android9:wifi开关打开流程（一）

背景：查看Android9原生系统设置WiFi源码，查看WiFi开关打开工作流程。
借鉴：https://blog.csdn.net/weixin_42093428/article/details/80822632?utm_medium=distribute.pc_relevant_t0.none-task-blog-BlogCommendFromMachineLearnPai2-1.nonecase&depth_1-utm_source=distribute.pc_relevant_t0.none-task-blog-BlogCommendFromMachineLearnPai2-1.nonecase
一、框架
1、应用层
/packages/apps/Settings/src/com/android/settings/wifi

2、java框架层
/frameworks/base/wifi/java/android/net/wifi
/frameworks/opt/net/wifi/service/java/com/android/server/wifi

3、HIDL层
Wifi到AndoidO之后不再使用jni，所以AndroidP也一样不再使用jni来实现Java代码与本地的C/C++代码交互，而是使用HIDL，Hardware Interface Define Language。
/hardware/interfaces/wifi

4、WPA适配层(硬件抽象层 HAL)
/frameworks/opt/net/wifi/libwifi_hal

5、wpa_supplicant
/external/wpa_supplicant_8

6、Linux Kernel（路径应该不对，后面再看）
kernel/driver/net/wireless/
vendor/gcom/opensource/wlan/

二、启动流程：
wifi服务在SystemService中启动，源码路径：
frameworks/base/services/java/com/android/server/SystemServer.java
先从打开开关入手：
（1）WifiSettings.java WiFi开关入口
/packages/apps/Settings/src/com/android/settings/wifi/WifiSettings.java

@Override
    public void onStart() {
        super.onStart();
        // On/off switch is hidden for Setup Wizard (returns null)
        mWifiEnabler = createWifiEnabler();
    }
    private WifiEnabler createWifiEnabler() {
        final SettingsActivity activity = (SettingsActivity) getActivity();
        return new WifiEnabler(activity, new SwitchBarController(activity.getSwitchBar()),
            mMetricsFeatureProvider);
    }

(2)WifiEnabler.java重写onSwitchToggled（）方法
/packages/apps/Settings/src/com/android/settings/wifi/WifiEnabler.java

@Override
    public boolean onSwitchToggled(boolean isChecked) {
    if (!mWifiManager.setWifiEnabled(isChecked)) {
            // Error
            mSwitchWidget.setEnabled(true);
            Toast.makeText(mContext, R.string.wifi_error, Toast.LENGTH_SHORT).show();
        }
        return true;
    }

（3）WifiManager.java 调用Wifiservice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）IWifiManager.java 声明setWifiEnabled()方法
/frameworks/base/wifi/java/android/net/wifi/IWifiManager.aidl

boolean setWifiEnabled(String packageName, boolean enable);

（5）WifiServiceImpl.java setWifiEnabled()方法得实现
/frameworks/opt/net/wifi/service/java/com/android/server/wifi/WifiServiceImpl.java

 @Override
    public synchronized boolean setWifiEnabled(String packageName, boolean enable)
            throws RemoteException {
            mWifiController.sendMessage(CMD_WIFI_TOGGLED);
        return true;
    }

（5）WifiController.java，处理CMD_WIFI_TOGGLED消息
/frameworks/opt/net/wifi/service/java/com/android/server/wifi/WifiController.java

class StaDisabledState extends State {
@Override
        public boolean processMessage(Message msg) {
            switch (msg.what) {
                case CMD_WIFI_TOGGLED:
                   //切换到DeviceActiveState状态
                   transitionTo(mDeviceActiveState);
                break;
            }
}

class DeviceActiveState extends State {
        @Override
        public void enter() {
            mWifiStateMachinePrime.enterClientMode();
            mWifiStateMachine.setHighPerfModeEnabled(false);
        }
      }

（6）WifiStateMachinePrime.java,enterClientMode()方法给ModeStateMachine状态机发送CMD_START_CLIENT_MODE消息
/frameworks/opt/net/wifi/service/java/com/android/server/wifi/WifiStateMachinePrime.java

public void enterClientMode() {
        changeMode(ModeStateMachine.CMD_START_CLIENT_MODE);
    }
    
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;
                }
}

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）WifiInjector.Java
/frameworks/opt/net/wifi/service/java/com/android/server/wifi/WifiStateMachinePrime.java

public ClientModeManager makeClientModeManager(ClientModeManager.Listener listener) {
        return new ClientModeManager(mContext, mWifiStateMachineHandlerThread.getLooper(),
                mWifiNative, listener, mWifiMetrics, mScanRequestProxy, mWifiStateMachine);
    }

（8）ClientModeManager.java ,调用start函数，发送CMD_START消息
/frameworks/opt/net/wifi/service/java/com/android/server/wifi/ClientModeManager.java

/**
     * Start client mode.
     */
    public void start() {
        mStateMachine.sendMessage(ClientModeStateMachine.CMD_START);
    }

 private class IdleState extends State {
 @Override
            public boolean processMessage(Message message) {
                switch (message.what) {
                    case CMD_START:
                    //调用wifi native 方法
                       mClientInterfaceName = mWifiNative.setupInterfaceForClientMode(
                                false /* not low priority */, mWifiNativeInterfaceCallback);
                    break;
                 }
           }
 }

（9）WifiNative.java ,启动Supplicant
/frameworks/opt/net/wifi/service/java/com/android/server/wifi/ClientModeManager.java

public String setupInterfaceForClientMode(boolean lowPrioritySta,
            @NonNull InterfaceCallback interfaceCallback) {
             if (!startSupplicant()) {
                Log.e(TAG, "Failed to start supplicant");
                mWifiMetrics.incrementNumSetupClientInterfaceFailureDueToSupplicant();
                return null;
            }
            }