Question

I need to create a phonegap plugin for ios which fetches all artists from the music library. I know how to do this in Objective C but I have no idea about javascript. I read the phongegap plugin docs for iOS but I dont understand the javascript parts. Please help.
Heres my code…

Artist.m

#import "Artist.h"
#import <MediaPlayer/MediaPlayer.h>
#import <PhoneGap/PGPlugin.h>
@implementation Artist

-(void)getArtistNames:(NSMutableArray*)arguments withDict:(NSMutableDictionary*)options
{
    MPMediaQuery *query=[MPMediaQuery artistsQuery];
    NSArray *artists=[query collections];
    artistNames=[[NSMutableArray alloc]init];
    for(MPMediaItemCollection *collection in artists)
    {
        MPMediaItem *item=[collection representativeItem];
        [artistNames addObject:[[item valueForProperty:MPMediaItemPropertyArtist]stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceAndNewlineCharacterSet]]];
    }
    uniqueNames=[[NSMutableArray alloc]init];

    for(id object in artistNames)
    {
        if(![uniqueNames containsObject:object])
        {
            [uniqueNames addObject:object];
        }
    }
    NSLog(@"%@",uniqueNames);

    PluginResult *pluginResult=[PluginResult resultWithStatus:PGCommandStatus_OK messageAsArray:uniqueNames];
    [self writeJavascript:[pluginResult toSuccessCallbackString:[arguments pop]]];

}

@end

Artist.js

var ArtistPlugin={};

ArtistPlugin.prototype.getArtistNames = function(types, success, fail)
{

          return PhoneGap.exec(success, fail, "Artist", "getArtistNames", types);
}

in index.html…

<script type="text/javascript" charset="utf-8" src="Artist.js"></script>

function onDeviceReady()
    {
        // do your thing!

        navigator.notification.alert("PhoneGap is working");
        alert('asdasd');
        var abc=Artist.getArtistNames(types, success, fail);

        alert(abc);
    }

Answer 1

A couple things:

1. It’s best to keep the names the same between your main class in Obj-C and JavaScript. In your case that would mean that either your Obj-C class should be called ArtistPlugin or the JavaScript object you create (and it’s filename) should be called Artist. I would go with all being called ArtistPlugin. Less likely to clash.

2. The final argument to PhoneGap.exec is an Array, so unless types is an array, it should probably look like: return PhoneGap.exec(success, fail, "Artist", "getArtistNames", [types]);

3. Lastly, make sure you have an entry in the plugins section of your PhoneGap.plist file. The key and value would be the homogenous name you chose from step #1 (i.e.: key: ArtistPlugin, value: ArtistPlugin).

Hope that helps.