Screanshot

alipishkari

Hi, I want to make an screanshot in IOS. not from my app,
I want to minimize my app and then make an screanshot.
Please help me.

LucasZhang

We could not capture the screenshot of HomePage in code manually because of apple policy . But we could get the image when user click the lock button and volume + button .

in AppDelegate

Firstly, you need to add the permission string in the info.plist:

<key>NSPhotoLibraryUsageDescription</key>
<string> photos description. </string>

Then request the dynamic authorization in the method FinishedLaunching like:

PHPhotoLibrary.RequestAuthorization((status) =>
{
   switch (status)
   {
       case PHAuthorizationStatus.Authorized:
           {
               Debug.WriteLine(“Authorized to access”);
               break;
           }
       case PHAuthorizationStatus.Denied: case PHAuthorizationStatus.Restricted:
           {
               Debug.WriteLine(“Not allowed”);
               break;
           }
       default:
           {
               Debug.WriteLine(“Not determined”);
               break;
           }
   }
});

Add the notification in the method FinishedLaunching so that the app will get the notification when user capture the screen shot .

using ObjCRuntime;
using AssetsLibrary;
using Photos;

 NSNotificationCenter.DefaultCenter.AddObserver(this,new Selector("IsScreenShot:"),UIApplication.UserDidTakeScreenshotNotification,null);
NSNotificationCenter.DefaultCenter.AddObserver(this, new Selector("GetScreenShot:"), UIApplication.UserDidTakeScreenshotNotification, null);

        bool isScreenShot;  

        [Export("IsScreenShot:")]
        void IsScreenShot(NSNotification notification)
        {
            ALAuthorizationStatus kStatus = ALAssetsLibrary.AuthorizationStatus;
            if (kStatus == ALAuthorizationStatus.Authorized)
            {
                isScreenShot = true;
            }
        }

        //get screenshot (the first photo in album)
        [Export("GetScreenShot:")]
        void GetScreenShot(NSNotification notification)
        {
            if(isScreenShot)
            {
                PHImageRequestOptions options = new PHImageRequestOptions();
                options.ResizeMode = PHImageRequestOptionsResizeMode.Fast;
                options.DeliveryMode = PHImageRequestOptionsDeliveryMode.FastFormat;
                options.Synchronous = true;

                var assets = PHAsset.FetchAssets(PHAssetMediaType.Image, null);
                PHImageManager manager = new PHImageManager();

                var LastAsset = assets[0] as PHAsset;
                manager.RequestImageForAsset(LastAsset, PHImageManager.MaximumSize, PHImageContentMode.Default, options,
                                               (image, info) =>
                                               {
                                                     //image is the screen shot , do something you want 
                                               });
            }

            isScreenShot = false;

        }