Transition in MotionLayout causing TextInputLayout setError message not work in Android 9

问题

I have created a sample project on github Please check it out to reproduce the problem I am facing.

Project Structure: I have basic TabLayout and Viewpager in MainActivity. I also have FirstFragment and SecondFragment which are hosted by my TabLayout. Everything fairly simple and straightforward there. Look at the screenshots:

Layout of MainActivity has MotionLayout as the root layout. When user moves from FirstFragment to SecondFragment, I increase the size of the CardView. My transition code in transition.xml:

<MotionScene
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:motion="http://schemas.android.com/apk/res-auto">

    <Transition
        motion:duration="200"
        motion:constraintSetEnd="@+id/end"
        motion:constraintSetStart="@+id/start">
    </Transition>

    <ConstraintSet android:id="@+id/start">
        <Constraint
            android:id="@+id/cardView"
            android:layout_width="0dp"
            android:layout_height="200dp"
            android:layout_marginStart="16dp"
            android:layout_marginTop="16dp"
            android:layout_marginEnd="16dp"
            motion:layout_constraintEnd_toEndOf="parent"
            motion:layout_constraintStart_toStartOf="parent"
            motion:layout_constraintTop_toTopOf="parent" />
    </ConstraintSet>

    <ConstraintSet android:id="@+id/end">
        <Constraint
            android:id="@+id/cardView"
            android:layout_width="0dp"
            android:layout_height="400dp"
            android:layout_marginStart="16dp"
            android:layout_marginTop="16dp"
            android:layout_marginEnd="16dp"
            motion:layout_constraintEnd_toEndOf="parent"
            motion:layout_constraintStart_toStartOf="parent"
            motion:layout_constraintTop_toTopOf="parent" />
    </ConstraintSet>
</MotionScene>

As you can see in the screenshots, SecondFragment has TextInputLayout and a continue Button. When Button is pressed, I check if the EditText is empty or not. If so, I set error message to TextInputLayout. When user enters some text and tries to continue again, I remove the error message from TextInputLayout. But, problem is that the extra space (that is added by TextInputLayout) to show error message is not being removed.

How I am removing the error message in MainActivity:

btnSurnameContinue.setOnClickListener {
            if(etSurname.text.isNullOrEmpty()) {
                tilSurname.isErrorEnabled = true
                tilSurname.error = "Oops empty detected"
            } else {
                tilSurname.error = ""
                tilSurname.isErrorEnabled = false
            }
        }

I have test and this issue is happening in Android 9 and Android 8. I checked the same issue on Android 5.0 and it worked pretty fine. I think the problem is specific to Android 9 and Android 8. I have not tested in other versions though.

IMPORTANT NOTE 1: If I remove app:layoutDescription="@xml/transition" from the MotionLayout in activity_main.xml, everything is working fine! But removing this means that there will be no animation. What is the point of using MotionLayout then?

IMPORTANT NOTE 2: After the issue happens, if I swipe to FirstFragment and come back to SecondFragment, everything starts to work fine. The extra space (which was added because of the error message) will also disappear. Also, error messages (which did not appear at first) starts to appear again (see Additional Problems 2 and 3). It is very strange. I am thinking this swipe back to FirstFragment and returning to SecondFragment back is causing the SecondFragment to re-render itself. Therefore, I am guessing everything starts to work/look correctly. What do you think? May be I am wrong here.

The problem gets even worse when you have mutiple TextInputLayouts in the SecondFragment. (I have only included one TextInputLayout for simplicity in the sample project). So the problems are:

Additional Problems:

1. When error is removed, the extra space added to show error is not dissappearing. (This is the main issue that I have explained above).
2. Sometimes, error messages are not even being shown. TextInputLayout is colored with accent color only and no error message shown at all.
3. Resetting error message to some other lengthier message causes the error message to be shown partially. Full error message will never be shown.

Please, checkout the github sample project.

来源：https://stackoverflow.com/questions/59968915/transition-in-motionlayout-causing-textinputlayout-seterror-message-not-work-in