Varargs Kotlin Java interop not working properly

Question

For the makeSceneTransitionAnimation there are two static functions

public static ActivityOptionsCompat makeSceneTransitionAnimation(Activity activity,
        View sharedElement, String sharedElementName)

and

    public static ActivityOptionsCompat makeSceneTransitionAnimation(Activity activity,
        Pair<View, String>... sharedElements)

The first function call works properly in Kotlin but when calling the second one, both these calls return errors

        val imageTransition = Pair<View, String>(imageView, imageView.getTransitionName());
        val textTransition = Pair<View, String>(textView, textView.getTransitionName());
        val transitionList = Array(2, { imageTransition });
        transitionList[1] = textTransition;
        val options = ActivityOptionsCompat.makeSceneTransitionAnimation(this, *transitionList);

and

        val imageTransition = Pair<View, String>(imageView, imageView.getTransitionName());
        val textTransition = Pair<View, String>(textView, textView.getTransitionName());
        val options = ActivityOptionsCompat.makeSceneTransitionAnimation(this, imageTransition, textTransition);

Is there a proper way to get this working or is this an issue with the interop?

Edit Added change to ensure that it is using the same classes

val imageView : View = view.findViewById(android.R.id.icon);
val textView : View = view.findViewById(android.R.id.text1);
imageView.setTransitionName("imageTransition");
textView.setTransitionName("textTransition")

val imageTransition : android.support.v4.util.Pair<android.view.View, java.lang.String> = android.support.v4.util.Pair.create(imageView, imageView.getTransitionName() as java.lang.String);
val textTransition : android.support.v4.util.Pair<android.view.View, java.lang.String> = android.support.v4.util.Pair.create(textView, textView.getTransitionName() as java.lang.String);
val transitionList = Array(2, { imageTransition });
transitionList[1] = textTransition;
val options = ActivityOptionsCompat.makeSceneTransitionAnimation(this, *transitionList);

Current compiler error:

Error:(72, 84) The spread operator (*foo) may only be applied in a vararg position
Error:(72, 99) No value passed for parameter sharedElementName

And another

val imageView : View = view.findViewById(android.R.id.icon);
val textView : View = view.findViewById(android.R.id.text1);
imageView.setTransitionName("imageTransition");
textView.setTransitionName("textTransition")

val imageTransition : android.support.v4.util.Pair<android.view.View, java.lang.String> = android.support.v4.util.Pair.create(imageView, imageView.getTransitionName() as java.lang.String);
val textTransition : android.support.v4.util.Pair<android.view.View, java.lang.String> = android.support.v4.util.Pair.create(textView, textView.getTransitionName() as java.lang.String);
val options = ActivityOptionsCompat.makeSceneTransitionAnimation(this, imageTransition, textTransition);

Current compiler error:

Error:(72, 84) Type mismatch: inferred type is android.support.v4.util.Pair<android.view.View, java.lang.String> but android.view.View! was expected
Error:(72, 101) Type mismatch: inferred type is android.support.v4.util.Pair<android.view.View, java.lang.String> but kotlin.String! was expected

What are the errors the compiler is reporting on these examples? — Andrey Breslav, Sep 16 '15 at 06:31
Error:(70, 84) The spread operator (*foo) may only be applied in a vararg position and Error:(70, 84) Type mismatch: inferred type is kotlin.Pair but android.view.View! was expected Error:(70, 101) Type mismatch: inferred type is kotlin.Pair but kotlin.String! was expected — Josh Feinberg, Sep 16 '15 at 13:02

score 11 · Accepted Answer · answered Sep 23 '15 at 13:37

The answer is the * symbol before array variable:

import android.support.v4.util.Pair as AndroidPair

// ...    

val pair1 = AndroidPair<View, String>(fab, 
    getString(R.string.transition_fab))
val pair2 = AndroidPair<View, String>(findViewById(R.id.app_bar),
    getString(R.string.transition_appbar))

ActivityOptionsCompat.makeSceneTransitionAnimation(this@MyActivity,
    *arrayOf(pair1, pair2)).toBundle();

score 4 · Answer 2 · answered Jul 15 '17 at 18:19

This worked for me:

import android.support.v4.util.Pair

// ...    

val options = ActivityOptionsCompat.makeSceneTransitionAnimation(activity,
        Pair<View, String>(image, image.transitionName),
        Pair<View, String>(title, title.transitionName))

startActivity(intent, options.toBundle())

score 2 · Answer 3 · answered Sep 16 '15 at 13:27

2

It may be the case that you're accidentally using kotlin.Pair instead of android.util.Pair. Please add the following import directive to the beginning of your file:

import android.util.Pair

answered Sep 16 '15 at 13:27

Alexander Udalov

31,429
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Nope, even tried doing `android.util.Pair.create(imageView, imageView.getTransitionName());` – Josh Feinberg Sep 17 '15 at 00:09
Does the compilation error message change after you do that? – Alexander Udalov Sep 18 '15 at 00:18
Well, the error message mentions kotlin.Pair so it must be used somehow in your code, unless there's something weird going on. Please try to create a [minimal reproducible sample](http://stackoverflow.com/help/mcve) and post the Kotlin code here so that we can investigate and help you. Thanks! – Alexander Udalov Sep 19 '15 at 01:46
I have updated my answer with what I believe to be a minimal reproducible sample. thank you for the help – Josh Feinberg Sep 19 '15 at 05:35

score 1 · Answer 4 · answered Feb 04 '19 at 04:39

This is a whole code snippet I would recommend for :

companion object {
    const val EXTRA_ITEM = "EXTRA_ITEM"
    const val TRANSITION_NAME_IMAGE = "TRANSITION_NAME_IMAGE"
    const val TRANSITION_NAME_TEXT = "TRANSITION_NAME_TEXT"
  }

  override fun onItemClick(pos: Int, item: Item, imageView: ImageView, textView: TextView) {
    val intent = Intent(context, YourActivity::class.java)
    intent.putExtra(EXTRA_ITEM, item)
    intent.putExtra(
      TRANSITION_NAME_IMAGE,
      ViewCompat.getTransitionName(imageView)
    )
    intent.putExtra(
      TRANSITION_NAME_TEXT,
      ViewCompat.getTransitionName(textView)
    )

    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
      val optionsCompat = ActivityOptionsCompat.makeSceneTransitionAnimation(
        context as Activity,
        androidx.core.util.Pair<View,String>(imageView, imageView.transitionName),
        androidx.core.util.Pair<View,String>(textView, textView.transitionName)
      )
      startActivity(intent, optionsCompat.toBundle())
    } else {
      startActivity(intent)
    }
  }

You have to also implement this method for transaction in your activity for back to Previous screen .

override fun onOptionsItemSelected(item: MenuItem): Boolean {
    val id = item.itemId
    if (id == android.R.id.home) {
      supportFinishAfterTransition()
      return true
    }
    return super.onOptionsItemSelected(item)
  }

Exact. Only this works! With androidx.core.util and making cast context as Activity or with AppCompatActivity. Congratulations! — Paulo Linhares - Packapps, Mar 13 '19 at 14:03

score 0 · Answer 5 · answered Oct 11 '18 at 02:12

0

The key is to initiate your Pair like this: Pair<View, String>(view, string) otherwise it complains.

answered Oct 11 '18 at 02:12

Joshua King

3,450
1
17
19

Varargs Kotlin Java interop not working properly

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