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本篇內容介紹了“android藍牙簡單開發的方法是什么”的有關知識，在實際案例的操作過程中，不少人都會遇到這樣的困境，接下來就讓小編帶領大家學習一下如何處理這些情況吧！希望大家仔細閱讀，能夠學有所成！
前段時間學習了一些藍牙開發的知識，記錄一下Android中藍牙的簡單開發。下面是最重要的兩個類。
BluetoothAdapter : 藍牙適配器，通過getDefaultAdapter ()去獲取一個實例，如果設備不支持藍牙的話，返回的是一個null對象，通過它，可以打開、關閉藍牙，掃描設備、向指定設備創建socket通道…
BluetoothDevice : 代表一個設備對象，可以通過它獲取設備的名字、地址、類型等，也可以創建匹配，建立socket通道等等。
<uses-permission android:name="android.permission.BLUETOOTH"/> 使用藍牙所需要的權限 <uses-permission android:name="android.permission.BLUETOOTH_ADMIN"/> 使用掃描和設置藍牙的權限（申明這一個權限必須申明上面一個權限）
Android6以上版本，掃描其他藍牙還需要位置權限
// Android 9 以下版本 <user-permission android:name="android.permission.ACCESS_COARSE_LOCATION"/> // Android 9 以上 <uses-permission android:name="android.permission.ACCESS_FINE_LOCATION"/>
mBluetoothAdapter = BluetoothAdapter.getDefaultAdapter();
// 如果設備不支持藍牙
if (mBluetoothAdapter == null){
return;
}
// 設備支持藍牙功能，調用startActivityForResult去啟動藍牙
if (!mBluetoothAdapter.isEnabled()){
startBlueTooth.launch(new Intent(BluetoothAdapter.ACTION_REQUEST_ENABLE));
}打開藍牙功能是通過startActivity去啟動的，但是startActivity這個函數已經過期了，所以我使用官方推薦的Activity Result替代它
ActivityResultLauncher<Intent> startBlueTooth = registerForActivityResult(new ActivityResultContracts.StartActivityForResult(),
new ActivityResultCallback<ActivityResult>() {
@Override
public void onActivityResult(ActivityResult result) {
if (result==null){
Toast.makeText(BlueToothActivity.this, "open failed", Toast.LENGTH_SHORT).show();
}else {
if (result.getResultCode() == RESULT_CANCELED){
Toast.makeText(BlueToothActivity.this,"用戶取消",Toast.LENGTH_SHORT);
}
}
}
});通過廣播去接收藍牙狀態的改變
class BluetoothStateChangeReceiver extends BroadcastReceiver{
public int DEFAULT_VALUE_BLUETOOTH = 1000;
@Override
public void onReceive(Context context, Intent intent) {
String action = intent.getAction();
if (BluetoothAdapter.ACTION_STATE_CHANGED.equals(action)){
int state = intent.getIntExtra(BluetoothAdapter.EXTRA_STATE,DEFAULT_VALUE_BLUETOOTH);
switch(state){
case BluetoothAdapter.STATE_ON:
Log.d(TAG, "onReceive: open");
break;
case BluetoothAdapter.STATE_OFF:
Log.d(TAG, "onReceive: off");
break;
case BluetoothAdapter.STATE_TURNING_ON :
Log.d(TAG, "onReceive: 正在打開");
break;
case BluetoothAdapter.STATE_TURNING_OFF:
Log.d(TAG, "onReceive: 正在關閉");
break;
}
}
}
}別忘了廣播的注冊和解注冊
IntentFilter filter = new IntentFilter(BluetoothAdapter.ACTION_STATE_CHANGED); stateReceiver = new BluetoothStateChangeReceiver() ; registerReceiver(stateReceiver,filter);
同樣通過廣播接收，action是BluetoothDevice.ACTION_FOUND
class MyReceiver extends BroadcastReceiver{
@Override
public void onReceive(Context context, Intent intent) {
String action = intent.getAction();
if (BluetoothDevice.ACTION_FOUND.equals(action)) {
// 從intent對象中獲取藍牙設備的信息
BluetoothDevice device = intent.getParcelableExtra(BluetoothDevice.EXTRA_DEVICE);
// 當發現新設備不存在于配對列表中時添加
if (device.getBondState() != BluetoothDevice.BOND_BONDED) {
blueNames.add(device.getName()+"\t"+device.getAddress());
}
blueAdpater.notifyDataSetChanged();
Log.d(TAG, "onReceive: " + device.getName());
}
}
}動態注冊廣播
IntentFilter filter = new IntentFilter(BluetoothDevice.ACTION_FOUND); registerReceiver(mReceiver,filter);
開啟掃描
mBluetoothAdapter.startDiscovery();
public class BondReceiver extends BroadcastReceiver{
@Override
public void onReceive(Context context, Intent intent) {
if (BluetoothDevice.ACTION_BOND_STATE_CHANGED.equals(intent.getAction())){
BluetoothDevice device = intent.getParcelableExtra(BluetoothDevice.EXTRA_DEVICE);
switch(device.getBondState()){
case BluetoothDevice.BOND_BONDED:
Log.d(TAG, "onReceive: 配對完成");
break;
case BluetoothDevice.BOND_BONDING:
Log.d(TAG, "onReceive: 正在配對");
break;
case BluetoothDevice.BOND_NONE:
Log.d(TAG, "onReceive: 取消配對");
break;
}
}
}
}已經配對的設備會被存儲起來，通過BluetoothAdpater直接獲取即可
Set<BluetoothDevice> paireDevices = mBluetoothAdapter.getBondedDevices();
if (paireDevices.size()>0){
for (BluetoothDevice pairedDevice : pairedDevices) {
blueNames.add(pairedDevice.getName()+" "+pairedDevice.getAddress());
Log.d(TAG, "onClick: "+pairedDevice.getName());
}
}想要在兩臺設備之間創建連接，必須實現客戶端和服務端機制，他們之間使用套接字機制進行連接，服務端開放服務器套接字，客戶端通過MAC地址向服務端發起連接。客戶端和服務端以不同的方式獲得BluetoothSocket,當客戶端和服務端在同一個RFCOMM通道上分別擁有已連接的BluetoothSocket時，將他們視為彼此已經連接，于是每臺設備都獲得輸入和輸出流式傳輸，并開始傳輸數據。
連接技術
一種實現技術是自動將每臺設備準備為一個服務器，從而使每臺設備開放一個服務套接字并偵聽連接，在此情況下，任何一臺設備都可以發起與另一臺設備的連接并稱為客戶端。
服務器
設置服務器套接字并接受連接，步驟依次如下
1、調用listenUsingRfcommWithServiceRecord（）獲取一個BluetoothServerSocket, 該函數需要兩個參數，第一個是服務器的名稱，自己取一個即可，第二個是UUID，用來對信息做唯一性標識，我們可以從網上眾多UUID生成器中隨機的生成一個，然后使用UUID.fromString(String)初始化一個UUID。
2、通過accept()函數開始偵聽連接請求
只有遠程設備發送的連接請求中UUID與使用此套接字注冊的UUID相匹配時服務器才會接受請求，accept函數會返回已連接的BluetoothSocket
3、連接成功后調用close()關閉BluetoothSocket
private class AcceptThread extends Thread{
private final BluetoothServerSocket mmServerSocket;
private String mSocketType;
public AcceptThread(boolean secure){
BluetoothServerSocket tmp = null;
mSocketType = secure ? "secure" : "Insercure";
try{
if (secure){
tmp = bluetoothAdapter.listenUsingRfcommWithServiceRecord(NAME_SECURE,MY_UUID_SECURE);
}else{
tmp = bluetoothAdapter.listenUsingRfcommWithServiceRecord(NAME_INSECURE,MY_UUID_INSECURE);
}
} catch (IOException e) {
Log.e(TAG,"socket type"+ mSocketType + "listen() failed",e);
}
mmServerSocket = tmp;
}
@Override
public void run() {
Log.d(TAG, "Socket Type: " + mSocketType +
"BEGIN mAcceptThread" + this);
setName("AcceptThread"+ mSocketType);
BluetoothSocket socket = null;
Log.d(TAG, "run: 開始監聽");
while (true){
try{
socket = mmServerSocket.accept();
Log.d("acceptThread", "run: 連接成功");
connected(socket,socket.getRemoteDevice(),mSocketType);
} catch (IOException e) {
Log.e(TAG, "Socket Type: " + mSocketType + "accept() failed", e);
break;
}
}
Log.i(TAG, "END mAcceptThread, socket Type: " + mSocketType);
}
public void cancel() {
Log.d(TAG, "Socket Type" + mSocketType + "cancel " + this);
try {
mmServerSocket.close();
} catch (IOException e) {
Log.e(TAG, "Socket Type" + mSocketType + "close() of server failed", e);
}
}
}上面的secure和Insecure只是使用了不同的UUID而已。
客戶端
遠程設備開啟監聽后，我們就發起向此設備的連接，首先必須先獲得遠程設備的BluetoothDevice對象，然后獲取BluetoothSocket發起連接。
基本步驟如下
1、使用BluetoothDevice通過調用createRfcommSocketToServiceRecord(UUID) 獲取 BluetoothSocket。
2、通過connect發起連接
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";
try {
if (secure){
tmp = device.createRfcommSocketToServiceRecord(MY_UUID_SECURE);
}else {
tmp = device.createRfcommSocketToServiceRecord(MY_UUID_INSECURE);
}
} catch (IOException e) {
Log.e(TAG, "Socket Type: " + mSocketType + "create() failed", e);
}
mmSocket = tmp;
}
@Override
public void run() {
Log.i(TAG, "BEGIN mConnectThread SocketType:" + mSocketType);
setName("ConnectThred"+mSocketType);
// 總是取消發現，因為它會減慢連接
bluetoothAdapter.cancelDiscovery();
// connect
// 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();
Log.d(TAG, "run: socket連接成功");
} catch (IOException e) {
// Close the socket
Log.d(TAG, "run: 關閉socket");
try {
mmSocket.close();
} catch (IOException e2) {
Log.e(TAG, "unable to close() " + mSocketType +
" socket during connection failure", e2);
}
return;
}
connected(mmSocket,mmDevice,mSocketType);
}
public void cancel(){
try{
mmSocket.close();
} catch (IOException e) {
Log.e(TAG, "close() of connect " + mSocketType + " socket failed", e);
}
}
}發送數據
連接成功后，我們就可以通過socket發送數據了，客戶端的Socket對象是BluetoothSocket, 服務端的socket是BluetoothServerSocket，特別注意不要混淆了。使用getInputStream和getOutputStream分別獲取通過套接字處理數據傳輸的InputStream和OutputStream。寫數據比較簡單，但是讀數據就需要一個單獨的線程一直監聽才行。
private class ConnectedThread extends Thread{
private final BluetoothSocket mmSocket;
private InputStream mmInStream;
private OutputStream mmOutStream;
public ConnectedThread(BluetoothSocket socket, String socketType) throws IOException {
Log.d(TAG, "create ConnectedThread: " + socketType);
mmSocket = socket;
InputStream tmpIn = null;
OutputStream tmpOut = null;
try{
tmpIn = socket.getInputStream();
tmpOut = socket.getOutputStream();
if (socket != null){
tmpOut.write(new String("hello").getBytes());
Log.d(TAG, "ConnectedThread: socket不是null");
}
} catch (IOException e) {
Log.e(TAG,"temp socket not created", e);
}
mmInStream = tmpIn;
mmOutStream = tmpOut;
// mmOutStream.write(new String("hello").getBytes());
}
@RequiresApi(api = Build.VERSION_CODES.KITKAT)
@Override
public void run() {
Log.i(TAG, "BEGIN mConnectedThread");
byte[] buffer = new byte[1024];
int bytes;
while (true){
try{
bytes = mmInStream.read(buffer);
// send the bytes to the ui Activity
String text = encodeByteToString(buffer,bytes);
Log.d(TAG, "run: 收到消息："+ text);
chatItems.add(text);
mHandler.sendMessage(mHandler.obtainMessage());
} catch (IOException e) {
Log.d(TAG, "run: 沒有收到消息");
e.printStackTrace();
break;
}
}
}
public String encodeByteToString(byte[] data,int length) {
byte[] temp = new byte[length];
for (int i = 0; i < length; i++) {
temp[i] = data[i];
}
try {
return new String(temp,"utf-8");
} catch (UnsupportedEncodingException e) {
return "";
}
}
public void write(byte[] buffer){
try{
mmOutStream.write(buffer);
// mHandler.obtainMessage(Constants.MESSAGE_WRITE,-1,-1,buffer).sendToTarget();
} catch (IOException e) {
e.printStackTrace();
}
}
public void cancel(){
try{
mmSocket.close();
Log.d(TAG, "cancel: connectedThread");
} catch (IOException e) {
Log.e(TAG, "close() of connect socket failed", e);
}
}
}“android藍牙簡單開發的方法是什么”的內容就介紹到這里了，感謝大家的閱讀。如果想了解更多行業相關的知識可以關注億速云網站，小編將為大家輸出更多高質量的實用文章！
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