Android9.0 Wifi开启流程
摘要：Android9.0里wifi的框架做了一些变动，包括wifi开启流程，前面与8.0差不多，到了WifiServiceImpl后面就有了很大变动，网上大都是总结的8.0的流程，然而Android10.0都出来了，所以这里我把9.0里Wifi开启流程梳理一遍。
总体代码路径可以就是这样： WIfiEnabler->WifiManager->WifiService->WifiServiceImpl->WIfiStateMachinePrime->WIfiStateMachine->WifiNative
下面进入主题： 1、在wifisettings activity的onStart函数中，创建一个WifiEnabler对象，用于实现wifi开关功能 /packages/apps/Settings/src/com/android/settings/wifi/WifiSettings.java
public void onStart() {
super.onStart();
// On/off switch is hidden for Setup Wizard (returns null)
mWifiEnabler = createWifiEnabler();
if (mIsRestricted) {
restrictUi();
return;
}
onWifiStateChanged(mWifiManager.getWifiState());
} private WifiEnabler createWifiEnabler() {
final SettingsActivity activity = (SettingsActivity) getActivity();
return new WifiEnabler(activity, new SwitchBarController(activity.getSwitchBar()),
mMetricsFeatureProvider);
}2、 WifiEnabler实现了SwitchWidgetController.OnSwitchChangeListener接口，所以重写了SwitchToggled方法。 WifiEnabler开关SwitchToggled中会调用WifiManager.setWifiEnabled方法。 /packages/apps/Settings/src/com/android/settings/wifi/WifiEnabler.java
public boolean onSwitchToggled(boolean isChecked) {
//Do nothing if called as a result of a state machine event
if (mStateMachineEvent) {
return true;
}
// Show toast message if Wi-Fi is not allowed in airplane mode
if (isChecked && !WirelessUtils.isRadioAllowed(mContext, Settings.Global.RADIO_WIFI)) {
Toast.makeText(mContext, R.string.wifi_in_airplane_mode, Toast.LENGTH_SHORT).show();
// Reset switch to off. No infinite check/listener loop.
mSwitchWidget.setChecked(false);
return false;
}
if (isChecked) {
mMetricsFeatureProvider.action(mContext, MetricsEvent.ACTION_WIFI_ON);
} else {
// Log if user was connected at the time of switching off.
mMetricsFeatureProvider.action(mContext, MetricsEvent.ACTION_WIFI_OFF,
mConnected.get());
}
if (!mWifiManager.setWifiEnabled(isChecked)) {
// Error
mSwitchWidget.setEnabled(true);
Toast.makeText(mContext, R.string.wifi_error, Toast.LENGTH_SHORT).show();
}
return true;
}3、WifiManager调用WifiService的方法。 /frameworks/base/wifi/java/android/net/wifi/WifiManager.java
public boolean setWifiEnabled(boolean enabled) {
try {
return mService.setWifiEnabled(mContext.getOpPackageName(), enabled);
} catch (RemoteException e) {
throw e.rethrowFromSystemServer();
}
}4、WiFiManager.aidl中写了setWifiEnabled()方法。 /frameworks/base/wifi/java/android/net/wifi/IWifiManager.aidl
boolean setWifiEnabled(String packageName, boolean enable);5、WifiServiceImpl中实现WifiManager的方法，在setWifiEnabled函数中向WifiStateMachinePrime发消息：CMD_WIFI_TOGGLED. /frameworks/opt/net/wifi/service/java/com/android/server/wifi/WifiServiceImpl.java
public synchronized boolean setWifiEnabled(String packageName, boolean enable)
throws RemoteException {
if (enforceChangePermission(packageName) != MODE_ALLOWED) {
return false;
}
.........
mWifiController.sendMessage(CMD_WIFI_TOGGLED);
return true;
}6、WifiStateMachinePrime对CMD_WIFI_TOGGLED消息进行处理，切换到DeviceActiveState状态
/frameworks/opt/net/wifi/service/java/com/android/server/wifi/WifiStateMachinePrime.java
class StaDisabledState extends State {
@Override
public boolean processMessage(Message msg) {
switch (msg.what) {
case CMD_WIFI_TOGGLED:
if (mSettingsStore.isWifiToggleEnabled()) {
if (doDeferEnable(msg)) {
if (mHaveDeferredEnable) {
// have 2 toggles now, inc serial number and ignore both
mDeferredEnableSerialNumber++;
}
mHaveDeferredEnable = !mHaveDeferredEnable;
break;
}
transitionTo(mDeviceActiveState);进入DeviceActiveState
class DeviceActiveState extends State {
@Override
public void enter() {
mWifiStateMachinePrime.enterClientMode();
mWifiStateMachine.setHighPerfModeEnabled(false);
}执行enterClientMode函数，给ModeStateMachine状态机发送CMD_START_CLIENT_MODE消息
public void enterClientMode() {
changeMode(ModeStateMachine.CMD_START_CLIENT_MODE);
}下面我们看ModeStateMachine对CMD_START_CLIENT_MODE的处理
private class ModeStateMachine extends StateMachine {
private boolean checkForAndHandleModeChange(Message message) {
switch(message.what) {
case ModeStateMachine.CMD_START_CLIENT_MODE:
Log.d(TAG, "Switching from " + getCurrentMode() + " to ClientMode");
mModeStateMachine.transitionTo(mClientModeActiveState);
break;然后我们看ClientModeActiveState的处理
class ClientModeActiveState extends ModeActiveState {
@Override
public void enter() {
Log.d(TAG, "Entering ClientModeActiveState");
mListener = new ClientListener();
mManager = mWifiInjector.makeClientModeManager(mListener);
mManager.start();
mActiveModeManagers.add(mManager);
updateBatteryStatsWifiState(true);
}7、ClientModeManager里首先是调用了start函数，如何发送消息CMD_START，消息是IdleState进行处理。 /frameworks/opt/net/wifi/service/java/com/android/server/wifi/ClientModeManager.java
public void start() {
mStateMachine.sendMessage(ClientModeStateMachine.CMD_START);
}我们看IdleState对CMD_START的处理方式：可以看到调用了wifinative的setupInterfaceForClientMode方法
private class IdleState extends State {
@Override
public boolean processMessage(Message message) {
switch (message.what) {
case CMD_START:
updateWifiState(WifiManager.WIFI_STATE_ENABLING,
WifiManager.WIFI_STATE_DISABLED);
mClientInterfaceName = mWifiNative.setupInterfaceForClientMode( //调用了wifinative的setupInterfaceForClientMode方法
false /* not low priority */, mWifiNativeInterfaceCallback);
if (TextUtils.isEmpty(mClientInterfaceName)) {
Log.e(TAG, "Failed to create ClientInterface. Sit in Idle");
updateWifiState(WifiManager.WIFI_STATE_UNKNOWN,
WifiManager.WIFI_STATE_ENABLING);
updateWifiState(WifiManager.WIFI_STATE_DISABLED,
WifiManager.WIFI_STATE_UNKNOWN);
break;
return HANDLED;
}
}8、下面我们看wifinative的setupInterfaceForClientMode方法
/frameworks/opt/net/wifi/service/java/com/android/server/wifi/WifiNative.java 我们看setupInterfaceForClientMode的相应处理，可以看到调用了startSupplicant函数
public String setupInterfaceForClientMode(boolean lowPrioritySta,
@NonNull InterfaceCallback interfaceCallback) {
if (!startHal()) {
Log.e(TAG, "Failed to start Hal");
mWifiMetrics.incrementNumSetupClientInterfaceFailureDueToHal();
return null;
}
if (!startSupplicant()) {
Log.e(TAG, "Failed to start supplicant");
mWifiMetrics.incrementNumSetupClientInterfaceFailureDueToSupplicant();
return null;
}
}启动supplicant
private boolean startSupplicant() {
synchronized (mLock) {
if (!mIfaceMgr.hasAnyStaIface()) {
if (!mWificondControl.enableSupplicant()) {
Log.e(TAG, "Failed to enable supplicant");
return false;
}
}总结：Android9.0与8.0相比，Wifi主要是多了WifiStateMachinePrime（状态机的前处理机制），wifiService不在直接与WifiStateMachine交互，而是通过WifiStateMachinePrime进行处理，再送往WifiStateMachine，中间多了一层ClientModeManager，在这里面进行初始化wpa_supplicant工作。
腾讯云开发者
