Ble蓝牙App（一）扫描 前言目录正文一、基本配置二、扫描准备三、扫描页面① 增加UI布局② 点击监听③ 扫描处理④ 广播处理 四、权限处理五、扫描结果① 列表适配器② 扫描结果处理③
关于低功耗的蓝牙介绍我已经做过很多了，只不过很多人不是奔着学习的目的去的，拿着源码就去运行，后面又发现连接设备后马上断开，然后不会自己看问题，这个现象就是快餐式的，你不了解里面的知识内容，自然就不知道是怎么回事，重复的问题我回答了好多次了。而我也是觉得写的有问题，本意上来说我是希望读者可以参考来写，能看一看文章内容，而结果绝大多数，看个标题看个运行效果，下载源码就运行，运行有问题就问你，没有什么思考。
针对这个情况，我决定做了系列性的Ble蓝牙App，尽可能的避免在你运行的时候出现bug，所以这是一个低功耗蓝牙工具App，可以让你了解到一些东西。注意是低功耗，不是经典蓝牙，如果你不知道两者之间的区别，建议你先了解一下。本文的效果：
App下载地址：GoodBle
本文将会重新创建一个项目，功能一个一个的做，尽量的做好每一个功能的优化，下面我们创建一个名为GoodBle的项目，语言为Kotlin。
至于为什么使用Kotlin，稳固一下，不然太久不用就会生疏，文本我们讲述的是扫描，你可能回想，一个扫描有什么好写，不就是开始、结束、显示设备嘛？至于单独作为一个功能来写一篇文章嘛？那么我们带着问题来看这篇文章，看看扫描到底有没有必要这样来做。
当前我们创建项目有一个MainActivity，然后我们需要打开viewBinding的开关，在app的build.gradle中的Android{}闭包中添加如下代码：
buildFeatures { viewBinding true }然后Sync Now，同步一下，开启成功。随后我们就可以在Activity中使用ViewBinding了，常规的使用方式是这样的：
class MainActivity : AppCompatActivity() { private lateinit var binding: ActivityMainBinding; override fun onCreate(savedInstanceState: Bundle?) { super.onCreate(savedInstanceState) binding = ActivityMainBinding.inflate(layoutInflater); setContentView(binding.root) }}在Java中封装通常采用反射的方式，在Kotlin中如果要对ViewBinding进行封装的话同时利用上Kotlin的一些特性的话，可以这样做，原文地址如下：Viewbinding使用和委托封装，感觉写得蛮好的，太久没用Kotlin了，还是看了一会才看懂，感兴趣的可以看看。
那么我们在com.llw.goodble下面创建一个base包，base包下创建BaseViewBinding.kt文件，里面的代码如下所示：
package com.llw.goodble.baseimport android.app.Activityimport android.view.LayoutInflaterimport androidx.viewbinding.ViewBindingimport kotlin.properties.ReadOnlyPropertyimport kotlin.reflect.KPropertyfun <VB : ViewBinding> viewBinding(viewInflater: (LayoutInflater) -> VB): ReadOnlyProperty<Activity, VB> = ActivityViewBindingProperty(viewInflater)class ActivityViewBindingProperty<VB : ViewBinding>( private val viewInflater: (LayoutInflater) -> VB) : ReadOnlyProperty<Activity, VB> { private var binding: VB? = null override fun getValue(thisRef: Activity, property: KProperty<*>): VB { return binding ?: viewInflater(thisRef.layoutInflater).also { thisRef.setContentView(it.root) binding = it } }}通过委托的方式进行封装，下面来看在MainActivity中怎么使用它，
class MainActivity : AppCompatActivity() { private val binding by viewBinding(ActivityMainBinding::inflate) override fun onCreate(savedInstanceState: Bundle?) { super.onCreate(savedInstanceState) setContentView(R.layout.activity_main) }}使用起来很简单，后面就采用这种方式，你可以运行一下，看看有没有问题，然后我们可以再创建一个ScanActivity类，用于扫描页面，修改一下activity_main.xml中的代码，如下所示：
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="Http://schemas.android.com/apk/res/android" xmlns:app="http://schemas.android.com/apk/res-auto" xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent" android:layout_height="match_parent" tools:context=".MainActivity"> <com.google.android.material.appbar.MaterialToolbar android:id="@+id/toolbar" android:layout_width="match_parent" android:layout_height="?attr/actionBarSize" android:background="@color/orange" app:layout_constraintEnd_toEndOf="parent" app:layout_constraintStart_toStartOf="parent" app:layout_constraintTop_toTopOf="parent" app:navigationIcon="@drawable/ic_scan_ble" app:title="GoodBle" app:titleCentered="true" app:titleTextColor="@color/white" />androidx.constraintlayout.widget.ConstraintLayout>这里用到了图标，代码如下所示：
<vector xmlns:android="http://schemas.android.com/apk/res/android" android:width="32dp" android:height="32dp" android:viewportWidth="1024" android:viewportHeight="1024"> <path android:fillColor="#ffffff" android:pathData="M761.5,141.1c-14.3,-9.6 -33.6,-5.9 -43.2,8.4 -9.6,14.2 -5.9,33.6 8.4,43.2 106,71.6 169.3,190.7 169.3,318.4 0,211.7 -172.2,384 -384,384S128,722.9 128,511.1c0,-127.8 63.3,-246.8 169.3,-318.4 14.2,-9.6 18,-29 8.4,-43.2s-29,-18 -43.2,-8.4C139.3,224.4 65.7,362.7 65.7,511.1c0,246.1 200.2,446.2 446.2,446.2S958.2,757.2 958.2,511.1C958.2,362.7 884.6,224.4 761.5,141.1z" /> <path android:fillColor="#ffffff" android:pathData="M402.1,157.6c17.2,0 31.1,-13.9 31.1,-31.1L433.2,96c0,-17.2 -13.9,-31.1 -31.1,-31.1s-31.1,13.9 -31.1,31.1l0,30.4C371,143.6 384.9,157.6 402.1,157.6z" /> <path android:fillColor="#ffffff" android:pathData="M624.3,157.6c17.2,0 31.1,-13.9 31.1,-31.1L655.5,96c0,-17.2 -13.9,-31.1 -31.1,-31.1s-31.1,13.9 -31.1,31.1l0,30.4C593.2,143.6 607.1,157.6 624.3,157.6z" /> <path android:fillColor="#ffffff" android:pathData="M428.3,227.4c11.2,18 41.8,48.4 85.9,48.4 43.8,0 74.9,-30.2 86.3,-48.1 9.3,-14.5 5.1,-33.7 -9.4,-43 -14.5,-9.3 -33.7,-5 -43,9.4 -0.1,0.2 -13.3,19.4 -33.9,19.4 -19.9,0 -32.3,-18 -33.2,-19.3 -9.1,-14.4 -28.2,-18.7 -42.7,-9.7C423.7,193.6 419.2,212.8 428.3,227.4z" /> <path android:fillColor="#ffffff" android:pathData="M306,440.9c-9.2,14.5 -4.8,33.8 9.7,42.9l142.7,90.1L314.1,665.1c-14.5,9.2 -18.9,28.4 -9.7,42.9 5.9,9.4 16,14.5 26.3,14.5 5.7,0 11.4,-1.6 16.6,-4.8l135.7,-85.7 0,148c0,10.6 4,20.2 10.3,27.8 0.4,0.5 0.8,1 1.2,1.4 8.4,9.3 20.5,15.3 34.1,15.3 2.4,0 4.8,-0.3 7,-0.9 5.8,-0.9 11.4,-2.8 16.5,-5.8 0.8,-0.5 1.6,-1 2.3,-1.5l134,-96.2c12.7,-8.2 20.5,-22.2 20.6,-37.2 0,-15.5 -8.4,-30.1 -21.2,-37.7l-113,-71.4 110.6,-69.9c13.6,-8.1 22,-22.8 21.9,-38.3 -0.1,-15 -8,-29 -20.7,-37.1l-132.4,-94.4c-0.8,-0.6 -1.6,-1.1 -2.5,-1.6 -21,-12.1 -47.9,-6.1 -61.4,13.7 -2.5,3.7 -4.1,7.8 -4.8,11.9 -1.7,3.9 -2.7,8.1 -2.7,12.7l0,144.9 -134.1,-84.7C334.4,422 315.2,426.4 306,440.9zM545.3,746.4 L545.3,628.9l87.1,55L545.3,746.4zM630.7,465.1l-85.4,53.9L545.3,404.3 630.7,465.1z" />vector>颜色值，在colors.xml中增加：
<color name="orange">#FF5722color> <color name="warm_yellow">#FFC107color> <color name="dark_orange">#FF9800color> <color name="light_orange">#FFF3E0color> <color name="gray_white">#F8F8F8color> <color name="gray">#989898color>这里给toolbar设置导航图标，点击这个导航到扫描页面，不过再次之前我们可以在base包下再创建一个BaseActivity，这里面可以写一些常用的函数，代码如下所示：
open class BaseActivity : AppCompatActivity() { private var context: Context? = null override fun onCreate(savedInstanceState: Bundle?) { super.onCreate(savedInstanceState) context = this } protected fun jumpActivity(clazz: Class<*>?, finish: Boolean = false) { startActivity(Intent(context, clazz)) if (finish) finish() } protected fun back(toolbar: Toolbar, finish: Boolean = false) = toolbar.setNavigationOnClickListener { if (finish) finish() else onBackPressed() } protected fun showMsg(msg: CharSequence) = Toast.makeText(context, msg, Toast.LENGTH_SHORT).show()protected open fun isAndroid12() = Build.VERSION.SDK_INT >= Build.VERSION_CODES.S protected open fun hasAccessFineLocation() = hasPermission(Manifest.permission.ACCESS_FINE_LOCATION) protected open fun hasCoarseLocation() = hasPermission(Manifest.permission.ACCESS_COARSE_LOCATION) @Requiresapi(Build.VERSION_CODES.S) protected open fun hasBluetoothConnect() = hasPermission(Manifest.permission.BLUETOOTH_CONNECT) @RequiresApi(Build.VERSION_CODES.S) protected open fun hasBluetoothScan() = hasPermission(Manifest.permission.BLUETOOTH_SCAN) protected open fun hasPermission(permission: String) = checkSelfPermission(permission) == PackageManager.PERMISSION_GRANTED protected open fun isOpenBluetooth(): Boolean { (getSystemService(BLUETOOTH_SERVICE) as BluetoothManager).also { it.adapter ?: return false return it.adapter.isEnabled } } protected open fun isOpenLocation(): Boolean { val locationManager = getSystemService(LOCATION_SERVICE) as LocationManager val gps = locationManager.isProviderEnabled(LocationManager.GPS_PROVIDER) val network = locationManager.isProviderEnabled(LocationManager.NETWORK_PROVIDER) val locationEnabled = isLocationEnabled() Log.d("TAG", "gps: $gps，network：$network，locationEnabled：$locationEnabled") return gps || network || locationEnabled } open fun isLocationEnabled(): Boolean { val locationMode = try { Settings.Secure.getInt(contentResolver, Settings.Secure.LOCATION_MODE) } catch (e: SettingNotFoundException) { e.printStackTrace() return false } return locationMode != Settings.Secure.LOCATION_MODE_OFF }}这里面就是一些比较基础的方法，在后面扫描页面会用到的，然后再修改一下MainActivity中的代码，继承BaseActivity，点击中跳转扫描页面：
class MainActivity : BaseActivity() { private val binding by viewBinding(ActivityMainBinding::inflate) override fun onCreate(savedInstanceState: Bundle?) { super.onCreate(savedInstanceState) setContentView(R.layout.activity_main) binding.toolbar.setNavigationOnClickListener { jumpActivity(ScanActivity::class.java) } }}为了保持一样的UI效果，下面更改一下themes.xml中的代码，如下所示：
<resources xmlns:tools="http://schemas.android.com/tools"> <style name="Theme.GoodBle" parent="Theme.MaterialComponents.DayNight.NoActionBar"> - "colorPrimary"
>@color/orange - "colorPrimaryVariant"
>@color/orange - "colorOnPrimary">@color/white
- "colorSecondary">@color/light_orange
- "colorSecondaryVariant">@color/dark_orange
- "colorOnSecondary">@color/white
- "android:statusBarColor">?attr/colorPrimaryVariant
- "android:windowBackground">@color/gray_white
style> <style name="BottomSheetDialogStyle" parent="Theme.Design.BottomSheetDialog"> - "android:windowFrame"
>@null - "android:windowIsFloating"
>true - "android:windowIsTranslucent"
>true - "android:background">@android:color/transparent
- "android:backgroundDimEnabled">true
- "android:colorBackground">@android:color/transparent
style>resources>主要就是修改状态栏颜色，窗口默认背景颜色，现在前置的条件都准备的差不多了，运行一下看看MainActivity的页面效果。
下面在com.llw.goodble包下新建一个ble包，里面我们需要创建一些类来处理扫描的相关事务，首先在ble包下创建一个BleCore类，里面先不写内容，然后我们在ble包下新建一个scan包。在scan包下新建一个BleScanCallback接口，这是一个扫描回调接口，代码如下所示：
interface BleScanCallback { fun onScanResult(result: ScanResult) fun onBatchScanResults(results: List<ScanResult>) {} fun onScanFailed(failed: String) {}}同时在扫描页面需要监听一下蓝牙和定位是否打开，在scan包下添加一个广播接收器的ReceiverCallback 接口，代码如下所示：
interface ReceiverCallback { fun bluetoothClose() fun locationClose()}下面在scan创建广播接收器ScanReceiver，代码如下所示：
class ScanReceiver : BroadcastReceiver() { private var callback: ReceiverCallback? = null fun setCallback(callback: ReceiverCallback?) { this.callback = callback } private var isSend = 0 override fun onReceive(context: Context, intent: Intent) { val action = intent.action if (action == BluetoothAdapter.ACTION_STATE_CHANGED) { when (intent.getIntExtra(BluetoothAdapter.EXTRA_STATE, BluetoothAdapter.ERROR)) { BluetoothAdapter.STATE_OFF -> Log.d(TAG, "STATE_OFF Phone bluetooth off") BluetoothAdapter.STATE_TURNING_OFF -> { callback!!.bluetoothClose() Log.d(TAG, "STATE_TURNING_OFF Phone bluetooth is turning off") } BluetoothAdapter.STATE_ON -> Log.d(TAG, "STATE_ON Phone bluetooth turned on") BluetoothAdapter.STATE_TURNING_ON -> Log.d(TAG, "STATE_TURNING_ON Phone bluetooth is on") } } else if (action == LocationManager.PROVIDERS_CHANGED_ACTION) { if (!isGPSOpen(context)) { isSend++ if (isSend == 1) { Log.d(TAG, "Positioning off") callback!!.locationClose() } else if (isSend == 4) { isSend = 0 } } } } compaNIOn object { val TAG: String = ScanReceiver::class.java.simpleName fun isGPSOpen(context: Context): Boolean { val locationMode = try { Settings.Secure.getInt(context.contentResolver, Settings.Secure.LOCATION_MODE) } catch (e: SettingNotFoundException) { e.printStackTrace() return false } return locationMode != Settings.Secure.LOCATION_MODE_OFF } }} 这里的代码相对简单就是广播接收器接收相关的动作信息，再进行回调，然后我们写一个用于扫描类，在scan包下新建一个BleScan类，代码如下所示：
@SuppressLint("MissingPermission", "InlinedApi")class BleScan private constructor(private val context: Context) { private var mScanFilters: List<ScanFilter> private var mScanSettings: ScanSettings private var bleScanCallback: BleScanCallback? = null var mIsScanning = false init { mScanFilters = ArrayList() mScanSettings = ScanSettings.Builder().build() } companion object { @SuppressLint("StaticFieldLeak") @Volatile private var instance: BleScan? = null private var mBluetoothAdapter: BluetoothAdapter? = null private var mScanner: BluetoothLeScanner? = null fun getInstance(context: Context) = instance ?: synchronized(this) { instance ?: BleScan(context).also { instance = it val manager = context.getSystemService(Context.BLUETOOTH_SERVICE) as BluetoothManager mBluetoothAdapter = manager.adapter if (mBluetoothAdapter != null) { mScanner = mBluetoothAdapter?.bluetoothLeScanner } } } } fun setScanFilters(scanFilters: List<ScanFilter>) { mScanFilters = scanFilters } fun setScanSettings(scanSettings: ScanSettings) { mScanSettings = scanSettings } fun setPhyScanCallback(bleScanCallback: BleScanCallback?) { this.bleScanCallback = bleScanCallback } fun isScanning() = mIsScanning private val scanCallback: ScanCallback = object : ScanCallback() { override fun onScanResult(callbackType: Int, result: ScanResult) { bleScanCallback?.onScanResult(result) } override fun onBatchScanResults(results: List<ScanResult>) { bleScanCallback?.onBatchScanResults(results) } override fun onScanFailed(errorCode: Int) { localScanFailed( when (errorCode) { SCAN_FAILED_ALREADY_STARTED -> "Fails to start scan as BLE scan with the same settings is already started by the app." SCAN_FAILED_APPLICATION_REGISTRATION_FAILED -> "Fails to start scan as app cannot be registered." SCAN_FAILED_INTERNAL_ERROR -> "Fails to start scan due an internal error" SCAN_FAILED_FEATURE_UNSUPPORTED -> "Fails to start power optimized scan as this feature is not supported." else -> "UNKNOWN_ERROR" } ) } } private fun localScanFailed(failed: String) = bleScanCallback?.onScanFailed(failed) @SuppressLint("MissingPermission") fun startScan() { if (!isOpenBluetooth()) { localScanFailed("Bluetooth is not turned on.") return } if (isAndroid12()) { if (!hasBluetoothScan()) { localScanFailed("Android 12 needs to dynamically request bluetooth scan permission.") return } } else { if (!hasAccessFineLocation()) { localScanFailed("Android 6 to 12 requires dynamic request location permission.") return } } if (mIsScanning) { localScanFailed("Currently scanning, please close the current scan and scan again.") return } if (mScanner == null) mScanner = mBluetoothAdapter?.bluetoothLeScanner if (!mBluetoothAdapter!!.isEnabled) { localScanFailed("Bluetooth not turned on.") return } mScanner?.startScan(mScanFilters, mScanSettings, scanCallback) mIsScanning = true } fun stopScan() { if (!mIsScanning) { localScanFailed("Not currently scanning, your stop has no effect.") return } if (mScanner == null) { localScanFailed("BluetoothLeScanner is Null.") return } if (!mBluetoothAdapter!!.isEnabled) { localScanFailed("Bluetooth not turned on.") return } mIsScanning = false mScanner?.stopScan(scanCallback) } private fun isOpenBluetooth() = if (mBluetoothAdapter == null) { localScanFailed("BluetoothAdapter is Null."); false } else mBluetoothAdapter!!.isEnabled private fun isAndroid12() = Build.VERSION.SDK_INT >= Build.VERSION_CODES.S private fun hasAccessFineLocation() = hasPermission(Manifest.permission.ACCESS_FINE_LOCATION) private fun hasBluetoothConnect() = hasPermission(Manifest.permission.BLUETOOTH_CONNECT) private fun hasBluetoothScan() = hasPermission(Manifest.permission.BLUETOOTH_SCAN) private fun hasPermission(permission: String) = context.checkSelfPermission(permission) == PackageManager.PERMISSION_GRANTED}这里首先是创建一个单例，在里面对当前类和一些变量进行初始化，核心就是一个扫描回调，开始和停止扫描的方法处理。因为后面还需要写Ble相关的数据处理，因此在ble包下创建一个BleCore类，代码如下所示：
class BleCore private constructor(private val context: Context) { @SuppressLint("StaticFieldLeak") companion object { @SuppressLint("StaticFieldLeak") @Volatile private var instance: BleCore? = null @SuppressLint("StaticFieldLeak") private lateinit var bleScan: BleScan fun getInstance(context: Context) = instance ?: synchronized(this) { instance ?: BleCore(context).also { instance = it //蓝牙扫描 bleScan = BleScan.getInstance(context) } } } fun setPhyScanCallback(bleScanCallback: BleScanCallback) { bleScan.setPhyScanCallback(bleScanCallback) } fun isScanning() = bleScan.isScanning() fun startScan() = bleScan.startScan() fun stopScan() = bleScan.stopScan()} 同样是一个单例，在里面初始化BleScan，然后增加几个函数去调用BleScan中的函数，最后我们在com.llw.goodble包下创建一个BleApp类，代码如下所示：
class BleApp : Application() { @SuppressLint("StaticFieldLeak") private lateinit var context: Context @SuppressLint("StaticFieldLeak") private lateinit var bleCore: BleCore override fun onCreate() { super.onCreate() context = applicationContext //初始化Ble核心库 bleCore = BleCore.getInstance(this) } fun getBleCore() = bleCore} 这里继承Application，通过自定义的方式在App启动的时候加载这个类，然后在onCreate()函数中，完成对于Ble核心类的初始化，顺便完成对于Ble扫描类的初始化。最后在AndroidManifest.xml中的application标签中配置这个BleApp，如下所示：
<application android:name=".BleApp" ...>在Android12及以上版本，使用蓝牙时需要请求扫描、连接权限、如果还需要使用手机作为从机的话，就请求广播权限，后面会提到的，同时在低版本Android中我们扫描蓝牙请求定位权限，那么首先我们就把权限的部分先做了。
首先声明静态权限，在AndroidManifest.xml中增加如下代码：
<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" /> <uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" /> <uses-permission android:name="android.permission.BLUETOOTH" /> <uses-permission android:name="android.permission.BLUETOOTH_ADMIN" /> <uses-permission android:name="android.permission.BLUETOOTH_CONNECT" /> <uses-permission android:name="android.permission.BLUETOOTH_SCAN" /> <uses-feature android:name="android.hardware.bluetooth_le"/>动态权限请求有两种方式，一种是进入这个页面一下子请求多个权限，另一种是一个一个来请求，让你知道为什么会请求这个权限，这里我们选择第二种，因此需要增加一些布局xml，如下图所示的布局XML。
下面我们依次创建，lay_android12_should_connect.xml
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:app="http://schemas.android.com/apk/res-auto" android:id="@+id/request_location_lay" android:layout_width="match_parent" android:layout_height="match_parent" android:background="@color/gray_white" android:gravity="center" android:orientation="vertical" android:paddingStart="16dp" android:paddingEnd="16dp"> <ImageView android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_gravity="center_horizontal" android:padding="16dp" android:src="@drawable/ic_bluetooth_connected" /> <TextView android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="需要蓝牙连接权限" android:textColor="@color/dark_orange" android:textSize="16sp" /> <TextView android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_marginTop="16dp" android:layout_marginBottom="16dp" android:text="从Android12.0开始，打开蓝牙之前需要请求此权限，使用蓝牙连接权限" app:titleTextColor="@color/black" /> <com.google.android.material.button.MaterialButton android:id="@+id/btn_request_connect_permission" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_gravity="center_horizontal" android:text="授予权限" android:textColor="@color/white" />LinearLayout>用到一个图标ic_bluetooth_connected.xml
<vector xmlns:android="http://schemas.android.com/apk/res/android" android:width="48dp" android:height="48dp" android:tint="@color/orange" android:viewportWidth="24.0" android:viewportHeight="24.0"> <path android:fillColor="@android:color/white" android:pathData="M7,12l-2,-2 -2,2 2,2 2,-2zM17.71,7.71L12,2h-1v7.59L6.41,5 5,6.41 10.59,12 5,17.59 6.41,19 11,14.41L11,22h1l5.71,-5.71 -4.3,-4.29 4.3,-4.29zM13,5.83l1.88,1.88L13,9.59L13,5.83zM14.88,16.29L13,18.17v-3.76l1.88,1.88zM19,10l-2,2 2,2 2,-2 -2,-2z" />vector>布局lay_android12_should_scan.xml
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:app="http://schemas.android.com/apk/res-auto" android:id="@+id/request_location_lay" android:layout_width="match_parent" android:layout_height="match_parent" android:background="@color/gray_white" android:gravity="center" android:orientation="vertical" android:paddingStart="16dp" android:paddingEnd="16dp"> <ImageView android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_gravity="center_horizontal" android:padding="16dp" android:src="@drawable/ic_bluetooth_scan" /> <TextView android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="需要扫描权限" android:textColor="@color/dark_orange" android:textSize="16sp" /> <TextView android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_marginTop="16dp" android:layout_marginBottom="16dp" android:text="从Android12.0开始，扫描设备不再需要请求定位权限，使用此权限" app:titleTextColor="@color/black" /> <com.google.android.material.button.MaterialButton android:id="@+id/btn_request_scan_permission" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_gravity="center_horizontal" android:text="授予权限" android:textColor="@color/white" />LinearLayout>图标ic_bluetooth_scan.xml
<vector xmlns:android="http://schemas.android.com/apk/res/android" android:width="48dp" android:height="48dp" android:autoMirrored="true" android:tint="@color/orange" android:viewportWidth="24.0" android:viewportHeight="24.0"> <path android:fillColor="@android:color/white" android:pathData="M14.24,12.01l2.32,2.32c0.28,-0.72 0.44,-1.51 0.44,-2.33 0,-0.82 -0.16,-1.59 -0.43,-2.31l-2.33,2.32zM19.53,6.71l-1.26,1.26c0.63,1.21 0.98,2.57 0.98,4.02s-0.36,2.82 -0.98,4.02l1.2,1.2c0.97,-1.54 1.54,-3.36 1.54,-5.31 -0.01,-1.89 -0.55,-3.67 -1.48,-5.19zM15.71,7.71L10,2L9,2v7.59L4.41,5 3,6.41 8.59,12 3,17.59 4.41,19 9,14.41L9,22h1l5.71,-5.71 -4.3,-4.29 4.3,-4.29zM11,5.83l1.88,1.88L11,9.59L11,5.83zM12.88,16.29L11,18.17v-3.76l1.88,1.88z" />vector>布局lay_empty.xml：
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:app="http://schemas.android.com/apk/res-auto" android:layout_width="match_parent" android:layout_height="match_parent" android:gravity="center" android:orientation="vertical"> <ImageView android:id="@+id/imageView" android:layout_width="100dp" android:layout_height="100dp" app:srcCompat="@mipmap/ic_scanning" /> <TextView android:id="@+id/textView2" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_marginTop="24dp" android:text="努力扫描中" android:textColor="@color/gray" android:textSize="18sp" android:textStyle="bold" />LinearLayout> 图标不是XML图片，去源码中获取，这是在扫描不到设备的时候显示的布局，布局lay_should_enable_bluetooth.xml。
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:app="http://schemas.android.com/apk/res-auto" android:layout_width="match_parent" android:layout_height="match_parent" android:background="@color/gray_white" android:gravity="center" android:orientation="vertical"> <ImageView android:layout_width="wrap_content" android:layout_height="wrap_content" android:padding="16dp" app:srcCompat="@drawable/ic_bluetooth_disabled" /> <TextView android:layout_width="wrap_content" android:layout_height="wrap_content" android:gravity="center_horizontal" android:text="蓝牙已禁用" android:textColor="@color/dark_orange" android:textSize="16sp" /> <TextView android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_marginTop="16dp" android:gravity="center_horizontal" android:text="蓝牙适配器已关闭，单击下面的按钮以启用它。" android:textColor="@color/black" /> <com.google.android.material.button.MaterialButton android:id="@+id/btn_enable_bluetooth" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_gravity="center_horizontal" android:layout_marginTop="16dp" android:text="启用" android:textColor="@color/white" />LinearLayout>图标ic_bluetooth_disabled.xml
<vector xmlns:android="http://schemas.android.com/apk/res/android" android:width="48dp" android:height="48dp" android:viewportWidth="24.0" android:viewportHeight="24.0"> <path android:fillColor="@color/orange" android:pathData="M13,5.83l1.88,1.88 -1.6,1.6 1.41,1.41 3.02,-3.02L12,2h-1v5.03l2,2v-3.2zM5.41,4L4,5.41 10.59,12 5,17.59 6.41,19 11,14.41V22h1l4.29,-4.29 2.3,2.29L20,18.59 5.41,4zM13,18.17v-3.76l1.88,1.88L13,18.17z" />vector>布局lay_should_enable_location.xml
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:app="http://schemas.android.com/apk/res-auto" android:layout_width="match_parent" android:layout_height="match_parent" android:background="@color/gray_white" android:gravity="center" android:orientation="vertical"> <ImageView android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_gravity="center_horizontal" android:padding="16dp" app:srcCompat="@drawable/ic_location_disabled" /> <TextView android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="位置已禁用" android:textColor="@color/dark_orange" android:textSize="16sp" /> <TextView android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_marginTop="16dp" android:gravity="center_horizontal" android:text="位置已关闭，单击下面的按钮以启用它。" android:textColor="@color/black" /> <com.google.android.material.button.MaterialButton android:id="@+id/btn_enable_location" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_gravity="center_horizontal" android:layout_marginTop="16dp" android:text="启用" android:textColor="@color/white" />LinearLayout>图标ic_location_disabled.xml
<vector xmlns:android="http://schemas.android.com/apk/res/android" android:width="48dp" android:height="48dp" android:tint="@color/orange" android:viewportWidth="24.0" android:viewportHeight="24.0"> <path android:fillColor="@android:color/white" android:pathData="M20.94,11c-0.46,-4.17 -3.77,-7.48 -7.94,-7.94L13,1h-2v2.06c-1.13,0.12 -2.19,0.46 -3.16,0.97l1.5,1.5C10.16,5.19 11.06,5 12,5c3.87,0 7,3.13 7,7 0,0.94 -0.19,1.84 -0.52,2.65l1.5,1.5c0.5,-0.96 0.84,-2.02 0.97,-3.15L23,13v-2h-2.06zM3,4.27l2.04,2.04C3.97,7.62 3.25,9.23 3.06,11L1,11v2h2.06c0.46,4.17 3.77,7.48 7.94,7.94L11,23h2v-2.06c1.77,-0.2 3.38,-0.91 4.69,-1.98L19.73,21 21,19.73 4.27,3 3,4.27zM16.27,17.54C15.09,18.45 13.61,19 12,19c-3.87,0 -7,-3.13 -7,-7 0,-1.61 0.55,-3.09 1.46,-4.27l9.81,9.81z" />vector>布局lay_should_location_lay.xml
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:app="http://schemas.android.com/apk/res-auto" android:id="@+id/request_location_lay" android:layout_width="match_parent" android:layout_height="match_parent" android:background="@color/gray_white" android:gravity="center" android:orientation="vertical" android:paddingStart="16dp" android:paddingEnd="16dp"> <ImageView android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_gravity="center_horizontal" android:padding="16dp" android:src="@drawable/ic_location_off" /> <TextView android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="需要位置许可" android:textColor="@color/dark_orange" android:textSize="16sp" /> <TextView android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_marginTop="16dp" android:layout_marginBottom="16dp" android:text="从 Android 6.0 Marshmallow 开始，应用程序需要位置权限才能扫描低功耗蓝牙设备。" /> <com.google.android.material.button.MaterialButton android:id="@+id/btn_request_location_permission" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_gravity="center_horizontal" android:text="授予权限" android:textColor="@color/white" />LinearLayout>图标ic_location_off.xml
<vector xmlns:android="http://schemas.android.com/apk/res/android" android:width="48dp" android:height="48dp" android:viewportWidth="24.0" android:viewportHeight="24.0"> <path android:fillColor="@color/orange" android:pathData="M12,6.5c1.38,0 2.5,1.12 2.5,2.5 0,0.74 -0.33,1.39 -0.83,1.85l3.63,3.63c0.98,-1.86 1.7,-3.8 1.7,-5.48 0,-3.87 -3.13,-7 -7,-7 -1.98,0 -3.76,0.83 -5.04,2.15l3.19,3.19c0.46,-0.52 1.11,-0.84 1.85,-0.84zM16.37,16.1l-4.63,-4.63 -0.11,-0.11L3.27,3 2,4.27l3.18,3.18C5.07,7.95 5,8.47 5,9c0,5.25 7,13 7,13s1.67,-1.85 3.38,-4.35L18.73,21 20,19.73l-3.63,-3.63z" />vector>好了，在我们的努力下这些布局总算是创建完成了，下面我们将它们放置到activity_scan.xml中，代码如下所示：
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:app="http://schemas.android.com/apk/res-auto" xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent" android:layout_height="match_parent" tools:context=".ScanActivity"> <com.google.android.material.appbar.MaterialToolbar android:id="@+id/toolbar" android:layout_width="match_parent" android:layout_height="?attr/actionBarSize" android:background="@color/orange" app:title="选择蓝牙设备" app:titleTextColor="@color/white"> <TextView android:id="@+id/tv_scan_status" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_gravity="end" android:layout_marginEnd="6dp" android:padding="10dp" android:text="搜索" android:textColor="@color/white" android:textSize="14sp" android:visibility="gone" /> com.google.android.material.appbar.MaterialToolbar> <ProgressBar android:id="@+id/pb_scan_loading" style="?android:attr/progressBarStyleHorizontal" android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_alignBottom="@+id/toolbar" android:layout_marginBottom="-10dp" android:indeterminate="true" android:indeterminateTint="@color/orange" android:visibility="invisible" /> <androidx.recyclerview.widget.RecyclerView android:id="@+id/rv_device" android:layout_width="match_parent" android:layout_height="match_parent" android:layout_below="@+id/toolbar" android:layout_marginTop="4dp" android:overScrollMode="never" /> <include android:id="@+id/empty_lay" layout="@layout/lay_empty" android:layout_width="match_parent" android:layout_height="match_parent" android:layout_below="@id/toolbar" /> <include android:id="@+id/request_bluetooth_scan_lay" layout="@layout/lay_android12_should_scan" android:layout_width="match_parent" android:layout_height="match_parent" android:layout_below="@id/toolbar" android:visibility="gone" /> <include android:id="@+id/enable_location_lay" layout="@layout/lay_should_enable_location" android:layout_width="match_parent" android:layout_height="match_parent" android:layout_below="@id/toolbar" android:visibility="gone" /> <include android:id="@+id/request_location_lay" layout="@layout/lay_should_location_lay" android:layout_width="match_parent" android:layout_height="match_parent" android:layout_below="@id/toolbar" android:visibility="gone" /> <include android:id="@+id/enable_bluetooth_lay" layout="@layout/lay_should_enable_bluetooth" android:layout_width="match_parent" android:layout_height="match_parent" android:layout_below="@id/toolbar" android:visibility="gone" /> <include android:id="@+id/request_bluetooth_connect_lay" layout="@layout/lay_android12_should_connect" android:layout_width="match_parent" android:layout_height="match_parent" android:layout_below="@id/toolbar" android:visibility="gone" />RelativeLayout>下面我们可以写代码了，在ScanActivity中，
首先是ScanActivity的一些基本配置，如下所示：
class ScanActivity : BaseActivity() { private val TAG = ScanActivity::class.java.simpleName private val binding by viewBinding(ActivityScanBinding::inflate) override fun onCreate(savedInstanceState: Bundle?) { super.onCreate(savedInstanceState) setContentView(R.layout.activity_scan) }}然后增加布局中按钮的点击监听，创建一个initView()函数，在onCreate()中调用它，代码如下所示：
override fun onCreate(savedInstanceState: Bundle?) { super.onCreate(savedInstanceState) setContentView(R.layout.activity_scan) initView() } private fun initView() { binding.requestBluetoothConnectLay.btnRequestConnectPermission.setOnClickListener(this) binding.enableBluetoothLay.btnEnableBluetooth.setOnClickListener(this) binding.requestLocationLay.btnRequestLocationPermission.setOnClickListener(this) binding.enableLocationLay.btnEnableLocation.setOnClickListener(this) binding.requestBluetoothScanLay.btnRequestScanPermission.setOnClickListener(this) binding.toolbar.setOnClickListener(this) binding.tvScanStatus.setOnClickListener(this) }然后实现点击监听
class ScanActivity : BaseActivity(), View.OnClickListener重写onClick()函数，代码如下所示：
override fun onClick(v: View) { when (v.id) { //请求蓝牙连接权限 R.id.btn_request_connect_permission -> {} //打开蓝牙开关 R.id.btn_enable_bluetooth -> {} //请求定位权限 R.id.btn_request_location_permission -> {} //打开位置开关 R.id.btn_enable_location -> {} //请求蓝牙扫描权限 R.id.btn_request_scan_permission -> {} //扫描或停止扫描 R.id.tv_scan_status -> {} else -> {} } }在这里我们先不写内容，后面再完善，然后我们可以先处理权限，再重写Activity的onResume()函数，代码如下所示：
override fun onResume() { super.onResume() if (isAndroid12()) { //蓝牙连接 binding.requestBluetoothConnectLay.root.visibility = if (hasBluetoothConnect()) View.GONE else View.VISIBLE if (!hasBluetoothConnect()) { Log.d(TAG, "onResume: 未获取蓝牙连接权限") return } //打开蓝牙开关 binding.enableBluetoothLay.root.visibility = if (isOpenBluetooth()) View.GONE else View.VISIBLE if (!isOpenBluetooth()) { Log.d(TAG, "onResume: 未打开蓝牙") return } //蓝牙扫描 binding.requestBluetoothScanLay.root.visibility = if (hasBluetoothScan()) View.GONE else View.VISIBLE if (!hasBluetoothScan()) { Log.d(TAG, "onResume: 未获取蓝牙扫描权限") return } } //打开蓝牙 binding.enableBluetoothLay.root.visibility = if (isOpenBluetooth()) View.GONE else View.VISIBLE if (!isOpenBluetooth()) { Log.d(TAG, "onResume: 未打开蓝牙") return } //打开定位 binding.enableLocationLay.root.visibility = if (isOpenLocation()) View.GONE else View.VISIBLE if (!isOpenLocation()) { Log.d(TAG, "onResume: 未打开位置") return } //请求定位 binding.requestLocationLay.root.visibility = if (hasCoarseLocation() && hasAccessFineLocation()) View.GONE else View.VISIBLE if (!hasAccessFineLocation()) { Log.d(TAG, "onResume: 未获取定位权限") return } binding.tvScanStatus.visibility = View.VISIBLE //开始扫描 }在这个函数中对activity_scan.xml中引入的布局判断是否显示，在请求权限或者是打开开关之后都会触发这个函数，然后进行检查，当所有检查都通过之后说明你可以开始扫描了。那么如果要扫描，我们需要得到BleCore的对象，先声明，然后在onCreate中进行实例化。
private lateinit var bleCore: BleCore override fun onCreate(savedInstanceState: Bundle?) { ... bleCore = (application as BleApp).getBleCore() }下面我们可以写扫描相关的方法，代码如下所示：
private fun startScan() { bleCore?.startScan() binding.tvScanStatus.text = "停止" binding.pbScanLoading.visibility = View.VISIBLE } private fun stopScan() { bleCore?.stopScan() binding.tvScanStatus.text = "搜索" binding.pbScanLoading.visibility = View.INVISIBLE }这里就是开始和停止扫描，别忘了还有扫描回调，这个回调应该写在哪里，首先是在onCreate()函数中，代码如下：
override fun onCreate(savedInstanceState: Bundle?) { ... //设置扫描回调 if (isOpenBluetooth()) bleCore!!.setPhyScanCallback(this@ScanActivity) }这里还判断了一下是否开启蓝牙，扫描的结果需要实现BleScanCallback接口，如下所示：
class ScanActivity : BaseActivity(), View.OnClickListener, BleScanCallback 重写onScanResult()函数，如下所示：
override fun onScanResult(result: ScanResult) { }然后别忘记了我们还有一个广播处理，在onCreate()函数中进行广播注册，代码如下所示：
override fun onCreate(savedInstanceState: Bundle?) {... //注册广播 registerReceiver( ScanReceiver().apply { setCallback(this@ScanActivity) }, IntentFilter().apply { addAction(BluetoothAdapter.ACTION_STATE_CHANGED) addAction(LocationManager.PROVIDERS_CHANGED_ACTION) }) }实现接口ReceiverCallback，代码如下所示：
class ScanActivity : BaseActivity(), View.OnClickListener, BleScanCallback, ReceiverCallback重写里面的函数，代码如下所示：
override fun bluetoothClose() { } override fun locationClose() { }下面我们进行权限和开关的请求处理，在ScanActivity中新增如下代码：
//蓝牙连接权限 private val requestConnect = registerForActivityResult(ActivityResultContracts.RequestPermission()) { showMsg(if (it) "可以打开蓝牙" else "Android12 中不授予此权限无法打开蓝牙") } //启用蓝牙 private val enableBluetooth = registerForActivityResult(ActivityResultContracts.StartActivityForResult()) { result -> if (result.resultCode == Activity.RESULT_OK) { showMsg("蓝牙已打开") Log.d(TAG, ": 蓝牙已打开") bleCore.setPhyScanCallback(this@ScanActivity) } } //请求定位 private val requestLocation = registerForActivityResult(ActivityResultContracts.RequestMultiplePermissions()) { result -> val coarseLocation = result[Manifest.permission.ACCESS_COARSE_LOCATION] val fineLocation = result[Manifest.permission.ACCESS_FINE_LOCATION] if (coarseLocation == true && fineLocation == true) { //开始扫描设备 showMsg("定位权限已获取") if (isOpenBluetooth()) bleCore.setPhyScanCallback(this@ScanActivity) } } //启用定位 private val enableLocation = registerForActivityResult(ActivityResultContracts.StartActivityForResult()) { result -> if (result.resultCode == Activity.RESULT_OK) { showMsg("位置已打开") Log.d(TAG, ": 位置已打开") if (isOpenBluetooth()) bleCore.setPhyScanCallback(this@ScanActivity) } } //蓝牙连接权限 private val requestScan = registerForActivityResult(ActivityResultContracts.RequestPermission()) { showMsg(if (it) "可以开始扫描设备了" else "Android12 Android12 中不授予此权限无法扫描蓝牙") }这里使用了Activity Result API，需要注意的是它们是与onCreate()函数平级的，下面修改onClick()函数中的代码：
override fun onClick(v: View) { when (v.id) { //请求蓝牙连接权限 R.id.btn_request_connect_permission -> if (isAndroid12()) requestConnect.launch(Manifest.permission.BLUETOOTH_CONNECT) //打开蓝牙开关 R.id.btn_enable_bluetooth -> enableBluetooth.launch(Intent(BluetoothAdapter.ACTION_REQUEST_ENABLE)) //请求定位权限 R.id.btn_request_location_permission -> requestLocation.launch( arrayOf( Manifest.permission.ACCESS_COARSE_LOCATION, Manifest.permission.ACCESS_FINE_LOCATION ) ) //打开位置开关 R.id.btn_enable_location -> enableLocation.launch(Intent(Settings.ACTION_LOCATION_SOURCE_SETTINGS)) //请求蓝牙扫描权限 R.id.btn_request_scan_permission -> if (isAndroid12()) requestScan.launch(Manifest.permission.BLUETOOTH_SCAN) //扫描或停止扫描 R.id.tv_scan_status -> if (bleCore.isScanning()) stopScan() else startScan() else -> {} } } 这里就比较的简单了，下面再修改bluetoothClose()和locationClose()函数，在回调时都判断当前是否正在扫描，在扫描则停止，同时显示对应的布局。
override fun bluetoothClose() { //蓝牙关闭时停止扫描 if (bleCore.isScanning()) { stopScan() binding.enableBluetoothLay.root.visibility = View.VISIBLE } } override fun locationClose() { //位置关闭时停止扫描 if (bleCore.isScanning()) { stopScan() binding.enableLocationLay.root.visibility = View.VISIBLE } }最后再增加一个onStop()函数，代码如下：
override fun onStop() { super.onStop() //页面停止时停止扫描 if (bleCore.isScanning()) stopScan() }当页面销毁了或者是进入后台了，那么触发回调，停止扫描。
要显示扫描结果，首先要做的是定义一个类去装载扫描结果，在ble包下新建一个BleDevice数据类，代码如下所示：
data class BleDevice( var realName: String? = "Unknown device", //蓝牙设备真实名称 var MacAddress: String, //蓝牙设备Mac地址 var rssi: Int, //信号强度 var device: BluetoothDevice,//蓝牙设备 var gatt: BluetoothGatt? = null//gatt)扫描的结果我们可以用列表来展示，选择使用RecyclerView，那么相应的会使用到适配器。
首先创建适配器的布局，在layout下新建一个item_device_rv.xml，代码如下所示：
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:app="http://schemas.android.com/apk/res-auto" xmlns:tools="http://schemas.android.com/tools" android:id="@+id/item_device" android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_marginBottom="1dp" android:background="@color/white" android:foreground="?attr/selectableItemBackground" android:orientation="vertical"> <ImageView android:id="@+id/imageView2" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_marginStart="16dp" android:src="@drawable/ic_bluetooth_blue" app:layout_constraintBottom_toBottomOf="parent" app:layout_constraintStart_toStartOf="parent" app:layout_constraintTop_toTopOf="parent" /> <TextView android:id="@+id/tv_device_name" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_marginStart="16dp" android:layout_marginTop="8dp" android:ellipsize="end" android:singleLine="true" android:text="设备名称" android:textColor="@color/black" android:textSize="16sp" app:layout_constraintStart_toEndOf="@+id/imageView2" app:layout_constraintTop_toTopOf="parent" /> <TextView android:id="@+id/tv_mac_address" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_marginBottom="8dp" android:ellipsize="end" android:singleLine="true" android:text="Mac地址" android:textSize="12sp" app:layout_constraintBottom_toBottomOf="parent" app:layout_constraintStart_toStartOf="@+id/tv_device_name" app:layout_constraintTop_toBottomOf="@+id/tv_device_name" /> <TextView android:id="@+id/tv_rssi" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_marginEnd="16dp" android:text="信号强度" android:textSize="12sp" app:layout_constraintBottom_toBottomOf="parent" app:layout_constraintEnd_toEndOf="parent" app:layout_constraintTop_toTopOf="parent" />androidx.constraintlayout.widget.ConstraintLayout> 这里的内容不多，主要内容就是设备名称、地址、信号强度，下面我们创建适配器，在com.llw.goodble包下新建一个adapter包，该包下新建一个OnItemClickListener接口，用于实现Item的点击监听，代码如下所示：
interface OnItemClickListener { fun onItemClick(view: View?, position: Int)}下面我们写适配器，在adapter包下新建一个BleDeviceAdapter类，代码如下所示：
class BleDeviceAdapter( private val mDevices: List<BleDevice>) : RecyclerView.Adapter<BleDeviceAdapter.ViewHolder>() { private var mOnItemClickListener: OnItemClickListener? = null fun setOnItemClickListener(mOnItemClickListener: OnItemClickListener?) { this.mOnItemClickListener = mOnItemClickListener } override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): ViewHolder { val viewHolder = ViewHolder(ItemDeviceRvBinding.inflate(LayoutInflater.from(parent.context), parent, false)) viewHolder.binding.itemDevice.setOnClickListener { v -> if (mOnItemClickListener != null) mOnItemClickListener!!.onItemClick(v, viewHolder.adapterPosition) } return viewHolder } override fun onBindViewHolder(holder: ViewHolder, position: Int) { val bleDevice: BleDevice = mDevices[position] val rssi: Int = bleDevice.rssi holder.binding.tvRssi.text = String.fORMat(Locale.getDefault(), "%d dBm", rssi) //设备名称 holder.binding.tvDeviceName.text = bleDevice.realName //Mac地址 holder.binding.tvMacAddress.text = bleDevice.macAddress } override fun getItemCount() = mDevices.size class ViewHolder(itemView: ItemDeviceRvBinding) : RecyclerView.ViewHolder(itemView.root) { var binding: ItemDeviceRvBinding init { binding = itemView } }} 这里就是基本的写法，结合了ViewBinding，在onBindViewHolder()中进行数据渲染，那么适配器就写好了，下面我们回到ScanActivity中，去完成后的扫描结果显示。
首先我们声明变量，在ScanActivity中增加如下代码：
private var mAdapter: BleDeviceAdapter? = null //设备列表 private val mList: MutableList<BleDevice> = mutableListOf() private fun findIndex(bleDevice: BleDevice, mList: MutableList<BleDevice>): Int { var index = 0 for (devi in mList) { if (bleDevice.macAddress.contentEquals(devi.macAddress)) return index index += 1 } return -1 }这个findIndex()函数用于在列表中找是否有添加过设备，下面修改扫描的回调函数onScanResult()，代码如下所示：
override fun onScanResult(result: ScanResult) { if (result.scanRecord!!.deviceName == null) return if (result.scanRecord!!.deviceName!!.isEmpty()) return val bleDevice = BleDevice( result.scanRecord!!.deviceName, result.device.address, result.rssi, result.device ) Log.d(TAG, "onScanResult: ${bleDevice.macAddress}") if (mList.size == 0) { mList.add(bleDevice) } else { val index = findIndex(bleDevice, mList) if (index == -1) { //添加新设备 mList.add(bleDevice) } else { //更新已有设备的rssi mList[index].rssi = bleDevice.rssi } } //如果未扫描到设备，则显示空内容布局 binding.emptyLay.root.visibility = if (mList.size == 0) View.VISIBLE else View.GONE //如果mAdapter为空则会执行run{}中的代码，进行相关配置，最终返回配置的结果mAdapter mAdapter ?: run { mAdapter = BleDeviceAdapter(mList) binding.rvDevice.apply { (itemAnimator as SimpleItemAnimator).supportsChangeAnimations = false layoutManager = LinearLayoutManager(this@ScanActivity) adapter = mAdapter } mAdapter!!.setOnItemClickListener(this@ScanActivity) mAdapter } mAdapter!!.notifyDataSetChanged() }那么在开始扫描的时候我们最好清理一下列表，修改一下startScan()函数，代码如下所示：
private fun startScan() { mList.clear() mAdapter?.notifyDataSetChanged() bleCore.startScan() binding.tvScanStatus.text = "停止" binding.pbScanLoading.visibility = View.VISIBLE }同时在扫描回调中还有一个适配器的Item点击监听，先实现它，修改代码：
class ScanActivity : BaseActivity(), View.OnClickListener, BleScanCallback, ReceiverCallback, OnItemClickListener {重写onItemClick()函数，代码如下：
override fun onItemClick(view: View?, position: Int) { if (bleCore.isScanning()) stopScan() //选中设备处理 val intent = Intent() intent.putExtra("device", mList[position].device) setResult(RESULT_OK, intent) finish() }我们是通过MainActivity进入到ScanActivity的，那么在选中设备之后将设备对象返回并销毁当前页面。ScanActivity中还有最后一个修改的地方，那就是在onResume()函数中增加开始扫描的代码，代码如下所示：
override fun onResume() { ... //开始扫描 if (!bleCore.isScanning()) startScan() }这里的意思就是当进入页面检查到条件都满足时就开始扫描。
最后我们在MainActivity中接收结果，修改代码如下所示：
class MainActivity : BaseActivity() { private val binding by viewBinding(ActivityMainBinding::inflate) @SuppressLint("MissingPermission") private val scanIntent = registerForActivityResult(ActivityResultContracts.StartActivityForResult()) { result -> if (result.resultCode == Activity.RESULT_OK) { if (result.data == null) return@registerForActivityResult //获取选中的设备 val device = if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.TIRAMISU) { result.data!!.getParcelableExtra("device", BluetoothDevice::class.java) } else { result.data!!.getParcelableExtra("device") as BluetoothDevice? } showMsg("${device?.name} , ${device?.address}") } } override fun onCreate(savedInstanceState: Bundle?) { super.onCreate(savedInstanceState) setContentView(R.layout.activity_main) binding.toolbar.setNavigationOnClickListener { scanIntent.launch(Intent(this,ScanActivity::class.java)) } }}下面我们运行一下：
如果对你有所帮助的话，不妨 Star 或 Fork，山高水长，后会有期~
源码地址：GoodBle
来源地址：https://blog.csdn.net/qq_38436214/article/details/131974318
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本文标题: Android Ble蓝牙App（一）扫描
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