问题：

扫描 BLE 设备后不调用Android BLE 扫描回调

章学义

2023-03-14

我正在创建一个Android应用程序，该应用程序使用Android Studio扫描所有附近的BLE（蓝牙低功耗）设备。

我想我已经实施了所有这些文件：

https://developer.android.com/guide/topics/connectivity/bluetooth/ble-overview
https://developer.android.com/guide/topics/connectivity/bluetooth/permissions#java
https://developer.android.com/guide/topics/connectivity/bluetooth/setup#java
https://developer.android.com/guide/topics/connectivity/bluetooth/find-ble-devices

但是，正如您在下面的日志中看到的，（问题）应用程序没有扫描任何BLE设备。

以下是日志中的日志：

我认为这可能发生，因为没有调用BLE扫描回调（日志中没有BLE扫描回调）。

所以我的问题是我的代码的解决方案是什么？我错过了编码什么吗？

这是我的密码

AndroidManifest.xml：

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.example">

    <uses-permission android:name="android.permission.BLUETOOTH" />
    <uses-permission android:name="android.permission.BLUETOOTH_ADMIN" />
    <uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />
    <uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" />

    <uses-feature
        android:name="android.hardware.bluetooth_le"
        android:required="true" />

    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:roundIcon="@mipmap/ic_launcher_round"
        android:supportsRtl="true"
        android:theme="@style/Theme.Example">
        <activity android:name=".ui.authentication.signin.SignInActivity" />
        <activity android:name=".ui.authentication.signup.SignUpActivity" />
        <activity android:name=".ui.home.HomeActivity">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>

</manifest>

BluetoothHelper.java：

package com.example.util;

import android.Manifest;
import android.app.Activity;
import android.bluetooth.BluetoothAdapter;
import android.bluetooth.BluetoothDevice;
import android.bluetooth.le.BluetoothLeScanner;
import android.bluetooth.le.ScanCallback;
import android.bluetooth.le.ScanResult;
import android.content.Context;
import android.content.Intent;
import android.content.pm.PackageManager;
import android.os.Build;
import android.os.Handler;
import android.util.Log;

import androidx.core.app.ActivityCompat;
import androidx.core.content.ContextCompat;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.Set;

public class BluetoothHelper {
    static int REQUEST_ENABLE_BT = 1;
    static int PERMISSION_CODE = 1;
    static String TAG = "Bluetooth";
    static boolean isScanning = false;

    // SOURCE FOR BLUETOOTH PERMISSION: https://developer.android.com/guide/topics/connectivity/bluetooth/permissions#java

    // CHECK FOR BLUETOOTH PERMISSION FOR ANDROID 10
    public static void android10BluetoothPermission (Context context, Activity activity) {
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.Q) {
            if (ContextCompat.checkSelfPermission(context,
                    Manifest.permission.ACCESS_BACKGROUND_LOCATION)
                    != PackageManager.PERMISSION_GRANTED) {
                ActivityCompat.requestPermissions(
                        activity,
                        new String[]{Manifest.permission.ACCESS_BACKGROUND_LOCATION},
                        PERMISSION_CODE
                );
            }
        }
    }

    // SOURCE FOR SET UP BLUETOOTH: https://developer.android.com/guide/topics/connectivity/bluetooth/setup#java

    // GET BLUETOOTH ADAPTER
    public static void setupBluetooth (BluetoothAdapter bluetoothAdapter) {
        if (bluetoothAdapter == null) {
            Log.d(TAG, "Bluetooth: " + "bluetooth adapter is null");
        }
        else {
            Log.d(TAG, "Bluetooth: " + "bluetooth is adapter not null");
        }
    }

    // ENABLE BLUETOOTH
    public static void enableBluetooth (Activity activity, BluetoothAdapter bluetoothAdapter) {
        Log.d(TAG, "Bluetooth: " + "bluetooth adapter is enabled: " + bluetoothAdapter.isEnabled());
        if (!bluetoothAdapter.isEnabled()) {
            Intent enableBtIntent = new Intent(BluetoothAdapter.ACTION_REQUEST_ENABLE);
            activity.startActivityForResult(enableBtIntent, REQUEST_ENABLE_BT);
            Log.d(TAG, "Bluetooth: " + "bluetooth is enabled");
        }
        else {
            Log.d(TAG, "Bluetooth: " + "bluetooth is already enabled");
        }
    }

    // SOURCE FOR FIND BLUETOOTH DEVICES: https://developer.android.com/guide/topics/connectivity/bluetooth/find-bluetooth-devices

    // QUERY PAIRED DEVICES
    public static Set<BluetoothDevice> queryPairedDevices (BluetoothAdapter bluetoothAdapter) {
        Set<BluetoothDevice> pairedDevices = bluetoothAdapter.getBondedDevices();
        Log.d(TAG, "PairedDevices: " + pairedDevices.toString());
        return pairedDevices;
    }

    // GET ALL NAMES AND MAC ADDRESSES
    public static ArrayList<HashMap<String, String>> getNamesAndMacAddresses(Set<BluetoothDevice> bluetoothDevices) {
        ArrayList<HashMap<String, String>> arrayList = new ArrayList<>();

        if (bluetoothDevices.size() > 0) {
            for (BluetoothDevice device : bluetoothDevices) {
                String deviceName = device.getName();
                String deviceMacAddress = device.getAddress();

                HashMap<String, String> hashMap = new HashMap<>();
                hashMap.put("deviceName", deviceName);
                hashMap.put("deviceMacAddress", deviceMacAddress);
                arrayList.add(hashMap);
            }
        }

        Log.d(TAG, "NamesAndMacAddress: " + arrayList);
        return arrayList;
    }

    // SOURCE FOR FIND BLE DEVICES: https://developer.android.com/guide/topics/connectivity/bluetooth/find-ble-devices#java

    // SCAN BLE DEVICES
    public static void scanBLEDevices (BluetoothLeScanner bluetoothLeScanner) {
        int SCAN_DURATION = 10000;

        if(!isScanning) {
            Handler handler = new Handler();
            handler.postDelayed(new Runnable() {
                @Override
                public void run() {
                    isScanning = false;
                    bluetoothLeScanner.stopScan(bleScanCallback);
                    Log.d(TAG, "ScanBLEDevices: " + "stop scanning");
                }
            }, SCAN_DURATION);

            isScanning = true;
            bluetoothLeScanner.startScan(bleScanCallback);
            Log.d(TAG, "ScanBLEDevices: " + "start scanning");
        }
        else {
            isScanning = false;
            bluetoothLeScanner.stopScan(bleScanCallback);
            Log.d(TAG, "ScanBLEDevices: " + "stop scanning");
        }
    }

    // BLE SCAN CALLBACK
    private static ScanCallback bleScanCallback = new ScanCallback() {
        @Override
        public void onScanResult(int callbackType, ScanResult result) {
            super.onScanResult(callbackType, result);
            Log.d(TAG, "ScanCallback: " + result.getDevice());
        }
    };
}

HomeActivity.java：

package com.example.ui.home;

import androidx.appcompat.app.AppCompatActivity;

import android.bluetooth.BluetoothAdapter;
import android.bluetooth.BluetoothDevice;
import android.bluetooth.le.BluetoothLeScanner;
import android.os.Bundle;
import android.view.View;

import com.example.R;
import com.example.databinding.ActivityHomeBinding;
import com.example.util.AuthenticationHelper;
import com.example.util.BluetoothHelper;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.Set;

public class HomeActivity extends AppCompatActivity implements View.OnClickListener {

    ActivityHomeBinding binding;
    Set<BluetoothDevice> pairedDevices;
    ArrayList<HashMap<String, String>> arrayList;
    BluetoothLeScanner bluetoothLeScanner;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        binding = ActivityHomeBinding.inflate(getLayoutInflater());
        setContentView(binding.getRoot());

        setUpBluetooth();

        binding.buttonKeluar.setOnClickListener(this);
    }

    @Override
    protected void onStart() {
        super.onStart();
        AuthenticationHelper.checkHasTheUserLoggedIn(this);
    }

    @Override
    public void onClick(View v) {
        if(v.getId() == R.id.buttonKeluar) {
            AuthenticationHelper.signOutUser(this);
        }
    }

    private void setUpBluetooth() {
        BluetoothHelper.android10BluetoothPermission(this, HomeActivity.this);
        BluetoothAdapter bluetoothAdapter = BluetoothAdapter.getDefaultAdapter();
        BluetoothHelper.setupBluetooth(bluetoothAdapter);
        BluetoothHelper.enableBluetooth(this, bluetoothAdapter);

        pairedDevices = BluetoothHelper.queryPairedDevices(bluetoothAdapter);
        arrayList = BluetoothHelper.getNamesAndMacAddresses(pairedDevices);

        bluetoothLeScanner = bluetoothAdapter.getBluetoothLeScanner();
        BluetoothHelper.scanBLEDevices(bluetoothLeScanner);
    }
}

我将这段代码添加到< code > bluetooth helper . Java 类中的< code > Android 10 bluetooth permission()函数中，但仍然无法运行。

if (ContextCompat.checkSelfPermission(context,
                Manifest.permission.ACCESS_FINE_LOCATION)
                != PackageManager.PERMISSION_GRANTED) {
            ActivityCompat.requestPermissions(
                    activity,
                    new String[]{Manifest.permission.ACCESS_FINE_LOCATION},
                    PERMISSION_CODE
            );
        }
        if (ContextCompat.checkSelfPermission(context,
                Manifest.permission.ACCESS_COARSE_LOCATION)
                != PackageManager.PERMISSION_GRANTED) {
            ActivityCompat.requestPermissions(
                    activity,
                    new String[]{Manifest.permission.ACCESS_COARSE_LOCATION},
                    PERMISSION_CODE
            );
        }

共有1个答案

刘建中

2023-03-14

最后，我修改了我的代码，所以代码现在可以工作了。这是:

ScanAndPairActivity.java（我正在创建一个用于扫描和配对BLE设备的新活动）：

package com.example.ui.scanandpair;

import androidx.annotation.NonNull;
import androidx.appcompat.app.AppCompatActivity;
import androidx.core.content.ContextCompat;
import androidx.recyclerview.widget.LinearLayoutManager;

import android.Manifest;
import android.app.Activity;
import android.app.AlertDialog;
import android.bluetooth.BluetoothAdapter;
import android.bluetooth.le.BluetoothLeScanner;
import android.bluetooth.le.ScanCallback;
import android.bluetooth.le.ScanFilter;
import android.bluetooth.le.ScanResult;
import android.bluetooth.le.ScanSettings;
import android.content.DialogInterface;
import android.content.Intent;
import android.content.pm.PackageManager;
import android.os.Build;
import android.os.Bundle;
import android.os.Handler;
import android.util.Log;
import android.view.View;
import android.widget.Toast;

import com.example.R;
import com.example.databinding.ActivityScanAndPairBinding;
import com.example.entity.BLEDeviceEntity;

import java.util.ArrayList;
import java.util.List;

public class ScanAndPairActivity extends AppCompatActivity {

    // GENERAL
    String TAG = getClass().getSimpleName();
    ActivityScanAndPairBinding binding;

    // BLUETOOTH
    int REQUEST_ENABLE_BT = 1;
    boolean isScanning = false;
    BluetoothAdapter bluetoothAdapter;
    BluetoothLeScanner bluetoothLeScanner;
    ScanAndPairAdapter scanAndPairAdapter;
    List<BLEDeviceEntity> bleDeviceEntityList;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        binding = ActivityScanAndPairBinding.inflate(getLayoutInflater());
        setContentView(binding.getRoot());

        android10BluetoothPermission();

        scanAndPairAdapter = new ScanAndPairAdapter(this);
        bleDeviceEntityList = new ArrayList<>();
    }

    // SOURCE FOR BLUETOOTH PERMISSION: https://developer.android.com/guide/topics/connectivity/bluetooth/permissions#java

    // CHECK FOR BLUETOOTH PERMISSION FOR ANDROID 10
    private void android10BluetoothPermission () {
        boolean isLocationPermissionRequired = Build.VERSION.SDK_INT >= Build.VERSION_CODES.N;
        boolean isBGLocationAccessNotGranted = false;
        if (android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.Q) {
            isBGLocationAccessNotGranted = ContextCompat.checkSelfPermission(
                    this, Manifest.permission.ACCESS_BACKGROUND_LOCATION) != PackageManager.PERMISSION_GRANTED;
        }
        boolean isLocationAccessNotGranted = ContextCompat.checkSelfPermission(
                this, Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED;

        if (isLocationPermissionRequired && isBGLocationAccessNotGranted && isLocationAccessNotGranted) {
            requestLocationPermission();
        }
        else {
            setUpBluetooth();
        }
    }

    private void requestLocationPermission() {
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
            if (shouldShowRequestPermissionRationale(Manifest.permission.ACCESS_FINE_LOCATION)) {
                AlertDialog.Builder alertDialogBuilder = new AlertDialog.Builder(this);
                alertDialogBuilder
                        .setTitle(getString(R.string.izinkan_lokasi))
                        .setMessage(getString(R.string.mohon_izinkan_aplikasi_mengakses_lokasi))
                        .setPositiveButton(getString(R.string.ya), new DialogInterface.OnClickListener() {
                            @Override
                            public void onClick(DialogInterface dialog, int which) {
                                makeLocationRequest();
                            }
                        });
                alertDialogBuilder.show();
            } else {
                makeLocationRequest();
            }
        }
    }

    private void makeLocationRequest() {
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
            requestPermissions(new String[]{"android.permission.ACCESS_FINE_LOCATION"}, 101);
        }
    }

    // ON REQUEST PERMISSION RESULT
    @Override
    public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
        super.onRequestPermissionsResult(requestCode, permissions, grantResults);
        switch(requestCode) {
            case 101:
                if (grantResults.length != 0 && grantResults[0] == 0) {
                    setUpBluetooth();
                }
                break;
            default:
                Toast.makeText(this, getString(R.string.maaf_izin_lokasi_harus_disetujui), Toast.LENGTH_LONG).show();
        }
    }

    private void setUpBluetooth() {
        bluetoothAdapter = BluetoothAdapter.getDefaultAdapter();
        checkBluetooth(bluetoothAdapter);
        enableBluetooth(this, bluetoothAdapter);

        bluetoothLeScanner = bluetoothAdapter.getBluetoothLeScanner();
        scanBLEDevices(bluetoothLeScanner);
    }

    // SOURCE FOR SET UP BLUETOOTH: https://developer.android.com/guide/topics/connectivity/bluetooth/setup#java

    // GET BLUETOOTH ADAPTER
    private void checkBluetooth (BluetoothAdapter bluetoothAdapter) {
        if (bluetoothAdapter == null) {
            Log.d(TAG, "Bluetooth: " + "bluetooth adapter is null");
        }
        else {
            Log.d(TAG, "Bluetooth: " + "bluetooth is adapter not null");
        }
    }

    // ENABLE BLUETOOTH
    private void enableBluetooth (Activity activity, BluetoothAdapter bluetoothAdapter) {
        Log.d(TAG, "Bluetooth: " + "bluetooth adapter is enabled: " + bluetoothAdapter.isEnabled());
        if (!bluetoothAdapter.isEnabled()) {
            Intent enableBtIntent = new Intent(BluetoothAdapter.ACTION_REQUEST_ENABLE);
            activity.startActivityForResult(enableBtIntent, REQUEST_ENABLE_BT);
            Log.d(TAG, "Bluetooth: " + "bluetooth is enabled");
        }
        else {
            Log.d(TAG, "Bluetooth: " + "bluetooth is already enabled");
        }
    }

    // SOURCE FOR FIND BLE DEVICES: https://developer.android.com/guide/topics/connectivity/bluetooth/find-ble-devices#java

    // SCAN BLE DEVICES
    private void scanBLEDevices (BluetoothLeScanner bluetoothLeScanner) {
        showProgressBar();

        int SCAN_DURATION = 5000;

        if(!isScanning) {
            Handler handler = new Handler();
            handler.postDelayed(new Runnable() {
                @Override
                public void run() {
                    isScanning = false;
                    bluetoothLeScanner.stopScan(bleScanCallback);
                    Log.d(TAG, "ScanBLEDevices: " + "stop scanning");
                    populateDataToRecyclerView();
                }
            }, SCAN_DURATION);

            isScanning = true;
            showProgressBar();
            bluetoothLeScanner.startScan(buildScanFilters(), buildScanSettings(), bleScanCallback);
            Log.d(TAG, "ScanBLEDevices: " + "start scanning");
        }
        else {
            isScanning = false;
            bluetoothLeScanner.stopScan(bleScanCallback);
            Log.d(TAG, "ScanBLEDevices: " + "stop scanning");
            populateDataToRecyclerView();
        }
    }

    private void showProgressBar() {
        binding.recylerViewFilm.setVisibility(View.GONE);
        binding.progressBar.setVisibility(View.VISIBLE);
    }

    private void hideProgressBar() {
        binding.recylerViewFilm.setVisibility(View.VISIBLE);
        binding.progressBar.setVisibility(View.GONE);
    }

    private void populateDataToRecyclerView() {
        hideProgressBar();
        scanAndPairAdapter.setBleDeviceEntityList(bleDeviceEntityList);
        scanAndPairAdapter.notifyDataSetChanged();

        binding.recylerViewFilm.setLayoutManager(new LinearLayoutManager(ScanAndPairActivity.this));
        binding.recylerViewFilm.setHasFixedSize(true);
        binding.recylerViewFilm.setAdapter(scanAndPairAdapter);

        scanAndPairAdapter.setOnItemClickCallback(new ScanAndPairAdapter.OnItemClickCallback() {
            @Override
            public void onItemClicked(BLEDeviceEntity bleDeviceEntity) {
                Toast.makeText(
                        ScanAndPairActivity.this, "try to connect to " + bleDeviceEntity.getName(), Toast.LENGTH_SHORT).show();
            }
        });
    }

    // BLE SCAN CALLBACK
    private ScanCallback bleScanCallback = new ScanCallback() {
        @Override
        public void onScanResult(int callbackType, ScanResult result) {
            super.onScanResult(callbackType, result);
            String deviceAddress = result.getDevice().getAddress();
            String deviceName = result.getDevice().getName();

            Log.d(TAG, "ScanCallback, deviceAddress: " + deviceAddress + ", deviceName: " + deviceName);
            if(bleDeviceEntityList.size() == 0) {
                bleDeviceEntityList.add(new BLEDeviceEntity(deviceAddress, deviceName));
            }
            else {
                for(BLEDeviceEntity bleDeviceEntity : bleDeviceEntityList){
                    if(!bleDeviceEntity.getAddress().equals(deviceAddress)) {
                        bleDeviceEntityList.add(new BLEDeviceEntity(deviceAddress, deviceName));
                    }
                }
            }

            Log.d(TAG, "bleDeviceEntityList: " + bleDeviceEntityList);
        }
    };

    // SOURCE FOR LATEST ANDROID BLE APPLICATION SAMPLE: https://github.com/android/connectivity-samples/tree/main/BluetoothAdvertisementsKotlin

    private static List<ScanFilter> buildScanFilters() {
        List<ScanFilter> scanFilters = new ArrayList<>();

        ScanFilter.Builder builder = new ScanFilter.Builder();
        // Comment out the below line to see all BLE devices around you
        // builder.setServiceUuid(Constants.Service_UUID);
        scanFilters.add(builder.build());
        return scanFilters;
    }

    private static ScanSettings buildScanSettings() {
        ScanSettings.Builder builder = new ScanSettings.Builder();
        builder.setScanMode(ScanSettings.SCAN_MODE_LOW_POWER);
        return builder.build();
    }
}

感谢大家的帮助，特别感谢Isaidamier在这里向我展示了示例应用程序。

类似资料：

扫描BLE设备不工作

我试图扫描BLE设备与（我知道它在新版本中已经过时了，但我只是想看看它是否能与我的手机配合使用[4.4]，我正在使用它）。因此，它开始扫描，然后继续，没有给出错误，但没有检测到设备。也会触发OnLEScan事件，但其中的设备参数为null。我的LE设备就在那里并已连接。在Google上，我发现如果BluetoothAdapter没有UUID，就会发生这种情况。如何设置UUID？何时调用/启动O
BLE扫描未找到BLE设备

我有3台Android设备，三星Galaxy S3手机，三星Tab4和Verizon OEM平板电脑。Verizon OEM平板电脑不支持BLE、API 17。我从android开发者网站安装了“BLE设备扫描”，并在Galaxy S3上运行。它只显示Verizon平板电脑是找到的设备。当我在三星Tab4上运行相同的应用程序时，它只显示Galaxy S3作为找到的设备。如果我只看Galaxy S3
AndroidBLE被动扫描

我想在我的Android应用程序中被动地扫描BLE广告商，但我找不到如何做到这一点。 > < li> 根据蓝牙4.0核心规范，存在被动扫描模式。< br >第6卷:核心系统包[低能耗控制器卷]，< br > D部分:4.1被动扫描< br > https://www.bluetooth.org/DocMan/handlers/DownloadDoc.ashx?doc_id=282159 “设备可
Android ble扫描蓝牙附近设备kotlin

我试图用BLE API扫描附近的蓝牙设备，但它似乎不起作用我已经在清单中添加了权限以下内容在创建对象时创建扫描仪回调对象并进一步扫描在logcat中，我只看到以下内容这是我的app build gradle } 有人能指出我在这里遗漏了什么吗？
设备蓝牙扫描

开启蓝牙扫描参数说明字段类型必须？说明 blePrefix String 是设备名称类型前缀示例代码 Swift: RokidMobileSDK.binder.startBLEScan(blePrefix: String) ->Bool Objc: [RokidMobileSDK.binder startBLEScanWithBlePrefix:@"Rokid-"]; 手机蓝牙未打
设备蓝牙扫描

扫描设备介绍需要传入扫描蓝牙设备的名称的前缀，回调均在主线程。如果传空，是无法获取设备列表。 1、单前缀蓝牙设备参数说明字段类型必须？说明 type String 是设备名称类型前缀举个大栗子 String type = "Rokid-" RokidMobileSDK.binder.startBTScan(type, new IBTScanCallBack() { @Ov

扫描 BLE 设备后不调用Android BLE 扫描回调

共有1个答案

相关问答

相关文章

相关阅读

相关工具

相关文档