sounding methods (`onCreate()`, `onStart()`, `onResume()`) called during initialization, and so many others (`onPause()`, `onStop...

How to remove a field completely from a MongoDB document?

``` { name: 'book', tags: { words: ['abc','123'], lat: 33, long: 22 } } ``` Suppose this is a document. How do I remove "`words`" completely from all the documen...

22 Sep at 17:57

How to rename a table in SQL Server?

The `SQL` query that I have used is : ``` ALTER TABLE oldtable RENAME TO newtable; ``` But, it gives me an error. > Server: Msg 156, Level 15, State 1, Line 1 Incorrect syntax near the keyword '...

10 Oct at 15:18

How to detect a textbox's content has changed

I want to detect whenever a textbox's content has changed. I can use the keyup method, but that will also detect keystrokes which do not generate letters, like the arrow keys. I thought of two methods...

3 Feb at 20:45

#pragma once vs include guards?

I'm working on a codebase that is known to only run on windows and be compiled under Visual Studio (it integrates tightly with excel so it's not going anywhere). I'm wondering if I should go with the ...

22 Nov at 03:7

jQuery Set Cursor Position in Text Area

How do you set the cursor position in a text field using jQuery? I've got a text field with content, and I want the users cursor to be positioned at a certain offset when they focus on the field. Th...

20 Mar at 13:5

Best algorithm for detecting cycles in a directed graph

Is there an efficient algorithm for detecting cycles within a directed graph? I have a directed graph representing a schedule of jobs that need to be executed, a job being a node and a dependency bein...

No Firebase App '[DEFAULT]' has been created - call Firebase.initializeApp() in Flutter and Firebase

I am building a Flutter application and I have integrated Firebase, but I keep getting this error when I click on a button either to register, login or logout. I have seen other people have asked the ...

How exactly does the android:onClick XML attribute differ from setOnClickListener?

From that I've read you can assign a `onClick` handler to a button in two ways. Using the `android:onClick` XML attribute where you just use the name of a public method with the signature`void name(V...

28 Feb at 12:11

Altering a column to be nullable

I want to alter a table column to be nullable. I have used: ``` ALTER TABLE Merchant_Pending_Functions Modify NumberOfLocations NULL ``` This gives an error at `Modify`. What is the correct syntax...

6 Mar at 14:12

What are the default access modifiers in C#?

What is the default access modifier for classes, methods, members, constructors, delegates and interfaces?

31 Oct at 08:36

Generating statistics from Git repository

I'm looking for some good tools/scripts that allow me to generate a few statistics from a git repository. I've seen this feature on some code hosting sites, and they contained information like... - -...

29 May at 14:23

Android Spinner: Get the selected item change event

How can you set the event listener for a Spinner when the selected item changes? Basically what I am trying to do is something similar to this: ``` spinner1.onSelectionChange = handleSelectionChange...

Why use pointers?

I know this is a really basic question, but I've just started with some basic C++ programming after coding a few projects with high-level languages. Basically I have three questions: 1. Why use po...

30 May at 20:49

How can I get npm start at a different directory?

I usually `cd` into the app directory and then run `npm start`. It is my feeling that there ought to be some way to run `npm start` with a path parameter. But, the [npm start documentation](https://d...

10 Feb at 08:32

Root password inside a Docker container

I'm using a Docker image which was built using the USER command to use a non-root user called `dev`. Inside a container, I'm "dev", but I want to edit the `/etc/hosts` file. So I need to be root. I'm...

15 Sep at 21:27

Checking if a string is empty or null in Java

I'm parsing HTML data. The `String` may be `null` or empty, when the word to parse does not match. So, I wrote it like this: ``` if(string.equals(null) || string.equals("")){ Log.d("iftrue", "s...

30 Jan at 08:9

change values in array when doing foreach

example: ``` var arr = ["one","two","three"]; arr.forEach(function(part){ part = "four"; return "four"; }) alert(arr); ``` The array is still with it's original values, is there any way to ha...

Filter LogCat to get only the messages from My Application in Android?

I observed that when i use Logcat with Eclipse with ADT for Android, I get messages from many other applications as well. Is there a way to filter this and show only messages from my own application o...

30 May at 14:47

Convert java.util.Date to String

I want to convert a `java.util.Date` object to a `String` in Java. The format is `2010-05-30 22:15:52`

26 Mar at 16:16

How to get an AWS EC2 instance ID from within that EC2 instance?

How can I find out the `instance id` of an ec2 instance from within the ec2 instance?

31 Oct at 15:15

How to generate UML diagrams (especially sequence diagrams) from Java code?

How can I generate UML diagrams (especially sequence diagrams) from existing Java code?

30 Mar at 11:0

VSCode showing only one file in the tab bar (can't open multiple files)

I hit some shortcut and I can't find the setting the turn it off. But opening multiple files doesn't show different tabs. Here's what I'm seeing [](https://i.stack.imgur.com/7aLOc.png) But this is ...

2 Feb at 19:40

Dependency Injection error: Unable to resolve service for type while attempting to activate, while class is registered

I created an .NET Core MVC application and use Dependency Injection and Repository Pattern to inject a repository to my controller. However, I am getting an error: > InvalidOperationException: Unable ...