Photos Framework. requestImageForAsset returning two results. Can't set image view

Question

So I am using the SwipeView library (https://github.com/nicklockwood/SwipeView) to show images using the Photos framework for iOS8.

However, when I call the requestImageForAsset I notice I am getting two results, a thumbnail size, and the bigger size that I want. However, the bigger image isn't loaded (it's called async I understand) in time to return, so it returns the small image.

This code might make more sense.

    func swipeView(swipeView: SwipeView!, viewForItemAtIndex index: Int, reusingView view: UIView!) -> UIView! {
            let asset: PHAsset = self.photosAsset[index] as PHAsset

    var imageView: UIImageView!

    let screenSize: CGSize = UIScreen.mainScreen().bounds.size
    let targetSize = CGSizeMake(screenSize.width, screenSize.height)


    var options = PHImageRequestOptions()
//        options.deliveryMode = PHImageRequestOptionsDeliveryMode.Opportunistic
    options.resizeMode = PHImageRequestOptionsResizeMode.Exact


    PHImageManager.defaultManager().requestImageForAsset(asset, targetSize: targetSize, contentMode: .AspectFill, options: options, resultHandler: {(result, info)in
        println("huhuhuh")
        println(result.size)
        println(info)
        imageView = UIImageView(image: result)
    })
    println("setting view)
    return imageView
}

Here is the log output:

Enteredhuhuhuh
(33.5,60.0)
SETTING VIEW
huhuhuh
(320.0,568.0)

As you can see it returns the image view before the big image is recieved. How do I make it return this larger image so it's not showing the thumbnai?

Thanks.

Answer 1

Read header of PHImageManager class

If -[PHImageRequestOptions isSynchronous] returns NO (or options is nil), resultHandler may be called 1 or more times. Typically in this case, resultHandler will be called asynchronously on the main thread with the requested results. However, if deliveryMode = PHImageRequestOptionsDeliveryModeOpportunistic, resultHandler may be called synchronously on the calling thread if any image data is immediately available. If the image data returned in this first pass is of insufficient quality, resultHandler will be called again, asychronously on the main thread at a later time with the "correct" results. If the request is cancelled, resultHandler may not be called at all. If -[PHImageRequestOptions isSynchronous] returns YES, resultHandler will be called exactly once, synchronously and on the calling thread. Synchronous requests cannot be cancelled. resultHandler for asynchronous requests, always called on main thread

So, what you want to do is that you make resultHandler to be called synchronously

PHImageRequestOptions *option = [PHImageRequestOptions new];
option.synchronous = YES;

[[PHImageManager defaultManager] requestImageForAsset:asset targetSize:target contentMode:PHImageContentModeAspectFill options:option resultHandler:^(UIImage *result, NSDictionary *info) {
        //this block will be called synchronously
}];

So your block will be called before ending your method

Good luck!