Java tutorial
package com.paulina.sadowska.robotwirelesscontroller.Bluetooth; /** * Created by palka on 10.11.15. */ /* * Copyright (C) 2014 The Android Open Source Project * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ import android.app.Activity; import android.bluetooth.BluetoothAdapter; import android.bluetooth.BluetoothDevice; import android.content.Intent; import android.os.Bundle; import android.os.Handler; import android.os.Message; import android.support.annotation.Nullable; import android.support.v4.app.Fragment; import android.support.v4.app.FragmentActivity; import android.support.v7.app.ActionBar; import android.support.v7.app.AppCompatActivity; import android.util.Log; import android.view.LayoutInflater; import android.view.Menu; import android.view.MenuInflater; import android.view.MenuItem; import android.view.View; import android.view.ViewGroup; import android.widget.TextView; import android.widget.Toast; import com.paulina.sadowska.robotwirelesscontroller.Constants; import com.paulina.sadowska.robotwirelesscontroller.MessageManager; import com.paulina.sadowska.robotwirelesscontroller.R; import com.paulina.sadowska.robotwirelesscontroller.Utilities; /** * This fragment controls Bluetooth to communicate with other devices. */ public class BluetoothFragment extends Fragment { private static final String TAG = "BluetoothFragment"; MessageManager messageManager; // Intent request codes private static final int REQUEST_CONNECT_DEVICE_SECURE = 1; private static final int REQUEST_CONNECT_DEVICE_INSECURE = 2; private static final int REQUEST_ENABLE_BT = 3; // Layout Views private TextView messageFlow; private Handler controlMessageThread; /** * Name of the connected device */ private String mConnectedDeviceName = null; /** * String buffer for outgoing messages */ private StringBuffer mOutStringBuffer; /** * Local Bluetooth adapter */ private BluetoothAdapter mBluetoothAdapter = null; /** * Member object for the chat services */ private BluetoothService mBluetoothService = null; BluetoothActivityCallback mCallback; // Container Activity must implement this interface public interface BluetoothActivityCallback { void onMessageReceivedCallback(); void onConnectionStateChangedCallback(boolean isConnected); } @Override public void onAttach(Activity activity) { super.onAttach(activity); try { mCallback = (BluetoothActivityCallback) activity; } catch (ClassCastException e) { throw new ClassCastException(activity.toString() + " must implement OnHeadlineSelectedListener"); } } // Define the task to be run here private Runnable sendControlMessage = new Runnable() { @Override public void run() { if (mBluetoothService.getState() == BluetoothService.STATE_CONNECTED) { sendMessage(messageManager.getMessageText()); // message in format with angle np {090089} (alpha = 90 velocity = 89) // Repeat this runnable code again every 0.1 seconds controlMessageThread.postDelayed(sendControlMessage, Constants.TIME_TO_SEND_CONTROL_MSG_MS); } else if (Utilities.isDeviceConnected()) { // Check if connected after 1 second controlMessageThread.postDelayed(sendControlMessage, Constants.TIME_TO_CHECK_CONNECTION_STATE); } else { // Check if connected after 1 second controlMessageThread.postDelayed(sendControlMessage, Constants.TIME_TO_CHECK_CONNECTION_STATE); } } }; @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setHasOptionsMenu(true); // Get local Bluetooth adapter mBluetoothAdapter = BluetoothAdapter.getDefaultAdapter(); // If the adapter is null, then Bluetooth is not supported if (mBluetoothAdapter == null) { FragmentActivity activity = getActivity(); Toast.makeText(activity, "Bluetooth is not available", Toast.LENGTH_LONG).show(); activity.finish(); } // Create the Handler object (on the main thread by default) controlMessageThread = new Handler(); messageManager = new MessageManager(new MessageManager.OnMessageReceived() { @Override public void messageReceived() { mCallback.onMessageReceivedCallback(); } }); } @Override public void onStart() { super.onStart(); // If BT is not on, request that it be enabled. // setupConnection() will then be called during onActivityResult if (!mBluetoothAdapter.isEnabled()) { Intent enableIntent = new Intent(BluetoothAdapter.ACTION_REQUEST_ENABLE); startActivityForResult(enableIntent, REQUEST_ENABLE_BT); // Otherwise, setup the chat session } else if (mBluetoothService == null) { setupConnection(); } } @Override public void onDestroy() { super.onDestroy(); if (mBluetoothService != null) { sendMessage(Constants.CONNECTION_STOP_MESSAGE); Utilities.setConnectionState(false); mBluetoothService.stop(); } } @Override public void onResume() { super.onResume(); // Performing this check in onResume() covers the case in which BT was // not enabled during onStart(), so we were paused to enable it... // onResume() will be called when ACTION_REQUEST_ENABLE activity returns. if (mBluetoothService != null) { // Only if the state is STATE_NONE, do we know that we haven't started already if (mBluetoothService.getState() == BluetoothService.STATE_NONE) { // Start the Bluetooth chat services mBluetoothService.start(); } } } @Override public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) { return inflater.inflate(R.layout.bluetooth_fragment, container, false); } @Override public void onViewCreated(View view, @Nullable Bundle savedInstanceState) { messageFlow = (TextView) view.findViewById(R.id.message_flow); } /** * Set up the UI and background operations for chat. */ private void setupConnection() { Log.d(TAG, "setupCommunication()"); // Initialize the BluetoothChatService to perform bluetooth connections mBluetoothService = new BluetoothService(getActivity(), mHandler); // Initialize the buffer for outgoing messages mOutStringBuffer = new StringBuffer(""); } /** * Sends a message. * * @param message A string of text to send. */ private void sendMessage(String message) { // Check that we're actually connected before trying anything if (mBluetoothService.getState() != BluetoothService.STATE_CONNECTED) { //Toast.makeText(getActivity(), R.string.not_connected, Toast.LENGTH_SHORT).show(); return; } // Check that there's actually something to send if (message.length() > 0) { // Get the message bytes and tell the BluetoothChatService to write byte[] send = message.getBytes(); mBluetoothService.write(send); // Reset out string buffer to zero mOutStringBuffer.setLength(0); } } /** * Updates the status on the action bar. * * @param resId a string resource ID */ private void setStatus(int resId) { AppCompatActivity activity = (AppCompatActivity) getActivity(); if (null == activity) { return; } final ActionBar actionBar = activity.getSupportActionBar(); if (null == actionBar) { return; } actionBar.setSubtitle(resId); } /** * Updates the status on the action bar. * * @param subTitle status */ private void setStatus(CharSequence subTitle) { AppCompatActivity activity = (AppCompatActivity) getActivity(); if (null == activity) { return; } final ActionBar actionBar = activity.getSupportActionBar(); if (null == actionBar) { return; } actionBar.setSubtitle(subTitle); } /** * The Handler that gets information back from the BluetoothChatService */ private final Handler mHandler = new Handler() { @Override public void handleMessage(Message msg) { FragmentActivity activity = getActivity(); switch (msg.what) { case Constants.MESSAGE_STATE_CHANGE: switch (msg.arg1) { case BluetoothService.STATE_CONNECTED: connectionWithDeviceEstablished(); setStatus(getString(R.string.title_connected_to, mConnectedDeviceName)); mCallback.onConnectionStateChangedCallback(true); break; case BluetoothService.STATE_CONNECTING: setStatus(R.string.title_connecting); mCallback.onConnectionStateChangedCallback(false); break; case BluetoothService.STATE_LISTEN: case BluetoothService.STATE_NONE: setStatus(R.string.title_not_connected); mCallback.onConnectionStateChangedCallback(false); break; } break; case Constants.MESSAGE_WRITE: byte[] writeBuf = (byte[]) msg.obj; // construct a string from the buffer String writeMessage = new String(writeBuf); messageFlow.append("Android : " + writeMessage + "\n"); break; case Constants.MESSAGE_READ: byte[] readBuf = (byte[]) msg.obj; // construct a string from the valid bytes in the buffer String readMessage = new String(readBuf, 0, msg.arg1); messageFlow.append(mConnectedDeviceName + ": " + readMessage + "\n"); messageManager.WriteReceivedMessageToInBuffer(readMessage); break; case Constants.MESSAGE_DEVICE_NAME: // save the connected device's name mConnectedDeviceName = msg.getData().getString(Constants.DEVICE_NAME); if (null != activity) { Toast.makeText(activity, "Connected to " + mConnectedDeviceName, Toast.LENGTH_SHORT).show(); } break; case Constants.MESSAGE_TOAST: if (null != activity) { Toast.makeText(activity, msg.getData().getString(Constants.TOAST), Toast.LENGTH_SHORT).show(); } break; } } }; void connectionWithDeviceEstablished() { sendMessage(Constants.CONNECTION_SETUP_MESSAGE); Utilities.setConnectionState(true); controlMessageThread.post(sendControlMessage); } public void onActivityResult(int requestCode, int resultCode, Intent data) { switch (requestCode) { case REQUEST_CONNECT_DEVICE_SECURE: // When DeviceListActivity returns with a device to connect if (resultCode == Activity.RESULT_OK) { connectDevice(data, true); } break; case REQUEST_CONNECT_DEVICE_INSECURE: // When DeviceListActivity returns with a device to connect if (resultCode == Activity.RESULT_OK) { connectDevice(data, false); } break; case REQUEST_ENABLE_BT: // When the request to enable Bluetooth returns if (resultCode == Activity.RESULT_OK) { // Bluetooth is now enabled, so set up a chat session setupConnection(); } else { // User did not enable Bluetooth or an error occurred Log.d(TAG, "BT not enabled"); Toast.makeText(getActivity(), R.string.bt_not_enabled_leaving, Toast.LENGTH_SHORT).show(); getActivity().finish(); } } } /** * Establish connection with other divice * * @param data An {@link Intent} with {@link DeviceListActivity#EXTRA_DEVICE_ADDRESS} extra. * @param secure Socket Security type - Secure (true) , Insecure (false) */ private void connectDevice(Intent data, boolean secure) { // Get the device MAC address String address = data.getExtras().getString(DeviceListActivity.EXTRA_DEVICE_ADDRESS); // Get the BluetoothDevice object BluetoothDevice device = mBluetoothAdapter.getRemoteDevice(address); // Attempt to connect to the device mBluetoothService.connect(device, secure); } @Override public void onCreateOptionsMenu(Menu menu, MenuInflater inflater) { inflater.inflate(R.menu.bluetooth_menu, menu); } @Override public boolean onOptionsItemSelected(MenuItem item) { switch (item.getItemId()) { case R.id.secure_connect_scan: { // Launch the DeviceListActivity to see devices and do scan Intent serverIntent = new Intent(getActivity(), DeviceListActivity.class); startActivityForResult(serverIntent, REQUEST_CONNECT_DEVICE_SECURE); return true; } /* case R.id.insecure_connect_scan: { // Launch the DeviceListActivity to see devices and do scan Intent serverIntent = new Intent(getActivity(), DeviceListActivity.class); startActivityForResult(serverIntent, REQUEST_CONNECT_DEVICE_INSECURE); return true; }*/ } return false; } }