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[Feature] new horizontal scrolling implementation #1

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Merged
dingyi222666 merged 1 commit into from
Jan 14, 2023
Merged

[Feature] new horizontal scrolling implementation #1

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7 changes: 0 additions & 7 deletions app/src/main/java/com/dingyi/treeview/MainActivity.kt
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Original file line number Diff line number Diff line change
Expand Up @@ -154,13 +154,6 @@ class MainActivity : AppCompatActivity() {
itemView.updateLayoutParams<ViewGroup.MarginLayoutParams> {
width = node.level * 10.dp
}

val itemView2 = if (getItemViewType(node) == 1)
ItemDirBinding.bind(holder.currentItemView).spaceRight
else ItemFileBinding.bind(holder.currentItemView).spaceRight
itemView2.updateLayoutParams<ViewGroup.MarginLayoutParams> {
width = this@MainActivity.resources.displayMetrics.widthPixels
}
//itemView.updatePadding(top = 0,right = 0, bottom = 0, left = node.level * 10.dp)

}
Expand Down
273 changes: 118 additions & 155 deletions treeview/src/main/java/io/github/dingyi222666/view/treeview/TreeView.kt
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Original file line number Diff line number Diff line change
@@ -1,23 +1,20 @@
package io.github.dingyi222666.view.treeview

import android.content.Context
import android.graphics.Canvas
import android.util.AttributeSet
import android.util.TypedValue
import android.view.MotionEvent
import android.view.View
import android.view.ViewGroup
import android.view.ViewTreeObserver.OnGlobalLayoutListener
import android.widget.HorizontalScrollView
import androidx.core.view.updateLayoutParams
import androidx.recyclerview.widget.DiffUtil
import androidx.recyclerview.widget.LinearLayoutManager
import androidx.recyclerview.widget.ListAdapter
import androidx.recyclerview.widget.RecyclerView
import kotlinx.coroutines.CoroutineScope
import kotlinx.coroutines.launch
import java.util.concurrent.locks.ReentrantReadWriteLock
import kotlin.concurrent.read
import kotlin.concurrent.write
import kotlin.math.abs
import kotlin.properties.Delegates
import kotlin.properties.ObservableProperty

class TreeView(context: Context, attrs: AttributeSet?, defStyleAttr: Int) :
RecyclerView(context, attrs, defStyleAttr), TreeNodeListener<Any> {
Expand All @@ -32,12 +29,25 @@ class TreeView(context: Context, attrs: AttributeSet?, defStyleAttr: Int) :

lateinit var binder: TreeViewBinder<Any>

private var horizontalOffset = 0f
private var maxChildWidth = 0f
private var pointerId = 0
private var pointerLastX = 0f
private var slopExceeded = false
private val horizontalTouchSlop = TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, 3f, resources.displayMetrics)
private val maxHorizontalOffset
get() = (maxChildWidth - width * 0.75f).coerceAtLeast(0f)


var nodeClickListener: TreeNodeListener<Any> = EmptyTreeNodeListener()

var supportHorizontalScroll by Delegates.observable(false) { _, old, new ->
if (!this::coroutineScope.isInitialized) {
if (!this::coroutineScope.isInitialized || old == new) {
return@observable
}
if (!new) {
horizontalOffset = 0f
}
coroutineScope.launch {
_adapter.refresh()
}
Expand All @@ -54,40 +64,13 @@ class TreeView(context: Context, attrs: AttributeSet?, defStyleAttr: Int) :
* in some cases the itemView may wrap a parent View.
*/
val currentItemView: View
) : RecyclerView.ViewHolder(rootView) {

internal var isLayoutFinish = false

fun requireCustomHorizontalScrollView(): CustomHorizontalScrollView {
return itemView as CustomHorizontalScrollView
}
}


override fun onScrollChanged(l: Int, t: Int, oldl: Int, oldt: Int) {
super.onScrollChanged(l, t, oldl, oldt)
}
) : RecyclerView.ViewHolder(rootView)

private inner class Adapter(val binder: TreeViewBinder<Any>) :
ListAdapter<TreeNode<*>, ViewHolder>(binder as DiffUtil.ItemCallback<TreeNode<*>>) {

internal val viewHolderList = arrayListOf<ViewHolder>()

private val viewHolderListLock = ReentrantReadWriteLock()

private var offsetX = 0

override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): ViewHolder {
val itemView = binder.createView(parent, viewType)
if (supportHorizontalScroll) {
val rootScrollView = CustomHorizontalScrollView(parent.context)
rootScrollView.isHorizontalScrollBarEnabled = false
rootScrollView.overScrollMode = OVER_SCROLL_NEVER

rootScrollView.layoutParams = MarginLayoutParams(itemView.layoutParams.width, itemView.layoutParams.height)
rootScrollView.addView(itemView, itemView.layoutParams.width, itemView.layoutParams.height)
return ViewHolder(rootScrollView, itemView)
}
return ViewHolder(itemView, itemView)
}

Expand All @@ -103,95 +86,28 @@ class TreeView(context: Context, attrs: AttributeSet?, defStyleAttr: Int) :
}
binder.bindView(holder, node, rootView as TreeNodeListener<Any>)

if (!supportHorizontalScroll) {
return
}

viewHolderListLock.write {
if (!viewHolderList.contains(holder)) {
viewHolderList.add(holder)
}
}

val rootScrollView = holder.requireCustomHorizontalScrollView()

rootScrollView.setOnCustomScrollChangeListener { _,
scrollX,
_,
_,
_ ->
offsetX = scrollX
viewHolderListLock.read {
viewHolderList.forEach { scrollViewHolder ->
if (scrollViewHolder !== holder /*&& !scrollViewHolder.isRecyclable*/) {
scrollViewHolder.requireCustomHorizontalScrollView()
.scrollTo(scrollX, 0)
}
}
}
}

rootScrollView.post {
if (!holder.isLayoutFinish) {
rootScrollView.scrollTo(offsetX, 0);
holder.isLayoutFinish = true
}
}

holder.itemView
.viewTreeObserver
.addOnGlobalLayoutListener {
if (!holder.isLayoutFinish) {
rootScrollView.scrollTo(offsetX, 0);
holder.isLayoutFinish = true
if (supportHorizontalScroll) {
holder.currentItemView.apply {
// Get child's preferred size
layoutParams =
LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT)
measure(
MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED),
MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED)
)
// Apply a large width and measured height
layoutParams.apply {
width = 1000000
height = holder.currentItemView.measuredHeight
}
// Save current measured width for later usage
setTag(
R.id.tag_measured_width,
holder.currentItemView.measuredWidth
)
}
}

override fun onViewDetachedFromWindow(holder: ViewHolder) {
super.onViewDetachedFromWindow(holder)

if (!supportHorizontalScroll) {
return
}
viewHolderListLock.write {
holder.isLayoutFinish = false
viewHolderList.remove(holder)
}
}

override fun onViewAttachedToWindow(holder: ViewHolder) {
super.onViewAttachedToWindow(holder)

if (!supportHorizontalScroll) {
return
}

viewHolderListLock.write {
if (!viewHolderList.contains(holder)) {
viewHolderList.add(holder)
}
}
}

override fun onViewRecycled(holder: ViewHolder) {
if (!supportHorizontalScroll) {
return
}

viewHolderListLock.write {
holder.isLayoutFinish = false
viewHolderList.remove(holder)
}
}

override fun onDetachedFromRecyclerView(recyclerView: RecyclerView) {
super.onDetachedFromRecyclerView(recyclerView)
if (!supportHorizontalScroll) {
return
}
viewHolderListLock.write {
viewHolderList.clear()
} else {
holder.currentItemView.layoutParams = LayoutParams(LayoutParams.MATCH_PARENT, LayoutParams.WRAP_CONTENT)
}
}

Expand All @@ -217,6 +133,85 @@ class TreeView(context: Context, attrs: AttributeSet?, defStyleAttr: Int) :
this.coroutineScope = coroutineScope
}

override fun onSizeChanged(w: Int, h: Int, oldw: Int, oldh: Int) {
super.onSizeChanged(w, h, oldw, oldh)
// Update horizontal offset
if (supportHorizontalScroll) {
horizontalOffset = horizontalOffset.coerceIn(0f, maxHorizontalOffset)
} else {
horizontalOffset = 0f
}
}

override fun onLayout(changed: Boolean, l: Int, t: Int, r: Int, b: Int) {
super.onLayout(changed, l, t, r, b)
if (supportHorizontalScroll) {
// Fetch children sizes and update max size of children
var maxWidth = 0
for (i in 0 until childCount) {
maxWidth = maxWidth.coerceAtLeast(
(getChildAt(i).getTag(R.id.tag_measured_width) as Int?) ?: 0
)
}
maxChildWidth = maxWidth.toFloat()
} else {
maxChildWidth = 0f
}
}

override fun onTouchEvent(e: MotionEvent): Boolean {
// Called by super's dispatchTouchEvent
if (supportHorizontalScroll && horizontalOffset != 0f) {
// Use original event for self
return super.onTouchEvent(generateTranslatedMotionEvent(e, -horizontalOffset, 0f))
}
return super.onTouchEvent(e)
}

override fun dispatchTouchEvent(ev: MotionEvent): Boolean {
if (ev.pointerCount == 1 && supportHorizontalScroll) {
// Check for horizontal scrolling
// This should be done with original coordinates
when (ev.actionMasked) {
MotionEvent.ACTION_DOWN -> {
// Take down the pointer id
pointerId = ev.getPointerId(0)
pointerLastX = ev.x
slopExceeded = false
}

MotionEvent.ACTION_MOVE -> {
if (ev.getPointerId(ev.actionIndex) == pointerId) {
if (abs(ev.x - pointerLastX) > horizontalTouchSlop) {
slopExceeded = true
}
if (slopExceeded) {
horizontalOffset = (pointerLastX - ev.x + horizontalOffset).coerceAtLeast(0f).coerceAtMost(maxHorizontalOffset)
pointerLastX = ev.x
invalidate()
}
}
}

MotionEvent.ACTION_UP, MotionEvent.ACTION_CANCEL -> {
pointerId = 0
}
}
}
if (supportHorizontalScroll && horizontalOffset != 0f) {
// Use fake coordinates for children
return super.dispatchTouchEvent(generateTranslatedMotionEvent(ev, horizontalOffset, 0f))
}
return super.dispatchTouchEvent(ev)
}

override fun dispatchDraw(canvas: Canvas) {
canvas.save()
// Translate canvas for rendering children
canvas.translate(-horizontalOffset, 0f)
super.dispatchDraw(canvas)
canvas.restore()
}

suspend fun refresh(fastRefresh: Boolean = false) {
if (!this::_adapter.isInitialized) {
Expand Down Expand Up @@ -253,38 +248,6 @@ class TreeView(context: Context, attrs: AttributeSet?, defStyleAttr: Int) :

}


class CustomHorizontalScrollView(context: Context, attrs: AttributeSet?, defStyleAttr: Int) :
HorizontalScrollView(context, attrs, defStyleAttr) {

var listener: OnCustomScrollChangeListener? = null

constructor(context: Context) : this(context, null)

constructor(context: Context, attrs: AttributeSet?) : this(context, attrs, 0)


override fun onScrollChanged(l: Int, t: Int, oldl: Int, oldt: Int) {
super.onScrollChanged(l, t, oldl, oldt)
listener?.onCustomScrollChange(this, l, t, oldl, oldt)
}

internal fun setOnCustomScrollChangeListener(listener: OnCustomScrollChangeListener) {
this.listener = listener
}

fun interface OnCustomScrollChangeListener {
fun onCustomScrollChange(
view: CustomHorizontalScrollView,
scrollX: Int,
scrollY: Int,
oldScrollX: Int,
oldScrollY: Int
)
}
}


abstract class TreeViewBinder<T : Any> : DiffUtil.ItemCallback<TreeNode<T>>(),
TreeNodeListener<T> {

Expand Down
31 changes: 31 additions & 0 deletions treeview/src/main/java/io/github/dingyi222666/view/treeview/Utils.kt
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Original file line number Diff line number Diff line change
@@ -0,0 +1,31 @@
package io.github.dingyi222666.view.treeview

import android.view.MotionEvent

internal fun generateTranslatedMotionEvent(origin: MotionEvent, dx: Float, dy: Float) =
MotionEvent.obtain(
origin.downTime - 1,
origin.eventTime,
origin.action,
origin.pointerCount,
Array(origin.pointerCount) { index ->
MotionEvent.PointerProperties().also {
origin.getPointerProperties(index, it)
}
},
Array(origin.pointerCount) { index ->
MotionEvent.PointerCoords().also {
origin.getPointerCoords(index, it)
it.x += dx
it.y += dy
}
},
origin.metaState,
origin.buttonState,
origin.xPrecision,
origin.yPrecision,
origin.deviceId,
origin.edgeFlags,
origin.source,
origin.flags
)
4 changes: 4 additions & 0 deletions treeview/src/main/res/values/ids.xml
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Original file line number Diff line number Diff line change
@@ -0,0 +1,4 @@
<?xml version="1.0" encoding="utf-8"?>
<resources>
<item name="tag_measured_width" type="id"></item>
</resources>