Android蓝牙详析 |
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Android蓝牙详析
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本系列笔记概述蓝牙传输优势：功耗低，传输距离还可以；蓝牙聊天室案例Android中蓝牙设备的使用 蓝牙权限（本文的讲解内容之一） 蓝牙功能开启（本文的讲解内容之一） 搜索蓝牙设备（本文的讲解内容之一） 与外设搭建RFCOMM通道（射频通道）蓝牙设备双向数据传输蓝牙聊天室案例框架 蓝牙权限
执行蓝牙通信需要权限BLUETOOTH，
例如：请求连接、接收连接和传输数据等；如果需要启动设备 或 操作蓝牙设置，则需声明BLUETOOTH_ADMIN权限
设置蓝牙——获取BlueAdapter
使用蓝牙需用到BlueAdapter。表示设备自身的蓝牙适配器；通过静态方法BlueAdapter.getDefaultAdapter()获得BlueAdapter；整个系统只有一个蓝牙适配器，application可使用此BlueAdapter对象与之交互；如果getDefaultAdapter()返回null，则表示该设备不支持蓝牙，
例如：BluetoothAdapter mBluetoothAdapter = BluetoothAdapter.getDefaultAdapter();
if(mBluetoothAdapter == null){
//Device does not support Bluetooth
} 启用蓝牙
调用isEnable()以检查当前是否已启用蓝牙；
如果此方法返回false，则表示蓝牙处于停用状态；要请求启用蓝牙，将通过ACTION_REQUEST_ENABLE向系统设置
发出启用蓝牙的请求（无需停止应用），
例如：...
private static final int REQUEST_ENABLE_BT = 10;//其是需要自己定义的局部常量。
...
if(mBluetoothAdapter.isEnabled()){
Intent enableBtIntent = new Intent(BluetoothAdapter.ACTION_REQUEST_ENABLE);
startActivityForResult(enableBtIntent, REQUEST_ENABLE_BT);
}demo（查看本机是否支持蓝牙，蓝牙是否开启，没开启则请求）：新建一个项目，添加好如上述两个权限，编写MainActivity.java：public class MainActivity extends AppCompatActivity {
private static final String TAG = "BluetoothChat";
private static final int REQUEST_ENABLE_BT = 10;//其是需要自己定义的局部常量。
private BluetoothAdapter mBluetoothAdapter;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mBluetoothAdapter = BluetoothAdapter.getDefaultAdapter();
if(mBluetoothAdapter == null){
//Device does not support Bluetooth
Log.e(TAG, "Device does not support Bluetooth");
}else {
Toast.makeText(this,"设备支持蓝牙！",Toast.LENGTH_SHORT).show();
}
}
@Override
protected void onStart() {
super.onStart();
if(!mBluetoothAdapter.isEnabled()){
//向系统请求开启蓝牙
Intent enableBtIntent = new Intent(BluetoothAdapter.ACTION_REQUEST_ENABLE);
startActivityForResult(enableBtIntent, REQUEST_ENABLE_BT);//结果返回回调到onActivityResult()
}else {
//已经开启了蓝牙
Toast.makeText(this,"蓝牙已经开启",Toast.LENGTH_SHORT).show();
}
}
@Override
protected void onActivityResult(int requestCode, int resultCode, @Nullable Intent data) {
super.onActivityResult(requestCode, resultCode, data);
if(requestCode == REQUEST_ENABLE_BT){
Toast.makeText(this,"蓝牙已经开启",Toast.LENGTH_SHORT).show();
}
}
} 查找设备——查找配对过的设备
getBondedDevices():返回已配对设备的一组BluetoothDevice Set pairedDevices = mBluetoothAdapter.getBondedDevices();
//If threre are paired devices
if (pairedDevices.size() > 0) {
//Loop through paired devices
for(BluetoothDevice device : pairedDevices){
//Add the name and address to an array adapter to show in a ListView
mArrayAdapter.add(device.getName() + "\n" + device.getAddress());
}
} 查找设备——发现设备
发现设备：startDiscovery()
该进程为异步进程，
该方法会立即返回一个布尔值，指示是否已成功启动发现操作；发现进程通常包含约12秒钟的查询扫描 广播接收： //广播接收
private BroadcastReceiver mBluetoothReceiver = new BroadcastReceiver() {
@Override
public void onReceive(Context context, Intent intent) {
String action = intent.getAction();//获取action
Log.d(TAG, "ACTION：" + action);
if(action.equals(BluetoothDevice.ACTION_FOUND)){
//如果扫描时发现蓝牙设备，取到发现的设备
BluetoothDevice device = intent.getParcelableExtra(BluetoothDevice.EXTRA_DEVICE);
}else if(action.equals(BluetoothAdapter.ACTION_DISCOVERY_FINISHED)){
//如果扫描完毕
}
}
};广播过滤、注册、注销：...
//为广播接收器注册过滤器
IntentFilter filter = new IntentFilter();
filter.addAction(BluetoothDevice.ACTION_FOUND);
filter.addAction(BluetoothAdapter.ACTION_DISCOVERY_FINISHED);
registerReceiver(mBluetoothReceiver,filter);
...
@Override
protected void onDestroy() {
super.onDestroy();
unregisterReceiver(mBluetoothReceiver);
}demo（查找已配对蓝牙，log打印出来）： 续上，修改activity_main.xml： 接着修改MainActivity.java: 实例化、绑定： ... //scan paired private Button mScanButton; private Button mPairedDeviceButton; ... //scan paired mPairedDeviceButton = (Button)findViewById(R.id.bt_paired_device); mScanButton = (Button)findViewById(R.id.bt_scan); ...添加onClick： mPairedDeviceButton.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { //paired 配对的 Set pairedDevices = mBluetoothAdapter.getBondedDevices(); //If threre are paired devices // if (pairedDevices.size() > 0) { //Loop through paired devices for(BluetoothDevice device : pairedDevices){ //You add the name and address to an array adapter to show in a ListView at this Log.d(TAG, "Device name " + device.getName());//打印匹配过的蓝牙设备的name Log.d(TAG, "Device addr " + device.getAddress()); } // } } }); mScanButton.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { if(mBluetoothAdapter.isDiscovering()){//如果正在扫描，令之停止扫描，重新开始扫描 mBluetoothAdapter.cancelDiscovery(); } mBluetoothAdapter.startDiscovery();//异步函数 } });运行之后点击“已配对设备”按钮，显示已配对蓝牙设备的信息：  此时java： public class MainActivity extends AppCompatActivity { private static final String TAG = "BluetoothChat"; private static final int REQUEST_ENABLE_BT = 10;//其是需要自己定义的局部常量。 private BluetoothAdapter mBluetoothAdapter; //scan paired private Button mScanButton; private Button mPairedDeviceButton; //广播接收 @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); //scan paired mPairedDeviceButton = (Button)findViewById(R.id.bt_paired_device); mScanButton = (Button)findViewById(R.id.bt_scan); mPairedDeviceButton.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { //paired 配对的 Set pairedDevices = mBluetoothAdapter.getBondedDevices(); //If threre are paired devices // if (pairedDevices.size() > 0) { //Loop through paired devices for(BluetoothDevice device : pairedDevices){ //Add the name and address to an array adapter to show in a ListView Log.d(TAG, "Device name " + device.getName());//打印匹配过的蓝牙设备的name Log.d(TAG, "Device addr " + device.getAddress()); } // } } }); mScanButton.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { if(mBluetoothAdapter.isDiscovering()){//如果正在扫描，令之停止扫描，重新开始扫描 mBluetoothAdapter.cancelDiscovery(); } mBluetoothAdapter.startDiscovery();//异步函数 } }); mBluetoothAdapter = BluetoothAdapter.getDefaultAdapter(); if(mBluetoothAdapter == null){ //Device does not support Bluetooth Log.e(TAG, "Device does not support Bluetooth"); }else { Toast.makeText(this,"设备支持蓝牙！",Toast.LENGTH_SHORT).show(); } } @Override protected void onStart() { ... } @Override protected void onActivityResult(int requestCode, int resultCode, @Nullable Intent data) { ... } } }demo（续上，监测扫描发现设备时、扫描完毕时两个状态，做对应处理）：点击“扫描附近蓝牙设备”按钮时，开始一轮新的扫描： mScanButton.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { if(mBluetoothAdapter.isDiscovering()){//如果正在扫描，令之停止扫描，重新开始扫描 mBluetoothAdapter.cancelDiscovery(); } mBluetoothAdapter.startDiscovery();//异步函数 } });注册广播接收器， 监测扫描发现设备时、扫描完毕时两个状态， 然后做对应处理： //广播接收 private BroadcastReceiver mBluetoothReceiver = new BroadcastReceiver() { @Override public void onReceive(Context context, Intent intent) { String action = intent.getAction();//获取action Log.d(TAG, "ACTION：" + action); if(action.equals(BluetoothDevice.ACTION_FOUND)){ //如果扫描时发现蓝牙设备，取到发现的设备 BluetoothDevice device = intent.getParcelableExtra(BluetoothDevice.EXTRA_DEVICE); Log.d(TAG, "new Device name " + device.getName());//打印匹配过的蓝牙设备的name Log.d(TAG, "new Device addr " + device.getAddress()); }else if(action.equals(BluetoothAdapter.ACTION_DISCOVERY_FINISHED)){ //如果扫描完毕 Toast.makeText(MainActivity.this,"Discovery done！",Toast.LENGTH_SHORT).show(); Log.d(TAG, "Discovery done！"); } } };在onCreate()末尾注册intent过滤器： //为广播接收器注册过滤器 IntentFilter filter = new IntentFilter(); filter.addAction(BluetoothDevice.ACTION_FOUND); filter.addAction(BluetoothAdapter.ACTION_DISCOVERY_FINISHED); registerReceiver(mBluetoothReceiver,filter);在onDestroy()中注销： @Override protected void onDestroy() { super.onDestroy(); unregisterReceiver(mBluetoothReceiver); } 运行效果如图，没有发现新设备，在扫描完毕后打印出对应的Log： 此时java：public class MainActivity extends AppCompatActivity {
private static final String TAG = "BluetoothChat";
private static final int REQUEST_ENABLE_BT = 10;//其是需要自己定义的局部常量。
private BluetoothAdapter mBluetoothAdapter;
//scan paired
private Button mScanButton;
private Button mPairedDeviceButton;
//广播接收
private BroadcastReceiver mBluetoothReceiver = new BroadcastReceiver() {
@Override
public void onReceive(Context context, Intent intent) {
String action = intent.getAction();//获取action
Log.d(TAG, "ACTION：" + action);
if(action.equals(BluetoothDevice.ACTION_FOUND)){
//如果扫描时发现蓝牙设备，取到发现的设备
BluetoothDevice device = intent.getParcelableExtra(BluetoothDevice.EXTRA_DEVICE);
Log.d(TAG, "new Device name " + device.getName());//打印匹配过的蓝牙设备的name
Log.d(TAG, "new Device addr " + device.getAddress());
}else if(action.equals(BluetoothAdapter.ACTION_DISCOVERY_FINISHED)){
//如果扫描完毕
Toast.makeText(MainActivity.this,"Discovery done！",Toast.LENGTH_SHORT).show();
Log.d(TAG, "Discovery done！");
}
}
};
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
//scan paired
mPairedDeviceButton = (Button)findViewById(R.id.bt_paired_device);
mScanButton = (Button)findViewById(R.id.bt_scan);
mPairedDeviceButton.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
//paired 配对的
Set pairedDevices = mBluetoothAdapter.getBondedDevices();
//If threre are paired devices
// if (pairedDevices.size() > 0) {
//Loop through paired devices
for(BluetoothDevice device : pairedDevices){
//Add the name and address to an array adapter to show in a ListView
Log.d(TAG, "Device name " + device.getName());//打印匹配过的蓝牙设备的name
Log.d(TAG, "Device addr " + device.getAddress());
}
// }
}
});
mScanButton.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
if(mBluetoothAdapter.isDiscovering()){//如果正在扫描，令之停止扫描，重新开始扫描
mBluetoothAdapter.cancelDiscovery();
}
mBluetoothAdapter.startDiscovery();//异步函数
}
});
mBluetoothAdapter = BluetoothAdapter.getDefaultAdapter();
if(mBluetoothAdapter == null){
//Device does not support Bluetooth
Log.e(TAG, "Device does not support Bluetooth");
}else {
Toast.makeText(this,"设备支持蓝牙！",Toast.LENGTH_SHORT).show();
}
//为广播接收器注册过滤器
IntentFilter filter = new IntentFilter();
filter.addAction(BluetoothDevice.ACTION_FOUND);
filter.addAction(BluetoothAdapter.ACTION_DISCOVERY_FINISHED);
registerReceiver(mBluetoothReceiver,filter);
}
@Override
protected void onStart() {
super.onStart();
if(!mBluetoothAdapter.isEnabled()){
//向系统请求开启蓝牙
Intent enableBtIntent = new Intent(BluetoothAdapter.ACTION_REQUEST_ENABLE);
startActivityForResult(enableBtIntent, REQUEST_ENABLE_BT);//结果返回回调到onActivityResult()
}else {
//已经开启了蓝牙
Toast.makeText(this,"蓝牙已经开启",Toast.LENGTH_SHORT).show();
}
}
@Override
protected void onActivityResult(int requestCode, int resultCode, @Nullable Intent data) {
super.onActivityResult(requestCode, resultCode, data);
if(requestCode == REQUEST_ENABLE_BT){
Toast.makeText(this,"蓝牙已经开启",Toast.LENGTH_SHORT).show();
}
}
@Override
protected void onDestroy() {
super.onDestroy();
unregisterReceiver(mBluetoothReceiver);
}
}
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