使用Kotlin连接WearOS配套手表应用失败，求解决方案

问题背景 #

我已多日尝试将Jetpack Compose应用连接到Wear OS手表模拟器，模拟器已成功配对（Wear OS应用显示已连接到模拟器），但应用内始终无法建立连接。查阅官方示例、文档及AI工具后仍未解决，怀疑遗漏了某些步骤。最终需求是将蓝牙类的数据发送至手表（拟使用MessageClient）。

现有手机端MyCapabilityListener代码如下，手表端仅实现了WearableListenerService并重写数据接收方法，但onCapabilityChanged回调从未触发，手动调用capabilityClient.getCapability始终返回“Not connected”日志，且已在onCreate中调用MyCapabilityListener(context).addListener。

class MyCapabilityListener(private val context: Context) :
    DataClient.OnDataChangedListener,
    MessageClient.OnMessageReceivedListener,
    CapabilityClient.OnCapabilityChangedListener {

    private val capabilityClient: CapabilityClient = Wearable.getCapabilityClient(context)
    private val dataClient: DataClient = Wearable.getDataClient(context)

    fun sendData(data: String) {
        val dataItem = PutDataMapRequest.create("/data/path").run {
            dataMap.putString("data", data)
            asPutDataRequest()
        }
        dataClient.putDataItem(dataItem)
    }

    override fun onCapabilityChanged(capabilityInfo: CapabilityInfo) {
        val nodes = capabilityInfo.nodes
        if (nodes.isNotEmpty()) {
            Log.v("Connected", "Connected to the watch")
        } else {
            Log.v("Not connected", "Not connected to the watch")
        }
    }

    fun addListener() {
        Wearable.getCapabilityClient(context)
        Wearable.getDataClient(context)
        capabilityClient.addListener(this, Uri.parse("wear://"), CapabilityClient.FILTER_REACHABLE)
        capabilityClient.getCapability("wear://", CapabilityClient.FILTER_REACHABLE)
            .addOnSuccessListener { capabilityInfo ->
                onCapabilityChanged(capabilityInfo)
            }
            .addOnFailureListener { e ->
                Log.e("Capability", "Failed to get capability: ${e.message}")
            }
    }

}

核心问题分析 #

代码中误用了Capability的引用方式：传递的wear://不是有效的Capability名称，Capability需要在两端配置文件中明确定义，才能被CapabilityClient识别。此外，Listener的生命周期管理不当也会导致回调失效。

修复步骤 #

1. 定义共享Capability #

在手机端和手表端的res/values/wear.xml中添加Capability定义（若文件不存在则创建）：

<resources>
    <string-array name="android_wear_capabilities">
        <item>data_transfer_capability</item>
    </string-array>
</resources>

2. 修正CapabilityClient调用逻辑 #

修改MyCapabilityListener中的addListener方法，使用正确的Capability名称：

fun addListener() {
    // 移除无效的重复获取客户端代码
    capabilityClient.addListener(
        this,
        Uri.parse("wear://*/data_transfer_capability"),
        CapabilityClient.FILTER_REACHABLE
    )
    capabilityClient.getCapability("data_transfer_capability", CapabilityClient.FILTER_REACHABLE)
        .addOnSuccessListener { capabilityInfo ->
            onCapabilityChanged(capabilityInfo)
        }
        .addOnFailureListener { e ->
            Log.e("Capability", "Failed to get capability: ${e.message}")
        }
}

3. 管理Listener生命周期 #

避免临时实例导致Listener被回收，在Activity或ViewModel中保留实例引用，并在合适时机移除Listener：

// 在Activity中
private lateinit var capabilityListener: MyCapabilityListener

override fun onCreate(savedInstanceState: Bundle?) {
    super.onCreate(savedInstanceState)
    capabilityListener = MyCapabilityListener(this)
    capabilityListener.addListener()
}

override fun onDestroy() {
    super.onDestroy()
    capabilityListener.capabilityClient.removeListener(capabilityListener)
}

4. 适配MessageClient发送需求（针对最终目标） #

添加基于MessageClient的消息发送方法，确保获取到可到达的手表节点：

// 在MyCapabilityListener中新增方法
fun sendBluetoothData(message: String) {
    capabilityClient.getCapability("data_transfer_capability", CapabilityClient.FILTER_REACHABLE)
        .addOnSuccessListener { capabilityInfo ->
            capabilityInfo.nodes.firstOrNull()?.let { targetNode ->
                Wearable.getMessageClient(context).sendMessage(
                    targetNode.id,
                    "/bluetooth_data_path",
                    message.toByteArray()
                )
                Log.v("Message", "Data sent to watch")
            } ?: Log.v("Message", "No reachable watch node found")
        }
}

5. 验证手表端Service配置 #

确保手表端的WearableListenerService在Manifest中正确注册：

<service
    android:name=".MyWearableListenerService"
    android:exported="true">
    <intent-filter>
        <action android:name="com.google.android.gms.wearable.DATA_CHANGED" />
        <action android:name="com.google.android.gms.wearable.MESSAGE_RECEIVED" />
        <data android:scheme="wear" android:host="*" />
    </intent-filter>
</service>

内容的提问来源于stack exchange，提问作者Swifty