Android 藍牙設備的查找和連接

1.權限
使用藍牙設備需要先在Manifest中開放權限，位置如下。
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<application ...>  
       ...  
</application>  

// 使用藍牙設備的權限  
<uses-permission android:name="android.permission.BLUETOOTH" />  
// 管理藍牙設備的權限  
<uses-permission android:name="android.permission.BLUETOOTH_ADMIN" />

2.打開藍牙
獲得藍牙適配器（android.bluetooth.BluetoothAdapter），檢查該設備是否支持藍牙，如果支持，就打開藍牙。
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// 檢查設備是否支持藍牙
adapter = BluetoothAdapter.getDefaultAdapter();
if (adapter == null)
{

// 設備不支持藍牙

}
// 打開藍牙
if (!adapter.isEnabled())
{

Intent intent = new Intent(BluetoothAdapter.ACTION_REQUEST_ENABLE);  
// 設置藍牙可見性，最多300秒  
intent.putExtra(BluetoothAdapter.EXTRA_DISCOVERABLE_DURATION, 300);  
context.startActivity(intent);

}

3.獲取已配對的藍牙設備（android.bluetooth.BluetoothDevice）
首次連接某藍牙設備需要先配對，一旦配對成功，該設備的信息會被保存，以后連接時無需再配對，所以已配對的設備不一定是能連接的。
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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.搜索周圍的藍牙設備
適配器搜索藍牙設備后將結果以廣播形式傳出去，所以需要自定義一個繼承廣播的類，在onReceive方法中獲得并處理藍牙設備的搜索結果。
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// 設置廣播信息過濾
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);
// 注冊廣播接收器，接收并處理搜索結果
context.registerReceiver(receiver, intentFilter);
// 尋找藍牙設備，android會將查找到的設備以廣播形式發出去
adapter.startDiscovery();

自定義廣播類
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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.藍牙設備的配對和狀態監視
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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)) {  
        // 獲取查找到的藍牙設備  
        BluetoothDevice device = intent.getParcelableExtra(BluetoothDevice.EXTRA_DEVICE);  
        System.out.println(device.getName());  
        // 如果查找到的設備符合要連接的設備，處理  
        if (device.getName().equalsIgnoreCase(name)) {  
            // 搜索藍牙設備的過程占用資源比較多，一旦找到需要連接的設備后需要及時關閉搜索  
            adapter.cancelDiscovery();  
            // 獲取藍牙設備的連接狀態  
            connectState = device.getBondState();  
            switch (connectState) {  
                // 未配對  
                case BluetoothDevice.BOND_NONE:  
                    // 配對  
                    try {  
                        Method createBondMethod = BluetoothDevice.class.getMethod("createBond");  
                        createBondMethod.invoke(device);  
                    } catch (Exception e) {   
                        e.printStackTrace();  
                    }  
                    break;  
                // 已配對  
                case BluetoothDevice.BOND_BONDED:  
                    try {  
                        // 連接  
                        connect(device);  
                    } catch (IOException e) {  
                        e.printStackTrace();  
                    }  
                    break;  
            }  
        }  
   } else if(BluetoothDevice.ACTION_BOND_STATE_CHANGED.equals(action)) {  
        // 狀態改變的廣播  
        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 {  
                        // 連接  
                        connect(device);  
                    } catch (IOException e) {  
                        e.printStackTrace();  
                    }  
                    break;  
            }  
        }  
    }  
}

}

6.藍牙設備的連接
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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();

}