欢迎页轮播动画

如图，引导开始，球从上落下，同时淡入文字，然后文字开始轮播，最后一页时停止，点击进入首页。

在来看看效果图。

重力球先不讲，主要欢迎轮播简单实现

首先新建一个类 TextTranslationXGuideView，用于动画展示

文本是类似的，最后会有个图片箭头动画，布局很简单，就是一个 TextView 跟 ImageView，直接写 xml 布局里方便了

所以 TextTranslationXGuideView 直接继承 FrameLayout，然后动态添加布局，控制动画

val root = LayoutInflater.from(context)
            .inflate(R.layout.login_layout_text_translation_x_guide, this, false)
        root.layoutParams = LayoutParams(LayoutParams.MATCH_PARENT, LayoutParams.MATCH_PARENT)
        addView(root)
        mBinding = LoginLayoutTextTranslationXGuideBinding.bind(root)

login_layout_text_translation_x_guide

<?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="wrap_content"
    android:layout_height="wrap_content"
    android:orientation="vertical"
    tools:background="@color/white"
    tools:layout_marginStart="@dimen/dp_24">

    <TextView
        android:id="@+id/tv_content"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:fontFamily="@font/misans_bold"
        android:lineSpacingExtra="@dimen/dp_20"
        android:textColor="@color/bl_black"
        android:textSize="@dimen/sp_36"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        tools:text="欢迎xxx\n111" />

    <ImageView
        android:id="@+id/iv_guide1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginTop="@dimen/dp_30"
        android:src="@drawable/login_guide_text_right_black"
        android:visibility="gone"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/tv_content"
        tools:visibility="visible" />

    <ImageView
        android:id="@+id/iv_guide2"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:src="@drawable/login_guide_text_right_end"
        android:visibility="gone"
        app:layout_constraintBottom_toBottomOf="@+id/iv_guide1"
        app:layout_constraintStart_toEndOf="@+id/iv_guide1"
        app:layout_constraintTop_toTopOf="@+id/iv_guide1"
        app:tint="@color/c_f4f4f4"
        tools:visibility="visible" />

</androidx.constraintlayout.widget.ConstraintLayout>

文字颜色换行等通过 span 设置，所以需要一个类去配置

data class TextTranslationXGuideBean(
        val content: String, //内容
        val bright: String?, //高亮文本
        val brightColor: Int = R.color.bl_black //高亮字体颜色
    )

轮播配置成动态的，所以这里使用一个集合去存储

private val guideList = mutableListOf<TextTranslationXGuideBean>()

/**
     * 添加单个引导文本
     * @param content 内容
     * @param bright 高亮文本
     * @param brightColor 高亮字体颜色
     * */
    fun addTextGuide(
        content: String,
        bright: String? = null,
        brightColor: Int? = null
    ): TextTranslationXGuideView {
        guideList.add(TextTranslationXGuideBean(content, bright, brightColor ?: R.color.bl_black))
        return this
    }

然后在动态设置内容跟图片

/** 设置引导内容 */
    private fun setGuideContent(bean: TextTranslationXGuideBean) {
        mBinding?.tvContent?.text = bean.content
        val span = SpanUtils.with(mBinding?.tvContent)
            .append(bean.content)
            .setForegroundColor(resources.getColor(R.color.bl_black, null))
        bean.bright?.let {
            span.append("\n${bean.bright}")
                .setForegroundColor(resources.getColor(bean.brightColor, null))
        }
        span.create()
    }

接下来需要两个动画，一个淡入，一个平移（TextView 自带的跑马灯不好控制，后期如果更换方案改动也大）

private var mTranslationAnimator: ValueAnimator? = null
private var mFlickerAnimator: ValueAnimator? = null

init {
        initView()
        initTranslationAnimation()
        initGuideRightAnimate()
    }

平移动画重复执行，轮播显示，通过下标控制，显示 guideList 中的数据，如果轮播到最后一条，展示箭头闪烁动画

private fun initTranslationAnimation() {
        val point = -ScreenUtils.getScreenWidth().toFloat()
        mTranslationAnimator = ValueAnimator.ofFloat(0f, point)
        mTranslationAnimator?.duration = 300
        mTranslationAnimator?.interpolator = LinearInterpolator()
        mTranslationAnimator?.addUpdateListener { animation ->
            val scrollX = animation.animatedValue as Float
            translationX = scrollX
            if (scrollX <= point) {
                mTranslationAnimator?.cancel()
                alpha = 0f
                translationX = 0f
                nextGuide()
            }
        }
    }

private fun initTranslationAnimation() {
        val point = -ScreenUtils.getScreenWidth().toFloat()
        mTranslationAnimator = ValueAnimator.ofFloat(0f, point)
        mTranslationAnimator?.duration = 300
        mTranslationAnimator?.interpolator = LinearInterpolator()
        mTranslationAnimator?.addUpdateListener { animation ->
            val scrollX = animation.animatedValue as Float
            translationX = scrollX
            if (scrollX <= point) {
                mTranslationAnimator?.cancel()
                alpha = 0f
                translationX = 0f
                nextGuide()
            }
        }
    }


/** 开始时调用 */
    fun initGuide() {
        position = 0
        if (guideList.size > 0) {
            guideList.getOrNull(position)?.let {
                setGuideContent(it)
            }
            //渐入
            alpha = 0f
            startAlphaAnimation(1500) {
                startTranslationAnimator()
            }
        }
    }

结束时清楚缓存跳转首页

fun clear() {
        guideList.clear()
        mTranslationAnimator?.cancel()
        mTranslationAnimator = null
        mFlickerAnimator?.cancel()
        mFlickerAnimator = null
    }

全部实现

/** 登录引导动画 */
class TextTranslationXGuideView(context: Context, attrs: AttributeSet?) :
    FrameLayout(context, attrs) {

    private var mBinding: LoginLayoutTextTranslationXGuideBinding? = null

    private var mTranslationAnimator: ValueAnimator? = null
    private var mFlickerAnimator: ValueAnimator? = null

    private val guideList = mutableListOf<TextTranslationXGuideBean>()
    private var position = 0//当前显示的引导索引

    var clickRight: (() -> Unit)? = null

    init {
        initView()
        initTranslationAnimation()
        initGuideRightAnimate()
    }

    private fun initView() {
        val root = LayoutInflater.from(context)
            .inflate(R.layout.login_layout_text_translation_x_guide, this, false)
        root.layoutParams = LayoutParams(LayoutParams.MATCH_PARENT, LayoutParams.MATCH_PARENT)
        addView(root)
        mBinding = LoginLayoutTextTranslationXGuideBinding.bind(root)
        mBinding?.ivGuide1?.setOnThrottledClickListener {
            clickRight?.invoke()
        }
        mBinding?.ivGuide2?.setOnThrottledClickListener {
            clickRight?.invoke()
        }
    }

    private fun initTranslationAnimation() {
        val point = -ScreenUtils.getScreenWidth().toFloat()
        mTranslationAnimator = ValueAnimator.ofFloat(0f, point)
        mTranslationAnimator?.duration = 300
        mTranslationAnimator?.interpolator = LinearInterpolator()
        mTranslationAnimator?.addUpdateListener { animation ->
            val scrollX = animation.animatedValue as Float
            translationX = scrollX
            if (scrollX <= point) {
                mTranslationAnimator?.cancel()
                alpha = 0f
                translationX = 0f
                nextGuide()
            }
        }
    }

    private fun startTranslationAnimator() {
        mTranslationAnimator?.start()
    }

    private fun initGuideRightAnimate() {
        mFlickerAnimator = ValueAnimator.ofFloat(0f, 1f)
        mFlickerAnimator?.duration = 600
        mFlickerAnimator?.interpolator = LinearInterpolator()
        mFlickerAnimator?.repeatMode = ValueAnimator.REVERSE
        mFlickerAnimator?.repeatCount = ValueAnimator.INFINITE
        mFlickerAnimator?.addUpdateListener { animation ->
            val alpha = animation.animatedValue as Float
            mBinding?.ivGuide2?.alpha = alpha
        }
    }

    private fun startGuideRightAnimator() {
        mBinding?.ivGuide2?.visibility = View.VISIBLE
        mBinding?.ivGuide2?.alpha = 0f
        mFlickerAnimator?.start()
    }

    /** 开始时调用 */
    fun initGuide() {
        position = 0
        if (guideList.size > 0) {
            guideList.getOrNull(position)?.let {
                setGuideContent(it)
            }
            //渐入
            alpha = 0f
            startAlphaAnimation(1500) {
                startTranslationAnimator()
            }
        }
    }

    /** 下一个引导 */
    private fun nextGuide() {
        position += 1
        //是否为最后一条数据
        val isEndGuide = position == guideList.size - 1
        //第一个图标需要先展示
        mBinding?.ivGuide1?.visibility = if (isEndGuide) View.VISIBLE else View.GONE
        guideList.getOrNull(position)?.let {
            setGuideContent(it)
            startAlphaAnimation {
                if (position < guideList.size - 1) {
                    //如果有，循环执行下一个引导
                    startTranslationAnimator()
                } else {
                    //最后一个，执行渐变闪烁动画
                    startGuideRightAnimator()
                }
            }
        }
    }

    private fun startAlphaAnimation(duration: Long = 1000L, endListener: (() -> Unit)) {
        animate().setDuration(duration).alpha(1f)
            .setListener(object : Animator.AnimatorListener {
                override fun onAnimationStart(p0: Animator?) {}

                override fun onAnimationEnd(p0: Animator?) {
                    endListener.invoke()
                }

                override fun onAnimationCancel(p0: Animator?) {}

                override fun onAnimationRepeat(p0: Animator?) {}
            })
    }

    /** 设置引导内容 */
    private fun setGuideContent(bean: TextTranslationXGuideBean) {
        mBinding?.tvContent?.text = bean.content
        val span = SpanUtils.with(mBinding?.tvContent)
            .append(bean.content)
            .setForegroundColor(resources.getColor(R.color.bl_black, null))
        bean.bright?.let {
            span.append("\n${bean.bright}")
                .setForegroundColor(resources.getColor(bean.brightColor, null))
        }
        span.create()
    }

    /**
     * 添加单个引导文本
     * @param content 内容
     * @param bright 高亮文本
     * @param brightColor 高亮字体颜色
     * */
    fun addTextGuide(
        content: String,
        bright: String? = null,
        brightColor: Int? = null
    ): TextTranslationXGuideView {
        guideList.add(TextTranslationXGuideBean(content, bright, brightColor ?: R.color.bl_black))
        return this
    }

    fun clear() {
        guideList.clear()
        mTranslationAnimator?.cancel()
        mTranslationAnimator = null
        mFlickerAnimator?.cancel()
        mFlickerAnimator = null
    }

    data class TextTranslationXGuideBean(
        val content: String, //内容
        val bright: String?, //高亮文本
        val brightColor: Int = R.color.bl_black //高亮字体颜色
    )

}