一.在看一下代码之前需要简单了解wifi的基本知识
802.11 协议 : wifi 用到的是 802.11b,802.11g( 是 802.11b 的 后继标准 )
station :携带无线网卡的设备,如智能手机,笔记本 , 底层会启动 wpa-supplicant: 实现 station 对无线网络的管理和控制功能。
AP : accesspoint 本身也是一个 station, 能为关联的 STA 提供分布式 服务( ds ),如路由器
DS : distributionservice: 分布式服务 ,BSS 和 LAN 组合在一起构成 一个 ESS 的就是 ds,ds 一般是指有线网络(通过它接入互联网)
BSS : BasicService Set, 是由上述原件组成的网络
基础结构型 BSS : 通常是指的 Infrastructurebasic Service Set, 有 AP参与。
独立型 BSS : 通常是指 IndependentBSS, 不需要 AP, 各个 STA 直接互 联,自组网络对等网络,通常我们所说的 BSS 是指基础结构型
ESS : ExtendedService Set 扩展服务集,包含一个或者多个 BSS.
SSID : ServiceSet Identification: 网络名
BSSID : 在基础结构型网络中,他就是 ap 的 MAC 地址,在独立型 BSS 中为随机生成,
wpa-supplicant : 使得无线网卡工作在 managed 模式,
softap : 软 AP 底层启动 :hostapd 的后台管理进程, 常见的为 hotspot
hostapd : 切换为 master 模式,模拟 AP, 建立一个无线开放的网络,
在谷歌提供的安卓源码中,网址如下:http://androidxref.com ,初学者学习,分析,留疑问,并且长期更新,修改错误,补充。
二.安卓的系统wifi模块,一般在设置—–>Wifi中WifiSettings显示的就是打开wifi的那个界面
需要先了解一些wifi模块的API如WifiManager类等。
WifiSettings继承SettingsPreferenceFragment,具有fragement的生命周期(可百度看一下)如sethasOptionsMenu(true)这方法是Fragment中的.界面一般包括
1.switchbar (控制开关,在WifiEnaber中实现),控制wifi的开关,
主要用WifiEnabler中的onSwitchChanged方法中实现调用 wifiManager 的setWifiEnabled(boolean ischeck)方法进行开关
preferenceScreen(用来显示ap(如路由器)列表)
2.OptionsMenu
选项菜单,通过 sethasOptionsMenu(true) 会自动调用oncreateOptionsMenu方法,方法中调用addOptionsMenuItems进行初始
包括新增网络,保存的网络,刷新,高级( 会有条件具体显示的菜单 ,如通过savedNetworksExist来判断“保存的网络”是否显示在菜单上)
3.ContextMenu
长按AP会弹出内容菜单,通过RegisterForContextMenu(listview),会自动调用OnCreateContextMenu方法.
包括连接,忘记,修改,写入NFC的功能(会有条件具体显示的菜单,如连接的,保存的,未连接的的ap)
三.这些方法在wifiSettings中都有具体的实现代码,可以分析
WifiSettings位于packages/apps/Settings/src/com/android/settings/wifi/WifiSettings.java
其中有两个类,其中的Multimap为多重映射,在 constructAccessPoints方法中会被调用
Multimap<String,AccessPoint> apMap = new Multimap<String, AccessPoint>()
apMap 用来存放 ssid 与 accesspoint 的键值,其中,相同的键可以有多个值(意味着可能存在 ssid 相同的多个 ap )
1.负责扫描,发送消息扫描,间隔 10 秒, startScan(), 连续三次扫描都失败就停止扫描。这个类在WifiSettings构造方法中被初始化.
private static class Scanner extends Handler {
private int mRetry = 0; private WifiSettings mWifiSettings = null; Scanner(WifiSettings wifiSettings) { mWifiSettings = wifiSettings; } void resume() { if (!hasMessages(0)) { sendEmptyMessage(0); } } void forceScan() { removeMessages(0); sendEmptyMessage(0); } void pause() { mRetry = 0; removeMessages(0); } @Override public void handleMessage(Message message) { if (mWifiSettings.mWifiManager.startScan()) { mRetry = 0; //当中有一次扫描成功mRetry=0 } else if (++mRetry >= 3) { //开始扫描的操作失败mRetry+1与3比较,超过三次就return mRetry = 0; Activity activity = mWifiSettings.getActivity(); if (activity != null) { Toast.makeText(activity, R.string.wifi_fail_to_scan, Toast.LENGTH_LONG).show(); } return; } sendEmptyMessageDelayed(0, WIFI_RESCAN_INTERVAL_MS); //每隔10秒,发起扫描的操作 } }
2.在wifiSettings构造方法中,增加了Intent过滤器和广播接受者,其中广播接受者的时间在HandleEvent(Intent intent)中处理,但是我有一个问题:为啥过滤器中注册了8个Action.
public WifiSettings() {
super(DISALLOW_CONFIG_WIFI); mFilter = new IntentFilter(); mFilter.addAction(WifiManager.WIFI_STATE_CHANGED_ACTION); mFilter.addAction(WifiManager.SCAN_RESULTS_AVAILABLE_ACTION); mFilter.addAction(WifiManager.NETWORK_IDS_CHANGED_ACTION); mFilter.addAction(WifiManager.SUPPLICANT_STATE_CHANGED_ACTION); mFilter.addAction(WifiManager.CONFIGURED_NETWORKS_CHANGED_ACTION); mFilter.addAction(WifiManager.LINK_CONFIGURATION_CHANGED_ACTION); mFilter.addAction(WifiManager.NETWORK_STATE_CHANGED_ACTION); mFilter.addAction(WifiManager.RSSI_CHANGED_ACTION); mReceiver = new BroadcastReceiver() { @Override public void onReceive(Context context, Intent intent) { handleEvent(intent); } }; mScanner = new Scanner(this);}
疑问:但是在HandleEvent方法中却只有6个action的处理,NETWORK_IDS_CHANGED_ACTION与SUPPLICANT_STATE_CHANGED_ACTION却没有处理,那么加入的目的?
3.HandleEvent处理广播的代码
private void handleEvent(Intent intent) {
String action = intent.getAction(); if (WifiManager.WIFI_STATE_CHANGED_ACTION.equals(action)) { updateWifiState(intent.getIntExtra(WifiManager.EXTRA_WIFI_STATE, WifiManager.WIFI_STATE_UNKNOWN)); //更新wifi状态改变,Enabled Enabling Disabled } else if (WifiManager.SCAN_RESULTS_AVAILABLE_ACTION.equals(action) || WifiManager.CONFIGURED_NETWORKS_CHANGED_ACTION.equals(action) || WifiManager.LINK_CONFIGURATION_CHANGED_ACTION.equals(action)) { updateAccessPoints(); //更新AccessPoints } else if (WifiManager.NETWORK_STATE_CHANGED_ACTION.equals(action)) { NetworkInfo info = (NetworkInfo) intent.getParcelableExtra( WifiManager.EXTRA_NETWORK_INFO); mConnected.set(info.isConnected()); changeNextButtonState(info.isConnected()); updateAccessPoints(); updateNetworkInfo(info); //更新ap再更新网络信息 } else if (WifiManager.RSSI_CHANGED_ACTION.equals(action)) { updateNetworkInfo(null); }}
4.不同的action对应处理不同的事件
WIFI_STATE_CHANGED_ACTION:当wifi状态改变的时候,updataWifiState(int state),根据不同的状态,做不同的处理:
private void updateWifiState(int state) {
Activity activity = getActivity(); if (activity != null) { activity.invalidateOptionsMenu(); } switch (state) { case WifiManager.WIFI_STATE_ENABLED: mScanner.resume(); //enabled的时候,发送扫描信息startScan() return; // not break, to avoid the call to pause() below //避免调用mScanner.pause()停止扫描 case WifiManager.WIFI_STATE_ENABLING: addMessagePreference(R.string.wifi_starting); //加入“正在打开wifi” break; case WifiManager.WIFI_STATE_DISABLED: setOffMessage(); //wifi不可用的时候,显示一些其他信息(通过provider判断) break; } mLastInfo = null; mLastNetworkInfo = null; mScanner.pause(); //停止扫描}
第二个的判断条件中有三个action:分别对应的是
SCAN_RESULTS_AVAILABLE_ACTION:
An access point scan has completed, and results are available from the supplicant.
一个AP扫描完成,并且从supplicant获得的结果是可用的
CONFIGURED_NETWORKS_CHANGED_ACTION:
Broadcast intent action indicating that the configured networks changed. This can be as a result of adding/updating/deleting a network
广播intent的动作表明配置的网络已经改变,比如增加/更新/删除一个网络
LINK_CONFIGURATION_CHANGED_ACTION:
Broadcast intent action indicating that the link configuration changed on wifi
广播intent的动作表明连接的配置已经改变
5.在这些情况下,都会更新wifi的信息updateAccessPoints();
private void updateAccessPoints() {
// Safeguard from some delayed event handling if (getActivity() == null) return; if (isUiRestricted()) addMessagePreference(R.string.wifi_empty_list_user_restricted); //判断是否有限制 return; } final int wifiState = mWifiManager.getWifiState(); //when we update the screen, check if verbose logging has been turned on or off mVerboseLogging = mWifiManager.getVerboseLoggingLevel(); switch (wifiState) { //根据wifi状态来处理 case WifiManager.WIFI_STATE_ENABLED: //当wifi状态可用的情况下 // AccessPoints are automatically sorted with TreeSet. final Collection<AccessPoint> accessPoints = constructAccessPoints(getActivity(), mWifiManager, mLastInfo, mLastNetworkInfo); //主要通过constructAccessPoints进行更新 getPreferenceScreen().removeAll(); if (accessPoints.size() == 0) { addMessagePreference(R.string.wifi_empty_list_wifi_on); //如果ap没有,则显示“正在搜索wlan网络” } for (AccessPoint accessPoint : accessPoints) { // Ignore access points that are out of range. if (accessPoint.getLevel() != -1) { getPreferenceScreen().addPreference(accessPoint); //遍历,增加到preferenceScreen中(可以阅读相关资料了解) } } break; case WifiManager.WIFI_STATE_ENABLING: getPreferenceScreen().removeAll(); //enabling的情况下,移出preferenceScreen中所有的ap break; case WifiManager.WIFI_STATE_DISABLING: addMessagePreference(R.string.wifi_stopping); //显示“正在关闭“ break; case WifiManager.WIFI_STATE_DISABLED: //不可用的时候,显示其他信息 setOffMessage(); break; } }
这里面最主要的方法就是constructAccessPoints这个方法了,之后在学习把。。NETWORK_STATE_CHANGED_ACTION
Broadcast intent action indicating that the state of Wi-Fi connectivity has changed. One extra provides the new statewifi
连通性被改变,提供了新的状态更新ap的同时,更新NetworkInfo,在安卓5.0的情况下名字为updateConnectionState(估计认为这是网络状态?怕理解成connected的ap???)
private void updateNetworkInfo(NetworkInfo networkInfo) {
/* sticky broadcasts can call this when wifi is disabled */ if (!mWifiManager.isWifiEnabled()) { mScanner.pause(); return; } if (networkInfo != null && networkInfo.getDetailedState() == DetailedState.OBTAINING_IPADDR) { mScanner.pause(); } else { mScanner.resume(); } mLastInfo = mWifiManager.getConnectionInfo(); if (networkInfo != null) { mLastNetworkInfo = networkInfo; } //倒序更新AccessPoint的信息,应该是更新了修改配置之后的ap的信息 for (int i = getPreferenceScreen().getPreferenceCount() - 1; i >= 0; --i) { // Maybe there's a WifiConfigPreference Preference preference = getPreferenceScreen().getPreference(i); if (preference instanceof AccessPoint) { final AccessPoint accessPoint = (AccessPoint) preference; accessPoint.update(mLastInfo, mLastNetworkInfo); } }}
RSSI_CHANGED_ACTION
The RSSI (signal strength) has changed.
显而易见,这指的是信号强度被改变的action,调用updateNetworkInfo,更新一下网络信息就可以了
以上是handleEvent的处理
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之前看到在updataAccessPoints中调用了这个方法:constructAccessPoints,看一下这个方法的源码把
private static List<AccessPoint> constructAccessPoints(Context context,
WifiManager wifiManager, WifiInfo lastInfo, NetworkInfo lastNetworkInfo) { ArrayList<AccessPoint> accessPoints = new ArrayList<AccessPoint>(); //存放ap的ArrayList,用来返回 /** Lookup table to more quickly update AccessPoints by only considering objects with the * correct SSID. Maps SSID -> List of AccessPoints with the given SSID. */ Multimap<String, AccessPoint> apMap = new Multimap<String, AccessPoint>();//多重映射,键SSID(网络名)--值(ap) final List<WifiConfiguration> configs = wifiManager.getConfiguredNetworks();//获取手机中保存过配置的连接信息 if (configs != null) { // Update "Saved Networks" menu option. //更新选项“saved Networks”的状态 if (savedNetworksExist != (configs.size() > 0)) { //比较式前后一致的返回值,更新Saved Networks的菜单选项 //例如:没有存储的wifi信息,那么savedNetworksExist为flase //例如:有存储的wifi信息,那么savedNetworksExist为true savedNetworksExist = !savedNetworksExist; if (context instanceof Activity) { ((Activity) context).invalidateOptionsMenu(); //刷新optionMenu } } for (WifiConfiguration config : configs) { //对配置过的信息进行遍历 if (config.selfAdded && config.numAssociation == 0) { // Number of time we associated to this configuration continue; //跳过本次循环 } AccessPoint accessPoint = new AccessPoint(context, config); if (lastInfo != null && lastNetworkInfo != null) { accessPoint.update(lastInfo, lastNetworkInfo); } accessPoints.add(accessPoint); //把ap加入List中 apMap.put(accessPoint.ssid, accessPoint); } } final List<ScanResult> results = wifiManager.getScanResults(); //wifi扫描结果的的处理 if (results != null) { for (ScanResult result : results) { //遍历扫描结果 // Ignore hidden and ad-hoc networks. //忽略隐藏的(没有SSID)以及ad-hoc(IBSS?) if (result.SSID == null || result.SSID.length() == 0 || result.capabilities.contains("[IBSS]")) { continue; } boolean found = false; //第一次的apMap中存放了配置过的信息 for (AccessPoint accessPoint : apMap.getAll(result.SSID)) { if (accessPoint.update(result)) //判断扫描结果ssid和security安全协议是否存在过,存在更新 found = true; } if (!found) { //未找到的情况下,加入accesspoints的 AccessPoint accessPoint = new AccessPoint(context, result); if (lastInfo != null && lastNetworkInfo != null) { accessPoint.update(lastInfo, lastNetworkInfo); } accessPoints.add(accessPoint); apMap.put(accessPoint.ssid, accessPoint); //放入apMap,再次遍历会调用 } } } // Pre-sort accessPoints to speed preference insertion Collections.sort(accessPoints); return accessPoints; }
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7.来了解一下所有的重写的方法:OptionsMenu:调用addOptionsMenuItems方法进行初始化
void addOptionsMenuItems(Menu menu) { //这里的通过wifi是否打开的状态设置menu中元素的enable状态
final boolean wifiIsEnabled = mWifiManager.isWifiEnabled(); TypedArray ta = getActivity().getTheme().obtainStyledAttributes( new int[] {R.attr.ic_menu_add, R.attr.ic_wps}); menu.add(Menu.NONE, MENU_ID_ADD_NETWORK, 0, R.string.wifi_add_network) .setIcon(ta.getDrawable(0)) .setEnabled(wifiIsEnabled) //增加网络,当wifi不可用的时候为false,不能点击 .setShowAsAction(MenuItem.SHOW_AS_ACTION_NEVER); if (savedNetworksExist) { menu.add(Menu.NONE, MENU_ID_SAVED_NETWORK, 0, R.string.wifi_saved_access_points_label) .setIcon(ta.getDrawable(0)) .setEnabled(wifiIsEnabled) //通过判断是否存在保存的网络,来决定显示与否 .setShowAsAction(MenuItem.SHOW_AS_ACTION_NEVER); } menu.add(Menu.NONE, MENU_ID_SCAN, 0, R.string.menu_stats_refresh) .setEnabled(wifiIsEnabled) .setShowAsAction(MenuItem.SHOW_AS_ACTION_NEVER);//刷新,通过判断wifi状态来决定是否能刷新 menu.add(Menu.NONE, MENU_ID_ADVANCED, 0, R.string.wifi_menu_advanced) .setShowAsAction(MenuItem.SHOW_AS_ACTION_NEVER); //高级选项 ta.recycle(); }
OptionMenuItems对应的点击事件为:onOptionsItemSelected,根据不同的item点开对应的dialog,当然,onCrateContextMenu中对应的点击事件为onContextItemSelected,根据不同的选项执行不同的操作。当然还有一些重写的方法,那就是生命周期的重写:如:
8.先执行构造方法,方法如下:
8.1 重写onActivityCreated(参数)
1.获得系统服务WifiManager
2.注册监听,connect,save,forget
3.savedInstanceState的状态判断,进行一些初始化
@Override
public void onActivityCreated(Bundle savedInstanceState) { super.onActivityCreated(savedInstanceState); //获得服务 mWifiManager = (WifiManager) getSystemService(Context.WIFI_SERVICE); //三种监听 mConnectListener = new WifiManager.ActionListener() { @Override public void onSuccess() { } @Override public void onFailure(int reason) { Activity activity = getActivity(); if (activity != null) { Toast.makeText(activity, R.string.wifi_failed_connect_message, Toast.LENGTH_SHORT).show(); } } }; mSaveListener = new WifiManager.ActionListener() { @Override public void onSuccess() { } @Override public void onFailure(int reason) { Activity activity = getActivity(); if (activity != null) { Toast.makeText(activity,R.string.wifi_failed_save_message, Toast.LENGTH_SHORT).show(); } } }; mForgetListener = new WifiManager.ActionListener() { @Override public void onSuccess() { } @Override public void onFailure(int reason) { Activity activity = getActivity(); if (activity != null) { Toast.makeText(activity, R.string.wifi_failed_forget_message, Toast.LENGTH_SHORT).show(); } } }; if (savedInstanceState != null) { mDlgEdit = savedInstanceState.getBoolean(SAVE_DIALOG_EDIT_MODE); if (savedInstanceState.containsKey(SAVE_DIALOG_ACCESS_POINT_STATE)) { mAccessPointSavedState = savedInstanceState.getBundle(SAVE_DIALOG_ACCESS_POINT_STATE); } } // if we're supposed to enable/disable the Next button based on our current connection // state, start it off in the right state Intent intent = getActivity().getIntent(); mEnableNextOnConnection = intent.getBooleanExtra(EXTRA_ENABLE_NEXT_ON_CONNECT, false); if (mEnableNextOnConnection) { if (hasNextButton()) { final ConnectivityManager connectivity = (ConnectivityManager) getActivity().getSystemService(Context.CONNECTIVITY_SERVICE); if (connectivity != null) { NetworkInfo info = connectivity.getNetworkInfo( ConnectivityManager.TYPE_WIFI); changeNextButtonState(info.isConnected()); } } } addPreferencesFromResource(R.xml.wifi_settings); mEmptyView = initEmptyView(); registerForContextMenu(getListView()); //这样会调用onCreateContextMenu(ContextMenu, View, ContextMenuInfo) 的方法 setHasOptionsMenu(true); //会调用onCreateOptionsMenu if (intent.hasExtra(EXTRA_START_CONNECT_SSID)) { String ssid = intent.getStringExtra(EXTRA_START_CONNECT_SSID); updateAccessPoints(); PreferenceScreen preferenceScreen = getPreferenceScreen(); for (int i = 0; i < preferenceScreen.getPreferenceCount(); i++) { Preference preference = preferenceScreen.getPreference(i); if (preference instanceof AccessPoint) { AccessPoint accessPoint = (AccessPoint) preference; if (ssid.equals(accessPoint.ssid) && accessPoint.networkId == -1 && accessPoint.security != AccessPoint.SECURITY_NONE) { onPreferenceTreeClick(preferenceScreen, preference); break; } } } } }
8.2 重写onstart(参数)
对WifiEnabler进行创建对象:主要是对switchbar进行操作
在wifiEnabler的构造方法中,加入intent-filter来接受广播
@Override
public void onStart() { super.onStart(); // On/off switch is hidden for Setup Wizard (returns null) mWifiEnabler = createWifiEnabler();}
8.3 重写onResume(参数)
做了三件事情:
1.加入switchbar的广播注册,加入switch的监听
2.WifiSettings注册广播
3.更新ap
@Override
public void onResume() { final Activity activity = getActivity(); super.onResume(); if (mWifiEnabler != null) { mWifiEnabler.resume(activity); } activity.registerReceiver(mReceiver, mFilter); updateAccessPoints();}
8.4 重写onPause(参数)
做了三件事:
1.wifiEnabler中解除广播注册,移出switch监听
2.WifiSettings移出广播
3.停止扫描移出scanner中的message
@Override
public void onPause() { super.onPause(); if (mWifiEnabler != null) { mWifiEnabler.pause(); } getActivity().unregisterReceiver(mReceiver); mScanner.pause();}
8.5 重写onDestroyView(参数)
1.隐藏switchbar:teardownSwitchbar()
@Override
public void onDestroyView() { super.onDestroyView(); if (mWifiEnabler != null) { mWifiEnabler.teardownSwitchBar(); } }