ViewPager2 嵌套 增加中间层处理事件拦截
ViewPager2 嵌套 ViewPager2
package com.tdx.tdxtappview
import android.content.Context
import android.util.AttributeSet
import android.view.MotionEvent
import android.widget.RelativeLayout
import androidx.viewpager2.widget.ViewPager2
import kotlin.math.abs
/**
* ViewPager2 嵌套 ViewPager2 滑动冲突处理
*/
class ViewPager2Container @JvmOverloads constructor(context: Context, attrs: AttributeSet? = null, defStyleAttr: Int = 0) : RelativeLayout(context, attrs, defStyleAttr) {
private var mViewPager2: ViewPager2? = null
private var disallowParentInterceptDownEvent = true
private var startX = 0
private var startY = 0
override fun onFinishInflate() {
super.onFinishInflate()
for (i in 0 until childCount) {
val childView = getChildAt(i)
if (childView is ViewPager2) {
mViewPager2 = childView
break
}
}
if (mViewPager2 == null) {
throw IllegalStateException("The root child of ViewPager2Container must contains a ViewPager2")
}
}
override fun onInterceptTouchEvent(ev: MotionEvent): Boolean {
val doNotNeedIntercept = (!mViewPager2!!.isUserInputEnabled
|| (mViewPager2?.adapter != null
&& mViewPager2?.adapter!!.itemCount <= 1))
if (doNotNeedIntercept) {
return super.onInterceptTouchEvent(ev)
}
when (ev.action) {
MotionEvent.ACTION_DOWN -> {
startX = ev.x.toInt()
startY = ev.y.toInt()
parent.requestDisallowInterceptTouchEvent(!disallowParentInterceptDownEvent)
}
MotionEvent.ACTION_MOVE -> {
val endX = ev.x.toInt()
val endY = ev.y.toInt()
val disX = abs(endX - startX)
val disY = abs(endY - startY)
if (mViewPager2!!.orientation == ViewPager2.ORIENTATION_VERTICAL) {
onVerticalActionMove(endY, disX, disY)
} else if (mViewPager2!!.orientation == ViewPager2.ORIENTATION_HORIZONTAL) {
onHorizontalActionMove(endX, disX, disY)
}
}
MotionEvent.ACTION_UP, MotionEvent.ACTION_CANCEL -> parent.requestDisallowInterceptTouchEvent(false)
}
return super.onInterceptTouchEvent(ev)
}
private fun onHorizontalActionMove(endX: Int, disX: Int, disY: Int) {
if (mViewPager2?.adapter == null) {
return
}
if (disX > disY) {
val currentItem = mViewPager2?.currentItem
val itemCount = mViewPager2?.adapter!!.itemCount
if (currentItem == 0 && endX - startX > 0) {
parent.requestDisallowInterceptTouchEvent(false)
} else {
parent.requestDisallowInterceptTouchEvent(currentItem != itemCount - 1
|| endX - startX >= 0)
}
} else if (disY > disX) {
parent.requestDisallowInterceptTouchEvent(false)
}
}
private fun onVerticalActionMove(endY: Int, disX: Int, disY: Int) {
if (mViewPager2?.adapter == null) {
return
}
val currentItem = mViewPager2?.currentItem
val itemCount = mViewPager2?.adapter!!.itemCount
if (disY > disX) {
if (currentItem == 0 && endY - startY > 0) {
parent.requestDisallowInterceptTouchEvent(false)
} else {
parent.requestDisallowInterceptTouchEvent(currentItem != itemCount - 1
|| endY - startY >= 0)
}
} else if (disX > disY) {
parent.requestDisallowInterceptTouchEvent(false)
}
}
/**
* 设置是否允许在当前View的{@link MotionEvent#ACTION_DOWN}事件中禁止父View对事件的拦截，该方法
* 用于解决CoordinatorLayout+CollapsingToolbarLayout在嵌套ViewPager2Container时引起的滑动冲突问题。
*
* 设置是否允许在ViewPager2Container的{@link MotionEvent#ACTION_DOWN}事件中禁止父View对事件的拦截，该方法
* 用于解决CoordinatorLayout+CollapsingToolbarLayout在嵌套ViewPager2Container时引起的滑动冲突问题。
*
* @param disallowParentInterceptDownEvent 是否允许ViewPager2Container在{@link MotionEvent#ACTION_DOWN}事件中禁止父View拦截事件，默认值为false
* true 不允许ViewPager2Container在{@link MotionEvent#ACTION_DOWN}时间中禁止父View的时间拦截，
* 设置disallowIntercept为true可以解决CoordinatorLayout+CollapsingToolbarLayout的滑动冲突
* false 允许ViewPager2Container在{@link MotionEvent#ACTION_DOWN}时间中禁止父View的时间拦截，
*/
fun disallowParentInterceptDownEvent(disallowParentInterceptDownEvent: Boolean) {
this.disallowParentInterceptDownEvent = disallowParentInterceptDownEvent
}
}
ViewPager2 嵌ViewPager
IllegalStateException: ViewPager2 does not support direct child views
viewPager.setAdapter(new FragmentPagerAdapter(getChildFragmentManager(),BEHAVIOR_RESUME_ONLY_CURRENT_FRAGMENT) {
package com.tdx.View
import android.content.Context
import android.util.AttributeSet
import android.util.Log
import android.view.GestureDetector
import android.view.MotionEvent
import android.view.View
import android.view.ViewConfiguration
import android.widget.FrameLayout
import androidx.viewpager.widget.ViewPager
import androidx.viewpager2.widget.ViewPager2
import androidx.viewpager2.widget.ViewPager2.ORIENTATION_HORIZONTAL
import kotlin.math.absoluteValue
import kotlin.math.sign
/**
* Layout to wrap a scrollable component inside a ViewPager2. Provided as a solution to the problem
* where pages of ViewPager2 have nested scrollable elements that scroll in the same direction as
* ViewPager2. The scrollable element needs to be the immediate and only child of this host layout.
*
* This solution has limitations when using multiple levels of nested scrollable elements
* (e.g. a horizontal RecyclerView in a vertical RecyclerView in a horizontal ViewPager2).
*/
class NestedScrollableHost : FrameLayout {
constructor(context: Context) : super(context)
constructor(context: Context, attrs: AttributeSet?) : super(context, attrs)
private var touchSlop = 0
private var initialX = 0f
private var initialY = 0f
private val parentViewPager: ViewPager2?
get() {
var v: View? = parent as? View
while (v != null && v !is ViewPager2) {
v = v.parent as? View
}
return v as? ViewPager2
}
private val child: View? get() = if (childCount > 0) getChildAt(0) else null
init {
touchSlop = ViewConfiguration.get(context).scaledTouchSlop
}
private fun canChildScroll(orientation: Int, delta: Float): Boolean {
val direction = -delta.sign.toInt()
return when (orientation) {
0 -> child?.canScrollHorizontally(direction) ?: false
1 -> child?.canScrollVertically(direction) ?: false
else -> throw IllegalArgumentException()
}
}
override fun onInterceptTouchEvent(e: MotionEvent): Boolean {
//处理子View 为ViewPager
if (child is ViewPager && e.action == MotionEvent.ACTION_MOVE){
var pager: ViewPager = child as ViewPager
val currentItem = pager?.currentItem
val itemCount = pager?.adapter!!.count
//最左侧左划，最右侧右滑 拦截不下发事件到ViewPager
var startScrollLeft = (currentItem == 0 && e.x - initialX > 0)
var endScrollRight = (currentItem == itemCount - 1 && e.x - initialX <= 0)
val dx = e.x - initialX
val dy = e.y - initialY
if (dx.absoluteValue > dy.absoluteValue && (startScrollLeft || endScrollRight)){
parent.requestDisallowInterceptTouchEvent(false)
return true
}
}
handleInterceptTouchEvent(e)
return super.onInterceptTouchEvent(e)
}
private fun handleInterceptTouchEvent(e: MotionEvent) {
val orientation = parentViewPager?.orientation ?: return
// Early return if child can't scroll in same direction as parent
if (!canChildScroll(orientation, -1f) && !canChildScroll(orientation, 1f)) {
return
}
if (e.action == MotionEvent.ACTION_DOWN) {
initialX = e.x
initialY = e.y
parent.requestDisallowInterceptTouchEvent(true)
} else if (e.action == MotionEvent.ACTION_MOVE) {
val dx = e.x - initialX
val dy = e.y - initialY
val isVpHorizontal = orientation == ORIENTATION_HORIZONTAL
// assuming ViewPager2 touch-slop is 2x touch-slop of child
val scaledDx = dx.absoluteValue * if (isVpHorizontal) .5f else 1f
val scaledDy = dy.absoluteValue * if (isVpHorizontal) 1f else .5f
if (scaledDx > touchSlop || scaledDy > touchSlop) {
if (isVpHorizontal == (scaledDy > scaledDx)) {
// Gesture is perpendicular, allow all parents to intercept
parent.requestDisallowInterceptTouchEvent(false)
} else {
// Gesture is parallel, query child if movement in that direction is possible
if (canChildScroll(orientation, if (isVpHorizontal) dx else dy)) {
// Child can scroll, disallow all parents to intercept
parent.requestDisallowInterceptTouchEvent(true)
} else {
// Child cannot scroll, allow all parents to intercept
parent.requestDisallowInterceptTouchEvent(false)
}
}
}
} else {
parent.requestDisallowInterceptTouchEvent(false)
}
}
}
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