In: Categories » Computers and technology » Flash » What are Loops and how do they work
|
Computers are great for doing repetitive tasks. Whereas a human gets bored doing the same thing a few times in a row, a computer is happy to repeat the same task hundreds or even millions of times. In fact, repetitive tasks are where computers really excel. Looping is an important part of every programming language. ActionScript is no exception. You can repeat a set of instructions a certain number of times, or until a certain condition is met. In fact, conditions are an important part of looping. All a loop needs is a starting and ending point, plus a condition that signifies the end of the loop. For instance, if you want to loop 10 times, a variable will be used to start counting at 0. Each time the loop loops, the counter is incremented by 1. When it reaches 9, the loop ends and the program continues past the end of the loop. The following is an illustration of a typical program loop:
In the preceding seven steps, step 1 only happens once. Then step 2 signifies the beginning of the loop. Steps 3, 4, 5, and 6 are executed 10 times. After the 10th time, step 7 is executed, and the program continues from there. So if the loop is to occur 10 times, why does it check to see whether the counter reaches 9? This is because the counter starts at 0. This is typical of most computer programming languages. The counter counts from 0 to 9 instead of from 1 to 10. Another important part of loops is when, exactly, the condition is examined. In some cases, it is examined before the commands in the loop are executed, and in other cases it is examined in the end. There are also ways to break out of loops prematurely, and ways to skip the rest of the commands in a loop and start back at the beginning.
|
legal disclaimer
1) Our website is not responsible for the information contained by this article as well for any and all copyright infringements by authors and writers. E-articles is a free information resource. If you suspect this article for any copyright infringements, please read the Terms of service and contact us to investigate the problem.
2) The E-articles directory team is not responsible for inaccuracies, falsehoods, or any other types of misinformation this tutorial may contain and will not be liable for any loss or damage suffered by a user through the user's reliance on the information gained here. Please read the Terms of service
Useful tools and features
If you like this article (tutorial), please link to it from your web page using the information above. Linking to this page, this is the only way to help us improve our service, the same time providing your visitors with a way to improve their online experience.
related articles
Create a custom MovieClip.drawTriangle( ) method using the Drawing API and invoke it on a movie clip. You can determine and plot the vertices of a triangle given the lengths of two sides and the angle between them. This is a better approach than specifying the lengths of the three sides because knowing the lengths of two sides and the angle between them always determines a triangle, whereas three arbitrary sides may not fit together to make a triangle. The custom drawTriangle( ) method accepts six parameters: ab ...
2. ActionScript: Filling a Shape with a Solid or Translucent Color
Use the beginFill( ) and endFill( ) methods to initiate and close a shape drawn at runtime. To draw a filled shape, call beginFill( ) prior to any other drawing methods, including the custom methods you have defined such as drawCircle( ) and drawPolygon( ). Invoke endFill( ) after calling other drawing methods to create the shape. You cannot apply a fill to an existing shape drawn at authoring time or runtime. You must invoke beginFill( ) before drawing the shape to be filled. This example creates a solid blue ...
3. Drawing a rectangle using ActionScript
Create a custom MovieClip.drawSimpleRectangle( ) method using the Drawing API and invoke it on a movie clip. To draw a simple rectangle, specify the stroke's attributes using the lineStyle( ) method and then draw four lines using the lineTo( ) method: // Create rectangle_mc with a depth of 1 on the main timeline. _root.createEmptyMovieClip("rectangle_mc", 1); // Specify a one-pixel, solid, black line. rectangle_mc.lineStyle(1, 0x000000, 100); // Draw four lines to form the perimeter ...
4. How to draw a rectangle with rounded corners
You want to draw a rectangle with rounded corners, an offset, or rotation.Create a custom MovieClip.drawRectangle( ) method using the Drawing API and invoke it on a movie clip. The drawSimpleRectangle( ) method is, as the name suggests, quite simple. Let's create a more complex version that also: Draws a rectangle with a specified angle of rotation Let's you specify the rectangle center's coordinates Can draw a rectangle with rounded corners The drawRectangle( ) method accepts...
You want to reuse code that you've created for one project in another Flash movie. Or you want to write your ActionScript code in an external text editor. Place your ActionScript code in external .as files and use the #include directive to add them to your Flash movies: // Adds all the code within MyActionScriptFile.as to your Flash movie. #include "MyActionScriptFile.as" Use the #include directive to incorporate code from external text files into your Flash movie during compilation from a .fla file ...
6. Drawing a Circle using ActionScript
Create a custom MovieClip.drawCircle( ) method using the Drawing API and invoke it on a movie clip. You can create a circle in ActionScript with eight curves. Fewer curves results in a distorted circle and too many curves hinders performance. Let's create a custom method of the MovieClip class for drawing circles. This method, drawCircle( ), allows for three parameters: radius The radius of the circle x The x coordinate of the circle's center point. If undefined, the circle is centered at x =...
7. ActionScript: Repeating a Task at Timed Intervals
You want to perform an action or actions at a specific timed interval. Use the setInterval( ) function. The setInterval( ) function allows you to specify an interval (in milliseconds) at which your Flash movie will invoke a function. Use setInterval( ) to perform a particular action over time but not necessarily at the frequency of the frame rate of the movie. // Define a function. function myIntervalFunction ( ) { // Output the difference between the current timer value and its value from the ...
8. Mouse Location Flash Script
Not only can you get the location of a movie clip on the screen, you can even get the location of the mouse, also known as the cursor. What is the difference between the mouse and the cursor? The mouse is the physical device attached to your computer. You may even have a track pad or tablet instead. The cursor is the graphic that moves around the screen as you move your mouse. So, technically, cursor is the term I should be using here. However, ActionScript uses the term mouse in its keywords. I will therefore use mouse and cursor i...
9. ActionScript: Performing Actions Conditionally
You want to perform an action only when a condition is true. Use an if statement or a switch statement. You often need your ActionScript code to make decisions, such as whether to execute a particular action or group of actions. To execute an action under certain circumstances, use one of ActionScript's conditional statements: if, switch, or the ternary conditional operator (? :). The conditional statements allow you to make logical decisions, and you'll learn from experience which is more appropriate for a given situ...
10. Enhancing Standalone Projector
You want to create an enhanced Standalone Projector with features such as borderless playback, custom titles, no Flash menus, and so on. Use a third-party tool such as SWF Studio or SWFKit to create the Projector from your completed Flash movie. SWF Studio is a third-party utility that helps you overcome some of the limitations of regular standalone Flash Projectors. However, SWF Studio produces Windows projectors only. Also note that the resultant projector files are rather hefty (minimum file size is around 1.5 MB). The...