feat(player): 增加进度条拖动画面预览

android/app/src/main/kotlin/com/stormg/lumadrama/MainActivity.kt

@@ -5,8 +5,13 @@ package com.stormg.lumadrama
 import android.content.Intent
 import android.app.PictureInPictureParams
 import android.content.res.Configuration
+import android.graphics.Bitmap
+import android.media.MediaMetadataRetriever
+import android.net.Uri
 import android.os.Build
 import android.os.Bundle
+import android.os.Handler
+import android.os.Looper
 import android.util.Rational
 import android.content.pm.PackageManager
 import android.view.WindowManager
@@ -15,12 +20,19 @@ import androidx.core.view.WindowInsetsCompat
 import io.flutter.embedding.android.FlutterActivity
 import io.flutter.embedding.engine.FlutterEngine
 import io.flutter.plugin.common.MethodChannel
+import java.io.ByteArrayOutputStream
+import java.util.concurrent.ExecutorService
+import java.util.concurrent.Executors
+import java.util.concurrent.atomic.AtomicBoolean
 
 class MainActivity : FlutterActivity() {
     private val shareRequestCode = 9041
+    private val thumbnailExecutor: ExecutorService = Executors.newSingleThreadExecutor()
+    private val thumbnailHandler = Handler(Looper.getMainLooper())
     private var pendingShare: MethodChannel.Result? = null
     private var pipChannel: MethodChannel? = null
     private var keyboardChannel: MethodChannel? = null
+    private var thumbnailChannel: MethodChannel? = null
     private var imeInset = 0
 
     override fun onCreate(savedInstanceState: Bundle?) {
@@ -86,6 +98,47 @@ class MainActivity : FlutterActivity() {
             emitImeInset(inset)
             result.success(inset)
         }
+        thumbnailChannel = MethodChannel(
+            flutterEngine.dartExecutor.binaryMessenger,
+            "com.stormg.lumadrama/thumbnail"
+        )
+        thumbnailChannel?.setMethodCallHandler { call, result ->
+            if (call.method != "frame") {
+                result.notImplemented()
+                return@setMethodCallHandler
+            }
+            val timeMs = (call.argument<Number>("timeMs"))?.toLong()
+            if (timeMs == null) {
+                result.success(null)
+                return@setMethodCallHandler
+            }
+            val localPath = call.argument<String>("localPath").orEmpty()
+            val remoteUrl = call.argument<String>("url").orEmpty()
+            val rawHeaders = call.argument<Map<*, *>>("headers")
+            val headers = rawHeaders?.entries
+                ?.associate { it.key.toString() to it.value.toString() }
+                .orEmpty()
+            val responded = AtomicBoolean(false)
+            val task = thumbnailExecutor.submit {
+                val bytes = renderThumbnail(
+                    timeMs = timeMs,
+                    localPath = localPath,
+                    remoteUrl = remoteUrl,
+                    headers = headers
+                )
+                thumbnailHandler.post {
+                    if (responded.compareAndSet(false, true)) {
+                        result.success(bytes)
+                    }
+                }
+            }
+            thumbnailHandler.postDelayed({
+                if (responded.compareAndSet(false, true)) {
+                    task.cancel(true)
+                    result.success(null)
+                }
+            }, thumbnailTimeoutMs)
+        }
         val decorView = window.decorView
         ViewCompat.setOnApplyWindowInsetsListener(decorView) { view, insets ->
             emitImeInset(insets.getInsets(WindowInsetsCompat.Type.ime()).bottom)
@@ -106,6 +159,59 @@ class MainActivity : FlutterActivity() {
         keyboardChannel?.invokeMethod("insetsChanged", value)
     }
 
+    private fun renderThumbnail(
+        timeMs: Long,
+        localPath: String,
+        remoteUrl: String,
+        headers: Map<String, String>
+    ): ByteArray? {
+        val retriever = MediaMetadataRetriever()
+        var frame: Bitmap? = null
+        var scaled: Bitmap? = null
+        return try {
+            when {
+                localPath.isNotEmpty() -> retriever.setDataSource(normalizeLocalPath(localPath))
+                remoteUrl.isNotEmpty() -> retriever.setDataSource(remoteUrl, headers)
+                else -> return null
+            }
+            frame = retriever.getFrameAtTime(
+                timeMs * 1000,
+                MediaMetadataRetriever.OPTION_CLOSEST_SYNC
+            )
+            val source = frame ?: return null
+            scaled = if (source.width > thumbnailMaxWidth) {
+                val targetHeight = (source.height * thumbnailMaxWidth / source.width)
+                    .coerceAtLeast(1)
+                Bitmap.createScaledBitmap(
+                    source,
+                    thumbnailMaxWidth,
+                    targetHeight,
+                    true
+                )
+            } else {
+                source
+            }
+            val outputBitmap = scaled ?: source
+            val output = ByteArrayOutputStream()
+            val compressed = outputBitmap.compress(
+                Bitmap.CompressFormat.JPEG,
+                thumbnailJpegQuality,
+                output
+            )
+            if (!compressed) return null
+            output.toByteArray()
+        } catch (_: Exception) {
+            null
+        } finally {
+            if (scaled != null && scaled !== frame) scaled.recycle()
+            frame?.recycle()
+            retriever.release()
+        }
+    }
+
+    private fun normalizeLocalPath(path: String): String =
+        if (path.startsWith("file:")) Uri.parse(path).path ?: path else path
+
     override fun onPictureInPictureModeChanged(isInPictureInPictureMode: Boolean, newConfig: Configuration) {
         super.onPictureInPictureModeChanged(isInPictureInPictureMode, newConfig)
         pipChannel?.invokeMethod("onPipChanged", isInPictureInPictureMode)
@@ -124,6 +230,16 @@ class MainActivity : FlutterActivity() {
         ViewCompat.setOnApplyWindowInsetsListener(window.decorView, null)
         keyboardChannel?.setMethodCallHandler(null)
         keyboardChannel = null
+        thumbnailChannel?.setMethodCallHandler(null)
+        thumbnailChannel = null
+        thumbnailHandler.removeCallbacksAndMessages(null)
+        thumbnailExecutor.shutdownNow()
         super.onDestroy()
     }
+
+    companion object {
+        private const val thumbnailMaxWidth = 240
+        private const val thumbnailJpegQuality = 70
+        private const val thumbnailTimeoutMs = 1500L
+    }
 }