self.downloadButton.initialTitle = @"Download";
self.downloadButton.completeTitle = @"Open";
// Add a target (like a regular button)
[self.downloadButton addTarget:self action:@selector(downloadButtonPressed:) forControlEvents:UIControlEventTouchUpInside];
-(void)downloadButtonPressed:(id)sender {
    // Update the button's state based on your downloading item's state
    if(!self.isDownloading && !self.isDownloaded) {
        [self.downloadButton startProgressing];
        [self downloadItem];
    } else if(self.isDownloaded) {
        [self openItem];
    } else {
        [self cancelDownloadingItem];
        [self.downloadButton setProgress:0 animated:YES withCompletion:^{
            [self.downloadButton reset];
        }];
    }
}
-(void)downloadProgressed:(CGFloat)progress {
  // Update the download button's progress when you get a progress update from your item
  [self.downloadButton setProgress:progress animated:YES];
}

self.downloadButton.tintColor = [UIColor redColor];