fix: 弹幕数量少于实际数量&优化弹幕请求 issues #78

lib/http/danmaku.dart

@@ -17,17 +17,11 @@ class DanmakaHttp {
       'oid': cid,
       'segment_index': segmentIndex,
     };
-
-    // 计算函数
-    Future<DmSegMobileReply> computeTask(Map<String, int> params) async {
-      var response = await Request().get(
-        Api.webDanmaku,
-        data: params,
-        extra: {'resType': ResponseType.bytes},
-      );
-      return DmSegMobileReply.fromBuffer(response.data);
-    }
-
-    return await compute(computeTask, params);
+    var response = await Request().get(
+      Api.webDanmaku,
+      data: params,
+      extra: {'resType': ResponseType.bytes},
+    );
+    return DmSegMobileReply.fromBuffer(response.data);
   }
 }

lib/pages/danmaku/controller.dart

@@ -10,22 +10,32 @@ class PlDanmakuController {
   // 按 6min 分段
   int segCount = 0;
   List<DmSegMobileReply> dmSegList = [];
-  int currentSegIndex = 0;
+  int currentSegIndex = 1;
   int currentDmIndex = 0;
 
   void calcSegment() {
+    dmSegList.clear();
+    // 视频分段数
     segCount = (videoDuration.inSeconds / (60 * 6)).ceil();
+    dmSegList = List<DmSegMobileReply>.generate(
+        segCount < 1 ? 1 : segCount, (index) => DmSegMobileReply());
+    // 当前分段
+    try {
+      currentSegIndex =
+          (playerController.position.value.inSeconds / (60 * 6)).ceil();
+      currentSegIndex = currentSegIndex < 1 ? 1 : currentSegIndex;
+    } catch (_) {}
   }
 
   Future<List<DmSegMobileReply>> queryDanmaku() async {
-    dmSegList.clear();
-    for (int segIndex = 1; segIndex <= segCount; segIndex++) {
-      DmSegMobileReply result =
-          await DanmakaHttp.queryDanmaku(cid: cid, segmentIndex: segIndex);
-      if (result.elems.isNotEmpty) {
-        result.elems.sort((a, b) => (a.progress).compareTo(b.progress));
-        dmSegList.add(result);
-      }
+    // dmSegList.clear();
+    DmSegMobileReply result =
+        await DanmakaHttp.queryDanmaku(cid: cid, segmentIndex: currentSegIndex);
+    if (result.elems.isNotEmpty) {
+      result.elems.sort((a, b) => (a.progress).compareTo(b.progress));
+      // dmSegList.add(result);
+      currentSegIndex = currentSegIndex < 1 ? 1 : currentSegIndex;
+      dmSegList[currentSegIndex - 1] = result;
     }
     if (dmSegList.isNotEmpty) {
       findClosestPositionIndex(playerController.position.value.inMilliseconds);

lib/pages/danmaku/view.dart

@@ -1,3 +1,4 @@
+import 'package:easy_debounce/easy_throttle.dart';
 import 'package:flutter/material.dart';
 import 'package:get/get.dart';
 import 'package:hive/hive.dart';
@@ -88,7 +89,15 @@ class _PlDanmakuState extends State<PlDanmaku> {
     PlDanmakuController ctr = _plDanmakuController;
     int currentPosition = position.inMilliseconds;
     blockTypes = playerController.blockTypes;
-
+    // 根据position判断是否有已缓存弹幕。没有则请求对应段
+    int segIndex = (currentPosition / (6 * 60 * 1000)).ceil();
+    segIndex = segIndex < 1 ? 1 : segIndex;
+    if (ctr.dmSegList[segIndex - 1].elems.isEmpty) {
+      ctr.currentSegIndex = segIndex;
+      EasyThrottle.throttle('follow', const Duration(seconds: 1), () {
+        ctr.queryDanmaku();
+      });
+    }
     if (!playerController.isOpenDanmu.value) {
       return;
     }
@@ -140,26 +149,30 @@ class _PlDanmakuState extends State<PlDanmaku> {
 
   @override
   Widget build(BuildContext context) {
-    return Obx(
-      () => AnimatedOpacity(
-        opacity: playerController.isOpenDanmu.value ? 1 : 0,
-        duration: const Duration(milliseconds: 100),
-        child: DanmakuView(
-          createdController: (DanmakuController e) async {
-            widget.playerController.danmakuController = _controller = e;
-          },
-          option: DanmakuOption(
-            fontSize: 15 * fontSizeVal,
-            area: showArea,
-            opacity: opacityVal,
-            hideTop: blockTypes.contains(5),
-            hideScroll: blockTypes.contains(2),
-            hideBottom: blockTypes.contains(4),
-            duration: danmakuSpeedVal * widget.playerController.playbackSpeed,
+    return LayoutBuilder(builder: (context, box) {
+      double initDuration = box.maxWidth / 12;
+      return Obx(
+        () => AnimatedOpacity(
+          opacity: playerController.isOpenDanmu.value ? 1 : 0,
+          duration: const Duration(milliseconds: 100),
+          child: DanmakuView(
+            createdController: (DanmakuController e) async {
+              widget.playerController.danmakuController = _controller = e;
+            },
+            option: DanmakuOption(
+              fontSize: 15 * fontSizeVal,
+              area: showArea,
+              opacity: opacityVal,
+              hideTop: blockTypes.contains(5),
+              hideScroll: blockTypes.contains(2),
+              hideBottom: blockTypes.contains(4),
+              duration: initDuration /
+                  (danmakuSpeedVal * widget.playerController.playbackSpeed),
+            ),
+            statusChanged: (isPlaying) {},
           ),
-          statusChanged: (isPlaying) {},
         ),
-      ),
-    );
+      );
+    });
   }
 }