http://blog.csdn.net/DrakeBlue/article/details/39049495

 

Android系统在外接物理键盘的时候，可以在Settings的Language&Input设置中，将默认的输入设置设为软键盘还是物理键盘。

Android系统在检测到有外接USB键盘的时候，默认是启用物理键盘，而软键盘将会隐藏。如果需要启用软键盘，需要将物理键盘OFF掉。

现在，我们修改源代码，将这个物理键盘默认改为OFF。

通过Settings的代码，我们找到该Dialog是通过IIputMethodManager.aidl的showInputMethodPickerFromClient()方法通知另外的地方弹出的对话。

而showInputMethodPickerFromClient()方法的实现是在frameworks/base/services/java/com/android/server/InputMethodManagerService.java中。

1795行，方法//

@Override
    public void showInputMethodPickerFromClient(IInputMethodClient client) {
        synchronized (mMethodMap) {
            if (mCurClient == null || client == null
                    || mCurClient.client.asBinder() != client.asBinder()) {
                Slog.w(TAG, "Ignoring showInputMethodPickerFromClient of uid "
                        + Binder.getCallingUid() + ": " + client);
            }

            // Always call subtype picker, because subtype picker is a superset of input method
            // picker.
            mHandler.sendEmptyMessage(MSG_SHOW_IM_SUBTYPE_PICKER);
        }
    }

该Handler的处理在2050行;

@Override
    public boolean handleMessage(Message msg) {
        HandlerCaller.SomeArgs args;
        switch (msg.what) {
            case MSG_SHOW_IM_PICKER:
                showInputMethodMenu();
                return true;

            case MSG_SHOW_IM_SUBTYPE_PICKER:
                showInputMethodSubtypeMenu();
                return true;
            ......

            ......

继续跟踪showInputMethodSubtypeMenu()方法; 2317行

private void showInputMethodSubtypeMenu() {
        showInputMethodMenuInternal(true);
    }

最后找到关键方法showInputMethodMenuInternal(); 2344行;

这个方法主要是获取系统输入法，然后进行弹框显示。而我们的物理键盘默认设置看在下面代码片段中。

final Switch hardKeySwitch =  ((Switch)mSwitchingDialogTitleView.findViewById(
                    com.android.internal.R.id.hard_keyboard_switch));
            Log.d(TAG, "input isEnabled: " + mWindowManagerService.isHardKeyboardEnabled());     
            hardKeySwitch.setChecked(mWindowManagerService.isHardKeyboardEnabled());

hardKeySwitch.setOnCheckedChangeListener(
                    new OnCheckedChangeListener() {
                        @Override
                        public void onCheckedChanged(
                                CompoundButton buttonView, boolean isChecked) {
                            mWindowManagerService.setHardKeyboardEnabled(isChecked);
                        }
                    });

我们看到该Switch的Checked设置是在调用的WindowManagerService的一个boolean值的get方法。接着往里走

/frameworks/base/services/java/com/android/server/wm/WindowManagerService.java

关键代码：行6618 computeScreenConfigurationLocked()方法中

boolean hardKeyboardAvailable = config.keyboard != Configuration.KEYBOARD_NOKEYS;
            if (hardKeyboardAvailable != mHardKeyboardAvailable) {
                mHardKeyboardAvailable = hardKeyboardAvailable;
                mHardKeyboardEnabled = !hardKeyboardAvailable;
                mH.removeMessages(H.REPORT_HARD_KEYBOARD_STATUS_CHANGE);
                mH.sendEmptyMessage(H.REPORT_HARD_KEYBOARD_STATUS_CHANGE);
            }
            if (!mHardKeyboardEnabled) {
                config.keyboard = Configuration.KEYBOARD_NOKEYS;
            }

这里将会读取物理键盘是否可用，如果可用将会赋值给mHardKeyboardEnabled为true，然后hardKeySwitch set的值将会是这个可用的true，

我这里将hardKeyboardAvailable取反赋给mHardKeyboardEnabled。