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/*
* Copyright (C) 2023 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.android.permissioncontroller.safetycenter.ui
import android.content.Context
import android.util.AttributeSet
import android.view.View
import android.view.ViewGroup
import android.view.ViewTreeObserver
import androidx.preference.Preference
import androidx.preference.PreferenceScreen
import androidx.preference.PreferenceViewHolder
import com.android.permissioncontroller.R
import com.android.settingslib.collapsingtoolbar.CollapsingToolbarBaseActivity
import com.android.settingslib.widget.FooterPreference
import kotlin.math.max
/**
* A preference that adds an empty space to the bottom of a Safety Center subpage.
*
* Due to the logic of [CollapsingToolbarBaseActivity], its content won't be scrollable if it fits
* the single page. This logic conflicts with the UX of collapsible and expandable items of Safety
* Center, and with some other use cases (i.e. opening the page from Search might scroll to bottom
* while the scroll is disabled). In such cases user won't be able to expand the collapsed toolbar
* by scrolling the screen content.
*
* [SpacerPreference] makes the page to be slightly bigger than the screen size to unlock the scroll
* regardless of the content length and to mitigate this UX problem.
*
* If a [FooterPreference] is added to the same [PreferenceScreen], its order should be decreased to
* keep it with the last visible content above the [SpacerPreference].
*/
internal class SpacerPreference(context: Context, attrs: AttributeSet) :
Preference(context, attrs) {
init {
setLayoutResource(R.layout.preference_spacer)
isVisible = SafetyCenterUiFlags.getShowSubpages()
// spacer should be the last item on screen
setOrder(Int.MAX_VALUE - 1)
}
private var maxKnownToolbarHeight = 0
override fun onBindViewHolder(holder: PreferenceViewHolder) {
super.onBindViewHolder(holder)
val spacer = holder.itemView
// we should ensure we won't add multiple listeners to the same view,
// and Preferences API does not allow to do cleanups when onViewRecycled,
// so we are keeping a track of the added listener attaching it as a tag to the View
val listener: View.OnLayoutChangeListener =
spacer.tag as? View.OnLayoutChangeListener
?: object : View.OnLayoutChangeListener {
override fun onLayoutChange(
v: View?,
left: Int,
top: Int,
right: Int,
bottom: Int,
oldLeft: Int,
oldTop: Int,
oldRight: Int,
oldBottom: Int
) {
adjustHeight(spacer)
}
}
.also { spacer.tag = it }
spacer.removeOnLayoutChangeListener(listener)
spacer.addOnLayoutChangeListener(listener)
}
private fun adjustHeight(spacer: View) {
val root = spacer.rootView as? ViewGroup
if (root == null) {
return
}
val contentParent =
root.findViewById<ViewGroup>(
com.android.settingslib.collapsingtoolbar.R.id.content_parent
)
if (contentParent == null) {
return
}
// when opening the Subpage from Search the layout pass may be triggered
// differently due to the auto-scroll to highlight a specific item,
// and in this case we need to wait the content parent to be measured
if (contentParent.height == 0) {
val globalLayoutObserver =
object : ViewTreeObserver.OnGlobalLayoutListener {
override fun onGlobalLayout() {
contentParent.viewTreeObserver.removeOnGlobalLayoutListener(this)
adjustHeight(spacer)
}
}
contentParent.viewTreeObserver.addOnGlobalLayoutListener(globalLayoutObserver)
return
}
val collapsingToolbar =
root.findViewById<View>(
com.android.settingslib.collapsingtoolbar.R.id.collapsing_toolbar
)
maxKnownToolbarHeight = max(maxKnownToolbarHeight, collapsingToolbar!!.height)
val contentHeight = spacer.top + maxKnownToolbarHeight
val desiredSpacerHeight =
if (contentHeight > contentParent.height) {
// making it 0 height will remove if from recyclerview
1
} else {
// to unlock the scrolling we need spacer to go slightly beyond the screen
contentParent.height - contentHeight + 1
}
val layoutParams = spacer.layoutParams
if (layoutParams.height != desiredSpacerHeight) {
layoutParams.height = desiredSpacerHeight
spacer.layoutParams = layoutParams
// need to let RecyclerView to update scroll position
spacer.post(::notifyChanged)
}
}
}
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