Android animation not working with View Binding-CodePudding

So I was trying animation on Android using View Binding and it was not working, I tried the old way of getting views (findViewById()) and it happened to work just fine. Any answer to why View Binding doesn't work with animations? Thanks in advance for any answer. Here the example code:

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout 
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="@drawable/sopint_background"
tools:context=".MainActivity">


<TextView
    android:id="@ id/tvLogo"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:background="@drawable/rectangle_bordered"
    android:fontFamily="@font/aldrich"
    android:lineSpacingExtra="12sp"
    android:padding="20dp"
    android:text="I am a text"
    android:textAlignment="center"
    android:textColor="#FFFFFF"
    android:textSize="24sp"
    android:textStyle="bold"
    app:layout_constraintBottom_toBottomOf="parent"
    app:layout_constraintEnd_toEndOf="parent"
    app:layout_constraintStart_toStartOf="parent"
    app:layout_constraintTop_toTopOf="parent" />


</androidx.constraintlayout.widget.ConstraintLayout>

logo_animation.xml

<?xml version="1.0" encoding="utf-8"?>
<set xmlns:android="http://schemas.android.com/apk/res/android">

<translate
    android:duration="2000"
    android:fromXDelta="0%"
    android:fromYDelta="-50%" />
<alpha
    android:duration="1500"
    android:fromAlpha="0.1"
    android:toAlpha="1.0" />

</set>

and MainActivity.kt

class MainActivity : AppCompatActivity() {

//Binding
lateinit var binding: ActivityMainBinding

//Variables
lateinit var topAnimation: Animation
lateinit var logo: TextView

override fun onCreate(savedInstanceState: Bundle?) {
    super.onCreate(savedInstanceState)
    binding = ActivityMainBinding.inflate(layoutInflater)
    setContentView(binding.root)
    setContentView(R.layout.activity_main)
    
    logo = findViewById(R.id.tvLogo)
    topAnimation = AnimationUtils.loadAnimation(applicationContext, R.anim.logo_animation)
    logo.startAnimation(topAnimation)

    //This does not work
    //binding.tvLogo.startAnimation((topAnimation))

}

}

CodePudding user response：

binding = ActivityMainBinding.inflate(layoutInflater)
setContentView(binding.root)
setContentView(R.layout.activity_main)

What you're doing here is

inflating a layout, storing it in binding
displaying that inflated layout
replacing that and displaying another inflated copy of the layout

binding.tvLogo.startAnimation((topAnimation))

This doesn't work because you can't see it happening - you're animating the View on the first layout you inflated, but it's the second one that's being displayed, and you're not interacting with that.

logo = findViewById(R.id.tvLogo)
logo.startAnimation(topAnimation)

Whereas this one works because you're looking up tvLogo on the currently displayed layout (the second one) and then animating that View. Because it's the one on the screen, you see the results

Basically, if you ever find yourself inflating a layout more than once, that's a sign you're doing something wrong (there can be situations where you would, but in that case you'd know why you're doing it!). And the same goes for multiple setContentView calls