How to prevent Kotlin from caching the state of ImageView inside an included XML layout by several fragments/activities

Question

I have an XML layout named layout_image like this:

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:layout_width="match_parent"
android:layout_height="wrap_content">

    <ImageView
        android:id="@+id/imageView"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:src="@drawable/grumpy_cat"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

</android.support.constraint.ConstraintLayout>

I include the XML in several activites/fragments

<include
    android:id="@+id/llytImage"
    layout="@layout/layout_image"
    android:layout_width="match_parent"
    android:layout_height="wrap_content" />

I set a color filter on imageViewin Actitivty A by accessing it with kotlinx synthetic:

import kotlinx.android.synthetic.main.layout_image.view.*

llytImage.imageView.setColorFilter(Color.RED)

It becomes red and I navigate to Activity B. Activity B also includes the same XML layout with the same id. However, imageView is still red in Activity B.

It seems Kotlin caches the state of imageView and use the same view aiming better performance.

However, I don't want it to cache imageView. I need the default state. I tried 2 ways to prevent Kotlin from caching it:

Using @ContainerOptions(CacheImplementation.NO_CACHE) annotation in activities which include the XML
Calling imageView.clearFindViewByIdCache() when navigating to Activity B

None of them worked for me.

If you know the true solution, I will be very appreciated. Thanks

Are you sure you aren't manipulating the drawable rather than the image view? There is a 0% chance that the image view is being cached between activities, Android doesn't work that way. However the drawable can be, and you need to make a copy by calling mutate() on it before changing it, otherwise you effect all access to the base drawable. — Gabe Sechan, May 30 '19 at 13:43
@GabeSechan It caches the state when `Activity A -> Acitivty B`. It does not cache the state when `Activity A -> MainActivity -> Activity B` I will try `mutate()` method whether it works. — Egemen Hamutçu, May 30 '19 at 13:55
No, it doesn't. Views are specific to a single activity, they are not cached between them ever — Gabe Sechan, May 30 '19 at 13:56
Looked into the view caching annotation you mentioned. That's a flag to optimize lookups within an activity. It does not work between activities at all. — Gabe Sechan, May 30 '19 at 13:59

score 0 · Accepted Answer · answered May 30 '19 at 14:23

Manipulating the drawable rather than the image view by calling mutate() worked for me:

import kotlinx.android.synthetic.main.layout_image.view.*

val drawable = llytImage.imageView.drawable.mutate()
val colorFilter = PorterDuffColorFilter(Color.RED, PorterDuff.Mode.SRC_IN)
drawable.colorFilter = colorFilter

How to prevent Kotlin from caching the state of ImageView inside an included XML layout by several fragments/activities

1 Answers1