蓝牙小车项目APP

/* * Copyright (C) 2009 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. */ package com.example.android.BluetoothChat; import java.io.IOException; import java.io.InputStream; import java.io.OutputStream; import java.util.UUID; import android.bluetooth.BluetoothAdapter; import android.bluetooth.BluetoothDevice; import android.bluetooth.BluetoothServerSocket; import android.bluetooth.BluetoothSocket; import android.content.Context; import android.os.Bundle; import android.os.Handler; import android.os.Message; import android.util.Log; /** * This class does all the work for setting up and managing Bluetooth * connections with other devices. It has a thread that listens for * incoming connections, a thread for connecting with a device, and a * thread for performing data transmissions when connected. * 这个类所做的工作是设置和管理本地蓝牙与其他设备的连接。它有一个线程是监听传入的连接，一个线程是连接一个设备， * 还有一个线程是在连接的时候进行数据传输 */ public class BluetoothChatService { // Debugging private static final String TAG = "BluetoothChatService"; private static final boolean D = true; // Name for the SDP record when creating server socket private static final String NAME = "BluetoothChat"; // Unique UUID for this application private static final UUID MY_UUID = UUID.fromString("00001101-0000-1000-8000-00805F9B34FB"); // Member fields private final BluetoothAdapter mAdapter;//本地蓝牙适配器 private final Handler mHandler;//Handler private AcceptThread mAcceptThread;//接受请求连接时的监听线程 private ConnectThread mConnectThread;//链接一个设备的线程 private ConnectedThread mConnectedThread;//链接之后的管理线程 private int mState;//当前的状态 // Constants that indicate the current connection state表示当前连接状态的常数 public static final int STATE_NONE = 0; // we're doing nothing等待连接 public static final int STATE_LISTEN = 1; // now listening for incoming connections监听连接 public static final int STATE_CONNECTING = 2; // now initiating an outgoing connection正在连接 public static final int STATE_CONNECTED = 3; // now connected to a remote device已经连接 /** * Constructor. Prepares a new BluetoothChat session. * @param context The UI Activity Context * @param handler A Handler to send messages back to the UI Activity */ //构造函数：取得本地蓝牙适配器、设置状态为STATE_NONE，设置传递进来的handler为mHandler。 public BluetoothChatService(Context context, Handler handler) { mAdapter = BluetoothAdapter.getDefaultAdapter(); mState = STATE_NONE; //将BluetoothChat中的Handle赋值给BluetoothChatService中的handler；这样就使得BluetoothChat和luetoothChatService中的是同一个Handler mHandler = handler; } /** * Set the current state of the chat connection * @param state An integer defining the current connection state */ //设置连接状态，并通知UI界面也同时更改状态 private synchronized void setState(int state) { if (D) Log.d(TAG, "setState() " + mState + " -> " + state); mState = state; // Give the new state to the Handler so the UI Activity can update //得到当前状态并发送给Handler，由于BluetoothChat和BluetoothChatService中的是同一个Handler，所以当前 //状态将会发送到BluetoothChat中Handler的handleMessage函数中，然后在handleMessage函数中更新当前状态即可 mHandler.obtainMessage(BluetoothChat.MESSAGE_STATE_CHANGE, state, -1).sendToTarget(); } /** * Return the current connection state. * 返回当前状态*/ public synchronized int getState() { return mState; } /************************************************************************************************* * 在BluetoothChatService这个类中的Start（）函数中实际上是取消所有链接并启动AcceptThread线程、 * connect(BluetoothDevice device)函数中实际上是启动ConnectThread线程、 * connected(BluetoothSocket socket, BluetoothDevice device)函数中实际上是启动ConnectedThread线程、 * ***********************************************************************************************/ /** * Start the chat service. Specifically start AcceptThread to begin a * session in listening (server) mode. Called by the Activity onResume() * 此Start（）函数并不是线程的Start函数，他只是BluetoothChatService这个类中自定义的一个函数名为Start的函数 * start函数用来开始聊天服务。特别是开始AcceptThread来开始一个监听（服务器）模式的会话。操作很简单，就是 * 首先取消另外两个进程，新建一个AcceptThread进程，并启动AcceptThread进程，最后设置状态 变为监听(STATE_LISTEN)， * 这时UI界面的title也将更新为监听状态，即等待设备的连接。*/ public synchronized void start() { if (D) Log.d(TAG, "start"); // 取消试图进行连接的任何线程（连接线程），来生成一个连接 if (mConnectThread != null) {mConnectThread.cancel(); mConnectThread = null;} // 取消正在运行连接的任何线程（已经连接的线程） if (mConnectedThread != null) {mConnectedThread.cancel(); mConnectedThread = null;} // 启动AcceptThread线程来监听BluetoothServerSocket if (mAcceptThread == null) { mAcceptThread = new AcceptThread(); mAcceptThread.start(); } setState(STATE_LISTEN); } /** * Start the ConnectThread to initiate a connection to a remote device. * @param device The BluetoothDevice to connect * 初始化ConnectThread线程来启动与远程设备连接 */ public synchronized void connect(BluetoothDevice device) { if (D) Log.d(TAG, "connect to: " + device); // 取消试图进行连接的任何线程（连接线程），来生成一个连接 if (mState == STATE_CONNECTING) { if (mConnectThread != null) {mConnectThread.cancel(); mConnectThread = null;} } // 取消正在运行连接的任何线程（已经连接的线程） if (mConnectedThread != null) {mConnectedThread.cancel(); mConnectedThread = null;} // 启动线程与给定的设备连接 mConnectThread = new ConnectThread(device); mConnectThread.start(); setState(STATE_CONNECTING); } /** * Start the ConnectedThread to begin managing a Bluetooth connection * @param socket The BluetoothSocket on which the connection was made * @param device The BluetoothDevice that has been connected * 初始化ConnectedThread线程来管理蓝牙连接 */ public synchronized void connected(BluetoothSocket socket, BluetoothDevice device) { if (D) Log.d(TAG, "connected"); //取消三个线程 // Cancel the thread that completed the connection if (mConnectThread != null) {mConnectThread.cancel(); mConnectThread = null;} // Cancel any thread currently running a connection if (mConnectedThread != null) {mConnectedThread.cancel(); mConnectedThread = null;} // Cancel the accept thread because we only want to connect to one device if (mAcceptThread != null) {mAcceptThread.cancel(); mAcceptThread = null;} // 启动线程来管理连接和进行传输 mConnectedThread = new ConnectedThread(socket); mConnectedThread.start(); // 发送链接的设备名称给UI Activity界面 Message msg = mHandler.obtainMessage(BluetoothChat.MESSAGE_DEVICE_NAME); Bundle bundle = new Bundle(); bundle.putString(BluetoothChat.DEVICE_NAME, device.get