配对和连接是两个不同的概念：
配对意思是两个设备相互意识到对方的存在，共享一个用来鉴别身份的链路键（link-key），能够与对方建立一个加密的连接。
连接意思是两个设备现在共享一个RFCOMM信道，能够相互传输数据。
目前Android Bluetooth API's要求设备在建立RFCOMM信道前必须配对（配对是在使用Bluetooth API初始化一个加密连接时自动完成的）。
检测蓝牙历史配对设备：
private void getDevices() {
BluetoothAdapter bluetoothAdapter = BluetoothAdapter.getDefaultAdapter();
Set<BluetoothDevice> bondedDevices = bluetoothAdapter.getBondedDevices();
for (BluetoothDevice bluetoothDevice : bondedDevices) {
Log.i(TAG, "name is : " + bluetoothDevice.getName() + " state is:" + bluetoothDevice.getBondState());
}
Log.i(TAG, "size:" + bondedDevices.size());
}检测蓝牙已经连接设备使用反射方式：
private void checkLinkState1() {
ArrayList<BluetoothDevice> deviceList = new ArrayList<>();
BluetoothAdapter adapter = BluetoothAdapter.getDefaultAdapter();
Class<BluetoothAdapter> bluetoothAdapterClass = BluetoothAdapter.class;//得到BluetoothAdapter的Class对象
try {
//得到连接状态的方法
Method method = bluetoothAdapterClass.getDeclaredMethod("getConnectionState", (Class[]) null);
//打开权限
method.setAccessible(true);
int state = (int) method.invoke(adapter, (Object[]) null);
if (state == BluetoothAdapter.STATE_CONNECTED) {
Log.i(TAG, "BluetoothAdapter.STATE_CONNECTED");
Set<BluetoothDevice> devices = adapter.getBondedDevices();
Log.i(TAG, "devices:" + devices.size());
for (BluetoothDevice device : devices) {
Method isConnectedMethod = BluetoothDevice.class.getDeclaredMethod("isConnected", (Class[]) null);
method.setAccessible(true);
boolean isConnected = (boolean) isConnectedMethod.invoke(device, (Object[]) null);
if (isConnected) {
Log.i(TAG, "connected:" + device.getName());
deviceList.add(device);
}
}
}
} catch (Exception e) {
e.printStackTrace();
}
}检测蓝牙已经连接设备使用配置文件方式：
private void checkLinkState() {
BluetoothAdapter bluetoothAdapter = BluetoothAdapter.getDefaultAdapter();
int flag = -1;
int a2dp = bluetoothAdapter.getProfileConnectionState(BluetoothProfile.A2DP);
int headset = bluetoothAdapter.getProfileConnectionState(BluetoothProfile.HEADSET);
int health = bluetoothAdapter.getProfileConnectionState(BluetoothProfile.HEALTH);
int health1 = bluetoothAdapter.getProfileConnectionState(BluetoothProfile.GATT);
int health2 = bluetoothAdapter.getProfileConnectionState(BluetoothProfile.GATT_SERVER);
int health3 = bluetoothAdapter.getProfileConnectionState(BluetoothProfile.HEADSET);
int health4 = bluetoothAdapter.getProfileConnectionState(BluetoothProfile.HEARING_AID);
int health5 = bluetoothAdapter.getProfileConnectionState(BluetoothProfile.HID_DEVICE);
int health6 = bluetoothAdapter.getProfileConnectionState(BluetoothProfile.SAP);
if (a2dp == BluetoothProfile.STATE_CONNECTED) {
flag = a2dp;
} else if (headset == BluetoothProfile.STATE_CONNECTED) {
flag = headset;
} else if (health == BluetoothProfile.STATE_CONNECTED) {
flag = health;
} else if (health1 == BluetoothProfile.STATE_CONNECTED) {
flag = health1;
} else if (health2 == BluetoothProfile.STATE_CONNECTED) {
flag = health2;
} else if (health3 == BluetoothProfile.STATE_CONNECTED) {
flag = health3;
} else if (health4 == BluetoothProfile.STATE_CONNECTED) {
flag = health4;
} else if (health5 == BluetoothProfile.STATE_CONNECTED) {
flag = health5;
} else if (health6 == BluetoothProfile.STATE_CONNECTED) {
flag = health6;
}
Log.e(TAG, "flag is " + flag);
if (flag != -1) {
bluetoothAdapter.getProfileProxy(this, new BluetoothProfile.ServiceListener() {
@Override
public void onServiceDisconnected(int profile) {
// TODO Auto-generated method stub
Log.i(TAG, "onServiceDisconnected");
}
@Override
public void onServiceConnected(int profile, BluetoothProfile proxy) {
// TODO Auto-generated method stub
List<BluetoothDevice> mDevices = proxy.getConnectedDevices();
if (mDevices != null && mDevices.size() > 0) {
for (BluetoothDevice device : mDevices) {
Log.i(TAG, "device name: " + device.getName());
}
} else {
Log.i(TAG, "mDevices is null");
}
}
}, flag);
}
}当然使用前需要注册监听，下面是完整activity：
import androidx.appcompat.app.AppCompatActivity;
import android.bluetooth.BluetoothAdapter;
import android.bluetooth.BluetoothDevice;
import android.bluetooth.BluetoothProfile;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import com.example.jumptest.R;
import java.lang.reflect.Method;
import java.util.ArrayList;
import java.util.List;
import java.util.Set;
public class BluetoothActivity extends AppCompatActivity {
private static final String TAG = "BluetoothActivity";
public static void goToBluetoothTest(Context context) {
Intent intent = new Intent(context, BluetoothActivity.class);
context.startActivity(intent);
}
@Override
protected void onCreate(Bundle savedInstanceState) {
Log.e(TAG, "BluetoothActivity onCreate");
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_bluetooth);
registerBroadcastReveiver();
findViewById(R.id.blue_btn).setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
//获取已经配对的蓝牙信息
getDevices();
//方式一：不用反射，个别设备无法检测到
checkLinkState();
//方式二：使用系统API反射，没有问题
checkLinkState1();//OK test
}
});
}
private void checkLinkState1() {
ArrayList<BluetoothDevice> deviceList = new ArrayList<>();
BluetoothAdapter adapter = BluetoothAdapter.getDefaultAdapter();
Class<BluetoothAdapter> bluetoothAdapterClass = BluetoothAdapter.class;//得到BluetoothAdapter的Class对象
try {
//得到连接状态的方法
Method method = bluetoothAdapterClass.getDeclaredMethod("getConnectionState", (Class[]) null);
//打开权限
method.setAccessible(true);
int state = (int) method.invoke(adapter, (Object[]) null);
if (state == BluetoothAdapter.STATE_CONNECTED) {
Log.i(TAG, "BluetoothAdapter.STATE_CONNECTED");
Set<BluetoothDevice> devices = adapter.getBondedDevices();
Log.i(TAG, "devices:" + devices.size());
for (BluetoothDevice device : devices) {
Method isConnectedMethod = BluetoothDevice.class.getDeclaredMethod("isConnected", (Class[]) null);
method.setAccessible(true);
boolean isConnected = (boolean) isConnectedMethod.invoke(device, (Object[]) null);
if (isConnected) {
Log.i(TAG, "connected:" + device.getName());
deviceList.add(device);
}
}
}
} catch (Exception e) {
e.printStackTrace();
}
}
private void checkLinkState() {
BluetoothAdapter bluetoothAdapter = BluetoothAdapter.getDefaultAdapter();
int flag = -1;
int a2dp = bluetoothAdapter.getProfileConnectionState(BluetoothProfile.A2DP);
int headset = bluetoothAdapter.getProfileConnectionState(BluetoothProfile.HEADSET);
int health = bluetoothAdapter.getProfileConnectionState(BluetoothProfile.HEALTH);
int health1 = bluetoothAdapter.getProfileConnectionState(BluetoothProfile.GATT);
int health2 = bluetoothAdapter.getProfileConnectionState(BluetoothProfile.GATT_SERVER);
int health3 = bluetoothAdapter.getProfileConnectionState(BluetoothProfile.HEADSET);
int health4 = bluetoothAdapter.getProfileConnectionState(BluetoothProfile.HEARING_AID);
int health5 = bluetoothAdapter.getProfileConnectionState(BluetoothProfile.HID_DEVICE);
int health6 = bluetoothAdapter.getProfileConnectionState(BluetoothProfile.SAP);
if (a2dp == BluetoothProfile.STATE_CONNECTED) {
flag = a2dp;
} else if (headset == BluetoothProfile.STATE_CONNECTED) {
flag = headset;
} else if (health == BluetoothProfile.STATE_CONNECTED) {
flag = health;
} else if (health1 == BluetoothProfile.STATE_CONNECTED) {
flag = health1;
} else if (health2 == BluetoothProfile.STATE_CONNECTED) {
flag = health2;
} else if (health3 == BluetoothProfile.STATE_CONNECTED) {
flag = health3;
} else if (health4 == BluetoothProfile.STATE_CONNECTED) {
flag = health4;
} else if (health5 == BluetoothProfile.STATE_CONNECTED) {
flag = health5;
} else if (health6 == BluetoothProfile.STATE_CONNECTED) {
flag = health6;
}
Log.e(TAG, "flag is " + flag);
if (flag != -1) {
bluetoothAdapter.getProfileProxy(this, new BluetoothProfile.ServiceListener() {
@Override
public void onServiceDisconnected(int profile) {
// TODO Auto-generated method stub
Log.i(TAG, "onServiceDisconnected");
}
@Override
public void onServiceConnected(int profile, BluetoothProfile proxy) {
// TODO Auto-generated method stub
List<BluetoothDevice> mDevices = proxy.getConnectedDevices();
if (mDevices != null && mDevices.size() > 0) {
for (BluetoothDevice device : mDevices) {
Log.i(TAG, "device name: " + device.getName());
}
} else {
Log.i(TAG, "mDevices is null");
}
}
}, flag);
}
}
private void getDevices() {
BluetoothAdapter bluetoothAdapter = BluetoothAdapter.getDefaultAdapter();
Set<BluetoothDevice> bondedDevices = bluetoothAdapter.getBondedDevices();
for (BluetoothDevice bluetoothDevice : bondedDevices) {
Log.i(TAG, "name is : " + bluetoothDevice.getName() + " state is:" + bluetoothDevice.getBondState());
}
Log.i(TAG, "size:" + bondedDevices.size());
}
@Override
protected void onDestroy() {
super.onDestroy();
unRegisterBroadcastReceiver();
}
private void registerBroadcastReveiver() {
IntentFilter connectStateChangeFilter = new IntentFilter(BluetoothAdapter.ACTION_CONNECTION_STATE_CHANGED);
IntentFilter stateChangeFilter = new IntentFilter(BluetoothAdapter.ACTION_STATE_CHANGED);
IntentFilter connectFilter = new IntentFilter(BluetoothDevice.ACTION_ACL_CONNECTED);
IntentFilter disConnectFilter = new IntentFilter(BluetoothDevice.ACTION_ACL_DISCONNECTED);
registerReceiver(stateChangeReceiver, connectStateChangeFilter);
registerReceiver(stateChangeReceiver, stateChangeFilter);
registerReceiver(stateChangeReceiver, connectFilter);
registerReceiver(stateChangeReceiver, disConnectFilter);
}
private void unRegisterBroadcastReceiver() {
unregisterReceiver(stateChangeReceiver);
}
private BroadcastReceiver stateChangeReceiver = new BroadcastReceiver() {
@Override
public void onReceive(Context context, Intent intent) {
String action = intent.getAction();
// Log.i(TAG, "bluetooth, stateChangeReceiver, action: " + action);
if (BluetoothDevice.ACTION_ACL_CONNECTED.equals(action)) {
Log.e(TAG, "connect");
}
if (BluetoothDevice.ACTION_ACL_DISCONNECTED.equals(action)) {
Log.e(TAG, "disconnect");
}
if (BluetoothAdapter.ACTION_CONNECTION_STATE_CHANGED.equals(action)) {
Log.e(TAG, "ACTION_CONNECTION_STATE_CHANGED");
}
if (BluetoothAdapter.ACTION_STATE_CHANGED.equals(action)) {
Log.e(TAG, "ACTION_STATE_CHANGED");
}
}
};
}相关参考：
https://blog.csdn.net/mapeifan/article/details/50683956