如何在第三方Android应用中从Google Home获取Matter启用设备列表

一、前提准备 #

• 完成Google Home开发者账号注册，创建项目并启用Home Graph API与Device Access API
• 为TestApp配置OAuth 2.0授权，确保应用具备访问用户智能家居设备数据的权限
• 确认用户已在Google Home中完成Nest Hub配对及MatterTestDevice的调配流程

二、核心实现步骤 #

1. 集成依赖库 #

在TestApp的build.gradle文件中添加相关依赖：

dependencies {
    implementation 'com.google.android.gms:play-services-auth:20.7.0'
    implementation 'com.google.apis:google-api-services-homegraph:v1-rev20240305-2.0.0'
}

2. 用户授权流程 #

通过Google OAuth 2.0引导用户授权TestApp访问其Home设备数据，需请求https://www.googleapis.com/auth/homegraph权限：

val googleSignInOptions = GoogleSignInOptions.Builder(GoogleSignInOptions.DEFAULT_SIGN_IN)
    .requestScopes(Scope("https://www.googleapis.com/auth/homegraph"))
    .requestEmail()
    .build()

val googleSignInClient = GoogleSignIn.getClient(this, googleSignInOptions)
// 启动授权页面
startActivityForResult(googleSignInClient.signInIntent, RC_SIGN_IN)

在onActivityResult中获取授权凭证：

override fun onActivityResult(requestCode: Int, resultCode: Int, data: Intent?) {
    super.onActivityResult(requestCode, resultCode, data)
    if (requestCode == RC_SIGN_IN) {
        val task = GoogleSignIn.getSignedInAccountFromIntent(data)
        try {
            val account = task.getResult(ApiException::class.java)
            val idToken = account.idToken
            // 调用接口获取设备列表
            fetchDevices(idToken)
        } catch (e: ApiException) {
            // 处理授权失败逻辑
        }
    }
}

3. 调用Home Graph API筛选Matter设备 #

通过devices.query接口获取全量设备，再筛选出Matter启用的设备：

private fun fetchDevices(idToken: String) {
    val homegraph = Homegraph.Builder(
        AndroidHttp.newCompatibleTransport(),
        GsonFactory.getDefaultInstance(),
        GoogleAccountCredential.usingOAuth2(this, listOf("https://www.googleapis.com/auth/homegraph"))
            .setSelectedAccount(GoogleSignIn.getLastSignedInAccount(this))
    ).setApplicationName("TestApp").build()

    val request = homegraph.devices().query(QueryRequest().apply {
        agentUserId = GoogleSignIn.getLastSignedInAccount(this@TestActivity)?.id
    })

    Thread {
        try {
            val response = request.execute()
            val devices = response.payload?.devices
            // 筛选Matter设备
            val matterDevices = devices?.filter { device ->
                device.traits?.contains("action.devices.traits.Matter") == true
            }
            // 定位并处理MatterTestDevice的信息
            matterDevices?.forEach { device ->
                if (device.name?.name == "MatterTestDevice") {
                    val deviceInfo = """
                        设备名称：${device.name?.name}
                        设备ID：${device.id}
                        设备类型：${device.type}
                        Matter相关属性：${device.traits?.joinToString(", ")}
                    """.trimIndent()
                    // 主线程更新UI展示信息
                    runOnUiThread {
                        tv_device_info.text = deviceInfo
                    }
                }
            }
        } catch (e: IOException) {
            // 处理API调用异常
        }
    }.start()
}

三、关键注意事项 #

• 需保证目标Matter设备已完成Google Home中的调配流程且处于在线状态
• 授权流程必须请求正确的权限范围，否则无法访问Home Graph数据
• API调用需在子线程执行，避免阻塞主线程
• 需处理网络错误、权限过期等异常场景

内容的提问来源于stack exchange，提问作者TechDubey