NullReferenceException in CropingRectangle.TouchBegin

[armin rasoulian]

I'm using this control to force user cropping image in square aspect ratio before uploading image to our server.

To do this first set all toolbar items invisible with the following method.

ImageEditor.SetToolbarItemVisibility("Text,Add,TextColor,FontFamily,Arial,Noteworthy,... ,  false);

Then set the source property of image editor:

ImageEditor.Source = ImageSource.FromStream(() => new MemoryStream(bytes));

Then on ImageLoaded event handler call this:

ImageEditor.ToggleCropping(1,1);

After user selects cropping area and pressed Crop button, the following code executes:

ImageEditor.Crop();
ImageEditor.ToggleCropping();

At this point, the header toolbar items (save, undo) will appear and the image will be properly cropped.

Now if the user touch on image we have the following exception: ( Stacktrace copied from hockeyapp)

CropingRectangle.TouchBegin 

android.runtime.JavaProxyThrowable: System.NullReferenceException: Object reference not set to an instance of an object 

Xamarin caused by: android.runtime.JavaProxyThrowable: System.NullReferenceException: Object reference not set to an instance of an object

Syncfusion.SfImageEditor.Android.CropingRectangle.TouchBegin(PointExt location)<7ad165d3dc074dfa8e99b8eae466a084>:0

Syncfusion.SfImageEditor.Android.CropingRectangle.OnTouchEvent(MotionEvent e)<7ad165d3dc074dfa8e99b8eae466a084>:0

Android.Views.View.n_OnTouchEvent_Landroid_view_MotionEvent_(IntPtr jnienv, IntPtr native__this, IntPtr native_e)<37d9e926f4d74728b29f22192d91a60d>:0

at (wrapper dynamic-method) System.Object.f312c808-6282-4695-8e57-6a1da602c7f4(intptr,intptr,intptr)

md5ee0b1c9c85cf2a7f14d638a8c0aa5d0f.CropingRectangle.n_onTouchEvent(Native Method)

md5ee0b1c9c85cf2a7f14d638a8c0aa5d0f.CropingRectangle.onTouchEvent()CropingRectangle.java:47

android.view.View.dispatchTouchEvent()View.java:9302

android.view.ViewGroup.dispatchTransformedTouchEvent()ViewGroup.java:2576

android.view.ViewGroup.dispatchTouchEvent()ViewGroup.java:2198

android.view.ViewGroup.dispatchTransformedTouchEvent()ViewGroup.java:2554

android.view.ViewGroup.dispatchTouchEvent()ViewGroup.java:2198

md51558244f76c53b6aeda52c8a337f2c37.VisualElementRenderer_1.n_dispatchTouchEvent(Native Method)

md51558244f76c53b6aeda52c8a337f2c37.VisualElementRenderer_1.dispatchTouchEvent()VisualElementRenderer_1.java:64

android.view.ViewGroup.dispatchTransformedTouchEvent()ViewGroup.java:2554

android.view.ViewGroup.dispatchTouchEvent()ViewGroup.java:2198

md5b5cbf9a5f989abac95309328170a059b.PopupPageRenderer.n_dispatchTouchEvent(Native Method)

md5b5cbf9a5f989abac95309328170a059b.PopupPageRenderer.dispatchTouchEvent()PopupPageRenderer.java:82

android.view.ViewGroup.dispatchTransformedTouchEvent()ViewGroup.java:2554

android.view.ViewGroup.dispatchTouchEvent()ViewGroup.java:2198

com.android.internal.policy.PhoneWindow$DecorView.superDispatchTouchEvent()PhoneWindow.java:2403

com.android.internal.policy.PhoneWindow.superDispatchTouchEvent()PhoneWindow.java:1737

android.app.Activity.dispatchTouchEvent()Activity.java:2843

md54045cd0ebe1c35dc2558553a65861a6c.MainActivity.n_dispatchTouchEvent(Native Method)

md54045cd0ebe1c35dc2558553a65861a6c.MainActivity.dispatchTouchEvent()MainActivity.java:42

android.support.v7.view.WindowCallbackWrapper.dispatchTouchEvent()WindowCallbackWrapper.java:68

android.support.v7.view.WindowCallbackWrapper.dispatchTouchEvent()WindowCallbackWrapper.java:68

com.android.internal.policy.PhoneWindow$DecorView.dispatchTouchEvent()PhoneWindow.java:2364

android.view.View.dispatchPointerEvent()View.java:9522

android.view.ViewRootImpl$ViewPostImeInputStage.processPointerEvent()ViewRootImpl.java:4248

android.view.ViewRootImpl$ViewPostImeInputStage.onProcess()ViewRootImpl.java:4101

android.view.ViewRootImpl$InputStage.deliver()ViewRootImpl.java:3647

android.view.ViewRootImpl$InputStage.onDeliverToNext()ViewRootImpl.java:3700

android.view.ViewRootImpl$InputStage.forward()ViewRootImpl.java:3666

android.view.ViewRootImpl$AsyncInputStage.forward()ViewRootImpl.java:3792

android.view.ViewRootImpl$InputStage.apply()ViewRootImpl.java:3674

android.view.ViewRootImpl$AsyncInputStage.apply()ViewRootImpl.java:3849

android.view.ViewRootImpl$InputStage.deliver()ViewRootImpl.java:3647

android.view.ViewRootImpl$InputStage.onDeliverToNext()ViewRootImpl.java:3700

android.view.ViewRootImpl$InputStage.forward()ViewRootImpl.java:3666

android.view.ViewRootImpl$InputStage.apply()ViewRootImpl.java:3674

android.view.ViewRootImpl$InputStage.deliver()ViewRootImpl.java:3647

android.view.ViewRootImpl.deliverInputEvent()ViewRootImpl.java:5944

android.view.ViewRootImpl.doProcessInputEvents()ViewRootImpl.java:5918

android.view.ViewRootImpl.enqueueInputEvent()ViewRootImpl.java:5879

android.view.ViewRootImpl$WindowInputEventReceiver.onInputEvent()ViewRootImpl.java:6047

android.view.InputEventReceiver.dispatchInputEvent()InputEventReceiver.java:185

android.os.MessageQueue.nativePollOnce(Native Method)

android.os.MessageQueue.next()MessageQueue.java:323

android.os.Looper.loop()Looper.java:135

android.app.ActivityThread.main()ActivityThread.java:5484

java.lang.reflect.Method.invoke(Native Method)

com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run()ZygoteInit.java:726

com.android.internal.os.ZygoteInit.main()ZygoteInit.java:616

[Michael Prabhu M]

Hi Armin, 

 

Greetings from Syncfusion, we have analyzed the reported issue and found this is caused because the ImageLoaded event is called twice (one during loading and the other after cropping which is an issue) and to overcome this issue please follow the below code snippet as a workaround. 

 

Code Snippet C# 

bool imageEditorLoaded;

void Editor_ImageLoaded(object sender, ImageLoadedEventArgs args)
{
   if (!imageEditorLoaded)
   {
      editor.ToggleCropping(1, 1);
      imageEditorLoaded = true;
   }
}

void Crop_Selected(object sender, System.EventArgs e)
{
   editor.Crop();
   // editor.ToggleCropping(); // No need to call this. 
} 

 

 

  

Meanwhile we will fix this issue in our Volume 2 SP 2 release which is scheduled to be rolled out at the end of August 2018. We appreciate your patience until then. 

 

Thanks, 

Michael