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/*
* Copyright 2018 Allan Wang
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
package com.pitchedapps.frost.web
import android.annotation.SuppressLint
import android.content.Context
import android.util.AttributeSet
import android.view.MotionEvent
import android.webkit.WebView
import androidx.core.view.NestedScrollingChild
import androidx.core.view.NestedScrollingChildHelper
import androidx.core.view.ViewCompat
/**
* Created by Allan Wang on 20/12/17.
*
* Webview extension that handles nested scrolls
*/
open class NestedWebView(
context: Context,
attrs: AttributeSet?,
defStyleAttr: Int
) : WebView(context, attrs, defStyleAttr), NestedScrollingChild {
// No JvmOverloads due to hilt
constructor(context: Context) : this(context, null)
constructor(context: Context, attrs: AttributeSet?) : this(context, attrs, 0)
private lateinit var childHelper: NestedScrollingChildHelper
private var lastY: Int = 0
private val scrollOffset = IntArray(2)
private val scrollConsumed = IntArray(2)
private var nestedOffsetY: Int = 0
init {
init()
}
fun init() {
// To avoid leaking constructor
childHelper = NestedScrollingChildHelper(this)
}
/**
* Handle nested scrolling against SwipeRecyclerView
* Courtesy of takahirom
*
* https://github.com/takahirom/webview-in-coordinatorlayout/blob/master/app/src/main/java/com/github/takahirom/webview_in_coodinator_layout/NestedWebView.java
*/
@SuppressLint("ClickableViewAccessibility")
final override fun onTouchEvent(ev: MotionEvent): Boolean {
val event = MotionEvent.obtain(ev)
val action = event.action
if (action == MotionEvent.ACTION_DOWN)
nestedOffsetY = 0
val eventY = event.y.toInt()
event.offsetLocation(0f, nestedOffsetY.toFloat())
val returnValue: Boolean
when (action) {
MotionEvent.ACTION_MOVE -> {
var deltaY = lastY - eventY
// NestedPreScroll
if (dispatchNestedPreScroll(0, deltaY, scrollConsumed, scrollOffset)) {
deltaY -= scrollConsumed[1]
}
lastY = eventY - scrollOffset[1]
returnValue = super.onTouchEvent(event)
// NestedScroll
if (dispatchNestedScroll(0, scrollOffset[1], 0, deltaY, scrollOffset)) {
event.offsetLocation(0f, scrollOffset[1].toFloat())
nestedOffsetY += scrollOffset[1]
lastY -= scrollOffset[1]
}
}
MotionEvent.ACTION_DOWN -> {
returnValue = super.onTouchEvent(event)
lastY = eventY
startNestedScroll(ViewCompat.SCROLL_AXIS_VERTICAL)
}
MotionEvent.ACTION_UP, MotionEvent.ACTION_CANCEL -> {
returnValue = super.onTouchEvent(event)
stopNestedScroll()
}
else -> return false
}
return returnValue
}
/*
* ---------------------------------------------
* Nested Scrolling Content
* ---------------------------------------------
*/
final override fun setNestedScrollingEnabled(enabled: Boolean) {
childHelper.isNestedScrollingEnabled = enabled
}
final override fun isNestedScrollingEnabled() = childHelper.isNestedScrollingEnabled
final override fun startNestedScroll(axes: Int) = childHelper.startNestedScroll(axes)
final override fun stopNestedScroll() = childHelper.stopNestedScroll()
final override fun hasNestedScrollingParent() = childHelper.hasNestedScrollingParent()
final override fun dispatchNestedScroll(
dxConsumed: Int,
dyConsumed: Int,
dxUnconsumed: Int,
dyUnconsumed: Int,
offsetInWindow: IntArray?
) = childHelper.dispatchNestedScroll(
dxConsumed,
dyConsumed,
dxUnconsumed,
dyUnconsumed,
offsetInWindow
)
final override fun dispatchNestedPreScroll(
dx: Int,
dy: Int,
consumed: IntArray?,
offsetInWindow: IntArray?
) = childHelper.dispatchNestedPreScroll(dx, dy, consumed, offsetInWindow)
final override fun dispatchNestedFling(velocityX: Float, velocityY: Float, consumed: Boolean) =
childHelper.dispatchNestedFling(velocityX, velocityY, consumed)
final override fun dispatchNestedPreFling(velocityX: Float, velocityY: Float) =
childHelper.dispatchNestedPreFling(velocityX, velocityY)
}
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