蓝牙socket读取数据需读累次才读全

蓝牙socket读取数据需读多次才读全

今天上班解决了一个问题：android程序通过蓝牙socket读取数据时，需要读多次才能把完整的响应APDU读全。当前用的方法来自android示例程序：

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public void run() {
    Log.i(TAG, "BEGIN mConnectedThread");
    byte[] buffer = new byte[1024];
    int bytes;

    // Keep listening to the InputStream while connected
    while (true) {
        try {
            // Read from the InputStream
        	Log.i(TAG, "Read from the InputStream...");
            bytes = mmInStream.read(buffer);                    
            Log.i(TAG, "Read from the InputStream, length is "+bytes);
            // Send the obtained bytes to the UI Activity
            mHandler.obtainMessage(BluetoothChat.MESSAGE_READ, bytes, -1, buffer)
                    .sendToTarget();
        } catch (IOException e) {
            Log.e(TAG, "disconnected", e);
            connectionLost();
            break;
        }
    }
}

 响应APDU是

02001580FFFFFFFF00A4040010D15600010180038000000001000000006A03，

接收三次，每次的结果都不一样：

（1）02001580FFFFFFFF00A4040010D1560001018003  8000000001000000006A  03

（2）02  001580FFFFFFFF00A4040010D15600010180038000000001000000006A  03

（3）02001580FFFFFFFF00A4040010D15600010180038000000001000000006A  03

修改示例代码：响应APDU是可以解析的，第3个字节的值加上10就等于响应APDU的长度，其中10是前缀和后缀的长度之和。

public void run() {
	Log.i(TAG, "BEGIN mConnectedThread");
	byte[] buffer = new byte[1024];
	// int bytes;

	int len = 0;
	int i = 0;

	// Keep listening to the InputStream while connected
	while (true) {
		try {
			// Read from the InputStream
			Log.i(TAG, "Read from the InputStream...");
			// bytes = mmInStream.read(buffer);
			buffer[i++] = (byte) mmInStream.read();
			if (i == 3) {
				len = buffer[2] + 10;
			}
			Log.i(TAG, "Read from the InputStream, data is "
					+ buffer[i - 1]);
			if (i == len) {
				// Send the obtained bytes to the UI Activity
				mHandler.obtainMessage(BluetoothChat.MESSAGE_READ, len,
						-1, buffer).sendToTarget();
				len = 0;
				i = 0;						
			}
		} catch (IOException e) {
			Log.e(TAG, "disconnected", e);
			connectionLost();
			break;
		}
	}
}