详解 Android 中的 BLE 蓝牙

在 Android 开发中，BLE（Bluetooth Low Energy）蓝牙技术被广泛应用于与外部设备进行通信，如智能手环、体重秤等。本文将详细介绍如何在 Android 应用程序中使用 BLE 蓝牙技术来实现设备间的通信。

BLE 蓝牙基础

BLE 蓝牙技术是一种低功耗的蓝牙通信协议，它可以让设备在低功耗状态下进行通信，适合用于需要长时间运行的设备。在 Android 中，BLE 蓝牙通信主要通过 BluetoothAdapter 和 BluetoothGatt 两个类来实现。

1. 初始化 BLE 蓝牙

要使用 BLE 蓝牙功能，首先需要通过 BluetoothManager 获取 BluetoothAdapter 实例：

BluetoothManager bluetoothManager = (BluetoothManager) getSystemService(Context.BLUETOOTH_SERVICE);
BluetoothAdapter bluetoothAdapter = bluetoothManager.getAdapter();

2. 搜索 BLE 设备

要搜索 BLE 设备，需要实现 BluetoothAdapter.LeScanCallback 接口，并调用 startLeScan() 方法：

bluetoothAdapter.startLeScan(new BluetoothAdapter.LeScanCallback() {
    @Override
    public void onLeScan(BluetoothDevice device, int rssi, byte[] scanRecord) {
        // 处理扫描到的设备信息
    }
});

3. 连接 BLE 设备

连接到 BLE 设备需要通过 BluetoothDevice 对象和 BluetoothGattCallback 回调函数：

BluetoothGattCallback gattCallback = new BluetoothGattCallback() {
    @Override
    public void onConnectionStateChange(BluetoothGatt gatt, int status, int newState) {
        // 处理连接状态改变事件
    }
};

BluetoothGatt gatt = device.connectGatt(context, false, gattCallback);

BLE 蓝牙应用

下面以一个简单的例子来演示如何在 Android 应用中使用 BLE 蓝牙：

示例：扫描并连接 BLE 设备

BluetoothAdapter.LeScanCallback leScanCallback = new BluetoothAdapter.LeScanCallback() {
    @Override
    public void onLeScan(BluetoothDevice device, int rssi, byte[] scanRecord) {
        if (device.getName().equals("MyDevice")) {
            gatt = device.connectGatt(context, false, gattCallback);
            bluetoothAdapter.stopLeScan(leScanCallback);
        }
    }
};

bluetoothAdapter.startLeScan(leScanCallback);

BLE 通信流程

gantt
    title BLE 通信流程
    section 扫描与连接
    扫描设备 :done, 2021-10-15, 1d
    连接设备 :done, 2021-10-16, 1d
    section 读写数据
    读取数据 :done, after 连接设备, 2d
    写入数据 :done, after 读取数据, 1d

结语

通过本文的介绍，读者可以了解到在 Android 应用中如何使用 BLE 蓝牙技术与外部设备进行通信。当然，实际应用中还需要根据具体需求来进一步完善功能和优化代码，希望本文能够帮助到您。