Tutorial by Examples: er

let playerLayoutChangeListener = new android.view.View.OnLayoutChangeListener( { onLayoutChange : function ( v:View, left:number, top:number, right:number, bottom:number, oldLeft:number, oldTop:number, oldRight:number, oldBottom:number):any { if (left != oldLeft || top != oldTop ...

You can overload a def if the signature is different: def printValue(x: Int) { println(s"My value is an integer equal to $x") } def printValue(x: String) { println(s"My value is a string equal to '$x'") } printValue(1) // prints "My value is an integer equal ...

We will look at how to implement custom comparisons by implementing a custom type, ordinal numbers. To simplify the implementation, we will focus on a small subset of these numbers: all ordinal numbers up to but not including ε₀. Our implementation is focused on simplicity, not speed; however, the i...

Julia supports a very large set of comparison operators. These include All of the following unicode sequences: > < >= ≥ <= ≤ == === ≡ != ≠ !== ≢ ∈ ∉ ∋ ∌ ⊆ ⊈ ⊂ ⊄ ⊊ ∝ ∊ ∍ ∥ ∦ ∷ ∺ ∻ ∽ ∾ ≁ ≃ ≄ ≅ ≆ ≇ ≈ ≉ ≊ ≋ ≌ ≍ ≎ ≐ ≑ ≒ ≓ ≔ ≕ ≖ ≗ ≘ ≙ ≚ ≛ ≜ ≝ ≞ ≟ ≣ ≦ ≧ ≨ ≩ ≪ ≫ ≬ ≭ ≮ ≯ ≰ ≱ ≲ ≳ ≴ ≵ ≶ ≷ ≸ ≹ ≺ ...

In languages such as C, the @goto statement is often used to ensure a function cleans up necessary resources, even in the event of an error. This is less important in Julia, because exceptions and try-finally blocks are often used instead. However, it is possible for Julia code to interface with C ...

If you implement or create a listener in an Activity, always pay attention to the lifecycle of the object that has the listener registered. Consider an application where we have several different activities/fragments interested in when a user is logged in or out. One way of doing this would be to h...

Consider the following code snippet: // Print the sum of the numbers 1 to 10 int count = 0; for (int i = 1; i < 010; i++) { // Mistake here .... count = count + i; } System.out.println("The sum of 1 to 10 is " + count); A Java beginner might be surprised to know that the...

context.globalCompositeOperation = 'source-atop' source-atop compositing clips new image inside an existing shape. // gold filled rect ctx.fillStyle='gold'; ctx.fillRect(100,100,100,75); // shadow ctx.shadowColor='black'; ctx.shadowBlur=10; // restrict new draw to cover existing pixels ct...

A lot of people who are new to multi-threading think that using threads automatically make an application go faster. In fact, it is a lot more complicated than that. But one thing that we can state with certainty is that for any computer there is a limit on the number of threads that can be run at ...

Given: x <- as.matrix(mtcars) One can use heatmap.2 - a more recent optimized version of heatmap, by loading the following library: require(gplots) heatmap.2(x) To add a title, x- or y-label to your heatmap, you need to set the main, xlab and ylab: heatmap.2(x, main = "My main t...

Render a white rectangle over an image with the composite operation ctx.globalCompositeOperation = 'difference'; The amount of the effect can be controled with the alpha setting // Render the image ctx.globalCompositeOperation='source-atop'; ctx.drawImage(image, 0, 0); // set the composite...

You can use a filter to log only messages "lower" than e.g. ERROR level. But the filter is not supported by PropertyConfigurator. So you must change to XML config to use it. See log4j-Wiki about filters. Example "specific level" <appender name="info-out" class=&quo...

In order to prevent a button from firing multiple times within a short period of time (let's say 2 clicks within 1 second, which may cause serious problems if the flow is not controlled), one can implement a custom SingleClickListener. This ClickListener sets a specific time interval as threshold (...

From the Apple documentation: A UIStoryboardSegue object is responsible for performing the visual transition between two view controllers. In addition, segue objects are used to prepare for the transition from one view controller to another. Segue objects contain information about the view contro...

PrepareForSegue: func prepareForSegue(_ segue:UIStoryboardSegue, sender sender:AnyObject?) Notifies the view controller that a segue is about to be performed Parameters segue: The segue object. sender: The object that initialized the segue. Example in Swift Perform a task if the ident...

ShouldPerformSegueWithIdentifier: func shouldPerformSegueWithIdentifier(_ identifier:String, sender sender:AnyObject?) -> Bool Determines whether the segue with the specified identifier should be performed. Parameters Identifier: String that identifies the triggered segue Sender: The...

PerformSegueWithIdentifier: func performSegueWithIdentifier(_ identifier:String, sender sender:AnyObject?) Initiates the segue with the specified identifier from the current view controller's storyboard file Parameters Identifier: String that identifies the triggered segue Sender: The ob...

Overview Gtk+ supports a workflow where the task of user interface design and the task of programming are decoupled. Although the user interface elements such as buttons, menus, layout etc. can be directly added from code, this approach not only clutters the code, but also makes changing the UI for...

In some instances, you will want to send data from JS client to the R server. Here is a basic example using javascript's Shiny.onInputChange function: library(shiny) runApp( list( ui = fluidPage( # create password input HTML('<input type="password" id="passw...

You can use the heroku create command to create a Heroku application. Each application you deploy to Heroku has its own code base, environment variables, addons, etc. Each Heroku application has a globally unique name. If you try to create a Heroku application whose name is already taken, you will ...