Web Development

HTML5 Series - Audio

Traditionally if you wanted Audio on your page you would embed it in a Flash object. But when Steve Jobs declared that the iPhone would never support Flash or any other plug in's, there was suddenly a demand that browsers would need to support this natively and in a consistent way between browsers.

In HTML5 we can do this using the Audio tag. e.g.

1<audio controls>
2     <source src="url of the file" type="audio/mp3">
3     Your browser doesn't support audio.
4</audio>

The above example demonstrates setting the file source for the audio with the source tag, the controls tag tells the browser to show audio controls and there is also some text that will be displayed if the browser doesn't support audio.

It is also possible to set multiple source tags to reference different file formats as not all browsers support the same ones. Alternatively when setting just one source, a src tag can be placed on the actual audio node rather than as a child element.

Other settings which could be set include:

autoplay - determines if the file should start playing on the page load
loop - specifies that the file should repeat when it's finished
preload - instructs the browser to start downloading the audio file when the page has loaded

HTML5 Series - Flexbox

If you've ever done any WPF, Silverlight, Windows Phone or Windows 8 development using xmal then you will appreciate how good it is to have controls like the StackPanel and Grid, and that HTML is rather lacking in its layout functionality. True you can produce most layouts but it just seems needlessely harder.

Thankfully HTML5 improves on this situation by introducing some new CSS properties.
The first is flexbox. When you define a div as a flexbox you can set its containing items to either space themselves out evenly, or you can set ratio values on each item to say how big it should be compared to the other items in the flexbox and they will stretch to fill the flebox.

Examples
In this example the flexbox is set to distributive which means the containing items will keep there size but distribute themselves evenly in the flexbox.

The key CSS is where the class example 1 sets the display to -ms-flexbox which makes example 1 div a flexbox container, and -ms-flex-pack: distribute, which set the flex mode to distribute the containing items evenly.

1   <style type="text/css">
2       .Example1 {
3           display:-ms-flexbox;
4           -ms-flex-pack:distribute;
5           width:400px;
6           border:solid 1px black;
7       }
8       .Example1 div:nth-child(1) {
9           background-color: red;
10           min-width:80px;
11           min-height:80px;
12       }
13       .Example1 div:nth-child(2) {
14           background-color: green;
15           min-width:80px;
16           min-height:80px;
17       }
18       .Example1 div:nth-child(3) {
19           background-color: blue;
20           min-width:80px;
21           min-height:80px;
22       }
23 
24   </style>
25<div class="Example1">
26       <div></div>
27       <div></div>
28       <div></div>
29   </div>

In the next example the containing items have had ratios set so that the second item is twice the width of the first and the third remains at a fixed size.

The key CSS to look at here is on the child div's styles where it says -ms-flex: 1 or -ms-flex: 2.

1<style type="text/css">
2    .Example2 {
3        display:-ms-flexbox;
4        width:400px;
5        border:solid 1px black;
6    }
7    .Example2 div {
8        min-width: 80px;
9        min-height: 80px;
10    }
11    .Example2 div:nth-child(1) {
12        background-color: red;
13        -ms-flex: 1 0 auto;
14    }
15    .Example2 div:nth-child(2) {
16        background-color: green;
17        -ms-flex: 2 0 auto;
18    }
19    .Example2 div:nth-child(3) {
20        background-color: blue;
21        min-width:80px;
22    }
23</style>
24 
25<div class="Example2">
26    <div></div>
27    <div></div>
28    <div></div>
29</div>

The third example shows how these techniques also work vertically as well as horizontally. See -ms-flex-direction:column on the containing div style.

1<style type="text/css">
2    .Example3 {
3        display:-ms-flexbox;
4        -ms-flex-direction:column;
5        width:400px;
6        border:solid 1px black;
7    }
8    .Example3 div {
9        min-width: 80px;
10        min-height: 80px;
11    }
12    .Example3 div:nth-child(1) {
13        background-color: red;
14        -ms-flex: 1 0 auto;
15    }
16    .Example3 div:nth-child(2) {
17        background-color: green;
18        -ms-flex: 2 0 auto;
19    }
20    .Example3 div:nth-child(3) {
21        background-color: blue;
22        min-width:80px;
23    }
24</style>
25<div class="Example3">
26    <div></div>
27    <div></div>
28    <div></div>
29</div>

Lastly in the fourth example I've shown how items can be set to wrap when they fill up a line with -ms-flex-wrap:wrap;

1<style type="text/css">
2    .Example4 {
3        display:-ms-flexbox;
4        -ms-flex-wrap:wrap;
5        width:400px;
6        border:solid 1px black;
7    }
8    .Example4 div {
9        min-width: 80px;
10        min-height: 80px;
11    }
12    .Example4 div:nth-child(1) {
13        background-color: red;
14    }
15    .Example4 div:nth-child(2) {
16        background-color: green;
17    }
18    .Example4 div:nth-child(3) {
19        background-color: blue;
20    }
21    .Example4 div:nth-child(4) {
22        background-color: yellow;
23    }
24    .Example4 div:nth-child(5) {
25        background-color: orange;
26    }
27    .Example4 div:nth-child(6) {
28        background-color: violet;
29    }
30</style>
31<div class="Example4">
32    <div></div>
33    <div></div>
34    <div></div>
35    <div></div>
36    <div></div>
37    <div></div>
38    <div></div>
39</div>

HTML5 SERIES – COLUMNS

I'm not sure I've ever needed to add columns where text flows from one into the other, but if your doing Windows 8 development where you would want a sideways scroll rather than vertical this could be quite useful.

To create columns using CSS3 you simply set the columns property to either the number of columns you want or the width each columns should be. e.g. This would produce 4 columns.

1<style type="text/css">
2        div {
3            columns: 4;
4        }
5</style>

There are a couple other properties that are also quite useful when using columns.

Column-Gap - Specifies the size of the gap between columns

Column-Fill - Can either be set to auto where columns are filled sequentially and have different lengths, or balance in which case the text will be balanced so each column is even. The default is balance.

Convert string or int to enum

Enum's a great, but you may be wondering how you can turn an integer or string value into the corresponding enum. For example you may have an api that's being sent XML or JSON, and then you need to turn one of the values within that into an enum to set on an object in your code.

Well it's very simple. If you have a string do this:

1YourEnum foo = (YourEnum) Enum.Parse(typeof(YourEnum), yourString);

or if you have an int do this (you could also just do the first example with a ToString() on the end.

1YourEnum foo = (YourEnum)yourInt;