Fix media gallery activity

Summary:
Weird edge case, this activity doesnt actualy contain the content and instead its in the decor view behind it, solution is to filter it out from traversal and snapshot

https://fb.workplace.com/groups/443457641253219/permalink/643518977913750/

Reviewed By: elboman, lblasa

Differential Revision: D50936817

fbshipit-source-id: 8c1e276d4d943c42c9c2085bf70113347cbd5c74

android/src/main/java/com/facebook/flipper/plugins/uidebugger/core/ActivityTracker.kt

@@ -12,6 +12,7 @@ import android.app.Activity
 import android.app.Application
 import android.os.Build
 import android.os.Bundle
+import android.view.View
 import java.lang.ref.WeakReference
 import java.lang.reflect.Field
 import java.lang.reflect.Method
@@ -103,6 +104,11 @@ object ActivityTracker : Application.ActivityLifecycleCallbacks {
       return stack
     }
 
+  val decorViewToActivityMap: Map<View, Activity>
+    get() {
+      return activitiesStack.toList().associateBy { it.window.decorView }
+    }
+
   /**
    * Activity tracker is used to track activities. However, it cannot track via life-cycle events
    * all those activities that were created prior to initialisation via the `start(application:

android/src/main/java/com/facebook/flipper/plugins/uidebugger/core/ApplicationRef.kt

@@ -9,6 +9,7 @@ package com.facebook.flipper.plugins.uidebugger.core
 
 import android.app.Activity
 import android.app.Application
+import android.view.View
 
 class ApplicationRef(val application: Application) {
   init {

android/src/main/java/com/facebook/flipper/plugins/uidebugger/core/DecorViewTracker.kt

@@ -7,6 +7,7 @@
 
 package com.facebook.flipper.plugins.uidebugger.core
 
+import android.app.Activity
 import android.util.Log
 import android.view.View
 import android.view.ViewTreeObserver
@@ -58,7 +59,14 @@ class DecorViewTracker(private val context: UIDContext, private val snapshotter:
             currentDecorView?.viewTreeObserver?.removeOnPreDrawListener(preDrawListener)
 
             // setup new listener on top most view, that will be the active child in traversal
-            val topView = rootViews.lastOrNull(ApplicationRefDescriptor::isUsefulRoot)
+
+            val decorViewToActivity: Map<View, Activity> = ActivityTracker.decorViewToActivityMap
+
+            val topView =
+                rootViews.lastOrNull { view ->
+                  val activityOrView = decorViewToActivity[view] ?: view
+                  ApplicationRefDescriptor.isUsefulRoot(activityOrView)
+                }
 
             if (topView != null) {
               val throttler =

android/src/main/java/com/facebook/flipper/plugins/uidebugger/core/Snapshot.kt

@@ -104,8 +104,8 @@ class PixelCopySnapshotter(
       bitmap: BitmapPool.ReusableBitmap
   ): Boolean {
 
-    val decorViewToActivity: Map<View, Activity> =
-        applicationRef.activitiesStack.toList().associateBy { it.window.decorView }
+    
+    val decorViewToActivity: Map<View, Activity> = ActivityTracker.decorViewToActivityMap     
 
     val activityForDecorView = decorViewToActivity[view] ?: return false
 

android/src/main/java/com/facebook/flipper/plugins/uidebugger/descriptors/ApplicationRefDescriptor.kt

@@ -10,6 +10,7 @@ package com.facebook.flipper.plugins.uidebugger.descriptors
 import android.app.Activity
 import android.view.View
 import android.view.ViewGroup
+import com.facebook.flipper.plugins.uidebugger.core.ActivityTracker
 import com.facebook.flipper.plugins.uidebugger.core.ApplicationRef
 import com.facebook.flipper.plugins.uidebugger.model.Bounds
 import com.facebook.flipper.plugins.uidebugger.util.DisplayMetrics
@@ -33,12 +34,11 @@ object ApplicationRefDescriptor : ChainedDescriptor<ApplicationRef>() {
   override fun onGetChildren(node: ApplicationRef): List<Any> {
     val children = mutableListOf<Any>()
 
-    val activeRoots = node.rootsResolver.rootViews()
+    val rootViews = node.rootsResolver.rootViews()
 
-    val decorViewToActivity: Map<View, Activity> =
-        node.activitiesStack.toList().associateBy { it.window.decorView }
+    val decorViewToActivity: Map<View, Activity> = ActivityTracker.decorViewToActivityMap
 
-    for (root in activeRoots) {
+    for (root in rootViews) {
       // if there is an activity for this root view use that,
       // if not just return the root view that was added directly to the window manager
       val activity = decorViewToActivity[root]
@@ -52,16 +52,31 @@ object ApplicationRefDescriptor : ChainedDescriptor<ApplicationRef>() {
     return children
   }
 
-  fun isUsefulRoot(obj: Any): Boolean {
-    if (obj is Activity) {
+  /**
+   * arg is either an acitivity if the root view has one other views the root view attached to the
+   * window manager returns boolean indicating whether we are interested in it and whether we should
+   * track, traverse and snapshot it
+   */
+  fun isUsefulRoot(rootViewOrActivity: Any): Boolean {
+    val className = rootViewOrActivity.javaClass.name
+
+    if (className.contains("mediagallery.ui.MediaGalleryActivity")) {
+      // this activity doesn't contain the content and its actually in the decor view behind it, so
+      // skip it :/
+      return false
+    }
+
+    if (rootViewOrActivity is Activity) {
+      // in general we want views attached to activities
       return true
     }
-    val isFoldableOverlayInfraView = javaClass.simpleName.contains("OverlayHandlerView")
+
+    val isFoldableOverlayInfraView = className.contains("OverlayHandlerView")
     return if (isFoldableOverlayInfraView) {
       false
-    } else if (obj is ViewGroup) {
+    } else if (rootViewOrActivity is ViewGroup) {
       // sometimes there is a root view on top that has no children that isn't useful to inspect
-      obj.childCount > 0
+      rootViewOrActivity.childCount > 0
     } else {
       false
     }