将现有项目中的现有 kotlin 文件迁移到 Jetpack Compose

Question

我已更新到 Kotlin 1.5.20，并且我看到 Google 打算让 Jetpack Compose 成为设计 UI 的首选选项。我想问我是否可以将我在 Kotlin 中为设计部分预先编写的代码迁移到 Jetpack Compose（因为我们可以将 Java 文件迁移到 Android Studio 中的 Kotlin）。

示例代码：

import android.animation.ArgbEvaluator
import android.animation.ValueAnimator
import android.graphics.Color
import android.os.Bundle
import android.view.View
import android.widget.ImageButton
import android.widget.TextView
import androidx.appcompat.app.AppCompatActivity
import androidx.constraintlayout.widget.ConstraintSet
import androidx.transition.TransitionManager
import kotlinx.android.synthetic.main.activity_main.*
import java.util.*


class MainActivity : AppCompatActivity() {

    private lateinit var coverImage: View
    private lateinit var menuButton: ImageButton
    private lateinit var movieStatus: TextView
    private lateinit var movieTitle: TextView
    private lateinit var movieDescription: TextView
    private lateinit var movieRating: TextView
    private lateinit var descriptionButton: ImageButton

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)

        window.decorView.systemUiVisibility = (View.SYSTEM_UI_FLAG_FULLSCREEN)

        setContentView(R.layout.activity_main)

        addConstraintSetAnimation()
    }

    private fun addConstraintSetAnimation() {
        coverImage = cover
        menuButton = menu_button
        movieStatus = status
        movieTitle = movie_title
        movieDescription = desc
        movieRating = rating
        descriptionButton = description_button

        var isCoverView = false
        var isDescriptionView = false

        val initialConstraint = ConstraintSet()
        initialConstraint.clone(root)

        val coverConstraint = ConstraintSet()
        coverConstraint.clone(this, R.layout.cover_view)

        val descriptionConstraint = ConstraintSet()
        descriptionConstraint.clone(this, R.layout.description_view)

        val mapOfDays: Map<TextView, TextView> = mapOf(
            day_1 to date_1,
            day_2 to date_2,
            day_3 to date_3,
            day_4 to date_4,
            day_5 to date_5,
            day_6 to date_6,
            day_7 to date_7
        )

        val days: List<TextView> = listOf(day_1, day_2, day_3, day_4, day_5, day_6, day_7)

        for (day in days) {
            day.setOnClickListener { selectDate(it as TextView, descriptionConstraint) }
        }

        for (day in mapOfDays) {
            day.value.setOnClickListener { selectDate(day.key, descriptionConstraint) }
        }

        coverImage.setOnClickListener {
            if (!isCoverView) {
                TransitionManager.beginDelayedTransition(root)
                coverConstraint.applyTo(root)

                val anim = ValueAnimator()
                anim.setIntValues(Color.BLACK, Color.WHITE)
                anim.setEvaluator(ArgbEvaluator())
                anim.addUpdateListener {
                    menuButton.setColorFilter(it.animatedValue as Int)
                    movieStatus.setTextColor(it.animatedValue as Int)
                    movieTitle.setTextColor(it.animatedValue as Int)
                    movieDescription.setTextColor(it.animatedValue as Int)
                    movieRating.setTextColor(it.animatedValue as Int)
                    descriptionButton.setColorFilter(it.animatedValue as Int)
                }

                anim.duration = 300
                anim.start()
                isCoverView = true
                isDescriptionView = false
            }

        }

        menuButton.setOnClickListener {
            if (isCoverView) {
                TransitionManager.beginDelayedTransition(root)
                initialConstraint.applyTo(root)

                val anim = ValueAnimator()
                anim.setIntValues(Color.WHITE, Color.BLACK)
                anim.setEvaluator(ArgbEvaluator())
                anim.addUpdateListener {
                    menuButton.setColorFilter(it.animatedValue as Int)
                    movieStatus.setTextColor(it.animatedValue as Int)
                    movieTitle.setTextColor(it.animatedValue as Int)
                    movieDescription.setTextColor(it.animatedValue as Int)
                    movieRating.setTextColor(it.animatedValue as Int)
                    descriptionButton.setColorFilter(it.animatedValue as Int)
                }

                anim.duration = 300
                anim.start()
                isCoverView = false
                isDescriptionView = false
            } else if (isDescriptionView) {
                TransitionManager.beginDelayedTransition(root)
                initialConstraint.applyTo(root)

                isCoverView = false
                isDescriptionView = false
            }

        }

        descriptionButton.setOnClickListener {
            if (!isDescriptionView) {
                TransitionManager.beginDelayedTransition(root)
                descriptionConstraint.applyTo(root)

                if (isCoverView) {
                    val anim = ValueAnimator()
                    anim.setIntValues(Color.WHITE, Color.BLACK)
                    anim.setEvaluator(ArgbEvaluator())
                    anim.addUpdateListener {
                        menuButton.setColorFilter(it.animatedValue as Int)
                        movieStatus.setTextColor(it.animatedValue as Int)
                        movieTitle.setTextColor(it.animatedValue as Int)
                        movieDescription.setTextColor(it.animatedValue as Int)
                        movieRating.setTextColor(it.animatedValue as Int)
                        descriptionButton.setColorFilter(it.animatedValue as Int)
                    }

                    anim.duration = 300
                    anim.start()
                    isCoverView = false
                }


                isDescriptionView = true
            }
        }
    }

    private fun selectDate(day: TextView, destinationConstraint: ConstraintSet) {
        destinationConstraint.connect(
            date_selector.id,
            ConstraintSet.START,
            day.id,
            ConstraintSet.START
        )
        destinationConstraint.connect(
            date_selector.id,
            ConstraintSet.END,
            day.id,
            ConstraintSet.END
        )
        TransitionManager.beginDelayedTransition(root)
        destinationConstraint.applyTo(root)
    }

Answer 1

简短回答：不，不是自动将 Java 转换为 Kotlin 的方式。

Jetpack Compose 使用完全不同的编程范例，其中包含与 Android View 工具包不同的行为和功能的全新小部件。直接的机械转换将是棘手的。

作为一个例子，组件的状态与视图中的状态不同。您不会从文本字段中检索文本，而是在文本字段更改时更新您的状态。