Android开发：如何实现WebView内输入打字时播放自定义音效

代码优化及修改说明 #

你原有代码存在两个可优化问题：

1. 每次调用soundOn()都重新创建SoundPool实例，会导致内存占用高、音效播放延迟，建议改为全局初始化一次
2. 变量名大小写错误：webSettings定义后使用时写成了小写开头的websettings

具体实现思路 #

通过注入JavaScript监听网页内所有输入框的按键事件，触发Android原生的音效播放逻辑，不需要修改网页源码，同时采用事件委托适配所有动态生成的输入元素。 #

完整修改后代码 #

public class WebViewActivity extends AppCompatActivity {
    private WebView webView;
    private SoundPool soundPool;
    private int soundId;
    String url = "www.google.com";

    // JS桥接接口类，供网页侧调用原生方法
    public class JsSoundInterface {
        @JavascriptInterface
        public void playTypeSound() {
            runOnUiThread(() -> soundOn());
        }
    }

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.webview);
        // 提前初始化音效池，避免重复创建
        initSoundPool();

        webView = findViewById(R.id.webView);
        WebSettings webSettings = webView.getSettings();

        webSettings.setDomStorageEnabled(true);
        webSettings.setJavaScriptEnabled(true);
        webView.getSettings().setAppCachePath(getApplicationContext().getFilesDir().getAbsolutePath() + "/cache");
        webView.getSettings().setDatabasePath(getApplicationContext().getFilesDir().getAbsolutePath() + "/databases");
        // 绑定JS桥接接口
        webView.addJavascriptInterface(new JsSoundInterface(), "AndroidSoundBridge");

        if (Build.VERSION.SDK_INT >= 21) {
            CookieManager.getInstance().setAcceptThirdPartyCookies(webView, true);
        } else {
            CookieManager.getInstance().setAcceptCookie(true);
        }

        webView.loadUrl(url);

        webView.setWebViewClient(new WebViewClient(){
            @Override
            public boolean shouldOverrideUrlLoading(WebView view, String url) {
                soundOn();
                view.loadUrl(url);
                return true;
            }
            @Override
            public void onPageFinished(WebView view, String url) {
                super.onPageFinished(view, url);
                // 注入全局按键监听JS，事件委托适配所有动态输入元素
                String injectJs = "javascript:(function() {" +
                        "document.addEventListener('keydown', function(e) {" +
                        "   var target = e.target;" +
                        "   if(target.tagName === 'INPUT' || target.tagName === 'TEXTAREA' || target.isContentEditable) {" +
                        "       window.AndroidSoundBridge.playTypeSound();" +
                        "   }" +
                        "});" +
                        "})()";
                if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.KITKAT) {
                    webView.evaluateJavascript(injectJs, null);
                } else {
                    webView.loadUrl(injectJs);
                }
            }
        });
    }

    private void initSoundPool() {
        soundPool = new SoundPool.Builder()
                .setMaxStreams(5)
                .build();
        // 预加载音效资源
        soundId = soundPool.load(getApplicationContext(), R.raw.mysound, 1);
    }

    private void soundOn() {
        // 直接播放预加载的音效，无需重复加载
        soundPool.play(soundId, 1f, 1f, 0, 0, 1);
    }

    @Override
    protected void onDestroy() {
        super.onDestroy();
        // 释放音效池资源
        if(soundPool != null) {
            soundPool.release();
            soundPool = null;
        }
    }
}

内容的提问来源于stack exchange，提问作者Gedanggoreng