由于按下后退按钮而导致的意外行为

Question

我有两个活动。活动 A 包含包含图像的卡片视图元素的回收器视图。在选择活动 A 中的元素时。图像的完整横向版本显示在活动 B 中。

活动 B 的布局文件如下所示：

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">

<androidx.appcompat.widget.AppCompatImageView
android:id="@+id/imageView"
android:layout_width="match_parent"
android:layout_height="match_parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
/>
</androidx.constraintlayout.widget.ConstraintLayout>

活动 B 的代码库如下所示：

class PosterViewActivity : AppCompatActivity()
{
private lateinit var imageView: AppCompatImageView
override fun onCreate(savedInstanceState: Bundle?)
{
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_poster_view)
init()
}
private fun init()
{
findViewsByID()
getBundle()
toggleHide()
}  
private fun getBundle()
{
if (intent != null)
{
var imageUrl = intent.getStringExtra(ARG_IMAGE_URL)
if (imageUrl != null)
{
Glide.with(this).load(imageUrl).centerInside().into(imageView)
}
}
}
private fun findViewsByID()
{
imageView = findViewById(R.id.imageView)
}
override fun onOptionsItemSelected(item: MenuItem): Boolean
{
if (item.itemId == android.R.id.home)
{
intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP)
}
return super.onOptionsItemSelected(item)
}
override fun onBackPressed()
{
super.onBackPressed()
intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP)
}
override fun onWindowFocusChanged(hasFocus: Boolean)
{
super.onWindowFocusChanged(hasFocus)
}
private fun toggleHide()
{
val uiOptions = window.decorView.systemUiVisibility
var newUiOptions = uiOptions
val isImmersiveModeEnabled = uiOptions or View.SYSTEM_UI_FLAG_IMMERSIVE_STICKY == uiOptions
if (isImmersiveModeEnabled)
{
Log.i("PosterViewActivity", "Turning immersive mode mode off. ")
}
else
{
Log.i("PosterViewActivity", "Turning immersive mode mode on.")
}
if (Build.VERSION.SDK_INT >= 14)
{
newUiOptions = newUiOptions xor View.SYSTEM_UI_FLAG_HIDE_NAVIGATION
}
// Status bar hiding: Backwards compatible to Jellybean
if (Build.VERSION.SDK_INT >= 16)
{
newUiOptions = newUiOptions xor View.SYSTEM_UI_FLAG_FULLSCREEN
}
if (Build.VERSION.SDK_INT >= 18)
{
newUiOptions = newUiOptions xor View.SYSTEM_UI_FLAG_IMMERSIVE_STICKY
}
window.decorView.systemUiVisibility = newUiOptions
}
}

但是，当我按下设备上的后退按钮而不是返回活动 A 时。状态和导航按钮将显示和隐藏，只需按 4 次后退按钮即可返回活动 A。我已经检查了后退堆栈，堆栈中有两个活动，即 A 和 B

活动 A 中的代码调用活动 B：

if(promoList.size >0)
{
noPromoImageView.visibility = View.GONE
noPromoTextView.visibility = View.GONE
promoAdapter = PromotionsAdapter(this, promoList!!)
promoRecyclerView.layoutManager = GridLayoutManager(this, 3)
promoRecyclerView.adapter = promoAdapter
promoRecyclerView.addOnItemTouchListener(
RecyclerTouchListener(applicationContext,
promoRecyclerView,
object : ClickListener
{
override fun onClick(view: View, position: Int)
{
openPosterView(position)
}
override fun onLongClick(view: View?, position: Int)
{
}
}))
}
else
{
noPromoImageView.visibility = View.VISIBLE
noPromoTextView.visibility = View.VISIBLE
}
}
private fun openPosterView(position: Int)
{
val posterImageDetails = displayedRules!![position]!!.imageDetails
if (posterImageDetails.isNotEmpty())
{
var cur = -1
for ((pos, item) in posterImageDetails.withIndex())
{
val key = item.containsValue("Fullscreen")
if (key)
{
cur = pos
}
}
var imagesLink: Map<String, String>
if (cur > -1)
{
imagesLink = posterImageDetails[cur]
var imageUrl = imagesLink?.get("ImageUrl")
if (imageUrl!!.isNotEmpty())
{
var intent = Intent(this, PosterViewActivity::class.java)
var bundle = Bundle()
bundle.putString(ARG_IMAGE_URL, imageUrl)
intent.putExtras(bundle)
this.startActivity(intent)
}
}
}
}
internal class RecyclerTouchListener(context: Context, recyclerView: RecyclerView, private val clickListener: ClickListener) : RecyclerView.OnItemTouchListener
{
private val gestureDetector: GestureDetector
init
{
gestureDetector = GestureDetector(
context,
object : GestureDetector.SimpleOnGestureListener()
{
override fun onSingleTapUp(e: MotionEvent): Boolean
{
return true
}
override fun onLongPress(e: MotionEvent)
{
val child = recyclerView.findChildViewUnder(e.x, e.y)
if (child != null && clickListener != null)
{
clickListener.onLongClick(child, recyclerView.getChildPosition(child))
}
}
})
}
override fun onInterceptTouchEvent(rv: RecyclerView, e: MotionEvent): Boolean
{
val child = rv.findChildViewUnder(e.x, e.y)
if (child != null && clickListener != null && gestureDetector.onTouchEvent(e))
{
clickListener.onClick(child, rv.getChildPosition(child))
}
return false
}
override fun onTouchEvent(rv: RecyclerView, e: MotionEvent)
{
}
override fun onRequestDisallowInterceptTouchEvent(disallowIntercept: Boolean)
{
}
}

Answer 1

在我看来，活动 A 的 clickListener 是错误的。项目计数可以是 4，单击项目时，项目的 onClickListener 可以调用活动 B 4 次。

Answer 2

正如Farid通过扩展recyclerview的ontouchlistener所建议的那样，它增加了更多的复杂性。我最初拥有并放弃的最简单的解决方案是在适配器中添加一个 OnClick 侦听器

inner class PromoViewHolder(view: View) : RecyclerView.ViewHolder(view), View.OnClickListener
{
override fun onClick(v: View?)
{
openPosterView(adapterPosition)
}
private val description: JustifiedTextView
private val duration: AppCompatTextView
private val startDate: AppCompatTextView
private val endDate: AppCompatTextView
private val imageViewCompact: AppCompatImageView
init
{
description = itemView.findViewById(R.id.textViewProductOnPromo)
duration = itemView.findViewById(R.id.textViewPromoDates)
imageViewCompact = itemView.findViewById(R.id.imageViewCompact)
startDate = itemView.findViewById(R.id.textViewStartDate)
endDate = itemView.findViewById(R.id.textViewEndDate)
view.setOnClickListener(this)
}
}