Support a swipe down to dismiss video (#2879)

* Support a swipe down to dismiss video

Images can already be dismissed with a swipe, this adds the same
functionality to videos.

- Add a VideoActionsListener interface for the hosting activity to dismiss
  the fragment
- Add a gesture listener for swipes
- Dismiss the fragment if a swipe has a greated Y component than X

Fixes https://github.com/tuskyapp/Tusky/issues/2833

* Scale the video view when dragging

Provides identical visual feedback to the same operation on images.

app/src/main/java/com/keylesspalace/tusky/ViewMediaActivity.kt

@@ -52,6 +52,7 @@ import com.keylesspalace.tusky.components.viewthread.ViewThreadActivity
 import com.keylesspalace.tusky.databinding.ActivityViewMediaBinding
 import com.keylesspalace.tusky.entity.Attachment
 import com.keylesspalace.tusky.fragment.ViewImageFragment
+import com.keylesspalace.tusky.fragment.ViewVideoFragment
 import com.keylesspalace.tusky.pager.ImagePagerAdapter
 import com.keylesspalace.tusky.pager.SingleImagePagerAdapter
 import com.keylesspalace.tusky.util.getTemporaryMediaFilename
@@ -68,7 +69,7 @@ import java.util.Locale
 
 typealias ToolbarVisibilityListener = (isVisible: Boolean) -> Unit
 
-class ViewMediaActivity : BaseActivity(), ViewImageFragment.PhotoActionsListener {
+class ViewMediaActivity : BaseActivity(), ViewImageFragment.PhotoActionsListener, ViewVideoFragment.VideoActionsListener {
 
     private val binding by viewBinding(ActivityViewMediaBinding::inflate)
 

app/src/main/java/com/keylesspalace/tusky/fragment/ViewVideoFragment.kt

@@ -18,27 +18,36 @@ package com.keylesspalace.tusky.fragment
 import android.animation.Animator
 import android.animation.AnimatorListenerAdapter
 import android.annotation.SuppressLint
+import android.content.Context
 import android.os.Bundle
 import android.os.Handler
 import android.os.Looper
 import android.text.method.ScrollingMovementMethod
+import android.view.GestureDetector
 import android.view.KeyEvent
 import android.view.LayoutInflater
+import android.view.MotionEvent
 import android.view.View
 import android.view.ViewGroup
 import android.widget.MediaController
+import androidx.core.view.GestureDetectorCompat
 import com.keylesspalace.tusky.ViewMediaActivity
 import com.keylesspalace.tusky.databinding.FragmentViewVideoBinding
 import com.keylesspalace.tusky.entity.Attachment
 import com.keylesspalace.tusky.util.hide
 import com.keylesspalace.tusky.util.visible
 import com.keylesspalace.tusky.view.ExposedPlayPauseVideoView
+import kotlin.math.abs
 
 class ViewVideoFragment : ViewMediaFragment() {
+    interface VideoActionsListener {
+        fun onDismiss()
+    }
 
     private var _binding: FragmentViewVideoBinding? = null
     private val binding get() = _binding!!
 
+    private lateinit var videoActionsListener: VideoActionsListener
     private lateinit var toolbar: View
     private val handler = Handler(Looper.getMainLooper())
     private val hideToolbar = Runnable {
@@ -52,6 +61,11 @@ class ViewVideoFragment : ViewMediaFragment() {
     private lateinit var mediaController: MediaController
     private var isAudio = false
 
+    override fun onAttach(context: Context) {
+        super.onAttach(context)
+        videoActionsListener = context as VideoActionsListener
+    }
+
     override fun setUserVisibleHint(isVisibleToUser: Boolean) {
         // Start/pause/resume video playback as fragment is shown/hidden
         super.setUserVisibleHint(isVisibleToUser)
@@ -168,6 +182,7 @@ class ViewVideoFragment : ViewMediaFragment() {
         return binding.root
     }
 
+    @SuppressLint("ClickableViewAccessibility")
     override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
         super.onViewCreated(view, savedInstanceState)
         val attachment = arguments?.getParcelable<Attachment>(ARG_ATTACHMENT)
@@ -177,6 +192,54 @@ class ViewVideoFragment : ViewMediaFragment() {
         }
         val url = attachment.url
         isAudio = attachment.type == Attachment.Type.AUDIO
+
+        val gestureDetector = GestureDetectorCompat(
+            requireContext(),
+            object : GestureDetector.SimpleOnGestureListener() {
+                override fun onDown(event: MotionEvent): Boolean {
+                    return true
+                }
+
+                override fun onFling(
+                    e1: MotionEvent,
+                    e2: MotionEvent,
+                    velocityX: Float,
+                    velocityY: Float
+                ): Boolean {
+                    if (abs(velocityY) > abs(velocityX)) {
+                        videoActionsListener.onDismiss()
+                        return true
+                    }
+                    return false
+                }
+            }
+        )
+
+        var lastY = 0f
+        binding.root.setOnTouchListener { _, event ->
+            if (event.action == MotionEvent.ACTION_DOWN) {
+                lastY = event.rawY
+            } else if (event.pointerCount == 1 && event.action == MotionEvent.ACTION_MOVE) {
+                val diff = event.rawY - lastY
+                if (binding.videoView.translationY != 0f || abs(diff) > 40) {
+                    binding.videoView.translationY += diff
+                    val scale = (-abs(binding.videoView.translationY) / 720 + 1).coerceAtLeast(0.5f)
+                    binding.videoView.scaleY = scale
+                    binding.videoView.scaleX = scale
+                    lastY = event.rawY
+                    return@setOnTouchListener true
+                }
+            } else if (event.action == MotionEvent.ACTION_UP || event.action == MotionEvent.ACTION_CANCEL) {
+                if (abs(binding.videoView.translationY) > 180) {
+                    videoActionsListener.onDismiss()
+                } else {
+                    binding.videoView.animate().translationY(0f).scaleX(1f).scaleY(1f).start()
+                }
+            }
+
+            gestureDetector.onTouchEvent(event)
+        }
+
         finalizeViewSetup(url, attachment.previewUrl, attachment.description)
     }