InspectUI Code Review

前言

一个类似 Android Studio Layout Inspector 的工具，可以非常方便的在手机上查看当前页面的 UI 信息，包括布局层级、View 树中各个 View 的属性。

UInspector

A UI inspector to traverse a view hierarchy on Android

Preview

带着问题去看源码

• 怎么初始化的？
• 为什么需要一个 Notification？怎么实现的？
• 怎么拦截事件的？
• 如何找到对应的 View 的？View 属性？
• 如何将拦截的事件再次分发出去的？
• 设计模式相关

初始化

Uinspector-optional-autoinstall

 @RestrictTo(RestrictTo.Scope.LIBRARY)
class UInspectorInstaller : ContentProvider() {

    override fun onCreate(): Boolean {
        UInspector.create(requireNotNull(context))
        return true
    }
    //... 
}

<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.pitaya.mobile.uinspector.optional.autoinstall">

    <application>
        <provider
            android:name="com.pitaya.mobile.uinspector.optional.UInspectorInstaller"
            android:authorities="${applicationId}.uinspector.optional.installer"
            android:exported="false" />
    </application>
</manifest>

类似 LeakCanary， 使用 ContentProvider 的 Context 进行初始化。

缺点：不灵活，但是作为 debug 工具，完全可以忽略。

优点：无侵入式的依赖

Uinspector.create

fun create(context: Context) {
    if (init.compareAndSet(false, true)) {
        application = context.applicationContext as Application
        installPlugins
        lifecycle.register(application)
        stop()
    }
}

Notification

前台 Service

• UInspectorNotificationService
  • setContentIntent
  • onStartCommand
  • UInspector.changeStateInner(pendingState)
  • 前后台

如何拦截事件

• UInspector

  • changePanelState
  • UInspectorPanel

• UInspectorDialogFragment

  • 拦截事件
  • UInspectorMask

• UInspectorMask

  • dispatchKeyEvent 拦截返回键
  • onTouchEvent 拦截 down 事件
    • isSingleTap = true 时 dispatchCancelEvent

• 如何找到 DecorView

val global by lazy(LazyThreadSafetyMode.NONE) {
    Class.forName("android.view.WindowManagerGlobal")
}

val windowManagerGlobal: Any by lazy(LazyThreadSafetyMode.NONE) {
    global.getDeclaredMethod("getInstance").invoke(null)
}

val getWindowViews by lazy(LazyThreadSafetyMode.NONE) {
    val f = global.getDeclaredField("mViews")
    f.isAccessible = true
    f
}

@Suppress("KDocUnresolvedReference")
fun findAllDecorViews(): List<View>? {
    try {
        @Suppress("UNCHECKED_CAST")
        return getWindowViews.get(windowManagerGlobal) as List<View>
    } catch (e: Throwable) {
        Log.e(LibName, e.toString())
        return null
    }
}

如何找到对应的 View 的？View 属性？

• 如何找到被点击的 View

    protected val firstTouchTarget: Field by lazy(LazyThreadSafetyMode.NONE) {
        val f = ViewGroup::class.java.getDeclaredField("mFirstTouchTarget")
        f.isAccessible = true
        f
    }

    protected val touchTargetChild: Field by lazy(LazyThreadSafetyMode.NONE) {
        val cls = Class.forName("android.view.ViewGroup\$TouchTarget")
        val f = cls.getDeclaredField("child")
        f.isAccessible = true
        f
    }

 /**
 * 1. Try to get the [view]'s 'mFirstTouchTarget' field
 * 2. If fail, use [findTouchTargetByEvent] instead
 */
protected open fun findFirstTouchTarget(view: View?, touchEvent: MotionEvent): View? {
    if (view is ViewGroup) {
        return try {
            val touchTarget = firstTouchTarget.get(view)
            if (touchTarget != null) {
                touchTargetChild.get(touchTarget) as? View
            } else {
                findTouchTargetByEvent(view, touchEvent)
            }
        } catch (e: Throwable) {
            Log.e(LibName, e.toString())
            findTouchTargetByEvent(view, touchEvent)
        }
    }
    return null
}

• 面板
  -UInspectorPopupPanelContainerImpl