Expo中Android模拟器出现Player is accessed on wrong thread错误求助

错误情况 #

• 应用重载时触发线程错误：

Player is accessed on the wrong thread.
Current thread: 'mqt_native_modules'
Expected thread: 'main'

• 卸载声音时日志报错：

LOG Sound loaded successfully
ERROR Error unloading sound: [Error: Player does not exist.]

测试代码 #

import { Audio } from 'expo-av';

useEffect(() => {
    const sound = new Audio.Sound();

    const loadAndPlaySound = async () => {
        try {
            await sound.loadAsync(require('../../sounds/app_notification.mp3'));
            await sound.playAsync();
            console.log('Sound played successfully');
        } catch (error) {
            console.error('Error loading or playing sound:', error);
        }
    };

    loadAndPlaySound();

    return () => {
        const unloadSound = async () => {
            try {
                await sound.unloadAsync();
                console.log('Sound unloaded successfully');
            } catch (error) {
                console.error('Error unloading sound:', error);
            }
        };

        unloadSound();
    };
}, []);

修复方案 #

核心问题 #

1. 卸载操作在非主线程执行，触发ExoPlayer的线程检查错误；
2. 组件卸载时声音可能还未完成加载，直接执行unloadAsync导致实例不存在报错。

修改后代码 #

import { Audio } from 'expo-av';
import { runOnUI } from 'expo-modules-core';

useEffect(() => {
    const sound = new Audio.Sound();
    let isSoundLoaded = false;

    const loadAndPlaySound = async () => {
        try {
            await sound.loadAsync(require('../../sounds/app_notification.mp3'));
            isSoundLoaded = true;
            await sound.playAsync();
            console.log('Sound played successfully');
        } catch (error) {
            console.error('Error loading or playing sound:', error);
        }
    };

    loadAndPlaySound();

    return () => {
        // 强制在主线程执行卸载逻辑
        runOnUI(async () => {
            if (isSoundLoaded) {
                try {
                    await sound.unloadAsync();
                    console.log('Sound unloaded successfully');
                } catch (error) {
                    console.error('Error unloading sound:', error);
                }
            }
        })();
    };
}, []);

关键改动说明 #

• 使用runOnUI将卸载逻辑切换到主线程，解决线程不匹配问题；
• 添加isSoundLoaded状态标记，仅在声音成功加载后执行卸载，避免实例不存在的错误。

内容的提问来源于stack exchange，提问作者sparkey