Android源码开发笔记 软键盘与内置物理键盘共存以及外接蓝牙键盘不共存逻辑

需求1： android设备自带九键的小键盘，此时小键盘被识别为HW Keyboard，默认与软键盘不能共存，需要使软键盘与物理键盘共存。

实现：

在网上找的别人总结的Android5.1的解决方法，需要解决的codebase为Android6.0，都可以用。

方法一：（此方法在Android8.0 codebase已不可用） frameworks/base/services/core/java/com/android/server/wm/WindowManagerService.java中，如果把updateShowImeWithHardKeyboard()方法中的showImeWithHardKeyboard变量直接置为true，则可以实现软键盘与物理键盘的同时使用。（原本为读取Setting数据库字段来判断，所以也可以直接修改Setting字段来实现）

    public void updateShowImeWithHardKeyboard() {
        synchronized (mWindowMap) {
            final boolean showImeWithHardKeyboard = Settings.Secure.getIntForUser(
                        mContext.getContentResolver(), Settings.Secure.SHOW_IME_WITH_HARD_KEYBOARD, 0,
                        mCurrentUserId) == 1;if (mShowImeWithHardKeyboard != showImeWithHardKeyboard) {
                mShowImeWithHardKeyboard = showImeWithHardKeyboard;
                mH.sendEmptyMessage(H.SEND_NEW_CONFIGURATION);
            }
        }
    }

方法二：frameworks/base/core/java/android/inputmethodservice/InputMethodService.java，修改onEvaluateInputViewShown()方法直接返回true

public boolean onEvaluateInputViewShown() {
    Configuration config = getResources().getConfiguration();
    //return config.keyboard == Configuration.KEYBOARD_NOKEYS
    //      || config.hardKeyboardHidden == Configuration.HARDKEYBOARDHIDDEN_YES;
    return  true;
}

方法三：在外部需要修改的合适位置，直接将Setting字段修改掉，随时可以改回来，一劳永逸。

Settings.Secure.putInt(mContext.getContentResolver(), Settings.Secure.SHOW_IME_WITH_HARD_KEYBOARD, 1);// 1: Disabled,0: Enabled

 默认共存的话，其实最好的是修改frameworks/base/packages/SettingsProvider/res/values/default.xml

<!-- Default for Settings.Secure.SHOW_IME_WITH_HARD_KEYBOARD -->
<bool name="def_show_ime_with_hard_keyboard">false</bool>

需求2：软键盘与内置物理键盘共存基础上，再外接蓝牙键盘。此时外接蓝牙键盘与软键盘不可共存。

分析：此时外接键盘也被视为物理键盘，按照上面需求1的方法修改后，使蓝牙键盘与软键盘是共存的，所以不符合需求。需要找到蓝牙键盘连接上的位置，来把前面需求1改的地方取消掉。

即：未连接蓝牙键盘时，将Setting字段改为共存模式，使软键盘与内置物理键盘共存；连接蓝牙键盘后，将Setting字段改为不共存模式，使软键盘与蓝牙键盘不共存（此时蓝牙键盘与内置物理键盘是共存的）。

实现：本需求的难点为找到恰当的位置来修改Setting字段，此恰当位置为：蓝牙键盘连接成功或断开，以及蓝牙关闭。

实现分析流程：

1. 通过Settings中Bluetooth Settings部分可以看到，连接蓝牙键盘时，蓝牙设备的类型已经可以通过图标区分出来。这样就不用怀疑是否能够区分蓝牙键盘和其他蓝牙设备了。

在packages/apps/Settings/src/com/android/settings/bluetooth/BluetoothDevicePreference.java中根据icon可以看到，不同种类的BT device已经可以区分了。

private int getBtClassDrawable() {
        BluetoothClass btClass = mCachedDevice.getBtClass();
        if (btClass != null) {
            switch (btClass.getMajorDeviceClass()) {
                case BluetoothClass.Device.Major.COMPUTER:
                    return R.drawable.ic_bt_laptop;

                case BluetoothClass.Device.Major.PHONE:
                    return R.drawable.ic_bt_cellphone;

                case BluetoothClass.Device.Major.PERIPHERAL:
                    return HidProfile.getHidClassDrawable(btClass);

                case BluetoothClass.Device.Major.IMAGING:
                    return R.drawable.ic_bt_imaging;

                default:
                    // unrecognized device class; continue
            }
        } else {
            Log.w(TAG, "mBtClass is null");
        }
...

需要的蓝牙键盘在 HidProfile.getHidClassDrawable(btClass)获得。

frameworks/base/packages/SettingsLib/src/com/android/settingslib/bluetooth/HidProfile.java

public static int getHidClassDrawable(BluetoothClass btClass) {
        switch (btClass.getDeviceClass()) {
            case BluetoothClass.Device.PERIPHERAL_KEYBOARD:
            case BluetoothClass.Device.PERIPHERAL_KEYBOARD_POINTING:
                return R.drawable.ic_lockscreen_ime;
            case BluetoothClass.Device.PERIPHERAL_POINTING:
                return R.drawable.ic_bt_pointing_hid;
            default:
                return R.drawable.ic_bt_misc_hid;
        }
    }

 2. 通过抓系统蓝牙profile log来确认断开连接蓝牙键盘时，会在framework里面的Bluetooth的哪边被trigger到。

adb logcat |grep Profile

在连接/断开蓝牙键盘时，可以抓到下面的log：

kunkka@kunkka-Lenovo:~$ adb logcat |grep Profile
12-22 03:55:00.524  1257  1257 I SystemServer: SamplingProfiler Service
12-22 04:29:41.923  3916  4051 D CachedBluetoothDevice: onProfileStateChanged: profile HID newProfileState 0
12-22 06:25:59.666  7284  7284 D CachedBluetoothDevice: onProfileStateChanged: profile HID newProfileState 2
12-22 06:25:59.668  3916  4051 D CachedBluetoothDevice: onProfileStateChanged: profile HID newProfileState 2
12-22 06:26:33.245  7284  7284 D CachedBluetoothDevice: onProfileStateChanged: profile HID newProfileState 0
12-22 06:26:33.245  3916  4051 D CachedBluetoothDevice: onProfileStateChanged: profile HID newProfileState 0
12-22 06:26:45.586  7284  7284 D CachedBluetoothDevice: onProfileStateChanged: profile HID newProfileState 2
12-22 06:26:45.587  3916  4051 D CachedBluetoothDevice: onProfileStateChanged: profile HID newProfileState 2
...

可以定位到frameworks/base/packages/SettingsLib/src/com/android/settingslib/bluetooth/CachedBluetoothDevice.java

在onProfileStateChanged方法中可以看到，蓝牙连接和断开时都可以走到！而且去获得蓝牙设备类型的context也都有！这样问题解决一大半！

在onProfileStateChanged方法中添加蓝牙连接和断开时的设备类型判断：

            if(mBtClass.getMajorDeviceClass() == BluetoothClass.Device.Major.PERIPHERAL
                    && (mBtClass.getDeviceClass() == BluetoothClass.Device.PERIPHERAL_KEYBOARD
                    || mBtClass.getDeviceClass() == BluetoothClass.Device.PERIPHERAL_KEYBOARD_POINTING)) {
                Log.i("Kunkka0", "getMajorDeviceClass = Peripheral & getDeviceClass = KeyBoard");
                if(newProfileState == 0) {// Disconnected
                    Log.i("Kunkka0","SET SHOW_IME_WITH_HARD_KEYBOARD TO 1");
                    Settings.Secure.putInt(mContext.getContentResolver(), Settings.Secure.SHOW_IME_WITH_HARD_KEYBOARD, 1);
                }else {
                    Log.i("Kunkka0","SET SHOW_IME_WITH_HARD_KEYBOARD TO 0");
                    Settings.Secure.putInt(mContext.getContentResolver(), Settings.Secure.SHOW_IME_WITH_HARD_KEYBOARD, 0);
                }
            }else {
                Log.i("Kunkka0","getMajorDeviceClass() = "+mBtClass.getMajorDeviceClass()+", getDeviceClass = "+mBtClass.getDeviceClass());
                Log.i("Kunkka0","PERIPHERAL = 1280, PERIPHERAL_KEYBOARD = 1344, PERIPHERAL_KEYBOARD_POINTING = 1472");
            }

加完编译出image来测试，功能实现！

但是，在关闭蓝牙时，蓝牙键盘就不能用了，但是此处不能收到状态变化！此时，关闭蓝牙，软键盘和蓝牙键盘都不能用了！

3. 为了解决关闭蓝牙时的问题，再去搜索蓝牙开关状态变化的事件：

在frameworks/base/packages/SettingsLib/src/com/android/settingslib/bluetooth/BluetoothCallback.java中可以看到有：

    void onBluetoothStateChanged(int bluetoothState);
    void onScanningStateChanged(boolean started);
    void onDeviceAdded(CachedBluetoothDevice cachedDevice);
    void onDeviceDeleted(CachedBluetoothDevice cachedDevice);
    void onDeviceBondStateChanged(CachedBluetoothDevice cachedDevice, int bondState);
    void onConnectionStateChanged(CachedBluetoothDevice cachedDevice, int state);

查看所有重载此事件的class，Open implementation-可以看到：

下面几个都是Settings中的，但我们的需求不止在Settings中，所以看上面KeyboardUI和systemui下面的statusbar。

StatusBar下面的BluetoothControllerImpl比较符合。

打开frameworks/base/packages/SystemUI/src/com/android/systemui/statusbar/policy/BluetoothControllerImpl.java

除了onBluetoothStateChanged外还有个updateConnected()方法，居然也可以侦测蓝牙设备连接状态！

所以我们只需要在onBluetoothStateChanged()和updateConnected()中都加入事件侦测来修改Settings字段就可以了！

4. 最终解决办法：

a. 在onBluetoothStateChanged()中，当蓝牙关闭时，使键盘共存，保证软键盘和内置物理键盘的共存。

    @Override
    public void onBluetoothStateChanged(int bluetoothState) {
        mEnabled = bluetoothState == BluetoothAdapter.STATE_ON;
    
        if(!mEnabled) {
            Log.i("Kunkka0","onBluetoothStateChanged: SET SHOW_IME_WITH_HARD_KEYBOARD TO 1");
            Settings.Secure.putInt(mContext.getContentResolver(), Settings.Secure.SHOW_IME_WITH_HARD_KEYBOARD, 1);
        }

        mHandler.sendEmptyMessage(H.MSG_STATE_CHANGED);
    }

b. 在updateConnected()中，当蓝牙键盘连接时，使软硬键盘不共存，蓝牙键盘断开时，使软硬件盘共存。

private void updateConnected() {
        ...
        for (CachedBluetoothDevice device : getDevices()) {
            if (device.isConnected()) {
                mLastDevice = device;
            }

            if(device.getBtClass().getMajorDeviceClass() == BluetoothClass.Device.Major.PERIPHERAL
                    && (device.getBtClass().getDeviceClass() == BluetoothClass.Device.PERIPHERAL_KEYBOARD
                    || device.getBtClass().getDeviceClass() == BluetoothClass.Device.PERIPHERAL_KEYBOARD_POINTING)) {
                Log.i("Kunkka0", "getMajorDeviceClass = Peripheral & getDeviceClass = KeyBoard");
                if(!device.isConnected()) {// Disconnected
                    Log.i("Kunkka0","SET SHOW_IME_WITH_HARD_KEYBOARD TO 1");
                    Settings.Secure.putInt(mContext.getContentResolver(), Settings.Secure.SHOW_IME_WITH_HARD_KEYBOARD, 1);
                }else {
                    Log.i("Kunkka0","SET SHOW_IME_WITH_HARD_KEYBOARD TO 0");
                    Settings.Secure.putInt(mContext.getContentResolver(), Settings.Secure.SHOW_IME_WITH_HARD_KEYBOARD, 0);
                }
            }else {
                Log.i("Kunkka0","getMajorDeviceClass() = "+device.getBtClass().getMajorDeviceClass()+", getDeviceClass = "+device.getBtClass().getDeviceClass());
                Log.i("Kunkka0","PERIPHERAL = 1280, PERIPHERAL_KEYBOARD = 1344, PERIPHERAL_KEYBOARD_POINTING = 1472");
            }
            
        }
        ...
    }

测试，验证通过！