fix: recover video playback after composition removal (#203)

Make VideoMetadata observable by Compose: convert the data class to a
regular class whose fields are backed by mutableStateOf, so in-place
mutations of width/height/etc. trigger recomposition. copy(), equals(),
hashCode() and toString() are preserved manually for API compatibility.

On Android, re-attach the ExoPlayer to the PlayerView inside the
AndroidView update callback when playerView.player is null. onReset
nulls the player and calls onPause() for LazyList recycling; without a
re-attach on update, the surface stayed blank when scrolling a recycled
item back into view.

Author: kdroidFilter

mediaplayer/src/androidMain/kotlin/io/github/kdroidfilter/composemediaplayer/VideoPlayerSurface.android.kt

@@ -207,12 +207,15 @@ private fun VideoPlayerContent(
                 },
                 update = { playerView ->
                     try {
-                        // Verify that the player is still valid before updating
-                        if (playerState is DefaultVideoPlayerState &&
-                            playerState.exoPlayer != null &&
-                            playerView.player != null
-                        ) {
-                            // Update the resize mode when contentScale changes
+                        val state = playerState as? DefaultVideoPlayerState
+                        if (state?.exoPlayer != null) {
+                            // Re-attach after LazyList recycle: onReset nulls playerView.player
+                            // and calls onPause(). Without this, the surface stays blank until
+                            // the user navigates away and back.
+                            if (playerView.player == null) {
+                                state.attachPlayerView(playerView)
+                                playerView.onResume()
+                            }
                             playerView.resizeMode = mapContentScaleToResizeMode(contentScale)
                         }
                     } catch (e: Exception) {

mediaplayer/src/commonMain/kotlin/io/github/kdroidfilter/composemediaplayer/VideoMetadata.kt

@@ -1,14 +1,16 @@
 package io.github.kdroidfilter.composemediaplayer
 
 import androidx.compose.runtime.Stable
+import androidx.compose.runtime.getValue
+import androidx.compose.runtime.mutableStateOf
+import androidx.compose.runtime.setValue
 
 /**
  * Represents metadata information of a video file.
  *
- * This data class holds various attributes related to the video content,
- * including its title, artist, duration, dimensions, codec details, and audio properties.
- * This metadata is typically used to provide detailed information about a video
- * during playback or for insights in media management systems.
+ * Properties are backed by [mutableStateOf] so mutations trigger Compose recomposition.
+ * This matters when callers update fields in place (e.g. on `onVideoSizeChanged` or HLS
+ * resolution changes) while the metadata instance is read from a composable.
  *
  * @property title The title of the video, if available.
  * @property duration The length of the video in milliseconds, if known.
@@ -21,21 +23,29 @@ import androidx.compose.runtime.Stable
  * @property audioSampleRate The sample rate of the audio track in the video, measured in Hz.
  */
 @Stable
-data class VideoMetadata(
-    var title: String? = null,
-    var duration: Long? = null, // Duration in milliseconds
-    var width: Int? = null,
-    var height: Int? = null,
-    var bitrate: Long? = null, // Bitrate in bits per second
-    var frameRate: Float? = null,
-    var mimeType: String? = null,
-    var audioChannels: Int? = null,
-    var audioSampleRate: Int? = null,
+class VideoMetadata(
+    title: String? = null,
+    duration: Long? = null,
+    width: Int? = null,
+    height: Int? = null,
+    bitrate: Long? = null,
+    frameRate: Float? = null,
+    mimeType: String? = null,
+    audioChannels: Int? = null,
+    audioSampleRate: Int? = null,
 ) {
+    var title: String? by mutableStateOf(title)
+    var duration: Long? by mutableStateOf(duration)
+    var width: Int? by mutableStateOf(width)
+    var height: Int? by mutableStateOf(height)
+    var bitrate: Long? by mutableStateOf(bitrate)
+    var frameRate: Float? by mutableStateOf(frameRate)
+    var mimeType: String? by mutableStateOf(mimeType)
+    var audioChannels: Int? by mutableStateOf(audioChannels)
+    var audioSampleRate: Int? by mutableStateOf(audioSampleRate)
+
     /**
      * Checks if all properties of this metadata object are null.
-     *
-     * @return true if all properties are null, false otherwise.
      */
     fun isAllNull(): Boolean =
         title == null &&
@@ -47,4 +57,59 @@ data class VideoMetadata(
             mimeType == null &&
             audioChannels == null &&
             audioSampleRate == null
+
+    fun copy(
+        title: String? = this.title,
+        duration: Long? = this.duration,
+        width: Int? = this.width,
+        height: Int? = this.height,
+        bitrate: Long? = this.bitrate,
+        frameRate: Float? = this.frameRate,
+        mimeType: String? = this.mimeType,
+        audioChannels: Int? = this.audioChannels,
+        audioSampleRate: Int? = this.audioSampleRate,
+    ): VideoMetadata =
+        VideoMetadata(
+            title = title,
+            duration = duration,
+            width = width,
+            height = height,
+            bitrate = bitrate,
+            frameRate = frameRate,
+            mimeType = mimeType,
+            audioChannels = audioChannels,
+            audioSampleRate = audioSampleRate,
+        )
+
+    override fun equals(other: Any?): Boolean {
+        if (this === other) return true
+        if (other !is VideoMetadata) return false
+        return title == other.title &&
+            duration == other.duration &&
+            width == other.width &&
+            height == other.height &&
+            bitrate == other.bitrate &&
+            frameRate == other.frameRate &&
+            mimeType == other.mimeType &&
+            audioChannels == other.audioChannels &&
+            audioSampleRate == other.audioSampleRate
+    }
+
+    override fun hashCode(): Int {
+        var result = title?.hashCode() ?: 0
+        result = 31 * result + (duration?.hashCode() ?: 0)
+        result = 31 * result + (width ?: 0)
+        result = 31 * result + (height ?: 0)
+        result = 31 * result + (bitrate?.hashCode() ?: 0)
+        result = 31 * result + (frameRate?.hashCode() ?: 0)
+        result = 31 * result + (mimeType?.hashCode() ?: 0)
+        result = 31 * result + (audioChannels ?: 0)
+        result = 31 * result + (audioSampleRate ?: 0)
+        return result
+    }
+
+    override fun toString(): String =
+        "VideoMetadata(title=$title, duration=$duration, width=$width, height=$height, " +
+            "bitrate=$bitrate, frameRate=$frameRate, mimeType=$mimeType, " +
+            "audioChannels=$audioChannels, audioSampleRate=$audioSampleRate)"
 }