从任意位置缩放到屏幕大小

发表于2021-10-27更新于2023-04-26
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代码实例：

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package com.example.androidx_branch.scalestudy

import android.animation.Animator
import android.animation.AnimatorSet
import android.animation.ObjectAnimator
import android.os.Bundle
import android.util.Log
import android.view.MotionEvent
import androidx.appcompat.app.AppCompatActivity
import androidx.appcompat.widget.ViewUtils
import androidx.constraintlayout.widget.ConstraintSet
import com.example.androidx_branch.R
import com.example.androidx_branch.scrollerpicker.library.util.ScreenUtil
import com.uppack.lksmall.baseyu.weight.util.ViewUtil
import kotlinx.android.synthetic.main.activity_picture.*
import kotlinx.android.synthetic.main.activity_scalea.*
import java.util.function.LongFunction

/**
 * @Author Yu
 * @Date 2021/10/27 9:51
 * @Description TODO
 */
class ScaleStudyActivity : AppCompatActivity() {
    lateinit var scaleAnimal: ObjectAnimator
    lateinit var scaleYAnimal: ObjectAnimator
    lateinit var scaleXAnimal: ObjectAnimator
    var animatorSet: AnimatorSet = AnimatorSet()
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_scalea)

        btnStart.setOnClickListener {
            beginBigToSmall(true)
            //beginSmallToBig(true)
            animatorSet.start()
        }
        btnEnd.setOnClickListener {
            beginBigToSmall(false)
           // beginSmallToBig(false)
            animatorSet.start()
        }
    }

    // 初始状态从小到达这么写
    fun beginSmallToBig(toBig: Boolean) {
        scaleXAnimal = ObjectAnimator.ofFloat(
            imgView,
            "scaleX",
            imgView.scaleX,
            if (toBig) ScreenUtil.getScreenWidth() / imgView.width.toFloat() else 1f
        )
        scaleYAnimal = ObjectAnimator.ofFloat(
            imgView,
            "scaleY",
            imgView.scaleY,
            if (toBig) ScreenUtil.getScreenHeight() / imgView.height.toFloat() else 1f
        )
        animatorSet.playTogether(scaleXAnimal, scaleYAnimal)
        animatorSet.setDuration(2000)
        imgView.pivotX =
            (imgView.left.toFloat()) / ((ScreenUtil.getScreenWidth() / imgView.width.toFloat()) - 1)
        imgView.pivotY =
            (imgView.top.toFloat()) / ((ScreenUtil.getScreenHeight() / imgView.height.toFloat()) - 1)
    }

    // 初始状态从大到小
    fun beginBigToSmall(toSmall: Boolean) {
        var targetX = ViewUtil.dip2px(40f)// 在实际项目中这个是目标最终的距离离x的位置
        var targetY = ViewUtil.dip2px(100f)// 在实际项目中这个是目标最终的距离离Y的位置
        scaleXAnimal = ObjectAnimator.ofFloat(
            imgView,
            "scaleX",
            imgView.scaleX,
            if (toSmall) ViewUtil.dip2px(100f) / imgView.width.toFloat() else 1f
        )
        scaleYAnimal = ObjectAnimator.ofFloat(
            imgView,
            "scaleY",
            imgView.scaleY,
            if (toSmall) ViewUtil.dip2px(90f) / imgView.height.toFloat() else 1f
        )
        animatorSet.playTogether(scaleXAnimal, scaleYAnimal)
        animatorSet.setDuration(2000)
        imgView.pivotX =targetX/(1f-ViewUtil.dip2px(100f)/imgView.width.toFloat() )
        imgView.pivotY =targetY/(1f-ViewUtil.dip2px(90f)/imgView.height.toFloat() )
    }

}
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<?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"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <ImageView
        android:id="@+id/imgView"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:background="@color/black"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintTop_toTopOf="parent" />
    <Button
        android:id="@+id/btnStart"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="开始"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

    <Button
        android:id="@+id/btnEnd"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="回去"
        app:layout_constraintLeft_toRightOf="@+id/btnStart"
        app:layout_constraintTop_toTopOf="parent" />

</androidx.constraintlayout.widget.ConstraintLayout>