feat: 简单实现弹幕功能

lib/pages/danmaku/controller.dart

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+import 'package:pilipala/http/danmaku.dart';
+import 'package:pilipala/models/danmaku/dm.pb.dart';
+import 'package:pilipala/plugin/pl_player/index.dart';
+
+class PlDanmakuController {
+  PlDanmakuController(this.cid, this.playerController);
+  final int cid;
+  final PlPlayerController playerController;
+  late Duration videoDuration;
+  // 按 6min 分段
+  int segCount = 0;
+  List<DmSegMobileReply> dmSegList = [];
+  int currentSegIndex = 0;
+  int currentDmIndex = 0;
+
+  void calcSegment() {
+    segCount = (videoDuration.inSeconds / (60 * 6)).ceil();
+  }
+
+  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);
+      }
+    }
+    if (dmSegList.isNotEmpty) {
+      findClosestPositionIndex(playerController.position.value.inMilliseconds);
+    }
+    return dmSegList;
+  }
+
+  /// 查询当前最接近的弹幕
+  void findClosestPositionIndex(int position) {
+    int segIndex = (position / (6 * 60 * 1000)).ceil() - 1;
+    if (segIndex < 0) segIndex = 0;
+    List elems = dmSegList[segIndex].elems;
+
+    if (segIndex < dmSegList.length) {
+      int left = 0;
+      int right = elems.length;
+
+      while (left < right) {
+        int mid = (right + left) ~/ 2;
+        var midPosition = elems[mid].progress;
+
+        if (midPosition >= position) {
+          right = mid;
+        } else {
+          left = mid + 1;
+        }
+      }
+
+      currentSegIndex = segIndex;
+      currentDmIndex = right;
+    } else {
+      currentSegIndex = segIndex;
+      currentDmIndex = 0;
+    }
+  }
+}

lib/pages/danmaku/index.dart

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+library pldanmaku;
+
+export './controller.dart';
+export 'view.dart';

lib/pages/danmaku/view.dart

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+import 'package:flutter/material.dart';
+import 'package:get/get.dart';
+import 'package:ns_danmaku/ns_danmaku.dart';
+import 'package:pilipala/pages/danmaku/index.dart';
+import 'package:pilipala/plugin/pl_player/index.dart';
+import 'package:pilipala/utils/danmaku.dart';
+
+/// 传入播放器控制器，监听播放进度，加载对应弹幕
+class PlDanmaku extends StatefulWidget {
+  final int cid;
+  final PlPlayerController playerController;
+
+  const PlDanmaku({
+    super.key,
+    required this.cid,
+    required this.playerController,
+  });
+
+  @override
+  State<PlDanmaku> createState() => _PlDanmakuState();
+}
+
+class _PlDanmakuState extends State<PlDanmaku> {
+  late PlPlayerController playerController;
+  late PlDanmakuController _plDanmakuController;
+  DanmakuController? _controller;
+  bool danmuPlayStatus = true;
+
+  @override
+  void initState() {
+    super.initState();
+    _plDanmakuController =
+        PlDanmakuController(widget.cid, widget.playerController);
+    if (mounted) {
+      playerController = widget.playerController;
+      _plDanmakuController.videoDuration = playerController.duration.value;
+      _plDanmakuController
+        ..calcSegment()
+        ..queryDanmaku();
+      playerController
+        ..addStatusLister(playerListener)
+        ..addPositionListener(videoPositionListen);
+    }
+  }
+
+  // 播放器状态监听
+  void playerListener(PlayerStatus? status) {
+    if (status == PlayerStatus.paused) {
+      _controller!.pause();
+    }
+    if (status == PlayerStatus.playing) {
+      _controller!.onResume();
+    }
+  }
+
+  void videoPositionListen(Duration position) {
+    if (!danmuPlayStatus) {
+      _controller!.onResume();
+      danmuPlayStatus = true;
+    }
+    PlDanmakuController ctr = _plDanmakuController;
+    int currentPosition = position.inMilliseconds;
+
+    // 超出分段数返回
+    if (ctr.currentSegIndex >= ctr.dmSegList.length) {
+      return;
+    }
+    if (ctr.dmSegList.isEmpty ||
+        ctr.dmSegList[ctr.currentSegIndex].elems.isEmpty) {
+      return;
+    }
+    // 超出当前分段的弹幕总数返回
+    if (ctr.currentDmIndex >= ctr.dmSegList[ctr.currentSegIndex].elems.length) {
+      ctr.currentDmIndex = 0;
+      ctr.currentSegIndex++;
+      return;
+    }
+    var element = ctr.dmSegList[ctr.currentSegIndex].elems[ctr.currentDmIndex];
+    var delta = currentPosition - element.progress;
+
+    if (delta >= 0 && delta < 200) {
+      _controller!.addItems([
+        DanmakuItem(
+          element.content,
+          color: DmUtils.decimalToColor(element.color),
+          time: element.progress,
+          type: DmUtils.getPosition(element.mode),
+        )
+      ]);
+      ctr.currentDmIndex++;
+    } else {
+      if (!playerController.isOpenDanmu.value) {
+        _controller!.pause();
+        danmuPlayStatus = false;
+        return;
+      }
+      ctr.findClosestPositionIndex(position.inMilliseconds);
+    }
+  }
+
+  @override
+  void dispose() {
+    playerController.removePositionListener(videoPositionListen);
+    super.dispose();
+  }
+
+  @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 {
+            _controller = e;
+          },
+          option: DanmakuOption(
+            fontSize: 15,
+            area: 0.5,
+            duration: 5,
+          ),
+          statusChanged: (isPlaying) {},
+        ),
+      ),
+    );
+  }
+}