[Android] Fix to Issue Java.Lang.IndexOutOfBoundsException: setSpan

[Transis-Felipe]

Fix to Issue #12762
Java.Lang.IndexOutOfBoundsException: setSpan (nn ... nn) ends beyond length n-1

[rmarinho]

I m not sure this is the right fix.. Maybe we need something like this:

void UpdateText()
{
	if (EditText == null || Element == null)
		return;

	var text = Element.UpdateFormsText(Element.Text, Element.TextTransform);

	if (EditText.Text == text)
		return;

	EditText.Text = text;
	if (EditText.IsFocused)
	{
		EditText.SetSelection(EditText.Text.Length);
		EditText.ShowKeyboard();
	}
}

[Transis-Felipe]

@rmarinho Yes, your solution is better.
Just to learn: You set the text to entry and the control will limit the size of string. So, it will never have an selection bigger than the size of the field, right?

Do you want to create an PR or I can change mine with your suggestion?

[rmarinho]

@transis2 yes that's my idea, or with the check above if EditText is null (was disposed) we just return to also make it safer.

I tried to reproduce this issue with a number ways but wasn't able, but that's the only idea i have right now to try to fix it.
You can update your PR.

[Transis-Felipe]

@rmarinho Update the PR with your suggestion.

Thanks!

[Transis-Felipe]

Hi @rmarinho

Our PR is showing that some checks were not successful.
May I create a new one from the latest XF version ?

[rmarinho]

@transis2 i think i fixed the issue, running a new build and tests

[felipemomm]

@rmarinho When is it going to be merged? I am facing the same issue in my project, so I had to implement my own UpdateText method on OnElementPropertyChanged to avoid it (XF 4.8).

Basically, I am receiving a text longer than the Entry's maxLen from the backend, it shows only up to the maxLen, however when I tap in the field to edit the text, it crashes.

[nrmiller]

@rmarinho Is this PR still being considered? It looks like it has been around for awhile, and I'm running into this error as late as Xamarin.Forms 5.0.0.2021 on a Google Pixel 3 XL

My scenario to trigger this bug with 100% reliability:

1. Set Entry.MaxLength to 5 via XAML
2. Enter "3910" with numeric keyboard.
3. Without dismissing the keyboard, tap a radio button* to trigger setting the text to "1539.37" via a view-model property.

*Specifically, I have two radio buttons (1 for centimeters and 1 for inches). The goal is to convert what the user enters upon changing the select radio button. Because converting 3910cm yields 1539.37in and because "1539.37" > 5 characters, the crash occurs.
I tried to trigger this issue by creating a simple button and setting the Text to "000000" in the bound view-model command. This did not work, so I'm assuming something tricky is happening specifically with triggering via RadioButtonGroup.SelectedValue. Perhaps this is related to how MessagingCenter is used under the hood?

FWIW, here's the stacktrace from the Xamarin Forms side (I'm stilling getting the IndexOutOfBounds on the Android side):

TargetInvocationException: Exception has been thrown by the target of an invocation.
      at System.Reflection.RuntimeMethodInfo.Invoke (System.Object obj, System.Reflection.BindingFlags invokeAttr, System.Reflection.Binder binder, System.Object[] parameters, System.Globalization.CultureInfo culture) [0x00086] in <98fdeeb5cad34f67b78b105df850970d>:0 
      at System.Reflection.MethodBase.Invoke (System.Object obj, System.Object[] parameters) [0x00000] in <98fdeeb5cad34f67b78b105df850970d>:0 
      at Xamarin.Forms.MessagingCenter+Subscription.InvokeCallback (System.Object sender, System.Object args) [0x00076] in <978ec34c5c9c4c4eb3d73b6da958bcd6>:0 
      at Xamarin.Forms.MessagingCenter.InnerSend (System.String message, System.Type senderType, System.Type argType, System.Object sender, System.Object args) [0x0006b] in <978ec34c5c9c4c4eb3d73b6da958bcd6>:0 
      at Xamarin.Forms.MessagingCenter.Xamarin.Forms.IMessagingCenter.Send[TSender,TArgs] (TSender sender, System.String message, TArgs args) [0x00013] in <978ec34c5c9c4c4eb3d73b6da958bcd6>:0 
      at Xamarin.Forms.MessagingCenter.Send[TSender,TArgs] (TSender sender, System.String message, TArgs args) [0x00005] in <978ec34c5c9c4c4eb3d73b6da958bcd6>:0 
      at Xamarin.Forms.RadioButtonGroup.UpdateRadioButtonGroup (Xamarin.Forms.RadioButton radioButton) [0x00028] in <978ec34c5c9c4c4eb3d73b6da958bcd6>:0 
      at Xamarin.Forms.RadioButton.OnIsCheckedPropertyChanged (System.Boolean isChecked) [0x00003] in <978ec34c5c9c4c4eb3d73b6da958bcd6>:0 
      at Xamarin.Forms.RadioButton+<>c.<.cctor>b__116_1 (Xamarin.Forms.BindableObject b, System.Object o, System.Object n) [0x00000] in <978ec34c5c9c4c4eb3d73b6da958bcd6>:0 
      at Xamarin.Forms.BindableObject.SetValueActual (Xamarin.Forms.BindableProperty property, Xamarin.Forms.BindableObject+BindablePropertyContext context, System.Object value, System.Boolean currentlyApplying, Xamarin.Forms.Internals.SetValueFlags attributes, System.Boolean silent) [0x0012a] in <978ec34c5c9c4c4eb3d73b6da958bcd6>:0 
      at Xamarin.Forms.BindableObject.SetValueCore (Xamarin.Forms.BindableProperty property, System.Object value, Xamarin.Forms.Internals.SetValueFlags attributes, Xamarin.Forms.BindableObject+SetValuePrivateFlags privateAttributes) [0x00173] in <978ec34c5c9c4c4eb3d73b6da958bcd6>:0 
      at Xamarin.Forms.BindableObject.SetValue (Xamarin.Forms.BindableProperty property, System.Object value, System.Boolean fromStyle, System.Boolean checkAccess) [0x0004d] in <978ec34c5c9c4c4eb3d73b6da958bcd6>:0 
      at Xamarin.Forms.BindableObject.SetValue (Xamarin.Forms.BindableProperty property, System.Object value) [0x00000] in <978ec34c5c9c4c4eb3d73b6da958bcd6>:0 
      at Xamarin.Forms.RadioButton.set_IsChecked (System.Boolean value) [0x00000] in <978ec34c5c9c4c4eb3d73b6da958bcd6>:0 
      at Xamarin.Forms.RadioButton.SelectRadioButton (System.Object sender, System.EventArgs e) [0x00008] in <978ec34c5c9c4c4eb3d73b6da958bcd6>:0 
      at Xamarin.Forms.TapGestureRecognizer.SendTapped (Xamarin.Forms.View sender) [0x0003b] in <978ec34c5c9c4c4eb3d73b6da958bcd6>:0 
      at Xamarin.Forms.Platform.Android.TapGestureHandler.OnTap (System.Int32 count, Xamarin.Forms.Point point) [0x000a2] in <04c545f414d24a37af95d995791bb9a9>:0 
      at Xamarin.Forms.Platform.Android.InnerGestureListener.Android.Views.GestureDetector.IOnGestureListener.OnSingleTapUp (Android.Views.MotionEvent e) [0x0002e] in <04c545f414d24a37af95d995791bb9a9>:0 
      at Android.Views.GestureDetector+IOnGestureListenerInvoker.n_OnSingleTapUp_Landroid_view_MotionEvent_ (System.IntPtr jnienv, System.IntPtr native__this, System.IntPtr native_e) [0x0000f] in <cdf69449759145adbc699e96b2eb3764>:0 
        at (wrapper dynamic-method) Android.Runtime.DynamicMethodNameCounter.140(intptr,intptr,intptr)