Motion Layout reset on navigating between activities

问题

I am using motion layout in my mainactivity. It is working proplerly. However when I move to other activities and navigate back to my mainactivity sometimes the activity is reset and the layout is in its starting state.How do I keep this from happening ? Apart from this I also have another question about motion layout which I have asked here

回答1:

You can add a transition listener to the motion layout & save a flag when the transition is completed. Afterwards, when the activity gets recreated, you can read that flag and use smth like:

motionLayout.setState(R.id.end, ConstraintSet.WRAP_CONTENT, ConstraintSet.WRAP_CONTENT)

Where R.id.end is the id from constraintSetEnd property.

回答2:

You have to save/restore the progress of your MotionLayout:

    override fun onSaveInstanceState(outState: Bundle) {
        super.onSaveInstanceState(outState)
        outState.putFloat("progress", motionLayout.progress)
    }

    override fun onCreate(savedInstanceState: Bundle?) {
        ...
        if (savedInstanceState != null)
            motionLayout.progress = savedInstanceState.getFloat("progress", 0f)
        ...
    }

来源：https://stackoverflow.com/questions/54002303/motion-layout-reset-on-navigating-between-activities