Android 蓝牙设备的查找和连接
1.权限
使用蓝牙设备需要先在Manifest中开放权限,位置如下。
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<application ...> ... </application> // 使用蓝牙设备的权限 <uses-permission android:name="android.permission.BLUETOOTH" /> // 管理蓝牙设备的权限 <uses-permission android:name="android.permission.BLUETOOTH_ADMIN" />
2.打开蓝牙
获得蓝牙适配器(android.bluetooth.BluetoothAdapter),检查该设备是否支持蓝牙,如果支持,就打开蓝牙。
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// 检查设备是否支持蓝牙
adapter = BluetoothAdapter.getDefaultAdapter();
if (adapter == null)
{
// 设备不支持蓝牙
}
// 打开蓝牙
if (!adapter.isEnabled())
{
Intent intent = new Intent(BluetoothAdapter.ACTION_REQUEST_ENABLE); // 设置蓝牙可见性,最多300秒 intent.putExtra(BluetoothAdapter.EXTRA_DISCOVERABLE_DURATION, 300); context.startActivity(intent);
}
3.获取已配对的蓝牙设备(android.bluetooth.BluetoothDevice)
首次连接某蓝牙设备需要先配对,一旦配对成功,该设备的信息会被保存,以后连接时无需再配对,所以已配对的设备不一定是能连接的。
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BluetoothAdapter adapter = BluetoothAdapter.getDefaultAdapter();
Set devices = adapter.getBondedDevices();
for(int i=0; i {
BluetoothDevice device = (BluetoothDevice) devices.iterator().next(); System.out.println(device.getName());
}
4.搜索周围的蓝牙设备
适配器搜索蓝牙设备后将结果以广播形式传出去,所以需要自定义一个继承广播的类,在onReceive方法中获得并处理蓝牙设备的搜索结果。
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// 设置广播信息过滤
IntentFilter intentFilter = new IntentFilter();
intentFilter.addAction(BluetoothDevice.ACTION_FOUND);
intentFilter.addAction(BluetoothDevice.ACTION_BOND_STATE_CHANGED);
intentFilter.addAction(BluetoothAdapter.ACTION_SCAN_MODE_CHANGED);
intentFilter.addAction(BluetoothAdapter.ACTION_STATE_CHANGED);
// 注册广播接收器,接收并处理搜索结果
context.registerReceiver(receiver, intentFilter);
// 寻找蓝牙设备,android会将查找到的设备以广播形式发出去
adapter.startDiscovery();
自定义广播类
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private BroadcastReceiver receiver = new BroadcastReceiver() {
@Override
public void onReceive(Context context, Intent intent) {
String action = intent.getAction(); if (BluetoothDevice.ACTION_FOUND.equals(action)) { BluetoothDevice device = intent.getParcelableExtra(BluetoothDevice.EXTRA_DEVICE); System.out.println(device.getName()); }
}
}
5.蓝牙设备的配对和状态监视
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private BroadcastReceiver receiver = new BroadcastReceiver() {
@Override public void onReceive(Context context, Intent intent) { String action = intent.getAction(); if (BluetoothDevice.ACTION_FOUND.equals(action)) { // 获取查找到的蓝牙设备 BluetoothDevice device = intent.getParcelableExtra(BluetoothDevice.EXTRA_DEVICE); System.out.println(device.getName()); // 如果查找到的设备符合要连接的设备,处理 if (device.getName().equalsIgnoreCase(name)) { // 搜索蓝牙设备的过程占用资源比较多,一旦找到需要连接的设备后需要及时关闭搜索 adapter.cancelDiscovery(); // 获取蓝牙设备的连接状态 connectState = device.getBondState(); switch (connectState) { // 未配对 case BluetoothDevice.BOND_NONE: // 配对 try { Method createBondMethod = BluetoothDevice.class.getMethod("createBond"); createBondMethod.invoke(device); } catch (Exception e) { e.printStackTrace(); } break; // 已配对 case BluetoothDevice.BOND_BONDED: try { // 连接 connect(device); } catch (IOException e) { e.printStackTrace(); } break; } } } else if(BluetoothDevice.ACTION_BOND_STATE_CHANGED.equals(action)) { // 状态改变的广播 BluetoothDevice device = intent.getParcelableExtra(BluetoothDevice.EXTRA_DEVICE); if (device.getName().equalsIgnoreCase(name)) { connectState = device.getBondState(); switch (connectState) { case BluetoothDevice.BOND_NONE: break; case BluetoothDevice.BOND_BONDING: break; case BluetoothDevice.BOND_BONDED: try { // 连接 connect(device); } catch (IOException e) { e.printStackTrace(); } break; } } } }
}
6.蓝牙设备的连接
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private void connect(BluetoothDevice device) throws IOException {
// 固定的UUID final String SPP_UUID = "00001101-0000-1000-8000-00805F9B34FB"; UUID uuid = UUID.fromString(SPP_UUID); BluetoothSocket socket = device.createRfcommSocketToServiceRecord(uuid); socket.connect();
}