android 10车载桌面ActivityView触摸事件源码详解分析

hi，粉丝朋友们：

背景

大家好！近来居然有好几个粉丝朋友居然问到了一个虚拟屏幕触摸相关的问题，还有老版本android 10上面有个车载桌面使用的ActivityView可以正常触摸的问题。
其实这个ActivityView在最新的版本已经没有了，所以以前的话没有去重点分析这个ActivityView触摸部分的原理剖析，但是发现虽然没有了ActivityView。但是很多同学还是喜欢自己在高版本又写一个类似的ActivityView。基于这个背景下，拿出老版本的ActivityView分析一下其实现原理还是有必要哈。前面的blog本身已经分析了ActivityView的显示Activity原理部分，本节就来重点分析ActvityView是怎么在系统中正常触摸的。
为了分析这个ActivityView的触摸原理，我这边特别下载了android 10的代码编译好了一个car的模拟器进行验证分析

车载桌面的当前表现

目前车载的桌面显示如下图，绿色的“”No maps …“”这个区域就是ActivityView，他属于搞了个新的虚拟Display然后启动的Activity。所以这里的就会存在在CarLauncher上面显示两个Activity，一个是桌面自己，一个是地图绿色的Activity，但是大家注意哈，这里的绿色区域的地图Activity明显属于另一个display，这里我们是知道的触摸都是每个display独立的，即多屏display显示都是有各自display的触摸节点。
但是目前画面都显示在主屏幕display0这个屏幕，所以我们触摸绿色区域，肯定触摸事件是display0的，肯定不会到虚拟display去，这个是我们的理论分析的哈，认为如果要虚拟display有事件，必须要手动注入模拟相关的触摸事件注入到虚拟display。但事实真的是这样吗？

在这里插入图片描述

认为绿色虚拟屏幕不可能有触摸事件接受，我们来验证一下是不是触摸没有触摸事件
为了验证，在地图容器Activity的dispatchTouchEvent有日志打印，以此来确定是否有事件到Activity。
实际上在触摸绿色区域时候，发现有对于事件：


```bash
11-13 00:29:48.738  3638  3638 I lsm11   : dispatchTouchEvent ev MotionEvent { action=ACTION_DOWN, actionButton=0, id[0]=0, x[0]=188.97656, y[0]=107.98242, toolType[0]=TOOL_TYPE_FINGER, buttonState=0, classification=NONE, metaState=0, flags=0x0, edgeFlags=0x0, pointerCount=1, historySize=0, eventTime=2719884, downTime=2719884, deviceId=0, source=0x1002, displayId=0 }

11-13 00:29:48.851  3638  3638 I lsm11   : dispatchTouchEvent ev MotionEvent { action=ACTION_UP, actionButton=0, id[0]=0, x[0]=188.97656, y[0]=107.98242, toolType[0]=TOOL_TYPE_FINGER, buttonState=0, classification=NONE, metaState=0, flags=0x0, edgeFlags=0x0, pointerCount=1, historySize=0, eventTime=2719996, downTime=2719884, deviceId=0, source=0x1002, displayId=0 }

看到结果是不是感觉自己被狠狠打脸了。。。。。
为啥可以收到触摸主屏幕触摸事件呢，activity明明显示在另一个display

问题追踪分析线索：

怀疑线索1：

11-13 00:29:48.738 3638 3638 I lsm11 : dispatchTouchEvent ev MotionEvent { action=ACTION_DOWN, actionButton=0, id[0]=0, x[0]=188.97656, y[0]=107.98242, toolType[0]=TOOL_TYPE_FINGER, buttonState=0, classification=NONE, metaState=0, flags=0x0, edgeFlags=0x0, pointerCount=1, historySize=0, eventTime=2719884, downTime=2719884, deviceId=0, source=0x1002, ~~displayId=0~~ }

看这里触摸事件时候大家是不是发现明明这个displayId居然还是0，明显不太和逻辑是吧，，，正常触摸事件是不是应该为displayId = 1（假设虚拟屏幕是displayId = 1）
不过换着想一下这个displayId决定是inputreader，即说明在inputreader时候就认为是主屏幕事件，故立马吧方向就不用放到inputreader部分

线索2：
dumpsys input

INPUT MANAGER (dumpsys input)

Input Manager State:
  Interactive: true
  System UI Visibility: 0x8008
  Pointer Speed: 0
  Pointer Gestures Enabled: true
  Show Touches: false
  Pointer Capture Enabled: false

Event Hub State:
  BuiltInKeyboardId: 2
  Devices:
    -1: Virtual
      Classes: 0x40000023
      Path: <virtual>
      Enabled: true
      Descriptor: a718a782d34bc767f4689c232d64d527998ea7fd
      Location: 
      ControllerNumber: 0
      UniqueId: <virtual>
      Identifier: bus=0x0000, vendor=0x0000, product=0x0000, version=0x0000
      KeyLayoutFile: /system/usr/keylayout/Generic.kl
      KeyCharacterMapFile: /system/usr/keychars/Virtual.kcm
      ConfigurationFile: 
      HaveKeyboardLayoutOverlay: false
      VideoDevice: <none>
    1: Power Button
      Classes: 0x00000001
      Path: /dev/input/event0
      Enabled: true
      Descriptor: 26d13db3fa0f6bd5d05831266fb01ea6c500b88c
      Location: LNXPWRBN/button/input0
      ControllerNumber: 0
      UniqueId: 
      Identifier: bus=0x0019, vendor=0x0000, product=0x0001, version=0x0000
      KeyLayoutFile: /system/usr/keylayout/Generic.kl
      KeyCharacterMapFile: /system/usr/keychars/Generic.kcm
      ConfigurationFile: 
      HaveKeyboardLayoutOverlay: false
      VideoDevice: <none>
    2: qwerty2 (aka device 0 - built-in keyboard)
      Classes: 0x000000bd
      Path: /dev/input/event1
      Enabled: true
      Descriptor: 04c0f71d9920e1e448166e8a4feebf80d1849c2f
      Location: 
      ControllerNumber: 0
      UniqueId: 
      Identifier: bus=0x0019, vendor=0x0000, product=0x0000, version=0x0000
      KeyLayoutFile: /system/usr/keylayout/qwerty.kl
      KeyCharacterMapFile: /system/usr/keychars/qwerty2.kcm
      ConfigurationFile: /system/usr/idc/qwerty2.idc
      HaveKeyboardLayoutOverlay: false
      VideoDevice: <none>
    3: goldfish_rotary
      Classes: 0x00001000
      Path: /dev/input/event2
      Enabled: true
      Descriptor: 9286b20e4aaa6bcaca619b728b030e3f7b422ee6
      Location: 
      ControllerNumber: 0
      UniqueId: 
      Identifier: bus=0x0019, vendor=0x0000, product=0x0000, version=0x0000
      KeyLayoutFile: 
      KeyCharacterMapFile: 
      ConfigurationFile: /vendor/usr/idc/goldfish_rotary.idc
      HaveKeyboardLayoutOverlay: false
      VideoDevice: <none>
  Unattached video devices:
    <none>

Input Reader State:
  Device -1: Virtual
    Generation: 2
    IsExternal: false
    AssociatedDisplayPort: <none>
    HasMic:     false
    Sources: 0x00000301
    KeyboardType: 2
    Keyboard Input Mapper:
      Parameters:
        OrientationAware: false
        HandlesKeyRepeat: false
      KeyboardType: 2
      Orientation: 0
      KeyDowns: 0 keys currently down
      MetaState: 0x0
      DownTime: 0
  Device 0: qwerty2
    Generation: 12
    IsExternal: false
    AssociatedDisplayPort: <none>
    HasMic:     false
    Sources: 0x80011307
    KeyboardType: 1
    Motion Ranges:
      X: source=0x00010004, min=-1.000, max=1.000, flat=0.000, fuzz=0.167, resolution=0.000
      Y: source=0x00010004, min=-1.000, max=1.000, flat=0.000, fuzz=0.167, resolution=0.000
      PRESSURE: source=0x00010004, min=0.000, max=1.000, flat=0.000, fuzz=0.000, resolution=0.000
      X: source=0x00001002, min=0.000, max=799.000, flat=0.000, fuzz=0.000, resolution=0.000
      Y: source=0x00001002, min=0.000, max=479.000, flat=0.000, fuzz=0.000, resolution=0.000
      PRESSURE: source=0x00001002, min=0.000, max=1.000, flat=0.000, fuzz=0.000, resolution=0.000
      SIZE: source=0x00001002, min=0.000, max=1.000, flat=0.000, fuzz=0.000, resolution=0.000
      TOUCH_MAJOR: source=0x00001002, min=0.000, max=932.952, flat=0.000, fuzz=0.000, resolution=0.000
      TOUCH_MINOR: source=0x00001002, min=0.000, max=932.952, flat=0.000, fuzz=0.000, resolution=0.000
      TOOL_MAJOR: source=0x00001002, min=0.000, max=932.952, flat=0.000, fuzz=0.000, resolution=0.000
      TOOL_MINOR: source=0x00001002, min=0.000, max=932.952, flat=0.000, fuzz=0.000, resolution=0.000
    Switch Input Mapper:
      SwitchValues: 0
    Keyboard Input Mapper:
      Parameters:
        OrientationAware: true
        HandlesKeyRepeat: false
      KeyboardType: 1
      Orientation: 0
      KeyDowns: 0 keys currently down
      MetaState: 0x0
      DownTime: 0
    Cursor Input Mapper:
      Parameters:
        HasAssociatedDisplay: true
        Mode: navigation
        OrientationAware: true
      XScale: 0.167
      YScale: 0.167
      XPrecision: 6.000
      YPrecision: 6.000
      HaveVWheel: false
      HaveHWheel: false
      VWheelScale: 1.000
      HWheelScale: 1.000
      Orientation: 0
      ButtonState: 0x00000000
      Down: false
      DownTime: 0
    Touch Input Mapper (mode - direct):
      Parameters:
        GestureMode: multi-touch
        DeviceType: touchScreen
        AssociatedDisplay: hasAssociatedDisplay=true, isExternal=false, displayId=''
        OrientationAware: true
      Raw Touch Axes:
        X: min=0, max=32767, flat=0, fuzz=0, resolution=0
        Y: min=0, max=32767, flat=0, fuzz=0, resolution=0
        Pressure: min=0, max=256, flat=0, fuzz=0, resolution=0
        TouchMajor: min=0, max=2147483647, flat=0, fuzz=0, resolution=0
        TouchMinor: unknown range
        ToolMajor: unknown range
        ToolMinor: unknown range
        Orientation: unknown range
        Distance: unknown range
        TiltX: unknown range
        TiltY: unknown range
        TrackingId: min=0, max=10, flat=0, fuzz=0, resolution=0
        Slot: min=0, max=9, flat=0, fuzz=0, resolution=0
      Calibration:
        touch.size.calibration: geometric
        touch.pressure.calibration: physical
        touch.orientation.calibration: none
        touch.distance.calibration: none
        touch.coverage.calibration: none
      Affine Transformation:
        X scale: 1.000
        X ymix: 0.000
        X offset: 0.000
        Y xmix: 0.000
        Y scale: 1.000
        Y offset: 0.000
      Viewport INTERNAL: displayId=0, uniqueId=local:0, port=0, orientation=0, logicalFrame=[0, 0, 800, 480], physicalFrame=[0, 0, 800, 480], deviceSize=[800, 480]
      SurfaceWidth: 800px
      SurfaceHeight: 480px
      SurfaceLeft: 0
      SurfaceTop: 0
      PhysicalWidth: 800px
      PhysicalHeight: 480px
      PhysicalLeft: 0
      PhysicalTop: 0
      SurfaceOrientation: 0
      Translation and Scaling Factors:
        XTranslate: 0.000
        YTranslate: 0.000
        XScale: 0.024
        YScale: 0.015
        XPrecision: 40.960
        YPrecision: 68.267
        GeometricScale: 0.020
        PressureScale: 0.004
        SizeScale: 0.000
        OrientationScale: 0.000
        DistanceScale: 0.000
        HaveTilt: false
        TiltXCenter: 0.000
        TiltXScale: 0.000
        TiltYCenter: 0.000
        TiltYScale: 0.000
      Last Raw Button State: 0x00000000
      Last Raw Touch: pointerCount=0
      Last Cooked Button State: 0x00000000
      Last Cooked Touch: pointerCount=0
      Stylus Fusion:
        ExternalStylusConnected: false
        External Stylus ID: -1
        External Stylus Data Timeout: 9223372036854775807
      External Stylus State:
        When: 9223372036854775807
        Pressure: 0.000000
        Button State: 0x00000000
        Tool Type: 0
  Device 1: Power Button
    Generation: 9
    IsExternal: false
    AssociatedDisplayPort: <none>
    HasMic:     false
    Sources: 0x00000101
    KeyboardType: 1
    Keyboard Input Mapper:
      Parameters:
        OrientationAware: false
        HandlesKeyRepeat: false
      KeyboardType: 1
      Orientation: 0
      KeyDowns: 0 keys currently down
      MetaState: 0x0
      DownTime: 0
  Device 3: goldfish_rotary
    Generation: 4
    IsExternal: false
    AssociatedDisplayPort: <none>
    HasMic:     false
    Sources: 0x00400000
    KeyboardType: 0
    Motion Ranges:
      26: source=0x00400000, min=-1.000, max=1.000, flat=0.000, fuzz=0.000, resolution=0.791
    Rotary Encoder Input Mapper:
      HaveWheel: true
  Configuration:
    ExcludedDeviceNames: []
    VirtualKeyQuietTime: 0.0ms
    PointerVelocityControlParameters: scale=1.000, lowThreshold=500.000, highThreshold=3000.000, acceleration=3.000
    WheelVelocityControlParameters: scale=1.000, lowThreshold=15.000, highThreshold=50.000, acceleration=4.000
    PointerGesture:
      Enabled: true
      QuietInterval: 100.0ms
      DragMinSwitchSpeed: 50.0px/s
      TapInterval: 150.0ms
      TapDragInterval: 300.0ms
      TapSlop: 20.0px
      MultitouchSettleInterval: 100.0ms
      MultitouchMinDistance: 15.0px
      SwipeTransitionAngleCosine: 0.3
      SwipeMaxWidthRatio: 0.2
      MovementSpeedRatio: 0.8
      ZoomSpeedRatio: 0.3
      Viewports:
        Viewport INTERNAL: displayId=0, uniqueId=local:0, port=0, orientation=0, logicalFrame=[0, 0, 800, 480], physicalFrame=[0, 0, 800, 480], deviceSize=[800, 480]

Input Classifier State:
  Motion Classifier:
    <nullptr>

Input Dispatcher State:
  DispatchEnabled: true
  DispatchFrozen: false
  InputFilterEnabled: false
  FocusedDisplayId: 2
  FocusedApplications:
    displayId=3, name='AppWindowToken{34ea2d9 token=Token{6cc1920 ActivityRecord{e2df023 u10 android.car.cluster/.FakeFreeNavigationActivity t1000019}}}', dispatchingTimeout=5000.000ms
    displayId=2, name='AppWindowToken{7f21912 token=Token{601109d ActivityRecord{c985374 u10 com.android.car.mapsplaceholder/.MapsPlaceholderActivity t1000018}}}', dispatchingTimeout=5000.000ms
    displayId=1, name='AppWindowToken{ba4478b token=Token{f67795a ActivityRecord{aba2505 u0 android.car.cluster/.MainClusterActivity t5}}}', dispatchingTimeout=5000.000ms
    displayId=0, name='AppWindowToken{b53bbef token=Token{3bc30ce ActivityRecord{f6201c9 u10 com.android.car.carlauncher/.CarLauncher t1000002}}}', dispatchingTimeout=5000.000ms
  FocusedWindows:
    displayId=0, name='Window{71ec913 u10 com.android.car.carlauncher/com.android.car.carlauncher.CarLauncher}'
    displayId=2, name='Window{36a3ea8 u10 com.android.car.mapsplaceholder/com.android.car.mapsplaceholder.MapsPlaceholderActivity}'
    displayId=3, name='Window{752545a u10 android.car.cluster/android.car.cluster.FakeFreeNavigationActivity}'
    displayId=1, name='Window{96a3c94 u0 android.car.cluster/android.car.cluster.MainClusterActivity}'
  TouchStates: <no displays touched>
  Display: 3
    Windows:
      0: name='Window{752545a u10 android.car.cluster/android.car.cluster.FakeFreeNavigationActivity}', displayId=3, portalToDisplayId=-1, paused=false, hasFocus=true, hasWallpaper=false, visible=true, canReceiveKeys=true, flags=0x01810520, type=0x00000001, layer=0, frame=[0,0][1280,520], globalScale=1.000000, windowScale=(1.000000,1.000000), touchableRegion=[0,0][1280,520], inputFeatures=0x00000000, ownerPid=3735, ownerUid=1001000, dispatchingTimeout=5000.000ms
  Display: 2
    Windows:
      0: name='Window{36a3ea8 u10 com.android.car.mapsplaceholder/com.android.car.mapsplaceholder.MapsPlaceholderActivity}', displayId=2, portalToDisplayId=-1, paused=false, hasFocus=true, hasWallpaper=false, visible=true, canReceiveKeys=true, flags=0x81810120, type=0x00000001, layer=0, frame=[12,69][474,384], globalScale=1.000000, windowScale=(1.000000,1.000000), touchableRegion=[12,69][474,384], inputFeatures=0x00000000, ownerPid=3638, ownerUid=1010066, dispatchingTimeout=5000.000ms
  Display: 1
    Windows:
      0: name='Window{96a3c94 u0 android.car.cluster/android.car.cluster.MainClusterActivity}', displayId=1, portalToDisplayId=-1, paused=false, hasFocus=true, hasWallpaper=false, visible=true, canReceiveKeys=true, flags=0x01810520, type=0x00000001, layer=0, frame=[0,0][1280,720], globalScale=1.000000, windowScale=(1.000000,1.000000), touchableRegion=[0,0][1280,720], inputFeatures=0x00000000, ownerPid=3472, ownerUid=1000, dispatchingTimeout=5000.000ms
  Display: 0
    Windows:
      0: name='Window{263dc87 u0 CarNavigationBar}', displayId=0, portalToDisplayId=-1, paused=false, hasFocus=false, hasWallpaper=false, visible=true, canReceiveKeys=false, flags=0x01840028, type=0x000007e3, layer=0, frame=[0,396][800,480], globalScale=1.000000, windowScale=(1.000000,1.000000), touchableRegion=[0,396][800,480], inputFeatures=0x00000000, ownerPid=2020, ownerUid=10099, dispatchingTimeout=5000.000ms
      1: name='Window{586637c u0 StatusBar}', displayId=0, portalToDisplayId=-1, paused=false, hasFocus=false, hasWallpaper=false, visible=true, canReceiveKeys=false, flags=0x81840048, type=0x000007d0, layer=0, frame=[0,0][800,57], globalScale=1.000000, windowScale=(1.000000,1.000000), touchableRegion=[0,0][800,57], inputFeatures=0x00000000, ownerPid=2020, ownerUid=10099, dispatchingTimeout=5000.000ms
      2: name='Window{71ec913 u10 com.android.car.carlauncher/com.android.car.carlauncher.CarLauncher}', displayId=0, portalToDisplayId=-1, paused=false, hasFocus=true, hasWallpaper=true, visible=true, canReceiveKeys=true, flags=0x81910120, type=0x00000001, layer=0, frame=[0,0][800,480], globalScale=1.000000, windowScale=(1.000000,1.000000), touchableRegion=[0,0][800,69]|[0,69][12,384]|[474,69][800,384]|[0,384][800,480], inputFeatures=0x00000000, ownerPid=3531, ownerUid=1001000, dispatchingTimeout=5000.000ms
      3: name='Surface(name=ActivityViewVirtualDisplay)/@0x8f6acba', displayId=0, portalToDisplayId=2, paused=false, hasFocus=false, hasWallpaper=false, visible=true, canReceiveKeys=false, flags=0x00800028, type=0x00000000, layer=0, frame=[12,69][474,384], globalScale=1.000000, windowScale=(1.000000,1.000000), touchableRegion=[12,69][474,384], inputFeatures=0x00000000, ownerPid=1875, ownerUid=1000, dispatchingTimeout=0.000ms
      4: name='Window{5bed72e u10 com.android.systemui.ImageWallpaper}', displayId=0, portalToDisplayId=-1, paused=false, hasFocus=false, hasWallpaper=false, visible=true, canReceiveKeys=false, flags=0x00014318, type=0x000007dd, layer=0, frame=[0,0][963,480], globalScale=1.000000, windowScale=(2.666667,2.666667), touchableRegion=[0,0][361,180], inputFeatures=0x00000000, ownerPid=2528, ownerUid=1010099, dispatchingTimeout=5000.000ms

这里我们仔细看我们发现主屏幕display 0有一个Window：

 3: name='Surface(name=ActivityViewVirtualDisplay)/@0x8f6acba', displayId=0, portalToDisplayId=2, paused=false, hasFocus=false, hasWallpaper=false, visible=true, canReceiveKeys=false, flags=0x00800028, type=0x00000000, layer=0, frame=[12,69][474,384], globalScale=1.000000, windowScale=(1.000000,1.000000), touchableRegion=[12,69][474,384], inputFeatures=0x00000000, ownerPid=1875, ownerUid=1000, dispatchingTimeout=0.000ms

这个Surface(name=ActivityViewVirtualDisplay)就是ActivityView专门创建的一个input层面的window，仔细分析他的时候发现有一个变量引起我们的注意：
portalToDisplayId=2,

明显其他窗口都是 -1，他是2，而且这个2又刚好是我们的虚拟display的Id，哈哈哈到了这里大家就是不是找到核心问题点。

原理流程分析：

寻找触摸事件接受窗口时候会根据判断这个portalToDisplayId值，如果有这个值，会重新遍历这个displayId上的window代替自己这个display的window。即实现了Surface(name=ActivityViewVirtualDisplay)/@0x8f6acba这窗口的触摸事件接受都转到了displayId = portalToDisplayId的window上：
0: name=‘Window{36a3ea8 u10 com.android.car.mapsplaceholder/com.android.car.mapsplaceholder.MapsPlaceholderActivity}’, displayId=2,
在这里插入图片描述