Ble Bluetooth App (1) scan
foreword
I have done a lot of introductions about low-power Bluetooth, but many people don’t go there for the purpose of learning, they run it with the source code, and later find that they disconnect immediately after connecting the device, and then they don’t know the problem by themselves. , This phenomenon is fast food-style. If you don’t understand the knowledge content in it, you naturally don’t know what’s going on. I have answered repeated questions many times. And I also feel that there is a problem with the writing. In my original intention, I hope that readers can refer to it and read the content of the article, but the vast majority of the results, look at the title to see the running effect, download the source code and run it, there is a problem with the operation Just ask you, no thinking.
In response to this situation, I decided to make a series of Ble Bluetooth Apps to avoid bugs when you run them as much as possible, so this is a low-power Bluetooth tool App that can let you know something. Note that it is low power consumption, not classic Bluetooth. If you don't know the difference between the two, I suggest you learn about it first. The effect of this article:
text
This article will re-create a project, do the functions one by one, and try to optimize each function as much as possible. Next, we will create a project named GoodBle, and the language is Kotlin.
As for why you use Kotlin, stabilize it, otherwise it will become rusty if you don’t use it for a long time. We are talking about scanning in the text. You may recall that what is good about a scan, isn’t it just the start, end, and display device? As for writing an article as a function alone? So let's look at this article with questions to see if scanning is necessary.
1. Basic configuration
Currently we create a project with a MainActivity, and then we need to turn on the viewBinding switch, and android{}add the following code to the closure in the app's build.gradle:
buildFeatures {
viewBinding true
}
Then Sync Now, synchronize and turn on successfully. Then we can use ViewBinding in Activity, and the normal usage is like this:
class MainActivity : AppCompatActivity() {
private lateinit var binding: ActivityMainBinding;
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
binding = ActivityMainBinding.inflate(layoutInflater);
setContentView(binding.root)
}
}
Encapsulation in Java usually uses reflection. In Kotlin, if you want to encapsulate ViewBinding and take advantage of some features of Kotlin, you can do so. The original address is as follows: Viewbinding uses and entrusts encapsulation. It feels pretty well written . I haven't used Kotlin for a long time, and I still understand it after reading it for a while. If you are interested, you can take a look.
Then we create a base package under com.llw.goodble, and create BaseViewBinding.kta file under the base package. The code inside is as follows:
package com.llw.goodble.base
import android.app.Activity
import android.view.LayoutInflater
import androidx.viewbinding.ViewBinding
import kotlin.properties.ReadOnlyProperty
import kotlin.reflect.KProperty
fun <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
}
}
}
Encapsulate by delegation, let's see how to use it in MainActivity,
class MainActivity : AppCompatActivity() {
private val binding by viewBinding(ActivityMainBinding::inflate)
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
}
}
It is very simple to use, and this method will be used later, you can run it to see if there is any problem, then we can create a ScanActivity class to scan the page, modify the code in activity_main.xml, as follows:
<?xml version="1.0" encoding="utf-8"?>
<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>
The icon is used here, the code is as follows:
<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>
Color value, add in colors.xml:
<color name="orange">#FF5722</color>
<color name="warm_yellow">#FFC107</color>
<color name="dark_orange">#FF9800</color>
<color name="light_orange">#FFF3E0</color>
<color name="gray_white">#F8F8F8</color>
<color name="gray">#989898</color>
Here we set the navigation icon for the toolbar, click this to navigate to the scanning page, but before again, we can create a BaseActivity under the base package, where we can write some commonly used functions, the code is as follows:
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)
/**
* 检查是有拥有某权限
*
* @param permission 权限名称
* @return true 有 false 没有
*/
protected open fun hasPermission(permission: String) = checkSelfPermission(permission) == PackageManager.PERMISSION_GRANTED
/**
* 蓝牙是否打开
*
* @return true or false
*/
protected open fun isOpenBluetooth(): Boolean {
(getSystemService(BLUETOOTH_SERVICE) as BluetoothManager).also {
it.adapter ?: return false
return it.adapter.isEnabled
}
}
/**
* 位置是否打开
*/
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
}
}
Here are some basic methods, which will be used to scan the page later, and then modify the code in MainActivity, inherit BaseActivity, and click to jump to the scanning page:
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) }
}
}
In order to keep the same UI effect, change the code in themes.xml as follows:
<resources xmlns:tools="http://schemas.android.com/tools">
<!-- Base application theme. -->
<style name="Theme.GoodBle" parent="Theme.MaterialComponents.DayNight.NoActionBar">
<!-- Primary brand color. -->
<item name="colorPrimary">@color/orange</item>
<item name="colorPrimaryVariant">@color/orange</item>
<item name="colorOnPrimary">@color/white</item>
<!-- Secondary brand color. -->
<item name="colorSecondary">@color/light_orange</item>
<item name="colorSecondaryVariant">@color/dark_orange</item>
<item name="colorOnSecondary">@color/white</item>
<!-- Status bar color. -->
<item name="android:statusBarColor">?attr/colorPrimaryVariant</item>
<!-- Customize your theme here. -->
<item name="android:windowBackground">@color/gray_white</item>
</style>
<style name="BottomSheetDialogStyle" parent="Theme.Design.BottomSheetDialog">
<item name="android:windowFrame">@null</item>
<item name="android:windowIsFloating">true</item>
<item name="android:windowIsTranslucent">true</item>
<item name="android:background">@android:color/transparent</item>
<item name="android:backgroundDimEnabled">true</item>
<item name="android:colorBackground">@android:color/transparent</item>
</style>
</resources>
The main thing is to modify the color of the status bar and the default background color of the window. Now that the pre-conditions are almost ready, run it to see the page effect of MainActivity.
2. Scan preparation
Next, com.llw.goodblecreate a new ble package under the package. In it, we need to create some classes to handle scanning related affairs. First, create a BleCoreclass under the ble package without writing the content, and then we create a new scan package under the ble package. Create a new interface under the scan package BleScanCallback, which is a scan callback interface, the code is as follows:
interface BleScanCallback {
/**
* 扫描结果
*/
fun onScanResult(result: ScanResult)
/**
* 批量扫描结果
*/
fun onBatchScanResults(results: List<ScanResult>) {
}
/**
* 扫描错误
*/
fun onScanFailed(failed: String) {
}
}
At the same time, you need to monitor whether the Bluetooth and positioning are turned on on the scan page, and add a broadcast receiver ReceiverCallbackinterface under the scan package. The code is as follows:
interface ReceiverCallback {
/**
* 蓝牙关闭
*/
fun bluetoothClose()
/**
* 位置关闭
*/
fun locationClose()
}
Next, create a broadcast receiver in scan ScanReceiver, the code is as follows:
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
}
}
}
The code here is relatively simple. The broadcast receiver receives the relevant action information, and then makes a callback. Then we write a class for scanning and scancreate a new class under the package BleScan. The code is as follows:
/**
* 低功耗扫描类
*/
@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
}
}
}
}
/**
* 设置扫描过滤
*/
fun setScanFilters(scanFilters: List<ScanFilter>) {
mScanFilters = scanFilters
}
/**
* 设置扫描设置选项
*/
fun setScanSettings(scanSettings: ScanSettings) {
mScanSettings = scanSettings
}
/**
* 设置扫描回调
*/
fun setPhyScanCallback(bleScanCallback: BleScanCallback?) {
this.bleScanCallback = bleScanCallback
}
fun isScanning() = mIsScanning
/**
* 扫描回调
*/
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"
}
)
}
}
/**
* 显示本地扫描错误
*/
private fun localScanFailed(failed: String) = bleScanCallback?.onScanFailed(failed)
/**
* 开始扫描
*/
@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
}
/**
* 停止扫描
*/
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)
}
/**
* 是否打开蓝牙
*/
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
}
The first thing here is to create a singleton, in which the current class and some variables are initialized. The core is a scanning callback, which starts and stops scanning. Because Ble-related data processing needs to be written later, a BleCore class is created under the ble package, and the code is as follows:
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()
}
It is also a singleton, initialize BleScan in it, and then add several functions to call BleScanthe functions in it, and finally we com.llw.goodblecreate a BleAppclass under the package, the code is as follows:
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
}
Inherited here Application, load this class when the App starts in a custom way, and then complete the initialization of the Ble core class in the onCreate() function, and complete the initialization of the Ble scanning class by the way. Finally, AndroidManifest.xmlconfigure this BleApp in the application tag in , as follows:
<application
android:name=".BleApp"
...>
3. Scan the page
In Android 12 and above, when using Bluetooth, you need to request scanning and connection permissions. If you still need to use the mobile phone as a slave, you need to request broadcast permissions, which will be mentioned later. At the same time, in lower versions of Android, we scan Bluetooth to request location permissions. So first of all, we will do the permission part first.
First declare static permissions, add the following code in AndroidManifest.xml:
<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"/>
① Add UI layout
There are two ways to request dynamic permissions. One is to enter this page to request multiple permissions at once, and the other is to request one by one to let you know why this permission is requested. Here we choose the second method, so we need to add some Layout xml, the layout XML shown in the figure below.
Next we create in turn,lay_android12_should_connect.xml
<?xml version="1.0" encoding="utf-8"?>
<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>
use an iconic_bluetooth_connected.xml
<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<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>
layoutlay_android12_should_scan.xml
<?xml version="1.0" encoding="utf-8"?>
<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>
iconic_bluetooth_scan.xml
<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<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>
layout lay_empty.xml:
<?xml version="1.0" encoding="utf-8"?>
<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>
The icon is not an XML picture, go to the source code to get it, this is the layout displayed when the device cannot be scanned lay_should_enable_bluetooth.xml.
<?xml version="1.0" encoding="utf-8"?>
<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>
iconic_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>
layoutlay_should_enable_location.xml
<?xml version="1.0" encoding="utf-8"?>
<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>
iconic_location_disabled.xml
<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<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>
layoutlay_should_location_lay.xml
<?xml version="1.0" encoding="utf-8"?>
<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>
iconic_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>
Well, with our hard work, these layouts have finally been created. Next, we will place them in activity_scan.xml. The code is as follows:
<?xml version="1.0" encoding="utf-8"?>
<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" />
<!--设备列表-->
<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" />
<!--未扫描到设备时显示-->
<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" />
<!-- Android 12蓝牙扫描权限为许可时显示 Shell_Unresponsive-->
<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" />
<!--Android 6 至 11 没有打开位置开关 无法扫描蓝牙-->
<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" />
<!-- 位置权限未许可时显示 -->
<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" />
<!-- 手机蓝牙未开启时显示 -->
<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" />
<!-- Android12 开启蓝牙需要先请求蓝牙连接权限 -->
<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>
Now we can write code, in ScanActivity,
② Click to monitor
The first is some basic configuration of ScanActivity, as follows:
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)
}
}
Then increase the click monitor of the button in the layout, create an initView() function, and call it in onCreate(), the code is as follows:
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)
}
Then implement click monitoring
class ScanActivity : BaseActivity(), View.OnClickListener
Rewrite the onClick() function, the code is as follows:
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 -> {
}
}
}
Here we don't write the content first, and we will improve it later. Then we can deal with the permissions first, and then rewrite the Activity's onResume() function. The code is as follows:
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
}
③ Scan processing
In this function, judge whether the layout introduced in activity_scan.xml is displayed. This function will be triggered after requesting permission or turning on the switch, and then check it. When all checks pass, you can start scanning. So if we want to scan, we need to get the BleCore object, declare it first, and then instantiate it in onCreate.
private lateinit var bleCore: BleCore
override fun onCreate(savedInstanceState: Bundle?) {
...
bleCore = (application as BleApp).getBleCore()
}
Next, we can write scanning related methods, the code is as follows:
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
}
Here is to start and stop scanning. Don’t forget that there is also a scanning callback. Where should this callback be written? First, in the onCreate() function, the code is as follows:
override fun onCreate(savedInstanceState: Bundle?) {
...
//设置扫描回调
if (isOpenBluetooth()) bleCore!!.setPhyScanCallback(this@ScanActivity)
}
It is also judged here whether to turn on Bluetooth, and the result of the scan needs to implement BleScanCallbackthe interface, as shown below:
class ScanActivity : BaseActivity(), View.OnClickListener, BleScanCallback
Rewrite onScanResult()the function as follows:
/**
* 扫描回调
*/
override fun onScanResult(result: ScanResult) {
}
④ Broadcast processing
Then don't forget that we also have a broadcast processing, broadcast registration in the onCreate() function, the code is as follows:
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)
})
}
Implement the interface ReceiverCallback, the code is as follows:
class ScanActivity : BaseActivity(), View.OnClickListener, BleScanCallback, ReceiverCallback
Rewrite the function inside, the code is as follows:
/**
* 蓝牙关闭
*/
override fun bluetoothClose() {
}
/**
* 位置关闭
*/
override fun locationClose() {
}
4. Permission processing
Next, we process permission and switch requests, and add the following code to ScanActivity:
//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")
}
The Activity Result API is used here. It should be noted that they are at onCreate()the same level as the function. Modify onClick()the code in the function as follows:
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 -> {
}
}
}
It is relatively simple here, bluetoothClose()and locationClose()the function will be modified next. When calling back, it will be judged whether it is currently scanning, and the scanning will stop, and the corresponding layout will be displayed at the same time.
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
}
}
Finally, add another onStop() function, the code is as follows:
override fun onStop() {
super.onStop()
//页面停止时停止扫描
if (bleCore.isScanning()) stopScan()
}
When the page is destroyed or enters the background, a callback is triggered to stop scanning.
5. Scan results
To display the scan results, the first thing to do is to define a class to load the scan results, create a new data class under the ble package BleDevice, the code is as follows:
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
)
We can display the scanning results in a list. If you choose to use RecyclerView, the adapter will be used accordingly.
① List Adapter
First create the layout of the adapter, create a new one under the layout item_device_rv.xml, the code is as follows:
<?xml version="1.0" encoding="utf-8"?>
<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>
There is not much content here, the main content is the device name, address, and signal strength. Next, we create an adapter, create com.llw.goodblean adapter package under the package OnItemClickListener, and create an interface under the package to realize the click monitoring of Item. The code is as follows:
interface OnItemClickListener {
fun onItemClick(view: View?, position: Int)
}
Next, we write the adapter and create a new class under the adapter package BleDeviceAdapter. The code is as follows:
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
}
}
}
Here is the basic writing method, combined ViewBinding, onBindViewHolder()data rendering in , then the adapter is written, let's go back to ScanActivity to display the scanned results after completion.
② Scan result processing
First, we declare variables and add the following code to ScanActivity:
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
}
The findIndex() function is used to find whether there is a device added in the list. The callback function of the scan is modified below onScanResult(). The code is as follows:
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()
}
Then when we start scanning, we'd better clean up the list and modify the startScan() function. The code is as follows:
private fun startScan() {
mList.clear()
mAdapter?.notifyDataSetChanged()
bleCore.startScan()
binding.tvScanStatus.text = "停止"
binding.pbScanLoading.visibility = View.VISIBLE
}
At the same time, there is an adapter's Item click monitor in the scan callback, implement it first, and modify the code:
class ScanActivity : BaseActivity(), View.OnClickListener, BleScanCallback, ReceiverCallback,
OnItemClickListener {
Rewrite onItemClick()the function, the code is as follows:
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()
}
We enter ScanActivity through MainActivity, then return the device object and destroy the current page after the device is selected. There is one final modification in ScanActivity, which is to add the code to start scanning in the onResume() function. The code is as follows:
override fun onResume() {
...
//开始扫描
if (!bleCore.isScanning()) startScan()
}
The meaning here is to start scanning when the entry page checks that the conditions are met.
③ Receive the result
Finally, we receive the result in MainActivity and modify the code as follows:
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)) }
}
}
Let's run it:
6. Source code
If it is helpful to you, you may wish to Star or Fork , the mountain is high and the water is long, there will be a period later~
Source address: GoodBle