Android：通过BLE发送大于20个字节的数据

Android：通过BLE发送大于20个字节的数据

BLE最多允许你传输20个字节。

如果要发送20个以上的字节，则应定义数组

byte[]

以包含所需的数据包数量。

如果你要发送少于160个字符（160个字节），以下示例可以很好地工作。

p / s：根据需要编辑以下内容。不要完全跟随我。

实际上，当我们使用BLE时，移动端和固件端需要设置密钥（例如

0x03...

）来定义双方之间的连接门。

这个想法是：

• 当我们继续传输数据包时，不是最后一个。门是

  byte[1] = 0x01

  。

• 如果我们发送最后一个，则门为

  byte[1] = 0x00

  。

数据构造（20字节）：

1–

Byte 1

定义

Gate ID

：例如。消息门ID

byte[0] = 0x03

。

2-

Byte 2

定义

recognization

：是最后一个数据包

0x00

还是继续发送数据包0x01。

3-

Byte 3

（在消除

Byte 1

＆之后，应为18个字节

Byte 2

）-在此处附加消息内容。

在阅读下面的代码之前，请先了解我的逻辑。

下面是发送带有许多数据包的消息的示例，每个数据包是一个大小为20字节的数组。

private void sendMessage(BluetoothGattCharacteristic characteristic, String CHARACTERS){        byte[] initial_packet = new byte[3];                initial_packet[0] = BLE.INITIAL_MESSAGE_PACKET;        if (Long.valueOf(     String.valueOf(CHARACTERS.length() + initial_packet.length))     > BLE.DEFAULT_BYTES_VIA_BLE) { sendingContinuePacket(characteristic, initial_packet, CHARACTERS);        } else { sendingLastPacket(characteristic, initial_packet, CHARACTERS);        }    }private void sendingContinuePacket(BluetoothGattCharacteristic characteristic, byte[] initial_packet, String CHARACTERS){                // Check the data length is large how many times with Default Data (BLE)        int times = Byte.valueOf(String.valueOf(     CHARACTERS.length() / BLE.DEFAULT_BYTES_IN_CONTINUE_PACKET));        Log.i(TAG, "CHARACTERS.length() " + CHARACTERS.length());        Log.i(TAG, "times " + times);        // TODO        // 100 : Success        // 101 : Error        byte[] sending_continue_hex = new byte[BLE.DEFAULT_BYTES_IN_CONTINUE_PACKET];        for (int time = 0; time <= times; time++) {  try {     Thread.sleep(200); } catch (InterruptedException e) {     e.printStackTrace(); } if (time == times) {     Log.i(TAG, "LAST PACKET ");                    int character_length = CHARACTERS.length()  - BLE.DEFAULT_BYTES_IN_CONTINUE_PACKET*times;     initial_packet[1] = Byte.valueOf(String.valueOf(character_length  + BLE.INITIAL_MESSAGE_PACKET_LENGTH));     initial_packet[2] = BLE.SENDING_LAST_PACKET;     Log.i(TAG, "character_length " + character_length);          // Hex file     byte[] sending_last_hex = new byte[character_length];     // Hex file : Get next bytes     for (int i = 0; i < sending_last_hex.length; i++) {         sending_last_hex[i] =       CHARACTERS.getBytes()[sending_continue_hex.length*time + i];     }     // Merge byte[]     byte[] last_packet =   new byte[character_length + BLE.INITIAL_MESSAGE_PACKET_LENGTH];     System.arraycopy(initial_packet, 0, last_packet,  0, initial_packet.length);     System.arraycopy(sending_last_hex, 0, last_packet,   initial_packet.length, sending_last_hex.length);     // Set value for characteristic     characteristic.setValue(last_packet); } else {     Log.i(TAG, "ConTINUE PACKET ");               int character_length = sending_continue_hex.length;          initial_packet[1] = Byte.valueOf(String.valueOf(  character_length + BLE.INITIAL_MESSAGE_PACKET_LENGTH));          initial_packet[2] = BLE.SENDING_CONTINUE_PACKET;          // Hex file : Get first 17 bytes     for (int i = 0; i < sending_continue_hex.length; i++) {         Log.i(TAG, "Send stt : "       + (sending_continue_hex.length*time + i));         // Get next bytes         sending_continue_hex[i] =       CHARACTERS.getBytes()[sending_continue_hex.length*time + i];     }     // Merge byte[]     byte[] sending_continue_packet =   new byte[character_length + BLE.INITIAL_MESSAGE_PACKET_LENGTH];     System.arraycopy(initial_packet, 0, sending_continue_packet,   0, initial_packet.length);     System.arraycopy(sending_continue_hex, 0, sending_continue_packet,   initial_packet.length, sending_continue_hex.length);     // Set value for characteristic     characteristic.setValue(sending_continue_packet); } // Write characteristic via BLE mBluetoothGatt.writeCharacteristic(characteristic);        }    }public boolean writeCharacteristic(BluetoothGattCharacteristic characteristic, String data) {        if (mBluetoothAdapter == null || mBluetoothGatt == null) { Log.w(TAG, "BluetoothAdapter not initialized"); return false;        }        if (ActivityBLEController.IS_FIRST_TIME) {  byte[] merge_title = sendTitle(data); // Set value for characteristic characteristic.setValue(merge_title); // Write characteristic via BLE mBluetoothGatt.writeCharacteristic(characteristic); // Reset ActivityBLEController.IS_FIRST_TIME = false; return true;        } else {  if (data.length() <= BLE.LIMIT_CHARACTERS) {     sendMessage(characteristic, data);     // Reset     ActivityBLEController.IS_FIRST_TIME = true;      return true; } else {     // Typed character     typed_character = data.length();     return false; }        }    }