第一部分：无障碍服务基础

1.1 无障碍服务概述

安卓无障碍服务(Accessibility Service)是一种特殊类型的服务，旨在帮助残障用户或需要辅助功能的用户更好地使用设备。但它的功能远不止于此，开发者可以利用它实现自动化操作、界面监控和交互等功能。

核心功能：

• 界面内容访问：获取屏幕上的UI元素信息
• 自动化操作：模拟点击、滑动等用户操作
• 事件监控：监听窗口变化、通知、焦点改变等系统事件
• 增强交互：为特定应用提供定制化辅助功能

1.2 基本原理与架构

1.3 开发环境配置

所需工具：

• Android Studio最新版
• 安卓设备或模拟器(API 16+)
• ADB调试工具

关键依赖：

dependencies {
    implementation 'androidx.core:core-ktx:1.7.0'
    implementation 'androidx.appcompat:appcompat:1.4.1'
}

第二部分：创建基础无障碍服务

2.1 服务声明配置

在AndroidManifest.xml中添加服务声明：

<service
    android:name=".MyAccessibilityService"
    android:permission="android.permission.BIND_ACCESSIBILITY_SERVICE"
    android:exported="true">
    <intent-filter>
        <action android:name="android.accessibilityservice.AccessibilityService" />
    </intent-filter>
    <meta-data
        android:name="android.accessibilityservice"
        android:resource="@xml/service_config" />
</service>

2.2 服务配置文件

创建res/xml/service_config.xml：

<accessibility-service xmlns:android="http://schemas.android.com/apk/res/android"
    android:description="@string/accessibility_service_description"
    android:accessibilityEventTypes="typeAllMask"
    android:accessibilityFlags="flagDefault|flagRetrieveInteractiveWindows"
    android:canRetrieveWindowContent="true"
    android:settingsActivity="com.example.android.accessibility.ServiceSettingsActivity"
    android:canRequestFilterKeyEvents="true"
    android:canPerformGestures="true"
    android:notificationTimeout="100"
    android:packageNames="com.example.targetapp" />

关键属性说明：

• accessibilityEventTypes：监听的事件类型
• packageNames：指定监控的应用包名(可选)
• canPerformGestures：允许执行手势操作(API 24+)

2.3 实现服务类

创建基础服务类MyAccessibilityService.kt：

class MyAccessibilityService : AccessibilityService() {

    override fun onServiceConnected() {
        Log.d("A11yService", "无障碍服务已连接")
        // 可以在此处进行服务配置更新
        val info = AccessibilityServiceInfo().apply {
            eventTypes = AccessibilityEvent.TYPE_VIEW_CLICKED or 
                       AccessibilityEvent.TYPE_WINDOW_STATE_CHANGED
            feedbackType = AccessibilityServiceInfo.FEEDBACK_GENERIC
            notificationTimeout = 100
            flags = AccessibilityServiceInfo.DEFAULT or
                   AccessibilityServiceInfo.FLAG_RETRIEVE_INTERACTIVE_WINDOWS
        }
        this.serviceInfo = info
    }

    override fun onAccessibilityEvent(event: AccessibilityEvent?) {
        event ?: return
        when (event.eventType) {
            AccessibilityEvent.TYPE_WINDOW_STATE_CHANGED -> {
                handleWindowChange(event)
            }
            AccessibilityEvent.TYPE_VIEW_CLICKED -> {
                handleViewClick(event)
            }
        }
    }

    override fun onInterrupt() {
        Log.w("A11yService", "无障碍服务被中断")
    }

    private fun handleWindowChange(event: AccessibilityEvent) {
        val rootNode = rootInActiveWindow ?: return
        Log.d("A11yService", "窗口变化: ${event.packageName}")
        // 遍历视图树
        traverseNode(rootNode)
    }

    private fun traverseNode(node: AccessibilityNodeInfo, depth: Int = 0) {
        if (node.childCount == 0) {
            Log.d("A11yTree", "${" ".repeat(depth)}${node.viewIdResourceName}")
            return
        }
        
        for (i in 0 until node.childCount) {
            node.getChild(i)?.let { child ->
                traverseNode(child, depth + 1)
                child.recycle()
            }
        }
    }
}

第三部分：高级功能实现

3.1 节点查找与操作

常用查找方法：

fun findNodes(root: AccessibilityNodeInfo) {
    // 通过文本查找
    val byText = root.findAccessibilityNodeInfosByText("搜索")
    
    // 通过View ID查找(全限定ID)
    val byId = root.findAccessibilityNodeInfosByViewId("com.example.app:id/btnSubmit")
    
    // 通过类名查找
    val editTexts = mutableListOf<AccessibilityNodeInfo>()
    val queue: Queue<AccessibilityNodeInfo> = LinkedList()
    queue.add(root)
    
    while (queue.isNotEmpty()) {
        val current = queue.poll()
        if (current.className == "android.widget.EditText") {
            editTexts.add(current)
        }
        for (i in 0 until current.childCount) {
            current.getChild(i)?.let { queue.add(it) }
        }
    }
}

节点操作示例：

fun performActions(node: AccessibilityNodeInfo) {
    // 点击操作
    if (node.isClickable) {
        node.performAction(AccessibilityNodeInfo.ACTION_CLICK)
    }
    
    // 文本输入
    val arguments = Bundle().apply {
        putCharSequence(AccessibilityNodeInfo.ACTION_ARGUMENT_SET_TEXT_CHARSEQUENCE, "Hello")
    }
    node.performAction(AccessibilityNodeInfo.ACTION_SET_TEXT, arguments)
    
    // 焦点控制
    node.performAction(AccessibilityNodeInfo.ACTION_FOCUS)
    
    // 滚动操作
    node.performAction(AccessibilityNodeInfo.ACTION_SCROLL_FORWARD)
}

3.2 手势模拟

Android支持通过无障碍服务模拟复杂手势：

fun performGesture(service: AccessibilityService) {
    val path = Path().apply {
        moveTo(100f, 100f)  // 起点
        lineTo(500f, 100f)   // 移动到右侧
        lineTo(500f, 500f)   // 向下移动
        lineTo(100f, 500f)   // 向左移动
        close()              // 闭合路径
    }
    
    val gestureBuilder = GestureDescription.Builder()
        .addStroke(GestureDescription.StrokeDescription(
            path, 
            0L,  // 开始时间
            1000L,  // 持续时间(毫秒)
            false  // 是否持续
        ))
    
    service.dispatchGesture(gestureBuilder.build(), object : AccessibilityService.GestureResultCallback() {
        override fun onCompleted(gestureDescription: GestureDescription?) {
            Log.d("Gesture", "手势完成")
        }
        
        override onCancelled(gestureDescription: GestureDescription?) {
            Log.w("Gesture", "手势取消")
        }
    }, null)
}

3.3 全局事件监听

监听系统级事件：

override fun onAccessibilityEvent(event: AccessibilityEvent) {
    when (event.eventType) {
        AccessibilityEvent.TYPE_NOTIFICATION_STATE_CHANGED -> {
            val notificationText = event.text.joinToString()
            Log.d("Notification", "新通知: $notificationText")
        }
        AccessibilityEvent.TYPE_ANNOUNCEMENT -> {
            Log.d("Announcement", "系统公告: ${event.text}")
        }
        AccessibilityEvent.TYPE_TOUCH_EXPLORATION_GESTURE_START -> {
            Log.d("Touch", "触摸探索开始")
        }
    }
}

第四部分：实战案例开发

4.1 自动填写表单

class FormFillerService : AccessibilityService() {

    private val formData = mapOf(
        "username" to "testuser",
        "password" to "secure123",
        "email" to "test@example.com"
    )

    override fun onAccessibilityEvent(event: AccessibilityEvent) {
        if (event.eventType != AccessibilityEvent.TYPE_WINDOW_CONTENT_CHANGED) return
        
        val rootNode = rootInActiveWindow ?: return
        
        formData.forEach { (fieldName, value) ->
            val nodes = rootNode.findAccessibilityNodeInfosByViewId("com.example.app:id/$fieldName")
            nodes.firstOrNull()?.let { field ->
                if (field.className == "android.widget.EditText") {
                    val args = Bundle().apply {
                        putCharSequence(AccessibilityNodeInfo.ACTION_ARGUMENT_SET_TEXT_CHARSEQUENCE, value)
                    }
                    field.performAction(AccessibilityNodeInfo.ACTION_SET_TEXT, args)
                }
            }
        }
        
        // 自动提交表单
        rootNode.findAccessibilityNodeInfosByViewId("com.example.app:id/submit")
            .firstOrNull()
            ?.performAction(AccessibilityNodeInfo.ACTION_CLICK)
    }
}

4.2 消息自动回复

class AutoReplyService : AccessibilityService() {

    private val replyMessages = listOf(
        "我正在开会，稍后回复您",
        "好的，收到",
        "谢谢通知"
    )

    override fun onAccessibilityEvent(event: AccessibilityEvent) {
        if (event.packageName != "com.whatsapp") return
        
        when (event.eventType) {
            AccessibilityEvent.TYPE_NOTIFICATION_STATE_CHANGED -> {
                // 处理通知事件
                val messages = event.text.filter { it.contains("发来消息") }
                if (messages.isNotEmpty()) {
                    replyToLatestMessage()
                }
            }
            AccessibilityEvent.TYPE_VIEW_TEXT_CHANGED -> {
                // 处理界面文本变化
                if (isChatOpen()) {
                    autoReplyInChat()
                }
            }
        }
    }
    
    private fun replyToLatestMessage() {
        // 实现打开聊天界面并回复的逻辑
    }
    
    private fun isChatOpen(): Boolean {
        // 检测当前是否在聊天界面
    }
    
    private fun autoReplyInChat() {
        val root = rootInActiveWindow ?: return
        val messageNodes = root.findAccessibilityNodeInfosByViewId("com.whatsapp:id/message_text")
        
        // 获取最后一条消息
        val lastMessage = messageNodes.lastOrNull()?.text ?: return
        
        // 随机选择回复内容
        val randomReply = replyMessages.random()
        
        // 找到输入框并发送
        root.findAccessibilityNodeInfosByViewId("com.whatsapp:id/entry")
            .firstOrNull()
            ?.let { input ->
                val args = Bundle().apply {
                    putCharSequence(AccessibilityNodeInfo.ACTION_ARGUMENT_SET_TEXT_CHARSEQUENCE, randomReply)
                }
                input.performAction(AccessibilityNodeInfo.ACTION_SET_TEXT, args)
                
                // 发送消息
                root.findAccessibilityNodeInfosByViewId("com.whatsapp:id/send")
                    .firstOrNull()
                    ?.performAction(AccessibilityNodeInfo.ACTION_CLICK)
            }
    }
}

4.3 游戏自动化辅助

class GameHelperService : AccessibilityService() {

    private var isRunning = false
    private val handler = Handler(Looper.getMainLooper())
    private val clickRunnable = object : Runnable {
        override fun run() {
            performAutoClick()
            if (isRunning) {
                handler.postDelayed(this, 1000) // 每秒点击一次
            }
        }
    }

    override fun onServiceConnected() {
        val info = AccessibilityServiceInfo().apply {
            eventTypes = AccessibilityEvent.TYPE_WINDOW_STATE_CHANGED
            feedbackType = AccessibilityServiceInfo.FEEDBACK_GENERIC
            flags = AccessibilityServiceInfo.FLAG_REPORT_VIEW_IDS
        }
        serviceInfo = info
    }

    override fun onAccessibilityEvent(event: AccessibilityEvent) {
        if (event.packageName != "com.game.package") return
        
        when (event.eventType) {
            AccessibilityEvent.TYPE_WINDOW_STATE_CHANGED -> {
                checkGameState()
            }
        }
    }
    
    private fun checkGameState() {
        val root = rootInActiveWindow ?: return
        val battleNode = root.findAccessibilityNodeInfosByViewId("com.game.package:id/battle_indicator")
        
        if (battleNode.isNotEmpty()) {
            startAutoClicking()
        } else {
            stopAutoClicking()
        }
    }
    
    private fun startAutoClicking() {
        if (!isRunning) {
            isRunning = true
            handler.post(clickRunnable)
        }
    }
    
    private fun stopAutoClicking() {
        isRunning = false
        handler.removeCallbacks(clickRunnable)
    }
    
    private fun performAutoClick() {
        val root = rootInActiveWindow ?: return
        val attackBtn = root.findAccessibilityNodeInfosByViewId("com.game.package:id/attack_button")
            .firstOrNull()
        
        attackBtn?.performAction(AccessibilityNodeInfo.ACTION_CLICK)
        
        // 随机位置点击，避免被检测为机器人
        if (Math.random() < 0.3) {
            val randomX = (100..500).random()
            val randomY = (200..800).random()
            dispatchGesture(createClickGesture(randomX, randomY), null, null)
        }
    }
    
    private fun createClickGesture(x: Int, y: Int): GestureDescription {
        val clickPath = Path().apply {
            moveTo(x.toFloat(), y.toFloat())
        }
        
        return GestureDescription.Builder()
            .addStroke(GestureDescription.StrokeDescription(
                clickPath, 0, 50))
            .build()
    }
}

第五部分：调试与优化

5.1 调试技巧

ADB调试命令：

# 查看已启用的无障碍服务
adb shell settings get secure enabled_accessibility_services

# 启用服务
adb shell settings put secure enabled_accessibility_services com.example.pkg/.MyAccessibilityService

# 查看无障碍事件日志
adb shell logcat -s AccessibilityEvent

日志记录最佳实践：

fun logNodeInfo(node: AccessibilityNodeInfo) {
    val sb = StringBuilder().apply {
        append("View ID: ${node.viewIdResourceName}\n")
        append("Text: ${node.text}\n")
        append("Class: ${node.className}\n")
        append("Bounds: ${node.boundsInScreen}\n")
        append("Actions: ${node.actionList.joinToString()}\n")
        append("ChildCount: ${node.childCount}\n")
    }
    Log.d("NodeInfo", sb.toString())
}

5.2 性能优化

优化建议：

1. 减少遍历深度：只查找必要的节点层级
2. 及时回收节点：调用recycle()释放资源
3. 事件过滤：只监听必要的事件类型
4. 延迟处理：对频繁事件使用防抖
5. 后台处理：将耗时操作移到工作线程

优化示例：

class OptimizedService : AccessibilityService() {

    private val eventQueue = LinkedBlockingQueue<AccessibilityEvent>()
    private val workerThread = HandlerThread("EventProcessor").apply { start() }
    private val workerHandler = Handler(workerThread.looper)
    
    private val eventProcessor = object : Runnable {
        override fun run() {
            while (true) {
                val event = eventQueue.take()
                processEvent(event)
            }
        }
    }
    
    override fun onCreate() {
        super.onCreate()
        workerHandler.post(eventProcessor)
    }
    
    override fun onAccessibilityEvent(event: AccessibilityEvent) {
        // 快速将事件加入队列，避免阻塞主线程
        eventQueue.put(event)
    }
    
    private fun processEvent(event: AccessibilityEvent) {
        // 实际处理逻辑
    }
    
    override fun onDestroy() {
        workerThread.quitSafely()
        super.onDestroy()
    }
}

第六部分：发布与安全

6.1 权限与隐私

必要权限声明：

<uses-permission android:name="android.permission.BIND_ACCESSIBILITY_SERVICE" />
<uses-permission android:name="android.permission.FOREGROUND_SERVICE" />

隐私注意事项：

1. 明确告知用户：在隐私政策中说明数据收集范围
2. 最小权限原则：只请求必要的权限
3. 敏感数据处理：避免收集密码等敏感信息
4. 数据加密：对存储的日志和数据进行加密

6.2 发布流程

1. 测试阶段：

   • 在不同安卓版本上测试
   • 在各种品牌设备上测试(特别是国产ROM)
   • 测试电池消耗情况

2. 应用商店要求：

   • 明确说明是无障碍辅助工具
   • 提供详细的使用说明视频
   • 如果是自动化工具，需遵守各商店政策

3. 持续更新：

   • 定期适配新安卓版本
   • 针对流行应用的特殊适配
   • 根据用户反馈优化功能

第七部分：高级主题

7.1 与其他技术的结合

与Tasker集成：

// 接收Tasker的广播意图
private val taskerReceiver = object : BroadcastReceiver() {
    override fun onReceive(context: Context, intent: Intent) {
        if (intent.action == "net.dinglisch.android.tasker.ACTION_TRIGGER") {
            val task = intent.getStringExtra("task")
            when (task) {
                "start_automation" -> startAutomation()
                "stop_automation" -> stopAutomation()
            }
        }
    }
}

override fun onCreate() {
    super.onCreate()
    registerReceiver(taskerReceiver, IntentFilter("net.dinglisch.android.tasker.ACTION_TRIGGER"))
}

使用机器学习：

// 使用ML Kit识别屏幕内容
fun detectTextFromScreen(bitmap: Bitmap): String {
    val recognizer = TextRecognition.getClient(TextRecognizerOptions.DEFAULT_OPTIONS)
    val image = InputImage.fromBitmap(bitmap, 0)
    
    return try {
        val result = recognizer.process(image).await()
        result.text
    } catch (e: Exception) {
        Log.e("ML", "识别失败", e)
        ""
    }
}

// 截图并处理
fun captureAndAnalyze() {
    val projection = MediaProjectionManager.createScreenCaptureIntent()
    // 需要先获取用户授权...
    
    val imageReader = ImageReader.newInstance(
        screenWidth, screenHeight, 
        PixelFormat.RGBA_8888, 2
    )
    
    imageReader.setOnImageAvailableListener({ reader ->
        val image = reader.acquireLatestImage()
        // 转换为Bitmap并传递给识别器
        val text = detectTextFromScreen(convertImageToBitmap(image))
        Log.d("ScreenText", "识别结果: $text")
        image.close()
    }, handler)
}

7.2 跨版本兼容性处理

版本差异处理表：

功能	API 16-22	API 23-28	API 29+
节点信息获取	基本支持	增强支持	受限
手势模拟	不支持	部分支持	完全支持
隐私限制	无	部分	严格
后台服务	允许	限制	严格限制

兼容性代码示例：

fun performActionCompat(node: AccessibilityNodeInfo, action: Int, args: Bundle? = null): Boolean {
    return if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
        node.performAction(action, args)
    } else {
        node.performAction(action)
    }
}

fun getNodeTextCompat(node: AccessibilityNodeInfo): String {
    return if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
        node.text?.toString() ?: ""
    } else {
        node.text ?: ""
    }
}