最近在做藍牙開鎖的小項目，手機去連接單片機總是出現問題，和手機的連接也不穩定，看了不少藍牙方面的文檔，做了個關於藍牙連接的小結。
在做android藍牙串口連接的時候一般會使用
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BluetoothSocket tmp = null;
// Get a BluetoothSocket for a connection with the
// given BluetoothDevice
try {
tmp = device.createRfcommSocketToServiceRecord(MY_UUID);
} catch (IOException e) {
Log.e(TAG, "create() failed", e);
}
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然后是tmp賦給BluetoothSocket,接着調用connect方法進行藍牙設備的連接。
可是 BluetoothSocket 的connect方法本身就會報很多異常錯誤。
以下根據對藍牙開發的一點研究可通過以下方法解決：
方法1.先進行藍牙自動配對，配對成功，通過UUID獲得BluetoothSocket,然后執行connect()方法。
方法2.通過UUID獲得BluetoothSocket,然后先根據mDevice.getBondState()進行判斷是否需要配對，最后執行connnect()方法。
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private class ConnectThread extends Thread {
String macAddress = "";
public ConnectThread(String mac) {
macAddress = mac;
}
public void run() {
connecting = true;
connected = false;
if(mBluetoothAdapter == null){
mBluetoothAdapter = BluetoothAdapter.getDefaultAdapter();
}
mBluetoothDevice = mBluetoothAdapter.getRemoteDevice(macAddress);
mBluetoothAdapter.cancelDiscovery();
try {
socket = mBluetoothDevice.createRfcommSocketToServiceRecord(uuid);
} catch (IOException e) {
// TODO Auto-generated catch block
//e.printStackTrace();
Log.e(TAG, "Socket", e);
}
//adapter.cancelDiscovery();
while (!connected && connetTime <= 10) {
connectDevice();
}
// 重置ConnectThread
//synchronized (BluetoothService.this) {
//ConnectThread = null;
//}
}
public void cancel() {
try {
socket.close();
socket = null;
} catch (Exception e) {
e.printStackTrace();
} finally {
connecting = false;
}
}
}
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接下來是調用的連接設備方法connectDevice():
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protected void connectDevice() {
try {
// 連接建立之前的先配對
if (mBluetoothDevice.getBondState() == BluetoothDevice.BOND_NONE) {
Method creMethod = BluetoothDevice.class
.getMethod("createBond");
Log.e("TAG", "開始配對");
creMethod.invoke(mBluetoothDevice);
} else {
}
} catch (Exception e) {
// TODO: handle exception
//DisplayMessage("無法配對！");
e.printStackTrace();
}
mBluetoothAdapter.cancelDiscovery();
try {
socket.connect();
//DisplayMessage("連接成功!");
//connetTime++;
connected = true;
} catch (IOException e) {
// TODO: handle exception
//DisplayMessage("連接失敗！");
connetTime++;
connected = false;
try {
socket.close();
socket = null;
} catch (IOException e2) {
// TODO: handle exception
Log.e(TAG, "Cannot close connection when connection failed");
}
} finally {
connecting = false;
}
}
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方法3.利用反射通過端口獲得BluetoothSocket,然后執行connect()方法。
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private class ConnectThread extends Thread {
String macAddress = "";
public ConnectThread(String mac) {
macAddress = mac;
}
public void run() {
connecting = true;
connected = false;
if(mBluetoothAdapter == null){
mBluetoothAdapter = BluetoothAdapter.getDefaultAdapter();
}
mBluetoothDevice = mBluetoothAdapter.getRemoteDevice(macAddress);
mBluetoothAdapter.cancelDiscovery();
initSocket();
//adapter.cancelDiscovery();
while (!connected && connetTime <= 10) {
try {
socket.connect();
connected = true;
} catch (IOException e1) {
connetTime++;
connected = false;
// 關閉 socket
try {
socket.close();
socket = null;
} catch (IOException e2) {
//TODO: handle exception
Log.e(TAG, "Socket", e2);
}
} finally {
connecting = false;
}
//connectDevice();
}
// 重置ConnectThread
//synchronized (BluetoothService.this) {
//ConnectThread = null;
//}
}
public void cancel() {
try {
socket.close();
socket = null;
} catch (Exception e) {
e.printStackTrace();
} finally {
connecting = false;
}
}
}
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接下來是初始化並得到BluetoothSocket的方法
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/**
* 取得BluetoothSocket
*/
private void initSocket() {
BluetoothSocket temp = null;
try {
Method m = mBluetoothDevice.getClass().getMethod(
"createRfcommSocket", new Class[] { int.class });
temp = (BluetoothSocket) m.invoke(mBluetoothDevice, 1);//這里端口為1
} catch (SecurityException e) {
e.printStackTrace();
} catch (NoSuchMethodException e) {
e.printStackTrace();
} catch (IllegalArgumentException e) {
e.printStackTrace();
} catch (IllegalAccessException e) {
e.printStackTrace();
} catch (InvocationTargetException e) {
e.printStackTrace();
}
socket = temp;
}
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要點：1.藍牙配對和連接是兩回事，不可混為一談。
2.藍牙串口連接可通過端口 （1-30）和UUID兩種方法進行操作。
3.通過UUID進行藍牙連接最好先進行配對操作。