Bluetooth—Android蓝牙4.0的数据通讯

1.检测手机是否支持蓝牙4.0（一般手机4.3以上的android系统都支持）

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if (!getPackageManager().hasSystemFeature(PackageManager.FEATURE_BLUETOOTH_LE)) {
showMsg(R.string.ble_not_supported);
finish();
}

2.检测蓝牙是否打开，提示用户打开蓝牙（在此之前需要加相应的权限）

添加权限：
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<uses-feature android:name="android.hardware.bluetooth_le" android:required="true"/>
<uses-permission android:name="android.permission.BLUETOOTH"/>
<uses-permission android:name="android.permission.BLUETOOTH_ADMIN"/>

获取蓝牙适配器

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final BluetoothManager bluetoothManager =
(BluetoothManager) getSystemService(Context.BLUETOOTH_SERVICE);
bluetoothAdapter = bluetoothManager.getAdapter();
如果蓝牙处于关闭状态，则通过下面代码提示用户启动蓝牙：
Intent enableBtIntent = new Intent(BluetoothAdapter.ACTION_REQUEST_ENABLE);
startActivityForResult(enableBtIntent, REQUEST_ENABLE_BT);

3.启动关闭蓝牙，获取蓝牙状态

判断蓝牙状态：bluetoothAdapter.isEnabled()

开启蓝牙：bluetoothAdapter.enable();

关闭蓝牙：bluetoothAdapter.disable();

4.蓝牙启动后，就该搜索设备了

开启搜索： bluetoothAdapter.startLeScan(mLeScanCallback);

停止搜索： bluetoothAdapter.stopLeScan(mLeScanCallback);

搜索回调：

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private BluetoothAdapter.LeScanCallback mLeScanCallback =
new BluetoothAdapter.LeScanCallback() {
@Override
public void onLeScan(final BluetoothDevice device, int rssi, byte[] scanRecord) {
runOnUiThread(new Runnable() {
@Override
public void run() {
//在这里将搜到的设备显示到界面
}
});
}

5.建立连接

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public boolean connect(BluetoothDevice device ) {
if (device == null) {
Log.w(TAG, "Device not found. Unable to connect.");
return false;
}
mBluetoothGatt = device.connectGatt(this, false, mGattCallback);
return true;

连接时需要注册一个回调接口：
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private final BluetoothGattCallback mGattCallback = new BluetoothGattCallback() {
//检测连接状态变化
@Override
public void onConnectionStateChange(BluetoothGatt gatt, int status, int newState) {
if (newState == BluetoothProfile.STATE_CONNECTED) {
} else if (newState == BluetoothProfile.STATE_DISCONNECTED) {
}
}
@Override
public void onServicesDiscovered(BluetoothGatt gatt, int status) {
}
@Override
public void onCharacteristicRead(BluetoothGatt gatt,
BluetoothGattCharacteristic characteristic,
int status) {
}
//接收蓝牙回传数据
@Override
public void onCharacteristicChanged(BluetoothGatt gatt,
BluetoothGattCharacteristic characteristic) {
System.out.println("接收数据");
byte[] data=characteristic.getValue();
}
//检测用户向蓝牙写数据的状态
@Override
public void onCharacteristicWrite(BluetoothGatt gatt,
BluetoothGattCharacteristic characteristic, int status) {
Log.e(TAG, "write status"+":"+status);
if(status==BluetoothGatt.GATT_SUCCESS){
System.out.println("——–write success—– status:");
}
super.onCharacteristicWrite(gatt, characteristic, status);
}
};

断开连接：

mBluetoothGatt.disconnect();

6.发送数据

//设置特性数据回传通知

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public void setCharacteristicNotification(BluetoothGattCharacteristic characteristic,
boolean enabled) {
if (mBluetoothAdapter == null || mBluetoothGatt == null) {
Log.w(TAG, "BluetoothAdapter not initialized");
return;
}
if (mBluetoothGatt.setCharacteristicNotification(characteristic, enabled)) {
BluetoothGattDescriptor descriptor = characteristic.getDescriptor(
UUID.fromString("00002902-0000-1000-8000-00805f9b34fb"));
descriptor.setValue(BluetoothGattDescriptor.ENABLE_NOTIFICATION_VALUE);
mBluetoothGatt.writeDescriptor(descriptor);
}
}
/**
* 向设备发送数据
* @param serviceUuid
* @param characterUuid
* @param notifactionUuid
* @param data
*/
public void writeDataToDevice(byte[] data){
if (mBluetoothGatt == null) {
return;
}
BluetoothGattService bluetoothGattService = mBluetoothGatt
.getService(UUID.fromString("0000fff0-0000-1000-8000-00805f9b34fb"));//蓝牙设备中需要使用的服务的UUID
if (bluetoothGattService == null) {
Log.e(TAG, "service:"+mBluetoothGatt.getServices().size());
Log.e(TAG, "service not found!");
return;
}
BluetoothGattCharacteristic mCharac = bluetoothGattService
.getCharacteristic("0000fff6-0000-1000-8000-00805f9b34fb");//需要使用该服务下具体某个特性的UUID
if (mCharac == null) {
Log.e(TAG, "HEART RATE Copntrol Point charateristic not found!");
return;
}
BluetoothGattCharacteristic nCharacteristic=bluetoothGattService.getCharacteristic("0000fff7-0000-1000-8000-00805f9b34fb");//蓝牙模块向手机端回传特性UUID
setCharacteristicNotification(nCharacteristic, true);
Log.e(TAG, "data:"+Arrays.toString(data));
mCharac.setValue(data); //设置需要发送的数据
try {
Thread.sleep(500);
} catch (InterruptedException e) {
e.printStackTrace();
}
writeCharacteristic(mCharac);
}
public void writeCharacteristic(BluetoothGattCharacteristic characteristic) {
if (mBluetoothAdapter == null || mBluetoothGatt == null) {
Log.e(TAG, "BluetoothAdapter not initialized");
return;
}
boolean result=mBluetoothGatt.writeCharacteristic(characteristic);//开始写入数据
if(result){
Log.e(TAG, "write success!");
}else {
Log.e(TAG, "write fail!");
}
}