Implementation of UIImageWriteToSavedPhotosAlbum in the Cordova plugin.

PhotosAlbum.m

#import "PhotosAlbum.h"
#import <Cordova/CDV.h>

@implementation PhotosAlbum

- (void)saveImageToPhotosAlbum:(CDVInvokedUrlCommand *)command {
    [self.commandDelegate runInBackground : ^{
        NSString *base64String = [command.arguments objectAtIndex:0];
        NSData *imageData = [[NSData alloc] initWithBase64EncodedString:base64String options:0];
        UIImage *image = [UIImage imageWithData:imageData];
        UIImageWriteToSavedPhotosAlbum(image, self, @selector(image:didFinishSavingWithError:contextInfo:), nil);
        
        // selector内で成功/失敗の結果を返却するので、このスレッドは NO_RESULT, setKeepCallbackAsBool:YES で終える
        CDVPluginResult *pluginResult = [CDVPluginResult resultWithStatus:CDVCommandStatus_NO_RESULT];
        [pluginResult setKeepCallbackAsBool:YES];
        [self.commandDelegate sendPluginResult:pluginResult callbackId:command.callbackId];
    }];
}

- (void)image:(UIImage *)image didFinishSavingWithError:(NSError *)error contextInfo:(void *)contextInfo {
    CDVPluginResult* pluginResult = nil;
    if (error != nil) {
        pluginResult = [CDVPluginResult resultWithStatus:CDVCommandStatus_ERROR messageAsString:[error localizedDescription]];
    } else {
        pluginResult = [CDVPluginResult resultWithStatus:CDVCommandStatus_OK messageAsString:@"The image was successfully saved to your Photo Library."];
    }
    
    [pluginResult setKeepCallbackAsBool:YES];
    [self.commandDelegate sendPluginResult:pluginResult callbackId:self.callbackId];
}

@end