Android扩大View点击区域[支持同时扩展多个子View]

一年多前写过一篇文章, Android扩大View点击区域, 此方法存在诸多限制，且只能对其中一个子View进行点击范围的扩展, 今天想到一个新的思路, 实现并支持扩展任意多个子View的点击范围，供君参考（源码见文末）。

使用实例

binding.cv1.setOnClickListener {
    ToastUtils.show("cv1 Click!!")
}
val dp20 = 20.dpToPx() 
ClickAreaExpander()
.addExpandView(binding.cv1, dp20, dp20)
//.addExpandView(binding.cv2, dp20, dp20)
//.....
.expandOn(binding.touchOutView)

XML示例

<FrameLayout
    android:id="@+id/touchOutView"
    android:layout_width="match_parent"
    android:layout_height="200dp">

    <View
        android:layout_width="50dp"
        android:layout_height="50dp"
        android:layout_gravity="center"
        android:background="#22000000" />

    <View
        android:id="@+id/cv1"
        android:layout_width="10dp"
        android:layout_height="10dp"
        android:layout_gravity="center"
        android:background="@drawable/shape_white_16" />

</FrameLayout>

源码实现

class ClickAreaExpander : View.OnTouchListener {

    private var touchDelegates: MutableList<TouchDelegate> = mutableListOf()
    private var enable = false
    private var mItems = mutableListOf<Item>()
    lateinit var vg: ViewGroup
    var needInit = true

    fun expandOn(viewGroup: ViewGroup) {
        vg = viewGroup
        enable = true
        vg.setOnTouchListener(this)
    }

    /**
     * 增加需要扩宽点击范围的View
     *
     * @param view 扩充点击/长按事件的VIew
     * @param leftTop 扩宽距离,单位px
     * @param rightBottom 扩宽距离,单位px
     */
    fun addExpandView(view: View, leftTop: Int, rightBottom: Int): ClickAreaExpander {
        mItems.add(Item(view, leftTop, rightBottom))
        needInit = true
        return this
    }

    /**
     * 移除
     */
    fun removeView(view: View): ClickAreaExpander {
        mItems.firstOrNull { x -> x.view == view }?.let {
            mItems.remove(it)
            needInit = true
        }
        return this
    }

    override fun onTouch(v: View?, event: MotionEvent?): Boolean {
        event ?: return false
        v ?: return false
        var handle = false
        if (enable) {
            if (needInit) {
                if (mItems.isEmpty()) {
                    enable = false
                    return false
                }
                initViews()
            }
            for (i in 0 until touchDelegates.size) {
                val item = touchDelegates[i]
                val h = item.onTouchEvent(event)
                if (h) {
                    handle = true
                    break
                }
            }
        }
        return handle
    }

    fun enable(e: Boolean = true) {
        enable = e
    }

    private fun initViews() {
        needInit = false
        touchDelegates.clear()
        mItems.forEach {
            val v = it.view
            if (vg.contains(v)) {
                val rect = Rect()
                v.getHitRect(rect)
                rect.inset(-it.leftTop, -it.rightBottom)
                touchDelegates.add(0, TouchDelegate(Rect(rect), v))
            }
        }
    }

    inner class Item(val view: View, val leftTop: Int, val rightBottom: Int)

}

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