CODEWITHSUNDEEP
androidandroid-constraintlayoutandroid-motionlayout
Johan Paul
Johan Paul

Reputation: 2456

MotionLayout <KeyPosition> cannot find attribute 'target'

I am using ConstraintLayout 2.0 to do some MotionLayout animations. I updated my ConstraintLayout 2.0 from alpha-3 to beta-3 and now when compiling, it complaints

src/main/res/xml/scene.xml:11: AAPT: error: attribute target (aka com.myapp:target) not found.

I didn't change anything in my MotionLayout scene file. Here's the offending parts:

  <MotionScene
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:motion="http://schemas.android.com/apk/res-auto"> 
...
     <Transition
        motion:constraintSetStart="@+id/start"
        motion:constraintSetEnd="@+id/end"
        motion:duration="1000">

        <KeyFrameSet>
            <KeyPosition
                motion:target="@+id/accent_background" <<-- Here
                motion:framePosition="80"
                motion:percentX="1"
                motion:percentY="1" />

I looked at the documentation of MotionLayout and to me this has not changed, but the target is still defined like that. Or am I missing something?

I did clear the cache and try to rebuild, but it didn't help.

Upvotes: 1

Views: 1242

Answers (1)

Johan Paul
Johan Paul

Reputation: 2456

Solved it.

The attribute has been renamed to motionTarget. So the definition should be

<KeyFrameSet>
   <KeyPosition
       motion:motionTarget="@+id/accent_background"
       motion:framePosition="80"
       motion:percentX="1"
       motion:percentY="1" />

The MotionLayout blog posts by Google (https://medium.com/google-developers/introduction-to-motionlayout-part-i-29208674b10d) have the old attribute names, but documentation has them updated (https://developer.android.com/reference/android/support/constraint/motion/MotionLayout#keyposition)

Upvotes: 10

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