Question

I am making a call to Objective C from a PhoneGap application to perform functions with Dropbox.

The problem I am having is that my callback to JavaScript is firing before a file is downloaded from Dropbox to the phone’s local filesystem.

Here is my Objective C method that begins the file download from Dropbox –

- (void) restore:(CDVInvokedUrlCommand*)command
{

    CDVPluginResult* pluginResult = nil;
    NSString* javaScript = nil;
    NSLog(@"Dropbox restore method is executing");

    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
    NSString *documentsDirectory = [paths objectAtIndex:0]; // Get documents directory
    NSString *localPath = [documentsDirectory stringByAppendingPathComponent:@"PocketHealth-backup.bk"];
    NSString *dropBoxFile = @"/PocketHealth-backup.bk";

    [[self restClient] loadFile:dropBoxFile intoPath:localPath];

    pluginResult = [CDVPluginResult resultWithStatus:CDVCommandStatus_OK];
    javaScript = [pluginResult toSuccessCallbackString:command.callbackId];

    [self writeJavascript:javaScript];

}

There is a method in Objective C that executes when the Dropbox file has been downloaded to the phone. I do get the NSLog that this method outputs after the Dropbox file download is complete. The problem is that I need to know when this event happens before I can return my JavaScript callback.

Here is the method that executes when the Dropbox file download is complete –

- (void) restClient:(DBRestClient*)client loadedFile:(NSString*)localPath 
{
    NSLog(@"File loaded into path: %@", localPath);
}

How can I wait until the Dropbox file download is complete before returning the JavaScript callback that is in the restore method?

Answer 1

Instead of writing the JavaScript into a local variable inside your restore method, add it as an iVar to your class, remove the call to writeJavascript: in your restore method and call writeJavascript from restClient:loadedFile:. Then it should get called when the download finished instead of when the actual download is started.

- (void) restore:(CDVInvokedUrlCommand*)command
{

    CDVPluginResult* pluginResult = nil;
    NSLog(@"Dropbox restore method is executing");

    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
    NSString *documentsDirectory = [paths objectAtIndex:0]; // Get documents directory
    NSString *localPath = [documentsDirectory stringByAppendingPathComponent:@"PocketHealth-backup.bk"];
    NSString *dropBoxFile = @"/PocketHealth-backup.bk";

    [[self restClient] loadFile:dropBoxFile intoPath:localPath];

    pluginResult = [CDVPluginResult resultWithStatus:CDVCommandStatus_OK];
    self.javaScript = [pluginResult toSuccessCallbackString:command.callbackId];
}

- (void) restClient:(DBRestClient*)client loadedFile:(NSString*)localPath 
{
    NSLog(@"File loaded into path: %@", localPath);
    [self writeJavascript:javaScript];
}