[안드로이드] ValueAnimator를 이용한 애니메이션 사용해보기

안녕하세요 남갯입니다.

오늘은 ValueAnimator와 ViewPager

를 이용한 회원가입 Step 만들기를 포스팅 해보려고합니다.

일단 회원가입 화면을 만듭니다.

<?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">

    <androidx.constraintlayout.widget.ConstraintLayout
        android:id="@+id/layoutRecordActionBar"
        android:layout_width="match_parent"
        android:layout_height="56dp"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintTop_toTopOf="parent">


        <TextView
            android:id="@+id/txtRecordTitle"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="회원가입"
            android:textColor="#000000"
            android:textSize="18sp"
            app:layout_constraintBottom_toBottomOf="parent"
            app:layout_constraintEnd_toEndOf="parent"
            app:layout_constraintStart_toStartOf="parent"
            app:layout_constraintTop_toTopOf="parent"
            tools:text="회원가입" />


    </androidx.constraintlayout.widget.ConstraintLayout>

    <LinearLayout
        android:id="@+id/layoutRecordProgressBar"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:animateLayoutChanges="true"
        android:weightSum="0.3"
        app:layout_constraintTop_toBottomOf="@+id/layoutRecordActionBar">

        <View
            android:id="@+id/viewRecordProgressColored"
            android:layout_width="0dp"
            android:layout_height="8dp"
            android:layout_weight="0.1"
            android:background="@color/colorPrimary" />

        <View
            android:id="@+id/viewRecordProgressNone"
            android:layout_width="0dp"
            android:layout_height="8dp"
            android:layout_weight="0.2"
            android:background="#cecece" />

    </LinearLayout>


    <androidx.viewpager.widget.ViewPager
        android:id="@+id/viewPagerRecord"
        android:layout_width="wrap_content"
        android:layout_height="0dp"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintTop_toBottomOf="@id/layoutRecordProgressBar" />


</androidx.constraintlayout.widget.ConstraintLayout>

여기서 중요한건 자신의 Step에 맞게 weighSum의 값을 조절해야합니다.

저는 3스텝으로 했으니 0.3으로 지정했습니다.

class MainViewPagerAdapter(
    fm: androidx.fragment.app.FragmentManager,
    private val fragmentList: ArrayList<Fragment>
) : androidx.fragment.app.FragmentStatePagerAdapter(
    fm, BEHAVIOR_RESUME_ONLY_CURRENT_FRAGMENT
) {
    override fun getItem(position: Int): Fragment = fragmentList[position]
    override fun getCount(): Int = fragmentList.size
}

ViewPager Adapter를 만듭니다.

class MainFragment : Fragment() {

    companion object {
        lateinit var drunkFragment: MainFragment

        fun newInstance(): MainFragment {
            synchronized(MainFragment::class) {
                drunkFragment = MainFragment()
                val args = Bundle()
                drunkFragment.arguments = args
                return drunkFragment
            }
        }
    }


    override fun onCreateView(
        inflater: LayoutInflater,
        container: ViewGroup?,
        savedInstanceState: Bundle?
    ): View? {
        return inflater.inflate(R.layout.fragment_main, container, false)
    }

    override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
        initRecyclerView()
        requestTodayDrunkList()
    }

    private fun initRecyclerView() {

    }

    private fun requestTodayDrunkList() {

    }



}

뷰페이저니까 뷰페이저를 구성할 프래그먼트를 생성한 뒤

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:orientation="vertical">

    <TextView
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="hello world!" />

</androidx.constraintlayout.widget.ConstraintLayout>

요건 xml

class MainActivity : AppCompatActivity() {

    private var progressPosition = 1

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)
        init()
    }



    private fun init() {
        initEvent()
        initViewPager()
    }

    private fun initEvent() {
    }


    private fun initViewPager() {
        //서버로 부터 받아온 페이지수 추가
        val fragmentList = ArrayList<Fragment>().apply {
            add(MainFragment.newInstance())
            add(MainFragment.newInstance())
            add(MainFragment.newInstance())
        }


        viewPagerRecord.apply {
            adapter = MainViewPagerAdapter(supportFragmentManager, fragmentList)
            offscreenPageLimit = 3
            currentItem = 0
            addOnPageChangeListener(object : ViewPager.OnPageChangeListener {
                override fun onPageScrollStateChanged(state: Int) {}
                override fun onPageScrolled(
                    position: Int,
                    positionOffset: Float,
                    positionOffsetPixels: Int
                ) {
                }

                override fun onPageSelected(position: Int) {
                    animateProgress(position)
                }
            })
        }
    }

    //progressAnimate
    fun animateProgress(position: Int) {
        val coloredWidthProgressAnimator: ValueAnimator = ValueAnimator.ofFloat(
            (PROGRESS_WEIGHT_STEP * progressPosition),
            (PROGRESS_WEIGHT_STEP * (position + 1))
        ).apply {
            duration = 300
            addUpdateListener {
                val value: Float = it.animatedValue as Float
                (viewRecordProgressColored.layoutParams as (LinearLayout.LayoutParams)).weight =
                    value
                viewRecordProgressColored.requestLayout()
            }
        }
        coloredWidthProgressAnimator.start()
        progressPosition = (position + 1)
    }

    companion object {
        const val PROGRESS_WEIGHT_STEP = 0.1f
    }
}

그 후 뷰페이저를 세팅하고 

valueAnimation을 세팅합니다.

아이템이 선택이 되면 animation을 동작시키도록 한 뒤

값이 변경됨에 따라 그 값에 맞춰 weight를 변경 하도록 합니다.

저는 아까 Sum = 0.3

0.1 -> 0.2 , 0.2 -> 0.3

색깔부분은 0.1로 초기 세팅을 했으니 시작값 -> 증가될값을 ValueAnimator에 세팅합니다.

해당 값이 업데이트 됨에따라 UpdateListener에서 weight를 변경하며 비율에 맞게 길이를 변경합니다.

코드는 아래의 링크에서 볼 수 있습니다

https://github.com/namget/ProgressAnimation

도움이 되셨다면 Star 부탁드립니다.