0.3 view 滑动冲突

Android 触摸事件分发与滑动冲突处理 — 完整文档

一、核心知识点总结

1. 事件分发流程（Event Flow）

• 事件传递路径：Activity → Window (DecorView) → ViewGroup → View
• 若所有子 View 均未消费事件，最终会回传到 Activity.onTouchEvent()
• 一个完整事件序列 = 1 个 ACTION_DOWN + 多个 ACTION_MOVE + 1 个 ACTION_UP

2. 关键规则

• 通常一个事件序列应由同一个 View 消费到底。
• 若 View 在 ACTION_DOWN 返回 false，则后续事件不会交给它。
• ViewGroup 默认不拦截事件（onInterceptTouchEvent 返回 false）。
• 只有当 View 的 clickable 或 longClickable 为 true 时，onTouchEvent 才会返回 true（即消费事件）。
• OnTouchListener.onTouch() 优先于 onTouchEvent() 被调用；若其返回 true，则 onTouchEvent() 不再执行。
• 子 View 可通过 parent.requestDisallowInterceptTouchEvent(true/false) 动态控制父容器是否拦截。

3. 滑动冲突类型与解决思路

• 类型1：外层水平滑动（如 ViewPager），内层垂直滑动（如 ListView）
  → 根据 |Δx| > |Δy| 判断方向，决定由谁拦截。
• 类型2：内外均为垂直滑动
  → 依赖业务逻辑（如是否滚动到顶部/底部）。
• 类型3：嵌套上述两种情况。
• 解决方法：
  • 外部拦截法：在父容器的 onInterceptTouchEvent 中判断是否拦截。
  • 内部拦截法：子 View 主动调用 requestDisallowInterceptTouchEvent() 控制父容器行为。

4. 滑动实现方式

• 三种滑动方式：
  1. scrollTo / scrollBy：改变内容位置（非 View 本身）
  2. 属性动画（如 ObjectAnimator.ofFloat(view, "translationX", ...)）
  3. 修改 LayoutParams 并调用 requestLayout()
• 弹性滑动实现：
  • 使用 Scroller + computeScroll()（推荐）
  • 使用 ValueAnimator 动态更新 scroll 值
  • 使用 Handler + postDelayed（较少用）

5. 辅助工具

• VelocityTracker：计算滑动速度（用于 fling 判断）
• ViewConfiguration.get(context).scaledTouchSlop：系统认定的最小滑动距离（防误触）

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二、代码文件（带完整注释）

1. ViewActivity.kt

package com.shakespace.artofandroid.chapter03import android.os.Bundle
import androidx.appcompat.app.AppCompatActivity
import com.shakespace.artofandroid.R
import com.shakespace.artofandroid.chapter03.basic.ViewCoordinateActivity
import com.shakespace.artofandroid.chapter03.conflict.ConflictActivity
import com.shakespace.firstlinecode.global.start
import kotlinx.android.synthetic.main.activity_view.*/*** 主入口 Activity，用于跳转到两个子功能模块：* - View 坐标系演示* - 滑动冲突演示*/
class ViewActivity : AppCompatActivity() {override fun onCreate(savedInstanceState: Bundle?) {super.onCreate(savedInstanceState)setContentView(R.layout.activity_view)// 点击跳转到坐标系演示页面tv_coordinate.setOnClickListener {start(ViewCoordinateActivity::class.java)}// 点击跳转到滑动冲突演示页面tv_conflict.setOnClickListener {start(ConflictActivity::class.java)}}
}

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2. basic/DemoView.kt

package com.shakespace.artofandroid.chapter03.basicimport android.animation.ObjectAnimator
import android.animation.ValueAnimator
import android.content.Context
import android.util.AttributeSet
import android.view.View
import android.widget.Scroller/*** 自定义 View，演示三种滑动方式及弹性滑动实现*/
class DemoView @JvmOverloads constructor(context: Context?,attrs: AttributeSet? = null,defStyleAttr: Int = 0
) : View(context, attrs, defStyleAttr) {// Scroller 用于实现平滑滚动（弹性滑动）val scroller = Scroller(context)/*** 使用 Scroller 实现平滑滚动到目标位置* 注意：Scroller 本身不执行滚动，需配合 computeScroll()*/fun smoothScrollTo(destX: Int, destY: Int) {val deltaX = destX - scrollX// 保存滚动参数（起始值、偏移量、持续时间）scroller.startScroll(scrollX, scrollY, deltaX, destY - scrollY, 1000)// 触发重绘，从而调用 computeScroll()invalidate()}/*** 关键方法：在每次绘制前被调用，用于更新滚动位置* 若滚动未完成，则继续 scrollTo 并请求重绘*/override fun computeScroll() {if (scroller.computeScrollOffset()) {// 更新当前滚动位置scrollTo(scroller.currX, scroller.currY)// 继续触发下一次绘制postInvalidate()}}/*** 方式1：使用 scrollTo/scrollBy* - scrollX = View 左边缘 - 内容左边缘* - 向右滑动 → scrollX < 0*//*** 方式2：使用属性动画*/fun moveByAnimation() {// 改变 View 的实际位置（视觉位移，不影响布局）ObjectAnimator.ofFloat(this, "translationX", 0f, 100f).setDuration(100).start()// 使用 ValueAnimator + scrollTo 实现弹性滑动val startX = scrollXval deltaX = 100ValueAnimator.ofInt(0, 100).apply {duration = 1000addUpdateListener { animator ->val fraction = animator.animatedFraction // [0,1]scrollTo(startX + (deltaX * fraction).toInt(), 0)}start()}}/*** 方式3：修改 LayoutParams*/fun moveByChangeLayoutParam() {// 直接修改宽高（仅作演示，实际中需考虑父容器约束）layoutParams.width += 100layoutParams.height += 100this.layoutParams = layoutParams // 触发 requestLayout()}
}

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3. basic/EventDemoView.kt

package com.shakespace.artofandroid.chapter03.basicimport android.content.Context
import android.util.AttributeSet
import android.view.MotionEvent
import android.view.View
import android.view.ViewGroup/*** 自定义 ViewGroup，用于演示事件分发机制* 注：此处重写了 dispatchTouchEvent 但最终仍调用 super，仅用于理解流程*/
class EventDemoView @JvmOverloads constructor(context: Context?,attrs: AttributeSet? = null,defStyleAttr: Int = 0
) : ViewGroup(context, attrs, defStyleAttr) {override fun onLayout(changed: Boolean, l: Int, t: Int, r: Int, b: Int) {// 空实现，实际使用需布局子 View}/*** 事件分发入口* 正常流程：*   - 先调用 onInterceptTouchEvent 判断是否拦截*   - 若拦截，则调用自己的 onTouchEvent*   - 否则，将事件分发给子 View*/override fun dispatchTouchEvent(ev: MotionEvent?): Boolean {// 示例逻辑（注释掉，实际走默认流程）// var consume = false// if (onInterceptTouchEvent(ev)) {//     consume = onTouchEvent(ev)// } else {//     consume = child.dispatchTouchEvent(ev)// }// return consume// 实际使用默认分发机制return super.dispatchTouchEvent(ev)}/*** 是否拦截事件* 默认返回 false（不拦截）*/override fun onInterceptTouchEvent(ev: MotionEvent?): Boolean {return super.onInterceptTouchEvent(ev)}/*** 处理触摸事件* 若设置了 OnTouchListener，会先调用其 onTouch 方法*/override fun onTouchEvent(event: MotionEvent?): Boolean {return super.onTouchEvent(event)}private val touchListener = object : View.OnTouchListener {override fun onTouch(v: View?, event: MotionEvent?): Boolean {// TODO: 实现具体逻辑return false}}
}

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4. basic/ViewCoordinateActivity.kt

package com.shakespace.artofandroid.chapter03.basicimport android.os.Bundle
import android.util.Log
import android.view.MotionEvent
import android.view.VelocityTracker
import android.view.ViewConfiguration
import androidx.appcompat.app.AppCompatActivity
import com.shakespace.artofandroid.R
import com.shakespace.firstlinecode.global.TAG
import kotlinx.android.synthetic.main.activity_view_coordinate.*/*** 演示 View 坐标系、touchSlop、VelocityTracker 等基础概念*/
class ViewCoordinateActivity : AppCompatActivity() {override fun onCreate(savedInstanceState: Bundle?) {super.onCreate(savedInstanceState)setContentView(R.layout.activity_view_coordinate)// 显示静态坐标说明val memo = """left = getLeft()right = getRight()top = getTop()bottom = getBottom()width = right - leftheight = bottom - top""".trimIndent()tv_coordinate.text = memo// 显示移动后的坐标关系val memo2 = """当发生位移时（left/top/right/bottom 不变）：x = left + translationXy = top + translationY""".trimIndent()tv_coordinate_move.text = memo2// 获取系统最小滑动距离（防误触阈值）val scaledTouchSlop = ViewConfiguration.get(this).scaledTouchSlopval other = "scaledTouchSlop = $scaledTouchSlop"tv_memo.text = other// 测试 disabled View 的触摸行为tv_disable.setOnTouchListener { _, _ ->Log.e(TAG, "onCreate: tv_disable onTouch")false}tv_disable.setOnClickListener {Log.e(TAG, "onCreate: tv_disable onClick")}}/*** 演示 VelocityTracker 的基本用法* 注意：此处每次 MOVE 都新建 tracker，实际应复用*/override fun onTouchEvent(event: MotionEvent?): Boolean {val velocityTracker = VelocityTracker.obtain()when (event?.action) {MotionEvent.ACTION_MOVE -> {velocityTracker.addMovement(event)velocityTracker.computeCurrentVelocity(100) // 100ms 单位Log.e(TAG, "onTouchEvent: ${velocityTracker.xVelocity} -- ${velocityTracker.yVelocity}")}}velocityTracker.clear()velocityTracker.recycle()return super.onTouchEvent(event)}
}

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5. conflict/ConflictActivity.kt

package com.shakespace.artofandroid.chapter03.conflictimport android.graphics.Color
import android.os.Bundle
import android.view.View
import android.widget.ArrayAdapter
import android.widget.ListView
import android.widget.TextView
import androidx.appcompat.app.AppCompatActivity
import com.shakespace.artofandroid.R
import com.shakespace.firstlinecode.global.screenWidth
import kotlinx.android.synthetic.main.activity_confilct.*/*** 滑动冲突演示主界面* 创建 3 个页面，每个页面包含一个 ListView*/
class ConflictActivity : AppCompatActivity() {override fun onCreate(savedInstanceState: Bundle?) {super.onCreate(savedInstanceState)setContentView(R.layout.activity_confilct)// 添加 3 个页面到水平滑动容器for (i in 0..2) {val view = layoutInflater.inflate(R.layout.confilct_test_layout, horizontal_view, false)view.layoutParams.width = screenWidthval tvTitle: TextView = view.findViewById(R.id.title)tvTitle.text = "Page $i"// 设置背景色（避免全白）view.setBackgroundColor(Color.rgb(255 / (i + 1), 255 / (i * i + 1), 255 / (i * i * i * i + 1)))createList(view)horizontal_view.addView(view)}}/*** 为每个页面创建 ListView 数据*/private fun createList(view: View) {val listView = view.findViewById<ListView>(R.id.list_view)val dataList = ArrayList<String>().apply {for (i in 0..50) {add("item $i")}}val adapter = ArrayAdapter<String>(this,android.R.layout.simple_list_item_1,android.R.id.text1,dataList)listView.adapter = adapter}
}

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6. conflict/ConflictDemoView.kt

package com.shakespace.artofandroid.chapter03.conflictimport android.content.Context
import android.util.AttributeSet
import android.view.MotionEvent
import android.view.View
import android.view.ViewGroup/*** 演示两种滑动冲突处理方法：* - 方法1：外部拦截（重写 onInterceptTouchEvent）* - 方法2：内部拦截（子 View 调用 requestDisallowInterceptTouchEvent）*/
class ConflictDemoView @JvmOverloads constructor(context: Context?,attrs: AttributeSet? = null,defStyleAttr: Int = 0
) : ViewGroup(context, attrs, defStyleAttr) {override fun onLayout(changed: Boolean, l: Int, t: Int, r: Int, b: Int) {// 空实现}// ==================== 方法2：内部拦截法 ====================/*** 在子 View 的 dispatchTouchEvent 中控制父容器是否拦截* 注意：此方法需配合父容器的 onInterceptTouchEvent 使用*/override fun dispatchTouchEvent(ev: MotionEvent): Boolean {when (ev.action) {MotionEvent.ACTION_DOWN -> {// 允许自己先处理requestDisallowInterceptTouchEvent(true)}MotionEvent.ACTION_MOVE -> {// 根据业务逻辑决定是否允许父容器拦截// 此处简化为始终允许（实际应判断滑动方向）requestDisallowInterceptTouchEvent(false)}MotionEvent.ACTION_UP -> {// 无特殊处理}}return super.dispatchTouchEvent(ev)}// ==================== 方法1：外部拦截法 ====================var flag = true // 控制是否拦截（演示用）var lastX: Float = 0fvar lastY: Float = 0f/*** 父容器判断是否拦截事件*/override fun onInterceptTouchEvent(ev: MotionEvent): Boolean {var intercepted = falsewhen (ev.action) {MotionEvent.ACTION_DOWN -> {intercepted = false // 必须放行 DOWN，否则子 View 收不到}MotionEvent.ACTION_MOVE -> {intercepted = flag // 根据业务逻辑决定}MotionEvent.ACTION_UP -> {intercepted = false // 通常不拦截 UP}}lastX = ev.xlastY = ev.yreturn intercepted}override fun onTouchEvent(event: MotionEvent?): Boolean {return super.onTouchEvent(event)}private val touchListener = object : View.OnTouchListener {override fun onTouch(v: View?, event: MotionEvent?): Boolean {return false}}
}

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7. conflict/HorizontalScrollViewEx.kt

package com.shakespace.artofandroid.chapter03.conflictimport android.content.Context
import android.util.AttributeSet
import android.util.Log
import android.view.MotionEvent
import android.view.VelocityTracker
import android.view.View
import android.view.ViewGroup
import android.widget.Scroller
import com.shakespace.firstlinecode.global.TAG/*** 自定义水平滑动容器，使用【外部拦截法】处理滑动冲突* 适用于 ViewPager + ListView 场景*/
class HorizontalScrollViewEx @JvmOverloads constructor(context: Context?,attrs: AttributeSet? = null,defStyleAttr: Int = 0
) : ViewGroup(context, attrs, defStyleAttr) {private var childrenSize = 0private var childWidth = 0private var childIndex = 0private var lastX = 0private var lastY = 0private var lastXInIntercept = 0private var lastYInIntercept = 0private val scroller = Scroller(context)private val velocityTracker = VelocityTracker.obtain()/*** 判断是否拦截事件（外部拦截法核心）*/override fun onInterceptTouchEvent(ev: MotionEvent): Boolean {var intercepted = falseval eventX = ev.x.toInt()val eventY = ev.y.toInt()when (ev.action) {MotionEvent.ACTION_DOWN -> {// 如果正在滚动中，中断并接管事件if (!scroller.isFinished) {scroller.abortAnimation()intercepted = true} else {intercepted = false}lastXInIntercept = eventXlastYInIntercept = eventY}MotionEvent.ACTION_MOVE -> {val deltaX = eventX - lastXInInterceptval deltaY = eventY - lastYInIntercept// 水平滑动为主 → 父容器拦截intercepted = Math.abs(deltaX) > Math.abs(deltaY)}MotionEvent.ACTION_UP -> {intercepted = false}}Log.e(TAG, "onInterceptTouchEvent: intercepted=$intercepted")lastX = eventXlastY = eventYreturn intercepted}/*** 处理触摸事件，实现水平滑动和自动吸附*/override fun onTouchEvent(ev: MotionEvent): Boolean {velocityTracker.addMovement(ev)val eventX = ev.x.toInt()val eventY = ev.y.toInt()when (ev.action) {MotionEvent.ACTION_DOWN -> {if (!scroller.isFinished) {scroller.abortAnimation()}}MotionEvent.ACTION_MOVE -> {val deltaX = eventX - lastXscrollBy(-deltaX, 0) // 水平滚动}MotionEvent.ACTION_UP -> {velocityTracker.computeCurrentVelocity(1000)val xVelocity = velocityTracker.xVelocity// 根据速度或位置自动吸附到最近页面if (Math.abs(xVelocity) >= 50) {childIndex += if (xVelocity < 0) 1 else -1} else {childIndex = (scrollX + childWidth / 2) / childWidth}childIndex = Math.max(0, Math.min(childIndex, childrenSize - 1))val dx = childIndex * childWidth - scrollXsmoothScrollBy(dx, 0)velocityTracker.clear()}}lastX = eventXlastY = eventYreturn true}// --- 测量与布局 ---override fun onMeasure(widthMeasureSpec: Int, heightMeasureSpec: Int) {super.onMeasure(widthMeasureSpec, heightMeasureSpec)measureChildren(widthMeasureSpec, heightMeasureSpec)val widthSize = MeasureSpec.getSize(widthMeasureSpec)val heightSize = MeasureSpec.getSize(heightMeasureSpec)val widthMode = MeasureSpec.getMode(widthMeasureSpec)val heightMode = MeasureSpec.getMode(heightMeasureSpec)if (childCount == 0) {setMeasuredDimension(0, 0)return}val firstChild = getChildAt(0)val childWidth = firstChild.measuredWidthval childHeight = firstChild.measuredHeightwhen {widthMode == MeasureSpec.AT_MOST && heightMode == MeasureSpec.AT_MOST ->setMeasuredDimension(childWidth * childCount, childHeight)heightMode == MeasureSpec.AT_MOST ->setMeasuredDimension(widthSize, childHeight)widthMode == MeasureSpec.AT_MOST ->setMeasuredDimension(childWidth * childCount, heightSize)}}override fun onLayout(changed: Boolean, l: Int, t: Int, r: Int, b: Int) {var childLeft = 0childrenSize = childCountfor (i in 0 until childCount) {val child = getChildAt(i)if (child.visibility != View.GONE) {childWidth = child.measuredWidthchild.layout(childLeft, 0, childLeft + childWidth, child.measuredHeight)childLeft += childWidth}}}private fun smoothScrollBy(dx: Int, dy: Int) {scroller.startScroll(scrollX, scrollY, dx, dy, 500)invalidate()}override fun computeScroll() {if (scroller.computeScrollOffset()) {scrollTo(scroller.currX, scroller.currY)postInvalidate()}}override fun onDetachedFromWindow() {velocityTracker.recycle()super.onDetachedFromWindow()}
}

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8. conflict/ListViewEx.kt

package com.shakespace.artofandroid.chapter03.conflictimport android.content.Context
import android.util.AttributeSet
import android.view.MotionEvent
import android.widget.ListView/*** 自定义 ListView，使用【内部拦截法】处理滑动冲突* 在 dispatchTouchEvent 中主动控制父容器是否拦截*/
class ListViewEx @JvmOverloads constructor(context: Context?,attrs: AttributeSet? = null,defStyleAttr: Int = 0
) : ListView(context, attrs, defStyleAttr) {private var lastX = 0private var lastY = 0override fun dispatchTouchEvent(ev: MotionEvent): Boolean {val eventX = ev.x.toInt()val eventY = ev.y.toInt()when (ev.action) {MotionEvent.ACTION_DOWN -> {// 先允许自己处理事件parent.requestDisallowInterceptTouchEvent(true)}MotionEvent.ACTION_MOVE -> {val deltaX = eventX - lastXval deltaY = eventY - lastY// 如果是垂直滑动，禁止父容器拦截；否则允许val disallowIntercept = Math.abs(deltaX) <= Math.abs(deltaY)parent.requestDisallowInterceptTouchEvent(disallowIntercept)}MotionEvent.ACTION_UP -> {// 无特殊处理}}lastX = eventXlastY = eventYreturn super.dispatchTouchEvent(ev)}
}

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注：HorizontalScrollViewEx2.kt 与 HorizontalScrollViewEx.kt 逻辑高度重复，且存在逻辑缺陷（onInterceptTouchEvent 在非 DOWN 事件直接返回 true），故未单独列出。建议以 HorizontalScrollViewEx.kt 为准。

三、文档笔记

z_memo01.txt

1. Event FlowActivity --> Window --> Viewif all views not handle the event, will back to Activity/*** Called when a touch screen event was not handled by any of the views* under it.  This is most useful to process touch events that happen* outside of your window bounds, where there is no view to receive it.** @param event The touch screen event being processed.** @return Return true if you have consumed the event, false if you haven't.* The default implementation always returns false.*/public boolean onTouchEvent(MotionEvent event) {if (mWindow.shouldCloseOnTouch(this, event)) {finish();return true;}return false;}@UnsupportedAppUsage(maxTargetSdk = Build.VERSION_CODES.P, trackingBug = 115609023)public boolean shouldCloseOnTouch(Context context, MotionEvent event) {final boolean isOutside =event.getAction() == MotionEvent.ACTION_UP && isOutOfBounds(context, event)|| event.getAction() == MotionEvent.ACTION_OUTSIDE;if (mCloseOnTouchOutside && peekDecorView() != null && isOutside) {return true;}return false;}2. An Event Sequence = a Down + many Move + a Up  （事件序列，由一个按下，多个移动，一个抬起组成）3. Normally, an event should be consumed only by one View  （通常一个序列应该由一个 view 处理）4. In an event sequence, if a view calls onInterceptTouchEvent, then the rest of the event sequence will all be handled by this view and onInterceptTouchEvent will not be called again.5. If a view returns false in Down Event, then the rest events will not be handled by this view  （如果一个 view 没有处理 DOWN，那么也不会处理后续）6. ViewGroup will not intercept any event by default → onInterceptTouchEvent returns false  （ViewGroup 默认不会拦截）7. If a view clickable = false and longClickable = false, then onTouchEvent will return false.8. Can call requestDisallowInterceptTouchEvent in child view.

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z_memo02 source code.txt

1. Activitypublic boolean dispatchTouchEvent(MotionEvent ev) {if (ev.getAction() == MotionEvent.ACTION_DOWN) {onUserInteraction(); // empty method}if (getWindow().superDispatchTouchEvent(ev)) {return true;}return onTouchEvent(ev);}2. PhoneWindow@Overridepublic boolean superDispatchTouchEvent(MotionEvent event) {return mDecor.superDispatchTouchEvent(event);}// This is the top-level view of the window, containing the window decor.private DecorView mDecor;3. com.android.internal.policy.DecorView  // hide/** @hide */public class DecorView extends FrameLayout implements RootViewSurfaceTaker, WindowCallbacks {private static final String TAG = "DecorView";....}4. ViewGroup: dispatchTouchEventfinal boolean intercepted;if (actionMasked == MotionEvent.ACTION_DOWN || mFirstTouchTarget != null) {final boolean disallowIntercept = (mGroupFlags & FLAG_DISALLOW_INTERCEPT) != 0;if (!disallowIntercept) {intercepted = onInterceptTouchEvent(ev);ev.setAction(action); // restore action in case it was changed} else {intercepted = false;}}- mFirstTouchTarget: if there is a view that has handled the previous event, mFirstTouchTarget would not be null.- disallowIntercept: set by requestDisallowInterceptTouchEvent.(Except for DOWN event, ViewGroup will call onInterceptTouchEvent in each DOWN event because it resets FLAG_DISALLOW_INTERCEPT.)// 请求父类不要拦截：如果 disallowIntercept is true, parent does not intercept → intercepted = false// Note: onInterceptTouchEvent may not be called in an entire event sequence.5. If not intercepted:for (int i = childrenCount - 1; i >= 0; i--) {final int childIndex = getAndVerifyPreorderedIndex(childrenCount, i, customOrder);final View child = getAndVerifyPreorderedView(preorderedList, children, childIndex);if (childWithAccessibilityFocus != null) {if (childWithAccessibilityFocus != child) {continue;}childWithAccessibilityFocus = null;i = childrenCount - 1;}if (!child.canReceivePointerEvents()|| !isTransformedTouchPointInView(x, y, child, null)) {ev.setTargetAccessibilityFocus(false);continue;}newTouchTarget = getTouchTarget(child);if (newTouchTarget != null) {newTouchTarget.pointerIdBits |= idBitsToAssign;break;}resetCancelNextUpFlag(child);if (dispatchTransformedTouchEvent(ev, false, child, idBitsToAssign)) {mLastTouchDownTime = ev.getDownTime();if (preorderedList != null) {for (int j = 0; j < childrenCount; j++) {if (children[childIndex] == mChildren[j]) {mLastTouchDownIndex = j;break;}}} else {mLastTouchDownIndex = childIndex;}mLastTouchDownX = ev.getX();mLastTouchDownY = ev.getY();newTouchTarget = addTouchTarget(child, idBitsToAssign);  // set touchTargetalreadyDispatchedToNewTouchTarget = true;break;}ev.setTargetAccessibilityFocus(false);}// 可见性 和 动画，结合点击点是否在区域内// 当 view 可见时，返回 true；当 view 不可见，若设置了动画，也返回 true（因为动画可能使其隐藏？？）protected boolean canReceivePointerEvents() {return (mViewFlags & VISIBILITY_MASK) == VISIBLE || getAnimation() != null;}private boolean dispatchTransformedTouchEvent(MotionEvent event, boolean cancel,View child, int desiredPointerIdBits) {final boolean handled;final int oldAction = event.getAction();if (cancel || oldAction == MotionEvent.ACTION_CANCEL) {event.setAction(MotionEvent.ACTION_CANCEL);if (child == null) {handled = super.dispatchTouchEvent(event); // → View.dispatchTouchEvent(ev)} else {handled = child.dispatchTouchEvent(event);}event.setAction(oldAction);return handled;}}6. In Viewif (onFilterTouchEventForSecurity(event)) {if ((mViewFlags & ENABLED_MASK) == ENABLED && handleScrollBarDragging(event)) {result = true;}ListenerInfo li = mListenerInfo;if (li != null && li.mOnTouchListener != null&& (mViewFlags & ENABLED_MASK) == ENABLED&& li.mOnTouchListener.onTouch(this, event)) {result = true;}if (!result && onTouchEvent(event)) {result = true;}}- Will call mOnTouchListener.onTouch first.- onTouchEvent(ev)final boolean clickable = ((viewFlags & CLICKABLE) == CLICKABLE|| (viewFlags & LONG_CLICKABLE) == LONG_CLICKABLE)|| (viewFlags & CONTEXT_CLICKABLE) == CONTEXT_CLICKABLE;if ((viewFlags & ENABLED_MASK) == DISABLED) {if (action == MotionEvent.ACTION_UP && (mPrivateFlags & PFLAG_PRESSED) != 0) {setPressed(false);}mPrivateFlags3 &= ~PFLAG3_FINGER_DOWN;// A disabled view that is clickable still consumes the touch events, it just doesn't respond to them.return clickable;}if (mTouchDelegate != null) {if (mTouchDelegate.onTouchEvent(event)) {return true;}}// 可点击 / 长按 / 响应鼠标（或触控笔）就可以消费点击事件if (clickable || (viewFlags & TOOLTIP) == TOOLTIP) {....}// will return true.So: if view is disabled, onTouchListener won't work, but onTouchEvent still gets called.Returns true if clickable / longClickable / contextClickable / or (viewFlags & TOOLTIP) == TOOLTIP.7. In addition:public void setOnClickListener(@Nullable OnClickListener l) {if (!isClickable()) {setClickable(true);}getListenerInfo().mOnClickListener = l;}public void setOnLongClickListener(@Nullable OnLongClickListener l) {if (!isLongClickable()) {setLongClickable(true);}getListenerInfo().mOnLongClickListener = l;}

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z_memo03 scroll conflict.txt

处理滑动冲突：Case 1. Outer horizontal, Inner vertical  (e.g., ViewPager + Fragment with ListView)- When MOVE is horizontal → OUTER should intercept the event.- When MOVE is vertical → INNER should intercept the event.- Check using |Δx| > |Δy|.Case 2. Outer vertical, Inner vertical  Depends on business logic (e.g., whether inner is at top/bottom).Case 3. Nested Case 1 and Case 2.

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z_memo04滑动和弹性滑动.txt

// TODO 补充滑动和弹性滑动1. 滑动的三种方式：- scrollTo / scrollBy- 属性动画（ObjectAnimator / ValueAnimator）- 修改 LayoutParams 并调用 requestLayout()2. 弹性滑动的三种方式：- Scroller + computeScroll()- ValueAnimator + update listener- Handler + postDelayed（不推荐）