package com.tonydicola.bletest.app;
import android.app.Activity;
import android.bluetooth.BluetoothAdapter;
import android.bluetooth.BluetoothAdapter.LeScanCallback;
import android.bluetooth.BluetoothDevice;
import android.bluetooth.BluetoothGatt;
import android.bluetooth.BluetoothGattCallback;
import android.bluetooth.BluetoothGattCharacteristic;
import android.bluetooth.BluetoothGattDescriptor;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.EditText;
import android.widget.TextView;
import java.nio.ByteBuffer;
import java.nio.ByteOrder;
import java.nio.charset.Charset;
import java.util.ArrayList;
import java.util.List;
import java.util.UUID;
public class MainActivity extends Activity {
// UUIDs for UAT service and associated characteristics.
public static UUID UART_UUID = UUID.fromString("6E400001-B5A3-F393-E0A9-E50E24DCCA9E");
public static UUID TX_UUID = UUID.fromString("6E400002-B5A3-F393-E0A9-E50E24DCCA9E");
public static UUID RX_UUID = UUID.fromString("6E400003-B5A3-F393-E0A9-E50E24DCCA9E");
// UUID for the BTLE client characteristic which is necessary for notifications.
public static UUID CLIENT_UUID = UUID.fromString("00002902-0000-1000-8000-00805f9b34fb");
// UI elements
private TextView messages;
private EditText input;
// BTLE state
private BluetoothAdapter adapter;
private BluetoothGatt gatt;
private BluetoothGattCharacteristic tx;
private BluetoothGattCharacteristic rx;
// Main BTLE device callback where much of the logic occurs.
private BluetoothGattCallback callback = new BluetoothGattCallback() {
// Called whenever the device connection state changes, i.e. from disconnected to connected.
@Override
public void onConnectionStateChange(BluetoothGatt gatt, int status, int newState) {
super.onConnectionStateChange(gatt, status, newState);
if (newState == BluetoothGatt.STATE_CONNECTED) {
writeLine("Connected!");
// Discover services.
if (!gatt.discoverServices()) {
writeLine("Failed to start discovering services!");
}
}
else if (newState == BluetoothGatt.STATE_DISCONNECTED) {
writeLine("Disconnected!");
}
else {
writeLine("Connection state changed. New state: " + newState);
}
}
// Called when services have been discovered on the remote device.
// It seems to be necessary to wait for this discovery to occur before
// manipulating any services or characteristics.
@Override
public void onServicesDiscovered(BluetoothGatt gatt, int status) {
super.onServicesDiscovered(gatt, status);
if (status == BluetoothGatt.GATT_SUCCESS) {
writeLine("Service discovery completed!");
}
else {
writeLine("Service discovery failed with status: " + status);
}
// Save reference to each characteristic.
tx = gatt.getService(UART_UUID).getCharacteristic(TX_UUID);
rx = gatt.getService(UART_UUID).getCharacteristic(RX_UUID);
// Setup notifications on RX characteristic changes (i.e. data received).
// First call setCharacteristicNotification to enable notification.
if (!gatt.setCharacteristicNotification(rx, true)) {
writeLine("Couldn't set notifications for RX characteristic!");
}
// Next update the RX characteristic's client descriptor to enable notifications.
if (rx.getDescriptor(CLIENT_UUID) != null) {
BluetoothGattDescriptor desc = rx.getDescriptor(CLIENT_UUID);
desc.setValue(BluetoothGattDescriptor.ENABLE_NOTIFICATION_VALUE);
if (!gatt.writeDescriptor(desc)) {
writeLine("Couldn't write RX client descriptor value!");
}
}
else {
writeLine("Couldn't get RX client descriptor!");
}
}
// Called when a remote characteristic changes (like the RX characteristic).
@Override
public void onCharacteristicChanged(BluetoothGatt gatt, BluetoothGattCharacteristic characteristic) {
super.onCharacteristicChanged(gatt, characteristic);
writeLine("Received: " + characteristic.getStringValue(0));
}
};
// BTLE device scanning callback.
private LeScanCallback scanCallback = new LeScanCallback() {
// Called when a device is found.
@Override
public void onLeScan(BluetoothDevice bluetoothDevice, int i, byte[] bytes) {
writeLine("Found device: " + bluetoothDevice.getAddress());
// Check if the device has the UART service.
if (parseUUIDs(bytes).contains(UART_UUID)) {
// Found a device, stop the scan.
adapter.stopLeScan(scanCallback);
writeLine("Found UART service!");
// Connect to the device.
// Control flow will now go to the callback functions when BTLE events occur.
gatt = bluetoothDevice.connectGatt(getApplicationContext(), false, callback);
}
}
};
// OnCreate, called once to initialize the activity.
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
// Grab references to UI elements.
messages = (TextView) findViewById(R.id.messages);
input = (EditText) findViewById(R.id.input);
adapter = BluetoothAdapter.getDefaultAdapter();
}
// OnResume, called right before UI is displayed. Start the BTLE connection.
@Override
protected void onResume() {
super.onResume();
// Scan for all BTLE devices.
// The first one with the UART service will be chosen--see the code in the scanCallback.
writeLine("Scanning for devices...");
adapter.startLeScan(scanCallback);
}
// OnStop, called right before the activity loses foreground focus. Close the BTLE connection.
@Override
protected void onStop() {
super.onStop();
if (gatt != null) {
// For better reliability be careful to disconnect and close the connection.
gatt.disconnect();
gatt.close();
gatt = null;
tx = null;
rx = null;
}
}
// Handler for mouse click on the send button.
public void sendClick(View view) {
String message = input.getText().toString();
if (tx == null || message == null || message.isEmpty()) {
// Do nothing if there is no device or message to send.
return;
}
// Update TX characteristic value. Note the setValue overload that takes a byte array must be used.
tx.setValue(message.getBytes(Charset.forName("UTF-8")));
if (gatt.writeCharacteristic(tx)) {
writeLine("Sent: " + message);
}
else {
writeLine("Couldn't write TX characteristic!");
}
}
// Write some text to the messages text view.
// Care is taken to do this on the main UI thread so writeLine can be called
// from any thread (like the BTLE callback).
private void writeLine(final CharSequence text) {
runOnUiThread(new Runnable() {
@Override
public void run() {
messages.append(text);
messages.append("\n");
}
});
}
// Filtering by custom UUID is broken in Android 4.3 and 4.4, see:
// http://stackoverflow.com/questions/18019161/startlescan-with-128-bit-uuids-doesnt-work-on-native-android-ble-implementation?noredirect=1#comment27879874_18019161
// This is a workaround function from the SO thread to manually parse advertisement data.
private List<UUID> parseUUIDs(final byte[] advertisedData) {
List<UUID> uuids = new ArrayList<UUID>();
int offset = 0;
while (offset < (advertisedData.length - 2)) {
int len = advertisedData[offset++];
if (len == 0)
break;
int type = advertisedData[offset++];
switch (type) {
case 0x02: // Partial list of 16-bit UUIDs
case 0x03: // Complete list of 16-bit UUIDs
while (len > 1) {
int uuid16 = advertisedData[offset++];
uuid16 += (advertisedData[offset++] << 8);
len -= 2;
uuids.add(UUID.fromString(String.format("%08x-0000-1000-8000-00805f9b34fb", uuid16)));
}
break;
case 0x06:// Partial list of 128-bit UUIDs
case 0x07:// Complete list of 128-bit UUIDs
// Loop through the advertised 128-bit UUID's.
while (len >= 16) {
try {
// Wrap the advertised bits and order them.
ByteBuffer buffer = ByteBuffer.wrap(advertisedData, offset++, 16).order(ByteOrder.LITTLE_ENDIAN);
long mostSignificantBit = buffer.getLong();
long leastSignificantBit = buffer.getLong();
uuids.add(new UUID(leastSignificantBit,
mostSignificantBit));
} catch (IndexOutOfBoundsException e) {
// Defensive programming.
//Log.e(LOG_TAG, e.toString());
continue;
} finally {
// Move the offset to read the next uuid.
offset += 15;
len -= 16;
}
}
break;
default:
offset += (len - 1);
break;
}
}
return uuids;
}
// Boilerplate code from the activity creation:
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
}
