在将目标SDK更改为28之前，我有一个在所有Android设备上都能正常运行的应用程序。在将Android 9设备上的SDK更改为28之后，蓝牙无法连接到蓝牙设备，并且活动尝试使用蓝牙重新启动。我没有logcat输出，因为这是在用户手机上发生的，不幸的是我没有任何配备Android 9的手机。但是，当我将目标SDK更改为26时， 在Android 9上成功完成了与蓝牙设备（在我的情况下为便携式打印机）的连接。请注意，此问题在Android 9上发生，但不是8或4。我手边有Android 8和4，但没有9。AS仅来自Android版本为9的用户的投诉。我可以得出结论，Android 9中存在错误。我已在下面发布了代码。只需注意将目标SDK更改为26即可解决问题。
apply plugin: 'com.android.application'
android {
compileSdkVersion 28
useLibrary 'org.apache.http.legacy'
flavorDimensions "default"
defaultConfig {
applicationId "ilia.anrdAcunt.ui"
minSdkVersion 15
targetSdkVersion 26//***28 restarts the Bluetooth activity
//If I change the taget SDK to 28 then there is an error
multiDexEnabled true
}
buildTypes {
release {
minifyEnabled false
proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.txt'
}
}
productFlavors {
demo_flavor {
minSdkVersion 15
applicationId 'ilia.anrdAcunt.uidemo'
targetSdkVersion 26//***28 restarts the Bluetooth activity
}
mainver_flavor {
minSdkVersion 15
applicationId 'ilia.anrdAcunt.ui'
targetSdkVersion 26//***28 restarts the Bluetooth activity
}
kasabeh_flavor {
minSdkVersion 15
applicationId 'ilia.anrdAcunt.ui'
targetSdkVersion 26//***28 restarts the Bluetooth activity
}
}
}
dependencies {
implementation project(':AnrdLib')
///compile 'com.android.support:support-v4:18.0.0'
implementation files('libs/itextg-5.5.4.jar')
implementation files('libs/sc-light-jdk15on-1.47.0.2.jar')
implementation files('libs/scpkix-jdk15on-1.47.0.2.jar')
implementation files('libs/scprov-jdk15on-1.47.0.2.jar')
implementation files('libs/WoosimLib231.jar')
implementation files('libs/commons-net-3.6.jar')
//implementation files('libs/adad-2.8.jar')
implementation 'com.android.support:appcompat-v7:28.0.0'
implementation 'com.android.support:design:28.0.0'
implementation 'com.android.support:support-v13:28.0.0'
implementation 'com.google.android.gms:play-services-auth:16.0.1'
}
所有口味通用的清单文件：
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:targetSandboxVersion="1"
package="ilia.anrdAcunt.ui">
<application
android:icon="@mipmap/ic_launcher"
android:label="@string/app_name"
android:theme="@style/AppTheme"
android:usesCleartextTraffic="true"
tools:replace="android:icon">
...
Manifest.xml文件中的权限（Flavor专用清单）：
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="ilia.anrdAcunt.ui"
android:versionCode="130"
android:versionName="8.55">
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.RECEIVE_BOOT_COMPLETED" />
<uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" />
<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />
<uses-permission android:name="android.permission.BLUETOOTH" />
<uses-permission android:name="android.permission.BLUETOOTH_ADMIN" />
<uses-permission android:name="android.permission.READ_CONTACTS" />
<uses-permission android:name="android.permission.RECEIVE_SMS" />
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.REQUEST_INSTALL_PACKAGES"/>
...
以及用于与蓝牙设备进行连接，写入和读取的代码：
package ilia.anrdAcunt.woosim.prnLib;
import ilia.anrdAcunt.ui.R;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.Arrays;
import java.util.UUID;
import android.bluetooth.BluetoothAdapter;
import android.bluetooth.BluetoothDevice;
import android.bluetooth.BluetoothSocket;
import android.content.Context;
import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
import android.util.Log;
/**
* This class does all the work for setting up and managing Bluetooth connections with printers.
* It has a thread for connecting with a printer, and a thread for performing data transmissions when connected.
*/
public class BluetoothPrintService {
// Debugging
private static final String TAG = "BluetoothPrintService";
private static final boolean D = true;
// Unique UUID for this application
private static final UUID SPP_UUID = UUID.fromString("00001101-0000-1000-8000-00805F9B34FB");
// Member fields
private final BluetoothAdapter mAdapter;
private final Handler mHandler;
private int mState;
private ConnectThread mConnectThread;
private ConnectedThread mConnectedThread;
// Constants that indicate the current connection state
public static final int STATE_NONE = 0; // we're doing nothing
public static final int STATE_LISTEN = 1; // now listening for incoming connections
public static final int STATE_CONNECTING = 2; // now initiating an outgoing connection
public static final int STATE_CONNECTED = 3; // now connected to a remote device
/**
* Constructor. Prepares a new Bluetooth session.
* @param context The UI Activity Context
* @param handler A Handler to send messages back to the UI Activity
*/
public BluetoothPrintService(Context context, Handler handler) {
mAdapter = BluetoothAdapter.getDefaultAdapter();
mState = STATE_NONE;
mHandler = handler;
}
/**
* Set the current state of the connection
* @param state An integer defining the current connection state
*/
private synchronized void setState(int state) {
if (D) Log.d(TAG, "setState() " + mState + " -> " + state);
mState = state;
}
/**
* Return the current connection state.
*/
public synchronized int getState() {
return mState;
}
/**
* Start the print service. Called by the Activity onResume()
*/
public synchronized void start() {
if (D) Log.d(TAG, "start");
// Cancel any thread attempting to make a connection
if (mConnectThread != null) {
mConnectThread.cancel();
mConnectThread = null;
}
// Cancel any thread currently running a connection
if (mConnectedThread != null) {
mConnectedThread.cancel();
mConnectedThread = null;
}
setState(STATE_LISTEN);
}
/**
* Start the ConnectThread to initiate a connection to a remote device.
* @param device The BluetoothDevice to connect
* @param secure Socket Security type - Secure (true) , Insecure (false)
*/
public synchronized void connect(BluetoothDevice device, boolean secure) {
if (D) Log.d(TAG, "connect to: " + device);
// Cancel any thread attempting to make a connection
if (mState == STATE_CONNECTING) {
if (mConnectThread != null) {
mConnectThread.cancel();
mConnectThread = null;
}
}
// Cancel any thread currently running a connection
if (mConnectedThread != null) {
mConnectedThread.cancel();
mConnectedThread = null;
}
// Start the thread to connect with the given device
mConnectThread = new ConnectThread(device, secure);
mConnectThread.start();
setState(STATE_CONNECTING);
}
/**
* Start the ConnectedThread to begin managing a Bluetooth connection
* @param socket The BluetoothSocket on which the connection was made
* @param device The BluetoothDevice that has been connected
*/
public synchronized void connected(BluetoothSocket socket, BluetoothDevice device, final String socketType) {
if (D) Log.d(TAG, "connected, Socket Type:" + socketType);
// Cancel the thread that completed the connection
if (mConnectThread != null) {
mConnectThread.cancel();
mConnectThread = null;
}
// Cancel any thread currently running a connection
if (mConnectedThread != null) {
mConnectedThread.cancel();
mConnectedThread = null;
}
// Start the thread to manage the connection and perform transmissions
mConnectedThread = new ConnectedThread(socket, socketType);
mConnectedThread.start();
// Send the name of the connected device back to the UI Activity
Message msg = mHandler.obtainMessage(WoosimPrnMng.MESSAGE_DEVICE_NAME);
Bundle bundle = new Bundle();
bundle.putString(WoosimPrnMng.DEVICE_NAME, device.getName());
msg.setData(bundle);
mHandler.sendMessage(msg);
setState(STATE_CONNECTED);
}
/**
* Stop all threads
*/
public synchronized void stop() {
if (D) Log.d(TAG, "stop");
if (mConnectThread != null) {
mConnectThread.cancel();
mConnectThread = null;
}
if (mConnectedThread != null) {
mConnectedThread.cancel();
mConnectedThread = null;
}
setState(STATE_NONE);
}
/**
* Write to the ConnectedThread in an unsynchronized manner
* @param out The bytes to write
* @see ConnectedThread#write(byte[])
*/
public void write(byte[] out) {
// Create temporary object
ConnectedThread r;
// Synchronize a copy of the ConnectedThread
synchronized (this) {
if (mState != STATE_CONNECTED) return;
r = mConnectedThread;
}
// Perform the write unsynchronized
r.write(out);
}
/**
* Indicate that the connection attempt failed and notify the UI Activity.
*/
private void connectionFailed() {
// When the application is destroyed, just return
if (mState == STATE_NONE) return;
// Send a failure message back to the Activity
Message msg = mHandler.obtainMessage(WoosimPrnMng.MESSAGE_TOAST);
Bundle bundle = new Bundle();
bundle.putInt(WoosimPrnMng.TOAST, R.string.wConnect_fail);
msg.setData(bundle);
mHandler.sendMessage(msg);
// Start the service over to restart listening mode
BluetoothPrintService.this.start();
}
/**
* Indicate that the connection was lost and notify the UI Activity.
*/
private void connectionLost() {
// When the application is destroyed, just return
if (mState == STATE_NONE) return;
// Send a failure message back to the Activity
Message msg = mHandler.obtainMessage(WoosimPrnMng.MESSAGE_TOAST);
Bundle bundle = new Bundle();
bundle.putInt(WoosimPrnMng.TOAST, R.string.wConnect_lost);
msg.setData(bundle);
mHandler.sendMessage(msg);
// Start the service over to restart listening mode
BluetoothPrintService.this.start();
}
/**
* This thread runs while attempting to make an outgoing connection
* with a device. It runs straight through; the connection either
* succeeds or fails.
*/
private class ConnectThread extends Thread {
private final BluetoothSocket mmSocket;
private final BluetoothDevice mmDevice;
private String mSocketType;
public ConnectThread(BluetoothDevice device, boolean secure) {
mmDevice = device;
BluetoothSocket tmp = null;
mSocketType = secure ? "Secure" : "Insecure";
// Get a BluetoothSocket for a connection with the
// given BluetoothDevice
try {
if (secure) {
tmp = device.createRfcommSocketToServiceRecord(SPP_UUID);
} else {
tmp = device.createInsecureRfcommSocketToServiceRecord(SPP_UUID);
}
} catch (IOException e) {
Log.e(TAG, "Socket Type: " + mSocketType + "create() failed", e);
}
mmSocket = tmp;
}
public void run() {
Log.i(TAG, "BEGIN mConnectThread SocketType:" + mSocketType);
setName("ConnectThread" + mSocketType);
// Always cancel discovery because it will slow down a connection
mAdapter.cancelDiscovery();
// Make a connection to the BluetoothSocket
try {
// This is a blocking call and will only return on a
// successful connection or an exception
mmSocket.connect();
} catch (IOException e) {
// Close the socket
try {
mmSocket.close();
} catch (IOException e2) {
Log.e(TAG, "unable to close() " + mSocketType + " socket during connection failure", e2);
}
Log.e(TAG, "Connection Failed", e);
connectionFailed();
return;
}
// Reset the ConnectThread because we're done
synchronized (BluetoothPrintService.this) {
mConnectThread = null;
}
// Start the connected thread
connected(mmSocket, mmDevice, mSocketType);
}
public void cancel() {
try {
mmSocket.close();
} catch (IOException e) {
Log.e(TAG, "close() of connect " + mSocketType + " socket failed", e);
}
}
}
/**
* This thread runs during a connection with a remote device.
* It handles all incoming and outgoing transmissions.
*/
private class ConnectedThread extends Thread {
private final BluetoothSocket mmSocket;
private final InputStream mmInStream;
private final OutputStream mmOutStream;
public ConnectedThread(BluetoothSocket socket, String socketType) {
Log.d(TAG, "create ConnectedThread: " + socketType);
mmSocket = socket;
InputStream tmpIn = null;
OutputStream tmpOut = null;
// Get the BluetoothSocket input and output streams
try {
tmpIn = socket.getInputStream();
tmpOut = socket.getOutputStream();
} catch (IOException e) {
Log.e(TAG, "temp sockets not created", e);
}
mmInStream = tmpIn;
mmOutStream = tmpOut;
}
public void run() {
Log.i(TAG, "BEGIN mConnectedThread");
byte[] buffer = new byte[1024];
int bytes;
// Keep listening to the InputStream while connected
while (true) {
try {
// Read from the InputStream
bytes = mmInStream.read(buffer);
// buffer can be over-written by next input stream data, so it should be copied
byte[] rcvData = new byte[bytes];
rcvData = Arrays.copyOf(buffer, bytes);
// Send the obtained bytes to the UI Activity
mHandler.obtainMessage(WoosimPrnMng.MESSAGE_READ, bytes, -1, rcvData).sendToTarget();
} catch (IOException e) {
Log.e(TAG, "Connection Lost", e);
connectionLost();
break;
}
}
}
/**
* Write to the connected OutStream.
* @param buffer The bytes to write
*/
public void write(byte[] buffer) {
try {
mmOutStream.write(buffer);
} catch (IOException e) {
Log.e(TAG, "Exception during write", e);
}
}
public void cancel() {
try {
mmInStream.close();
mmOutStream.close();
mmSocket.close();
} catch (IOException e) {
Log.e(TAG, "close() of connect socket failed", e);
}
}
}
}
最后，我认为问题只是由于向Android 9添加了额外的安全性而引起的。我希望向Android 9添加安全性（或更好地增加限制）的那些精明的工程师之一发布解决方案。 / p>