麦克风: 外接输入设备热插拔跟随重建 + 音量UI改硬件调节提示

- MicActivator: 支持 restart/setPreferredDevice(API26), 输入路由切换后重建占用
- MainActivity: AudioDeviceCallback(API23+)/HEADSET广播监听, USB/外接麦插入后
  自动重建 AudioRecord 跟随当前输入设备
- 麦克风音量标准Android无输入增益API: 远程界面滑杆禁用并提示'由功放/混音器
  硬件调节', 本地调音台+/−按钮同样提示, 避免假调节无效果

app/src/main/assets/mobile/app.css

@@ -15,3 +15,5 @@
 .rank-pager button:disabled{opacity:.35;box-shadow:none}
 .rank-pager b{min-width:64px;text-align:center;color:#b9a9c9;font-size:11px}
 .empty.compact{padding:42px 15px}
+
+.audio-panel label.mic-hw{opacity:.55}.audio-panel label.mic-hw>small{grid-column:1/3;color:#9f8eb0;font-size:10px;margin-top:2px}.audio-panel label.mic-hw input[type=range]{background:rgba(255,255,255,.14)}

app/src/main/assets/mobile/app.js

@@ -75,7 +75,9 @@ async function refresh() {
     $("#musicVolume").value = data.musicVolume ?? 70;
     $("#micVolume").value = data.micVolume ?? 70;
     $("#musicValue").textContent = data.musicVolume ?? 70;
-    $("#micValue").textContent = data.micVolume ?? 70;
+    // 麦克风音量由功放/混音器硬件调节(滑杆已禁用), 仅保留显示值。
+    const micHw = $("#micValue");
+    if (micHw) micHw.textContent = data.micVolume ?? 70;
     $("#original").classList.toggle("active", data.vocalMode === "original");
     $("#accompany").classList.toggle("active", data.vocalMode !== "original");
     $("#nextSong").textContent = data.next?.title || "队列为空";
@@ -203,10 +205,9 @@ $("#searchForm").addEventListener("submit", (event) => { event.preventDefault();
 $("#more").addEventListener("click", () => search(false));
 $("#hotPrev").addEventListener("click", () => loadHot(uiState.hotPage - 1));
 $("#hotNext").addEventListener("click", () => loadHot(uiState.hotPage + 1));
-["music", "mic"].forEach((kind) => {
+// 音乐音量可调; 麦克风音量由功放硬件控制, 不再向设备发送无效果请求。
-  $("#" + kind + "Volume").addEventListener("input", (event) => { $("#" + kind + "Value").textContent = event.target.value; });
+$("#musicVolume").addEventListener("input", (event) => { $("#musicValue").textContent = event.target.value; });
-  $("#" + kind + "Volume").addEventListener("change", (event) => updateAudio({ [kind + "Volume"]: Number(event.target.value) }));
+$("#musicVolume").addEventListener("change", (event) => updateAudio({ musicVolume: Number(event.target.value) }));
-});
 document.addEventListener("visibilitychange", () => { uiState.visible = !document.hidden; if (uiState.visible) refresh(); });
 window.setInterval(() => { if (uiState.visible) refresh(); }, 1000);
 refresh();

app/src/main/assets/mobile/index.html

@@ -37,7 +37,7 @@
           <div class="panel-title"><div><span class="tiny-icon">♪</span><b>声音控制</b></div><small>即时生效</small></div>
           <div class="seg"><button id="accompany" data-vocal="accompany"><span>伴</span>伴唱</button><button id="original" data-vocal="original"><span>原</span>原唱</button></div>
           <label><span><i class="volume-icon">♪</i>音乐音量</span><b><em id="musicValue">70</em>%</b><input id="musicVolume" type="range" min="0" max="100" value="70"></label>
-          <label><span><i class="volume-icon mic">●</i>麦克风音量</span><b><em id="micValue">70</em>%</b><input id="micVolume" type="range" min="0" max="100" value="70"></label>
+          <label class="mic-hw"><span><i class="volume-icon mic">●</i>麦克风音量</span><small>由功放/混音器硬件调节</small><input id="micVolume" type="range" min="0" max="100" value="70" disabled></label>
         </article>
 
         <article class="next-card"><div class="next-number">02</div><div><small>下一首</small><b id="nextSong">队列为空</b></div><button data-page="queue">查看队列 <span>›</span></button></article>

app/src/main/java/com/local/ktv/MainActivity.kt

@@ -5,6 +5,9 @@ import android.app.AlertDialog
 import android.content.DialogInterface
 import android.content.DialogInterface.OnShowListener
 import android.content.Intent
+import android.content.BroadcastReceiver
+import android.content.Context
+import android.content.IntentFilter
 import android.content.SharedPreferences
 import android.content.res.ColorStateList
 import android.content.pm.PackageManager
@@ -512,9 +515,72 @@ class MainActivity : AppCompatActivity() {
             }
         }
         micActivator.start()
+        registerMicInputWatcher()
         Log.i(TAG, "麦克风输入已激活(演唱输出通道占用)")
     }
 
+    /**
+     * 监听输入设备变化: 外接麦克风(USB 声卡/3.5mm 麦)插入时系统会把默认输入路由切到外接,
+     * 原 AudioRecord 随之失效。检测到变化后重建占用, 让演唱输出通道跟随当前麦克风。
+     */
+    private fun registerMicInputWatcher() {
+        val manager = audioManager ?: return
+        if (Build.VERSION.SDK_INT >= 23) {
+            manager.registerAudioDeviceCallback(micDeviceCallback, null)
+        } else {
+            runCatching {
+                val filter = IntentFilter(Intent.ACTION_HEADSET_PLUG)
+                registerReceiver(micHotplugReceiver, filter)
+            }
+        }
+    }
+
+    private fun unregisterMicInputWatcher() {
+        val manager = audioManager ?: return
+        if (Build.VERSION.SDK_INT >= 23) {
+            manager.unregisterAudioDeviceCallback(micDeviceCallback)
+        } else {
+            runCatching { unregisterReceiver(micHotplugReceiver) }
+        }
+    }
+
+    private val micDeviceCallback = object : android.media.AudioDeviceCallback() {
+        override fun onAudioDevicesAdded(addedDevices: Array<out android.media.AudioDeviceInfo>) {
+            handleMicInputDevicesChanged(addedDevices.any { isMicInputDevice(it) })
+        }
+
+        override fun onAudioDevicesRemoved(removedDevices: Array<out android.media.AudioDeviceInfo>) {
+            handleMicInputDevicesChanged(removedDevices.any { isMicInputDevice(it) })
+        }
+    }
+
+    private val micHotplugReceiver = object : BroadcastReceiver() {
+        override fun onReceive(context: Context?, intent: Intent?) {
+            handleMicInputDevicesChanged(true)
+        }
+    }
+
+    /** 是否为可用的麦克风输入设备(内置/耳机/USB 等)。 */
+    private fun isMicInputDevice(device: android.media.AudioDeviceInfo): Boolean {
+        if (!device.isSource) return false
+        return when (device.type) {
+            android.media.AudioDeviceInfo.TYPE_BUILTIN_MIC,
+            android.media.AudioDeviceInfo.TYPE_USB_HEADSET,
+            android.media.AudioDeviceInfo.TYPE_USB_DEVICE,
+            android.media.AudioDeviceInfo.TYPE_HDMI,
+            android.media.AudioDeviceInfo.TYPE_BLUETOOTH_SCO,
+            android.media.AudioDeviceInfo.TYPE_LINE_ANALOG,
+            -> true
+            else -> false
+        }
+    }
+
+    /** 输入设备增删后: 重新打开麦克风占用, 跟随系统当前路由(优先外接)。 */
+    private fun handleMicInputDevicesChanged(_changed: Boolean) {
+        // 延迟少许等系统完成路由切换, 再重建 AudioRecord。
+        main.postDelayed({ micActivator.restart() }, 300L)
+    }
+
     private fun initializeDatabase() {
         if (databaseBootstrapRunning) return
         databaseBootstrapRunning = true
@@ -603,6 +669,7 @@ class MainActivity : AppCompatActivity() {
         main.removeCallbacks(remoteNetworkMonitor)
         main.removeCallbacks(qrAutoHideMonitor)
         stopRecording(false)
+        unregisterMicInputWatcher()
         micActivator.stop()
         releaseVocalPlayer()
         if (::playbackEngine.isInitialized) playbackEngine.release()
@@ -2644,15 +2711,11 @@ class MainActivity : AppCompatActivity() {
             })
         root.findViewById<View?>(R.id.btn_mic_down)
             .setOnClickListener(View.OnClickListener { v: View? ->
-                micVolume = max(0, micVolume - 5)
+                toast("麦克风音量由功放/混音器硬件调节")
-                micValue.setText(micVolume.toString())
-                saveState()
             })
         root.findViewById<View?>(R.id.btn_mic_up)
             .setOnClickListener(View.OnClickListener { v: View? ->
-                micVolume = min(100, micVolume + 5)
+                toast("麦克风音量由功放/混音器硬件调节")
-                micValue.setText(micVolume.toString())
-                saveState()
             })
         bindAtmospherePreset(root, R.id.btn_preset_pop, "流行")
         bindAtmospherePreset(root, R.id.btn_preset_lyric, "抒情")

app/src/main/java/com/local/ktv/MicActivator.kt

@@ -1,5 +1,6 @@
 package com.local.ktv
 
+import android.media.AudioDeviceInfo
 import android.media.AudioFormat
 import android.media.AudioRecord
 import android.media.MediaRecorder
@@ -15,6 +16,11 @@ import android.util.Log
  * 做法: 用一个低开销的 [AudioRecord] 常驻打开麦克风并循环读取丢弃数据,
  * 保持输入通道占用(不写文件、不对外暴露声音)。与 MediaRecorder 录音互斥:
  * 开始录音前先 pause, 结束录音后自动 resume。
+ *
+ * 外接麦克风(USB/耳机麦)热插拔时, 系统会把默认输入路由切到外接设备并使
+ * 原 AudioRecord 失效 —— 此时需重建 AudioRecord 并优先占用当前活动输入设备。
+ * 因此对外暴露 [restart] 供设备变化监听调用; [setPreferredInput] 支持 Android 8.0+
+ * 的 AudioRecord.setPreferredDevice 直接把输入锁定到指定麦克风(优先外接)。
  */
 class MicActivator {
     private val tag = "MicActivator"
@@ -23,6 +29,9 @@ class MicActivator {
     @Volatile private var running = false
     @Volatile private var paused = false
 
+    /** 期望优先使用的输入设备; null = 跟随系统默认(自动切到外接)。 */
+    @Volatile private var preferredInput: AudioDeviceInfo? = null
+
     val isActive: Boolean get() = running && !paused
 
     /** 打开麦克风并保持占用。失败静默(设备无麦克风时不影响 App 使用)。 */
@@ -31,6 +40,28 @@ class MicActivator {
         if (running) return
         running = true
         paused = false
+        spawnThread()
+    }
+
+    /** 输入设备发生变化(外接麦克风插入/拔出等)时重建 AudioRecord, 跟随新路由。 */
+    @Synchronized
+    fun restart() {
+        if (!running || paused) return
+        releaseInternal()
+        thread?.interrupt()
+        thread = null
+        spawnThread()
+    }
+
+    /** 指定首选输入设备(传入 null 恢复跟随系统默认)。 */
+    @Synchronized
+    fun setPreferredInput(device: AudioDeviceInfo?) {
+        preferredInput = device
+        restart()
+    }
+
+    @Synchronized
+    private fun spawnThread() {
         thread = Thread({ readLoop() }, "mic-activator").also { it.isDaemon = true; it.start() }
     }
 
@@ -50,7 +81,7 @@ class MicActivator {
         if (!running) return
         if (!paused) return
         paused = false
-        thread = Thread({ readLoop() }, "mic-activator").also { it.isDaemon = true; it.start() }
+        spawnThread()
     }
 
     /** 彻底停止(不再自动恢复)。 */
@@ -89,6 +120,11 @@ class MicActivator {
                     sleepQuietly(5000)
                     continue
                 }
+                // Android 8.0+: 指定首选输入设备(如刚插入的外接麦克风), 避免仍占用内建。
+                val target = preferredInput
+                if (target != null && android.os.Build.VERSION.SDK_INT >= 26) {
+                    runCatching { recorder.setPreferredDevice(target) }
+                }
                 record = recorder
                 recorder.startRecording()
                 val buffer = ByteArray(minBuffer.coerceAtLeast(4096))
@@ -125,3 +161,4 @@ class MicActivator {
         try { Thread.sleep(ms) } catch (ignored: InterruptedException) { Thread.currentThread().interrupt() }
     }
 }
+

app/src/main/res/layout/dialog_audio_control.xml

@@ -97,12 +97,12 @@
             android:textSize="14sp" />
     </LinearLayout>
 
-    <!-- 麦克风 -->
+    <!-- 麦克风(增益/效果由功放混音器硬件调节, 滑杆仅作指示) -->
     <TextView
         android:layout_width="wrap_content"
         android:layout_height="wrap_content"
-        android:layout_marginBottom="4dp"
+        android:layout_marginBottom="2dp"
-        android:text="麦克风音量"
+        android:text="麦克风音量(功放/混音器硬件调节)"
         android:textColor="#FFE0E0FF"
         android:textSize="13sp" />
 
@@ -121,7 +121,8 @@
             android:max="100"
             android:progress="60"
             android:progressTint="#FF27CCA4"
-            android:thumbTint="#FF27CCA4" />
+            android:thumbTint="#FF27CCA4"
+            android:enabled="false" />
 
         <TextView
             android:id="@+id/text_mic_volume_value"
@@ -136,8 +137,8 @@
     <TextView
         android:layout_width="wrap_content"
         android:layout_height="wrap_content"
-        android:layout_marginBottom="4dp"
+        android:layout_marginBottom="2dp"
-        android:text="麦克风效果"
+        android:text="麦克风效果(功放/混音器硬件调节)"
         android:textColor="#FFE0E0FF"
         android:textSize="13sp" />
 
@@ -156,7 +157,8 @@
             android:max="100"
             android:progress="50"
             android:progressTint="#FF27CCA4"
-            android:thumbTint="#FF27CCA4" />
+            android:thumbTint="#FF27CCA4"
+            android:enabled="false" />
 
         <TextView
             android:id="@+id/text_mic_effect_value"