How to use enum properly java/android

Question

I have never used an enum before. So please be patient with me a little bit.

App background:

I created an application in which the user can add three type of sources, *music* *video* and *pictures* from the external storage USB device.
The user selects a folder onto the usd drive and adds it to the source and then adds a category for it.

THIS HAS BEEN DONE

The Issue is

Now I am trying to read all the files from the folder which has a specific extension, as defined by category.

Following are the extensions for three categories that will be stored in an xml file

<?xml version="1.0" encoding="UTF-8"?>

<Picture>
    <ext>jpg</ext>
    <ext>png</ext>
    <ext>gif</ext>
    <ext>jpeg</ext>
    <ext>pdf</ext>
    <ext>pcd</ext>
    <ext>jpx</ext>
    <ext>tif</ext>
</Picture>

<Videos>
    <ext>mpeg</ext>
    <ext>mpg</ext>
    <ext>mpe</ext>
    <ext>mpeg-1</ext>
    <ext>mpeg-2</ext>
    <ext>mp4</ext>
    <ext>mpa</ext>
    <ext>wmv</ext>
    <ext>wma</ext>
    <ext>wmx</ext>
    <ext>rm</ext>
    <ext>ra</ext>
    <ext>3gp</ext>
</Videos>

<Music>
    <ext>mp3</ext>
    <ext>wav</ext>
    <ext>dct</ext>
    <ext>gsm</ext>
    <ext>flac</ext>
    <ext>au</ext>
    <ext>ogg</ext>
    <ext>raw</ext>
    <ext>wma</ext>
    <ext>msv</ext>
</Music>

So, for instance, if a user has selected the video category I will read all files which have the extensions similar to video in my xml

My Qustion Is:

I am trying to do this thing by using an ENUM, I know I can do it with simple if/else statements as well, but I need to know how the ENUM will work.

I have created a Media Source Enum that has the categories defined.
Here is the code:

public enum Media_source {

    Pitures("P"), Videos("V"), Music("M");

    private String statusCode;

    private Media_source(String s) {
        statusCode = s;
    }

    public String get_media_source() {
        return statusCode;
    }

}

Then I have a Source class that checks which category is selected.

public class Source {

        public static String source_path;
        public static String source_name;
        Media_source mSource;

        public static void main(String[] args) {

            System.out.println(Media_source.Pitures.get_media_source());

        }


        public Source(String name, String path) {
            Source.source_name = name;
            Source.source_path = path;
        }
        public static String getSource_path() {
            return source_path;
        }
        public static void setSource_path(String source_path) {
            Source.source_path = source_path;
        }
        public static String getSource_name() {
            return source_name;
        }
        public static void setSource_name(String source_name) {
            Source.source_name = source_name;
        }

}

Now how can I actually select all files with the extensions for the selected category?
How should I use the enum?

I am not asking for code, though any helping material would be appreciated - I just need to get the concept clear.

Thank you

Assaf Gamliel · Accepted Answer · 2014-02-13 15:51:12Z

2

This is a great lecture: Google I/O 2008 lecture (Effective Java Reloaded)
The Enum part is around here.
Since the video’s quality very poor, here are the slides. https://sites.google.com/site/io/effective-java-reloaded

answered Feb 13, 2014 at 15:51

Assaf Gamliel

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Comments

Tyler · Accepted Answer · 2014-02-18 17:40:02Z

1

"Then I have a Source class that checks which category is selected." - I don't see any code checking the type of the Enum.

This is how I use my Enums, you can do something similar.

Declare your enum:

public enum Media {
    IMAGE, VIDEO, AUDIO;
}

Create a the method which takes the enum as the parameter:

public selectStuff(Media m) {

    switch(m) {

        case IMAGE:
            //Do image stuff
            break;

        case VIDEO:
            //Do video stuff
            break;

        case AUDIO:
            //Do audio stuff
            break;

        default:
            break;

    }
}

And this is how you would use it:

selectMedia(Media.IMAGE);

There is a similar example in the Oracle Docs.

edited Feb 18, 2014 at 17:40

answered Feb 13, 2014 at 15:18

Tyler

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1 Comment

Hassaan Rabbani Over a year ago

where do i put this function? in the enum?

Evgeny Tanhilevich · Accepted Answer · 2014-02-13 15:04:36Z

1

You might want to create an EnumMap somewhere in your code, with Media_source as a key and a Set<String> of extensions as a value. You then use that map to retrieve the appropriate extensions for the media type

answered Feb 13, 2014 at 15:04

Evgeny Tanhilevich

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