Android 4.2 Wifi Display之Settings源码分析（二）

首先，回顾下应用层，当用户在搜寻完设备后，可以选择设备进行连接，当然正在进行连接或已经连接配对的设备，再次点击配置后，会弹出对话框供用户选择断开连接。
packages/apps/Settings/src/com/android/settings/wfd/WifiDisplaySettings.java
public boolean onPreferenceTreeClick(PreferenceScreen preferenceScreen,
            Preference preference) {
        if (preference instanceof WifiDisplayPreference) {
            WifiDisplayPreference p = (WifiDisplayPreference)preference;
            WifiDisplay display = p.getDisplay();

            if (display.equals(mWifiDisplayStatus.getActiveDisplay())) {
                showDisconnectDialog(display);
            } else {
                mDisplayManager.connectWifiDisplay(display.getDeviceAddress());
            }
        }

        return super.onPreferenceTreeClick(preferenceScreen, preference);
    }
如同设备发现的调用流程，当用户选择设备进行连接后，程序会调用DisplayManager的connectWifiDisplay()函数接口。该函数会进一步根据DisplayManagerGlobal提供的单实例对象调用AIDL提供的接口函数connectWifiDisplay()，这又是上一回已经提到过的调用模式。其实际的调用实现是Displaymanager service中提供的connectWifiDisplay()函数，
frameworks/base/services/java/com/android/server/display/DisplayManagerService.java
public void connectWifiDisplay(String address) {
        if (address == null) {
            throw new IllegalArgumentException("address must not be null");
        }

        final boolean trusted = canCallerConfigureWifiDisplay();
        final long token = Binder.clearCallingIdentity();
        try {
            synchronized (mSyncRoot) {
                if (mWifiDisplayAdapter != null) {
                    mWifiDisplayAdapter.requestConnectLocked(address, trusted);
                }
            }
        } finally {
            Binder.restoreCallingIdentity(token);
        }
    }

   到此，我们容易发现连接WifiDisplay设备的函数调用流程与发现设备的流程一致，这里将不做多余解释（详见），在此会罗列出之后的基本流程。
frameworks/base/services/java/com/android/server/display/WifiDisplayAdapter.java
public void requestConnectLocked(final String address, final boolean trusted) {
        if (DEBUG) {
            Slog.d(TAG, "requestConnectLocked: address=" + address + ", trusted=" + trusted);
        }

        if (!trusted) {
            synchronized (getSyncRoot()) {
                if (!isRememberedDisplayLocked(address)) {   //如果设备地址不在保存列表中则忽略不做处理
                   ...
                    return;
                }
            }
        }

        getHandler().post(new Runnable() {
            @Override
            public void run() {
                if (mDisplayController != null) {
                    mDisplayController.requestConnect(address);
                }
            }
        });
    }

frameworks/base/services/java/com/android/server/display/WifiDisplayController.java
public void requestConnect(String address) {
        for (WifiP2pDevice device : mAvailableWifiDisplayPeers) {
            if (device.deviceAddress.equals(address)) {
                connect(device);
            }
        }
    }

    private void connect(final WifiP2pDevice device) {
        if (mDesiredDevice != null
                && !mDesiredDevice.deviceAddress.equals(device.deviceAddress)) { //如果设备已经正在连接则返回
            if (DEBUG) {
               ...
            }
            return;
        }

        if (mConnectedDevice != null
                && !mConnectedDevice.deviceAddress.equals(device.deviceAddress)
                && mDesiredDevice == null) {//如果设备已经连接则返回
            if (DEBUG) {
                 ...
            }
            return;
        }

mDesiredDevice = device;
mConnectionRetriesLeft = CONNECT_MAX_RETRIES

补充：移动开发 , Android ,