Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 12147e69 authored by George Lin's avatar George Lin
Browse files

Fix race condition for clock carousel 

Carousel.mMotionLayout is only ready after attachedToWindow. We can only
bind the view after attachedToWindow; otherwise, whenever the flow emits
any events before attachedToWindow and triggers calls to
Carousel.mMotionLayout, there will be a null pointer exception.

Test: Manually tested the app does not crash when emits early
Fixes: 278784117
Change-Id: Id65ed932b1526062063e453e910d16e01e1508dd
parent cd6f9606

src/com/android/customization/picker/clock/ui/view/ClockCarouselView.kt

+1 −1
Original line number Diff line number Diff line
@@ -38,7 +38,7 @@ class ClockCarouselView( 


    var isCarouselInTransition = false



    private val carousel: Carousel

    val carousel: Carousel

    private val motionLayout: MotionLayout

    private lateinit var adapter: ClockCarouselAdapter

    private lateinit var scalingUpClockController: ClockController

src/com/android/customization/picker/preview/ui/section/PreviewWithClockCarouselSectionController.kt

+36 −9
Original line number Diff line number Diff line
@@ -20,8 +20,10 @@ package com.android.customization.picker.preview.ui.section 
import android.app.Activity

import android.content.Context

import android.view.View

import android.view.View.OnAttachStateChangeListener

import android.view.ViewGroup

import android.view.ViewStub

import androidx.constraintlayout.helper.widget.Carousel

import androidx.lifecycle.LifecycleOwner

import androidx.lifecycle.lifecycleScope

import com.android.customization.picker.clock.ui.binder.ClockCarouselViewBinder
@@ -39,6 +41,7 @@ import com.android.wallpaper.picker.customization.domain.interactor.WallpaperInt 
import com.android.wallpaper.picker.customization.ui.section.ScreenPreviewSectionController

import com.android.wallpaper.picker.customization.ui.section.ScreenPreviewView

import com.android.wallpaper.util.DisplayUtils

import kotlinx.coroutines.Job

import kotlinx.coroutines.launch



/** Controls the screen preview section. */
@@ -90,6 +93,18 @@ class PreviewWithClockCarouselSectionController( 
            val singleClockViewStub: ViewStub = view.requireViewById(R.id.single_clock_view_stub)

            singleClockViewStub.layoutResource = R.layout.single_clock_view

            val singleClockView = singleClockViewStub.inflate() as ViewGroup



            /**

             * Only bind after [Carousel.onAttachedToWindow]. This is to avoid the race condition

             * that the flow emits before attached to window where [Carousel.mMotionLayout] is still

             * null.

             */

            var onAttachStateChangeListener: OnAttachStateChangeListener? = null

            var bindJob: Job? = null

            onAttachStateChangeListener =

                object : OnAttachStateChangeListener {

                    override fun onViewAttachedToWindow(view: View?) {

                        bindJob =

                            lifecycleOwner.lifecycleScope.launch {

                                ClockCarouselViewBinder.bind(

                                    carouselView = carouselView,
@@ -98,7 +113,19 @@ class PreviewWithClockCarouselSectionController( 
                                    clockViewFactory = clockViewFactory,

                                    lifecycleOwner = lifecycleOwner,

                                )

                                if (onAttachStateChangeListener != null) {

                                    carouselView.carousel.removeOnAttachStateChangeListener(

                                        onAttachStateChangeListener,

                                    )

                                }

                            }

                    }



                    override fun onViewDetachedFromWindow(view: View?) {

                        bindJob?.cancel()

                    }

                }

            carouselView.carousel.addOnAttachStateChangeListener(onAttachStateChangeListener)

        }



        return view