运行的时候，会报错：
java.lang.NullPointerException: Attempt to invoke virtual method 'void android.app.ActionBar.setSubtitle(int)' on a null object reference
解决办法：
发现时是 actionBar出错，解决方法如下：
1、在这个onCreate函数中天加 getWindow().requestFeature(Window.FEATURE_ACTION_BAR);
2、将actionBar.setSubtitle(resId)注释掉，这样就不会使用到actionbar了。
这个Demo最重要的是3个类：BluetoothChat；DeviceListActivity；BluetoothChatService
BluetoothChat源码：
/* * 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 android.annotation.TargetApi; import android.app.ActionBar; import android.app.Activity; import android.bluetooth.BluetoothAdapter; import android.bluetooth.BluetoothDevice; import android.content.Intent; import android.os.Build; import android.os.Bundle; import android.os.Handler; import android.os.Message; import android.util.Log; import android.view.KeyEvent; import android.view.Menu; import android.view.MenuInflater; import android.view.MenuItem; import android.view.View; import android.view.Window; import android.view.View.OnClickListener; import android.view.inputmethod.EditorInfo; import android.widget.ArrayAdapter; import android.widget.Button; import android.widget.EditText; import android.widget.ListView; import android.widget.TextView; import android.widget.Toast; /** * This is the main Activity that displays the current chat session. */ @TargetApi(Build.VERSION_CODES.HONEYCOMB) public class BluetoothChat extends Activity { // Debugging private static final String TAG = "BluetoothChat"; private static final boolean D = true; // Message types sent from the BluetoothChatService Handler public static final int MESSAGE_STATE_CHANGE = 1; public static final int MESSAGE_READ = 2; public static final int MESSAGE_WRITE = 3; public static final int MESSAGE_DEVICE_NAME = 4; public static final int MESSAGE_TOAST = 5; // Key names received from the BluetoothChatService Handler public static final String DEVICE_NAME = "device_name"; public static final String TOAST = "toast"; // 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 ListView mConversationView; private EditText mOutEditText; private Button mSendButton; // Name of the connected device private String mConnectedDeviceName = null; // Array adapter for the conversation thread private ArrayAdapter<String> mConversationArrayAdapter; // String buffer for outgoing messages private StringBuffer mOutStringBuffer; // Local Bluetooth adapter private BluetoothAdapter mBluetoothAdapter = null; // Member object for the chat services private BluetoothChatService mChatService = null; @Override public void onCreate(Bundle savedInstanceState) { getWindow().requestFeature(Window.FEATURE_ACTION_BAR); super.onCreate(savedInstanceState); if(D) Log.e(TAG, "+++ ON CREATE +++"); // Set up the window layout setContentView(R.layout.main); // Get local Bluetooth adapter mBluetoothAdapter = BluetoothAdapter.getDefaultAdapter(); // If the adapter is null, then Bluetooth is not supported if (mBluetoothAdapter == null) { Toast.makeText(this, "Bluetooth is not available", Toast.LENGTH_LONG).show(); finish(); return; } } @Override public void onStart() { super.onStart(); if(D) Log.e(TAG, "++ ON START ++"); // If BT is not on, request that it be enabled. // setupChat() 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 (mChatService == null) setupChat(); } } @Override public synchronized void onResume() { super.onResume(); if(D) Log.e(TAG, "+ ON RESUME +"); // 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 (mChatService != null) { // Only if the state is STATE_NONE, do we know that we haven't started already if (mChatService.getState() == BluetoothChatService.STATE_NONE) { // Start the Bluetooth chat services mChatService.start(); } } } private void setupChat() { Log.d(TAG, "setupChat()"); // Initialize the array adapter for the conversation thread mConversationArrayAdapter = new ArrayAdapter<String>(this, R.layout.message); mConversationView = (ListView) findViewById(R.id.in); mConversationView.setAdapter(mConversationArrayAdapter); // Initialize the compose field with a listener for the return key mOutEditText = (EditText) findViewById(R.id.edit_text_out); mOutEditText.setOnEditorActionListener(mWriteListener); // Initialize the send button with a listener that for click events mSendButton = (Button) findViewById(R.id.button_send); mSendButton.setOnClickListener(new OnClickListener() { public void onClick(View v) { // Send a message using content of the edit text widget TextView view = (TextView) findViewById(R.id.edit_text_out); String message = view.getText().toString(); sendMessage(message); } }); // Initialize the BluetoothChatService to perform bluetooth connections mChatService = new BluetoothChatService(this, mHandler); // Initialize the buffer for outgoing messages mOutStringBuffer = new StringBuffer(""); } @Override public synchronized void onPause() { super.onPause(); if(D) Log.e(TAG, "- ON PAUSE -"); } @Override public void onStop() { super.onStop(); if(D) Log.e(TAG, "-- ON STOP --"); } @Override public void onDestroy() { super.onDestroy(); // Stop the Bluetooth chat services if (mChatService != null) mChatService.stop(); if(D) Log.e(TAG, "--- ON DESTROY ---"); } private void ensureDiscoverable() { if(D) Log.d(TAG, "ensure discoverable"); if (mBluetoothAdapter.getScanMode() != BluetoothAdapter.SCAN_MODE_CONNECTABLE_DISCOVERABLE) { Intent discoverableIntent = new Intent(BluetoothAdapter.ACTION_REQUEST_DISCOVERABLE); discoverableIntent.putExtra(BluetoothAdapter.EXTRA_DISCOVERABLE_DURATION, 300); startActivity(discoverableIntent); } } /** * 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 (mChatService.getState() != BluetoothChatService.STATE_CONNECTED) { Toast.makeText(this, 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(); mChatService.write(send); // Reset out string buffer to zero and clear the edit text field mOutStringBuffer.setLength(0); mOutEditText.setText(mOutStringBuffer); } } // The action listener for the EditText widget, to listen for the return key private TextView.OnEditorActionListener mWriteListener = new TextView.OnEditorActionListener() { public boolean onEditorAction(TextView view, int actionId, KeyEvent event) { // If the action is a key-up event on the return key, send the message if (actionId == EditorInfo.IME_NULL && event.getAction() == KeyEvent.ACTION_UP) { String message = view.getText().toString(); sendMessage(message); } if(D) Log.i(TAG, "END onEditorAction"); return true; } }; private final void setStatus(int resId) { final ActionBar actionBar = getActionBar(); actionBar.setSubtitle(resId); } private final void setStatus(CharSequence subTitle) { final ActionBar actionBar = getActionBar(); actionBar.setSubtitle(subTitle); } // The Handler that gets information back from the BluetoothChatService private final Handler mHandler = new Handler() { @Override public void handleMessage(Message msg) { switch (msg.what) { case MESSAGE_STATE_CHANGE: if(D) Log.i(TAG, "MESSAGE_STATE_CHANGE: " + msg.arg1); switch (msg.arg1) { case BluetoothChatService.STATE_CONNECTED: setStatus(getString(R.string.title_connected_to, mConnectedDeviceName)); mConversationArrayAdapter.clear(); break; case BluetoothChatService.STATE_CONNECTING: setStatus(R.string.title_connecting); break; case BluetoothChatService.STATE_LISTEN: case BluetoothChatService.STATE_NONE: setStatus(R.string.title_not_connected); break; } break; case MESSAGE_WRITE: byte[] writeBuf = (byte[]) msg.obj; // construct a string from the buffer String writeMessage = new String(writeBuf); mConversationArrayAdapter.add("Me: " + writeMessage); break; case 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); mConversationArrayAdapter.add(mConnectedDeviceName+": " + readMessage); break; case MESSAGE_DEVICE_NAME: // save the connected device's name mConnectedDeviceName = msg.getData().getString(DEVICE_NAME); Toast.makeText(getApplicationContext(), "Connected to " + mConnectedDeviceName, Toast.LENGTH_SHORT).show(); break; case MESSAGE_TOAST: Toast.makeText(getApplicationContext(), msg.getData().getString(TOAST), Toast.LENGTH_SHORT).show(); break; } } }; public void onActivityResult(int requestCode, int resultCode, Intent data) { if(D) Log.d(TAG, "onActivityResult " + resultCode); 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 setupChat(); } else { // User did not enable Bluetooth or an error occurred Log.d(TAG, "BT not enabled"); Toast.makeText(this, R.string.bt_not_enabled_leaving, Toast.LENGTH_SHORT).show(); finish(); } } } 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 mChatService.connect(device, secure); } @Override public boolean onCreateOptionsMenu(Menu menu) { MenuInflater inflater = getMenuInflater(); inflater.inflate(R.menu.option_menu, menu); return true; } @Override public boolean onOptionsItemSelected(MenuItem item) { Intent serverIntent = null; switch (item.getItemId()) { case R.id.secure_connect_scan: // Launch the DeviceListActivity to see devices and do scan serverIntent = new Intent(this, 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 serverIntent = new Intent(this, DeviceListActivity.class); startActivityForResult(serverIntent, REQUEST_CONNECT_DEVICE_INSECURE); return true; case R.id.discoverable: // Ensure this device is discoverable by others ensureDiscoverable(); return true; } return false; } }
其中，先执行了onCreate(),onStart(),onResume()方法
@Override public void onCreate(Bundle savedInstanceState) { getWindow().requestFeature(Window.FEATURE_ACTION_BAR); super.onCreate(savedInstanceState); if(D) Log.e(TAG, "+++ ON CREATE +++"); // Set up the window layout setContentView(R.layout.main); // Get local Bluetooth adapter mBluetoothAdapter = BluetoothAdapter.getDefaultAdapter(); // If the adapter is null, then Bluetooth is not supported if (mBluetoothAdapter == null) { Toast.makeText(this, "Bluetooth is not available", Toast.LENGTH_LONG).show(); finish(); return; } } @Override public void onStart() { super.onStart(); if(D) Log.e(TAG, "++ ON START ++"); // If BT is not on, request that it be enabled. // setupChat() 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 (mChatService == null) setupChat(); } } @Override public synchronized void onResume() { super.onResume(); if(D) Log.e(TAG, "+ ON RESUME +"); // 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 (mChatService != null) { // Only if the state is STATE_NONE, do we know that we haven't started already if (mChatService.getState() == BluetoothChatService.STATE_NONE) { // Start the Bluetooth chat services mChatService.start(); } } }
常量：
// 调试用的日志标志TAG与是否打印日志的标志D private static final String TAG = "BluetoothChat"; private static final boolean D = true; // 从BluetoothChatService传回来交给Handler处理的消息类型 public static final int MESSAGE_STATE_CHANGE = 1; // 蓝牙socket状态改变，居然有4个状态监听、正在连接、已连接、无。具体可以看Handler的handMessage方法 public static final int MESSAGE_READ = 2; // 这个消息类型被发送回来是因为蓝牙服务socket在读别的设备发来的内容 public static final int MESSAGE_WRITE = 3; // 这个消息类型被发送回来是因为蓝牙socket在写要发送的内容 public static final int MESSAGE_DEVICE_NAME = 4; // 这个消息发送回来是因为连接到了一个设备，并且获得了对方的名字，好像是手机的型号 public static final int MESSAGE_TOAST = 5; // 这个消息发送回来是有要用Toast控件广播的内容 // 从BluetoothChatService的发送回来消息内容里的键值 public static final String DEVICE_NAME = "device_name"; // 在发回设备名(MESSAGE_DEVICE_NAME)消息时，获取设备名时的键值 public static final String TOAST = "toast"; // 同样是键值，指向的是要Toast控件广播的内容 // Intent的请求值，在startActivityForResult时使用 private static final int REQUEST_CONNECT_DEVICE = 1; // 在要请求去搜索设备的时候使用到 private static final int REQUEST_ENABLE_BT = 2; // 在请求要使蓝牙可用的时候用到
主要是Menu菜单触发事件：
@Override public boolean onCreateOptionsMenu(Menu menu) { MenuInflater inflater = getMenuInflater(); inflater.inflate(R.menu.option_menu, menu); return true; } @Override public boolean onOptionsItemSelected(MenuItem item) { Intent serverIntent = null; switch (item.getItemId()) { case R.id.secure_connect_scan: // Launch the DeviceListActivity to see devices and do scan serverIntent = new Intent(this, 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 serverIntent = new Intent(this, DeviceListActivity.class); startActivityForResult(serverIntent, REQUEST_CONNECT_DEVICE_INSECURE); return true; case R.id.discoverable: // Ensure this device is discoverable by others ensureDiscoverable(); return true; } return false; }
额外：
然后是ListView从底下开始显示：需要XML里一句：
android:stackFromBottom="true"
学到了EditText注册了一个监听器，然后实现了软键盘按回车return键发送消息（一般我们在EditText里按return键是换行）
// 用于监听EditText的一个return键事件 private TextView.OnEditorActionListener mWriteListener = new TextView.OnEditorActionListener() { public boolean onEditorAction(TextView view, int actionId, KeyEvent event) { // If the action is a key-up event on the return key, send the message if (actionId == EditorInfo.IME_NULL && event.getAction() == KeyEvent.ACTION_UP) { String message = view.getText().toString(); sendMessage(message); } if(D) Log.i(TAG, "END onEditorAction"); return true; } };
DeviceListActivity源码：
This Activity appears as a dialog. It lists any paired devices and devices detected in the area after discovery. When a device is chosen by the user, the MAC address of the device is sent back to the parent Activity in the result Intent.
这个Aty以对话框的形式显示。显示任何已经配对的设备和查找的设备。当用户选择一个设备的时候，将会返回MAC地址到上一个Aty。
/* * 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.util.Set; import android.app.Activity; import android.bluetooth.BluetoothAdapter; import android.bluetooth.BluetoothDevice; import android.content.BroadcastReceiver; import android.content.Context; import android.content.Intent; import android.content.IntentFilter; import android.os.Bundle; import android.util.Log; import android.view.View; import android.view.Window; import android.view.View.OnClickListener; import android.widget.AdapterView; import android.widget.ArrayAdapter; import android.widget.Button; import android.widget.ListView; import android.widget.TextView; import android.widget.AdapterView.OnItemClickListener; /** * This Activity appears as a dialog. It lists any paired devices and * devices detected in the area after discovery. When a device is chosen * by the user, the MAC address of the device is sent back to the parent * Activity in the result Intent. */ public class DeviceListActivity extends Activity { // Debugging private static final String TAG = "DeviceListActivity"; private static final boolean D = true; // Return Intent extra public static String EXTRA_DEVICE_ADDRESS = "device_address"; // Member fields private BluetoothAdapter mBtAdapter; private ArrayAdapter<String> mPairedDevicesArrayAdapter; private ArrayAdapter<String> mNewDevicesArrayAdapter; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); // Setup the window requestWindowFeature(Window.FEATURE_INDETERMINATE_PROGRESS); setContentView(R.layout.device_list); // Set result CANCELED in case the user backs out setResult(Activity.RESULT_CANCELED); // Initialize the button to perform device discovery Button scanButton = (Button) findViewById(R.id.button_scan); scanButton.setOnClickListener(new OnClickListener() { public void onClick(View v) { doDiscovery(); v.setVisibility(View.GONE); } }); // Initialize array adapters. One for already paired devices and // one for newly discovered devices mPairedDevicesArrayAdapter = new ArrayAdapter<String>(this, R.layout.device_name); mNewDevicesArrayAdapter = new ArrayAdapter<String>(this, R.layout.device_name); // Find and set up the ListView for paired devices ListView pairedListView = (ListView) findViewById(R.id.paired_devices); pairedListView.setAdapter(mPairedDevicesArrayAdapter); pairedListView.setOnItemClickListener(mDeviceClickListener); // Find and set up the ListView for newly discovered devices ListView newDevicesListView = (ListView) findViewById(R.id.new_devices); newDevicesListView.setAdapter(mNewDevicesArrayAdapter); newDevicesListView.setOnItemClickListener(mDeviceClickListener); // Register for broadcasts when a device is discovered IntentFilter filter = new IntentFilter(BluetoothDevice.ACTION_FOUND); this.registerReceiver(mReceiver, filter); // Register for broadcasts when discovery has finished filter = new IntentFilter(BluetoothAdapter.ACTION_DISCOVERY_FINISHED); this.registerReceiver(mReceiver, filter); // Get the local Bluetooth adapter mBtAdapter = BluetoothAdapter.getDefaultAdapter(); // Get a set of currently paired devices Set<BluetoothDevice> pairedDevices = mBtAdapter.getBondedDevices(); // If there are paired devices, add each one to the ArrayAdapter if (pairedDevices.size() > 0) { findViewById(R.id.title_paired_devices).setVisibility(View.VISIBLE); for (BluetoothDevice device : pairedDevices) { mPairedDevicesArrayAdapter.add(device.getName() + " " + device.getAddress()); } } else { String noDevices = getResources().getText(R.string.none_paired).toString(); mPairedDevicesArrayAdapter.add(noDevices); } } @Override protected void onDestroy() { super.onDestroy(); // Make sure we're not doing discovery anymore if (mBtAdapter != null) { mBtAdapter.cancelDiscovery(); } // Unregister broadcast listeners this.unregisterReceiver(mReceiver); } /** * Start device discover with the BluetoothAdapter */ private void doDiscovery() { if (D) Log.d(TAG, "doDiscovery()"); // Indicate scanning in the title setProgressBarIndeterminateVisibility(true); setTitle(R.string.scanning); // Turn on sub-title for new devices findViewById(R.id.title_new_devices).setVisibility(View.VISIBLE); // If we're already discovering, stop it if (mBtAdapter.isDiscovering()) { mBtAdapter.cancelDiscovery(); } // Request discover from BluetoothAdapter mBtAdapter.startDiscovery(); } // The on-click listener for all devices in the ListViews private OnItemClickListener mDeviceClickListener = new OnItemClickListener() { public void onItemClick(AdapterView<?> av, View v, int arg2, long arg3) { // Cancel discovery because it's costly and we're about to connect mBtAdapter.cancelDiscovery(); // Get the device MAC address, which is the last 17 chars in the View String info = ((TextView) v).getText().toString(); String address = info.substring(info.length() - 17); // Create the result Intent and include the MAC address Intent intent = new Intent(); intent.putExtra(EXTRA_DEVICE_ADDRESS, address); // Set result and finish this Activity setResult(Activity.RESULT_OK, intent); finish(); } }; // The BroadcastReceiver that listens for discovered devices and // changes the title when discovery is finished private final BroadcastReceiver mReceiver = new BroadcastReceiver() { @Override public void onReceive(Context context, Intent intent) { String action = intent.getAction(); // When discovery finds a device if (BluetoothDevice.ACTION_FOUND.equals(action)) { // Get the BluetoothDevice object from the Intent BluetoothDevice device = intent.getParcelableExtra(BluetoothDevice.EXTRA_DEVICE); // If it's already paired, skip it, because it's been listed already if (device.getBondState() != BluetoothDevice.BOND_BONDED) { mNewDevicesArrayAdapter.add(device.getName() + " " + device.getAddress()); } // When discovery is finished, change the Activity title } else if (BluetoothAdapter.ACTION_DISCOVERY_FINISHED.equals(action)) { setProgressBarIndeterminateVisibility(false); setTitle(R.string.select_device); if (mNewDevicesArrayAdapter.getCount() == 0) { String noDevices = getResources().getText(R.string.none_found).toString(); mNewDevicesArrayAdapter.add(noDevices); } } } }; }
这边，学习到了3点：
第一点：
在onCreate()方法中，设置：如果用户按下返回键，设置CANCELED
// Set result CANCELED in case the user backs out setResult(Activity.RESULT_CANCELED);
第二点：
将aty以dialog形式显示：需要在AndroidManifest.xml配置
<activity android:name=".DeviceListActivity" android:label="@string/select_device" android:theme="@android:style/Theme.Holo.Dialog" android:configChanges="orientation|keyboardHidden" />
第三点：
将result设置成public static的。
// Return Intent extra public static String EXTRA_DEVICE_ADDRESS = "device_address";
// Create the result Intent and include the MAC address Intent intent = new Intent(); intent.putExtra(EXTRA_DEVICE_ADDRESS, address);
前一个aty：
// Get the device MAC address String address = data.getExtras().getString(DeviceListActivity.EXTRA_DEVICE_ADDRESS);
BluetoothChatService源码：
/* * 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. */ 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_SECURE = "BluetoothChatSecure"; private static final String NAME_INSECURE = "BluetoothChatInsecure"; // Unique UUID for this application private static final UUID MY_UUID_SECURE = UUID.fromString("fa87c0d0-afac-11de-8a39-0800200c9a66"); private static final UUID MY_UUID_INSECURE = UUID.fromString("8ce255c0-200a-11e0-ac64-0800200c9a66"); // Member fields private final BluetoothAdapter mAdapter; private final Handler mHandler; private AcceptThread mSecureAcceptThread; private AcceptThread mInsecureAcceptThread; private ConnectThread mConnectThread; private ConnectedThread mConnectedThread; private int mState; // Constants that indicate the current connection state public static final int STATE_NONE = 0; // we're doing nothing public static final int STATE_LISTEN = 1; // now listening for incoming connections public static final int STATE_CONNECTING = 2; // now initiating an outgoing connection public static final int STATE_CONNECTED = 3; // now connected to a remote device /** * Constructor. Prepares a new BluetoothChat session. * @param context The UI Activity Context * @param handler A Handler to send messages back to the UI Activity */ public BluetoothChatService(Context context, Handler handler) { mAdapter = BluetoothAdapter.getDefaultAdapter(); mState = STATE_NONE; mHandler = handler; } /** * Set the current state of the chat connection * @param state An integer defining the current connection state */ 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 mHandler.obtainMessage(BluetoothChat.MESSAGE_STATE_CHANGE, state, -1).sendToTarget(); } /** * Return the current connection state. */ public synchronized int getState() { return mState; } /** * Start the chat service. Specifically start AcceptThread to begin a * session in listening (server) mode. Called by the Activity onResume() */ public synchronized void start() { if (D) Log.d(TAG, "start"); // Cancel any thread attempting to make a connection if (mConnectThread != null) {mConnectThread.cancel(); mConnectThread = null;} // Cancel any thread currently running a connection if (mConnectedThread != null) {mConnectedThread.cancel(); mConnectedThread = null;} setState(STATE_LISTEN); // Start the thread to listen on a BluetoothServerSocket if (mSecureAcceptThread == null) { mSecureAcceptThread = new AcceptThread(true); mSecureAcceptThread.start(); } if (mInsecureAcceptThread == null) { mInsecureAcceptThread = new AcceptThread(false); mInsecureAcceptThread.start(); } } /** * Start the ConnectThread to initiate a connection to a remote device. * @param device The BluetoothDevice to connect * @param secure Socket Security type - Secure (true) , Insecure (false) */ public synchronized void connect(BluetoothDevice device, boolean secure) { if (D) Log.d(TAG, "connect to: " + device); // Cancel any thread attempting to make a connection if (mState == STATE_CONNECTING) { if (mConnectThread != null) {mConnectThread.cancel(); mConnectThread = null;} } // Cancel any thread currently running a connection if (mConnectedThread != null) {mConnectedThread.cancel(); mConnectedThread = null;} // Start the thread to connect with the given device mConnectThread = new ConnectThread(device, secure); 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 */ public synchronized void connected(BluetoothSocket socket, BluetoothDevice device, final String socketType) { if (D) Log.d(TAG, "connected, Socket Type:" + socketType); // 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 (mSecureAcceptThread != null) { mSecureAcceptThread.cancel(); mSecureAcceptThread = null; } if (mInsecureAcceptThread != null) { mInsecureAcceptThread.cancel(); mInsecureAcceptThread = null; } // Start the thread to manage the connection and perform transmissions mConnectedThread = new ConnectedThread(socket, socketType); mConnectedThread.start(); // Send the name of the connected device back to the UI Activity Message msg = mHandler.obtainMessage(BluetoothChat.MESSAGE_DEVICE_NAME); Bundle bundle = new Bundle(); bundle.putString(BluetoothChat.DEVICE_NAME, device.getName()); msg.setData(bundle); mHandler.sendMessage(msg); setState(STATE_CONNECTED); } /** * Stop all threads */ public synchronized void stop() { if (D) Log.d(TAG, "stop"); if (mConnectThread != null) { mConnectThread.cancel(); mConnectThread = null; } if (mConnectedThread != null) { mConnectedThread.cancel(); mConnectedThread = null; } if (mSecureAcceptThread != null) { mSecureAcceptThread.cancel(); mSecureAcceptThread = null; } if (mInsecureAcceptThread != null) { mInsecureAcceptThread.cancel(); mInsecureAcceptThread = null; } setState(STATE_NONE); } /** * Write to the ConnectedThread in an unsynchronized manner * @param out The bytes to write * @see ConnectedThread#write(byte[]) */ public void write(byte[] out) { // Create temporary object ConnectedThread r; // Synchronize a copy of the ConnectedThread synchronized (this) { if (mState != STATE_CONNECTED) return; r = mConnectedThread; } // Perform the write unsynchronized r.write(out); } /** * Indicate that the connection attempt failed and notify the UI Activity. */ private void connectionFailed() { // Send a failure message back to the Activity Message msg = mHandler.obtainMessage(BluetoothChat.MESSAGE_TOAST); Bundle bundle = new Bundle(); bundle.putString(BluetoothChat.TOAST, "Unable to connect device"); msg.setData(bundle); mHandler.sendMessage(msg); // Start the service over to restart listening mode BluetoothChatService.this.start(); } /** * Indicate that the connection was lost and notify the UI Activity. */ private void connectionLost() { // Send a failure message back to the Activity Message msg = mHandler.obtainMessage(BluetoothChat.MESSAGE_TOAST); Bundle bundle = new Bundle(); bundle.putString(BluetoothChat.TOAST, "Device connection was lost"); msg.setData(bundle); mHandler.sendMessage(msg); // Start the service over to restart listening mode BluetoothChatService.this.start(); } /** * This thread runs while listening for incoming connections. It behaves * like a server-side client. It runs until a connection is accepted * (or until cancelled). */ private class AcceptThread extends Thread { // The local server socket private final BluetoothServerSocket mmServerSocket; private String mSocketType; public AcceptThread(boolean secure) { BluetoothServerSocket tmp = null; mSocketType = secure ? "Secure":"Insecure"; // Create a new listening server socket try { if (secure) { tmp = mAdapter.listenUsingRfcommWithServiceRecord(NAME_SECURE, MY_UUID_SECURE); } else { tmp = mAdapter.listenUsingInsecureRfcommWithServiceRecord( NAME_INSECURE, MY_UUID_INSECURE); } } catch (IOException e) { Log.e(TAG, "Socket Type: " + mSocketType + "listen() failed", e); } mmServerSocket = tmp; } public void run() { if (D) Log.d(TAG, "Socket Type: " + mSocketType + "BEGIN mAcceptThread" + this); setName("AcceptThread" + mSocketType); BluetoothSocket socket = null; // Listen to the server socket if we're not connected while (mState != STATE_CONNECTED) { try { // This is a blocking call and will only return on a // successful connection or an exception socket = mmServerSocket.accept(); } catch (IOException e) { Log.e(TAG, "Socket Type: " + mSocketType + "accept() failed", e); break; } // If a connection was accepted if (socket != null) { synchronized (BluetoothChatService.this) { switch (mState) { case STATE_LISTEN: case STATE_CONNECTING: // Situation normal. Start the connected thread. connected(socket, socket.getRemoteDevice(), mSocketType); break; case STATE_NONE: case STATE_CONNECTED: // Either not ready or already connected. Terminate new socket. try { socket.close(); } catch (IOException e) { Log.e(TAG, "Could not close unwanted socket", e); } break; } } } } if (D) Log.i(TAG, "END mAcceptThread, socket Type: " + mSocketType); } public void cancel() { if (D) Log.d(TAG, "Socket Type" + mSocketType + "cancel " + this); try { mmServerSocket.close(); } catch (IOException e) { Log.e(TAG, "Socket Type" + mSocketType + "close() of server failed", e); } } } /** * This thread runs while attempting to make an outgoing connection * with a device. It runs straight through; the connection either * succeeds or fails. */ private class ConnectThread extends Thread { private final BluetoothSocket mmSocket; private final BluetoothDevice mmDevice; private String mSocketType; public ConnectThread(BluetoothDevice device, boolean secure) { mmDevice = device; BluetoothSocket tmp = null; mSocketType = secure ? "Secure" : "Insecure"; // Get a BluetoothSocket for a connection with the // given BluetoothDevice try { if (secure) { tmp = device.createRfcommSocketToServiceRecord( MY_UUID_SECURE); } else { tmp = device.createInsecureRfcommSocketToServiceRecord( MY_UUID_INSECURE); } } catch (IOException e) { Log.e(TAG, "Socket Type: " + mSocketType + "create() failed", e); } mmSocket = tmp; } public void run() { Log.i(TAG, "BEGIN mConnectThread SocketType:" + mSocketType); setName("ConnectThread" + mSocketType); // Always cancel discovery because it will slow down a connection mAdapter.cancelDiscovery(); // Make a connection to the BluetoothSocket try { // This is a blocking call and will only return on a // successful connection or an exception mmSocket.connect(); } catch (IOException e) { // Close the socket try { mmSocket.close(); } catch (IOException e2) { Log.e(TAG, "unable to close() " + mSocketType + " socket during connection failure", e2); } connectionFailed(); return; } // Reset the ConnectThread because we're done synchronized (BluetoothChatService.this) { mConnectThread = null; } // Start the connected thread connected(mmSocket, mmDevice, mSocketType); } public void cancel() { try { mmSocket.close(); } catch (IOException e) { Log.e(TAG, "close() of connect " + mSocketType + " socket failed", e); } } } /** * This thread runs during a connection with a remote device. * It handles all incoming and outgoing transmissions. */ private class ConnectedThread extends Thread { private final BluetoothSocket mmSocket; private final InputStream mmInStream; private final OutputStream mmOutStream; public ConnectedThread(BluetoothSocket socket, String socketType) { Log.d(TAG, "create ConnectedThread: " + socketType); mmSocket = socket; InputStream tmpIn = null; OutputStream tmpOut = null; // Get the BluetoothSocket input and output streams try { tmpIn = socket.getInputStream(); tmpOut = socket.getOutputStream(); } catch (IOException e) { Log.e(TAG, "temp sockets not created", e); } mmInStream = tmpIn; mmOutStream = tmpOut; } 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 bytes = mmInStream.read(buffer); // 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(); // Start the service over to restart listening mode BluetoothChatService.this.start(); break; } } } /** * Write to the connected OutStream. * @param buffer The bytes to write */ public void write(byte[] buffer) { try { mmOutStream.write(buffer); // Share the sent message back to the UI Activity mHandler.obtainMessage(BluetoothChat.MESSAGE_WRITE, -1, -1, buffer) .sendToTarget(); } catch (IOException e) { Log.e(TAG, "Exception during write", e); } } public void cancel() { try { mmSocket.close(); } catch (IOException e) { Log.e(TAG, "close() of connect socket failed", e); } } } }
AcceptThread：蓝牙服务端socket监听线程.：
private class AcceptThread extends Thread { // 本地的服务端socket private final BluetoothServerSocket mmServerSocket; public AcceptThread() { BluetoothServerSocket tmp = null; // 创建一个用于监听的服务端socket，通过下面这个方法，NAME参数没关系，MY_UUID是确定唯一通道的标示符，用于连接的socket也要通过它产生 try { tmp = mAdapter.listenUsingRfcommWithServiceRecord(NAME, MY_UUID); } catch (IOException e) { Log.e(TAG, "listen() failed", e); } mmServerSocket = tmp; } public void run() { if (D) Log.d(TAG, "BEGIN mAcceptThread" + this); setName("AcceptThread"); BluetoothSocket socket = null; // 不断的监听，直到状态被改变成已连接状态 while (mState != STATE_CONNECTED) { try { // 这是一个会产生阻塞的方法accept，要不就是成功地建立一个连接，要不就是返回一个异常 socket = mmServerSocket.accept(); } catch (IOException e) { Log.e(TAG, "accept() failed", e); break; } // 连接已经建立成功 if (socket != null) { synchronized (BluetoothChatService.this) { // 同步块，同一时间，只有一个线程可以访问该区域 switch (mState) { case STATE_LISTEN: case STATE_CONNECTING: // 状态正常，开始进行线程通信，实际就是开启通信线程ConnectedThread connected(socket, socket.getRemoteDevice()); break; case STATE_NONE: case STATE_CONNECTED: // 未准备或已连接状态. 关闭新建的这个socket. try { socket.close(); } catch (IOException e) { Log.e(TAG, "Could not close unwanted socket", e); } break; } } } } if (D) Log.i(TAG, "END mAcceptThread"); } public void cancel() { //关闭服务端的socket if (D) Log.d(TAG, "cancel " + this); try { mmServerSocket.close(); } catch (IOException e) { Log.e(TAG, "close() of server failed", e); } } }
ConnectThread：蓝牙socket连接线程：
private class ConnectThread extends Thread { private final BluetoothSocket mmSocket; private final BluetoothDevice mmDevice; public ConnectThread(BluetoothDevice device) { mmDevice = device; BluetoothSocket tmp = null; // 通过远程设备以及唯一的UUID创建一个用于连接的socket try { tmp = device.createRfcommSocketToServiceRecord(MY_UUID); } catch (IOException e) { Log.e(TAG, "create() failed", e); } mmSocket = tmp; } public void run() { Log.i(TAG, "BEGIN mConnectThread"); setName("ConnectThread"); // 一定要停止扫描，不然会减慢连接速度 mAdapter.cancelDiscovery(); // 连接到服务端的socket try { // connect方法也会造成阻塞，直到成功连接，或返回一个异常 mmSocket.connect(); } catch (IOException e) { connectionFailed(); //连接失败发送要Toast的消息 // 关闭socket try { mmSocket.close(); } catch (IOException e2) { Log.e(TAG, "unable to close() socket during connection failure", e2); } // 连接失败了，把软件变成监听模式，可以让别的设备来连接 BluetoothChatService.this.start(); return; } // 重置连接线程，因为我们已经完成了 synchronized (BluetoothChatService.this) { mConnectThread = null; } // 开始进行线程通信，实际就是开启通信线程ConnectedThread connected(mmSocket, mmDevice); } public void cancel() { // 关闭连接用的socket try { mmSocket.close(); } catch (IOException e) { Log.e(TAG, "close() of connect socket failed", e); } } }
ConnectedThread：连接后的通信线程：
private class ConnectedThread extends Thread { private final BluetoothSocket mmSocket; private final InputStream mmInStream; private final OutputStream mmOutStream; public ConnectedThread(BluetoothSocket socket) { Log.d(TAG, "create ConnectedThread"); mmSocket = socket; // 这个是之前的用于连接的socket InputStream tmpIn = null; OutputStream tmpOut = null; // 从连接的socket里获取InputStream和OutputStream try { tmpIn = socket.getInputStream(); tmpOut = socket.getOutputStream(); } catch (IOException e) { Log.e(TAG, "temp sockets not created", e); } mmInStream = tmpIn; mmOutStream = tmpOut; } public void run() { Log.i(TAG, "BEGIN mConnectedThread"); byte[] buffer = new byte[1024]; int bytes; // 已经连接上以后持续从通道中监听输入流的情况 while (true) { try { // 从通道的输入流InputStream中读取数据到buffer数组中 bytes = mmInStream.read(buffer); // 将获取到数据的消息发送到UI界面，同时也把内容buffer发过去显示 mHandler.obtainMessage(BluetoothChat.MESSAGE_READ, bytes, -1, buffer) .sendToTarget(); } catch (IOException e) { Log.e(TAG, "disconnected", e); connectionLost(); // 连接异常断开的时候发送一个需要Toast的消息，让软件进行Toast break; } } } /** * Write to the connected OutStream. * @param buffer The bytes to write */ public void write(byte[] buffer) { // 这个方法用于把发送内容写到通道的OutputStream中，会在发信息是被调用 try { mmOutStream.write(buffer); //将buffer内容写进通道 // 用于将自己发送给对方的内容也在UI界面显示 mHandler.obtainMessage(BluetoothChat.MESSAGE_WRITE, -1, -1, buffer) .sendToTarget(); } catch (IOException e) { Log.e(TAG, "Exception during write", e); } } public void cancel() { //关闭socket，即关闭通道 try { mmSocket.close(); } catch (IOException e) { Log.e(TAG, "close() of connect socket failed", e); } } }
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