當系統的語言改變時，選擇的輸入法會變成默認輸入法：
實現的過程在：InputMethodManagerService.java中的：
mContext.registerReceiver(// 這里對語言改變廣播的監聽。
??????????????? new BroadcastReceiver() {
??????????????????? @Override
??????????????????? public void onReceive(Context context, Intent intent) {
??????????????????????? synchronized(mMethodMap) {
??????????????????????????? checkCurrentLocaleChangedLocked();//當接收到語言改變發送的廣播時執行方法
??????????????????????? }
??????????????????? }
??????????????? }, filter);
?????? ?
在checkCurrentLocaleChangedLocked()方法中：
有個updateFromSettingsLocked()方法
updateFromSettingsLocked()這個方法：
?? void updateFromSettingsLocked() {
??????? // We are assuming that whoever is changing DEFAULT_INPUT_METHOD and
??????? // ENABLED_INPUT_METHODS is taking care of keeping them correctly in
??????? // sync, so we will never have a DEFAULT_INPUT_METHOD that is not
??????? // enabled.
??????? String id = Settings.Secure.getString(mContext.getContentResolver(),
??????????????? Settings.Secure.DEFAULT_INPUT_METHOD);//獲取默認輸入法
??????? // There is no input method selected, try to choose new applicable input method.
??????? if (TextUtils.isEmpty(id) && chooseNewDefaultIMELocked()) {
??????????? id = Settings.Secure.getString(mContext.getContentResolver(),
??????????????????? Settings.Secure.DEFAULT_INPUT_METHOD);
??????? }
??????? if (!TextUtils.isEmpty(id)) {
??????????? try {
??????????????? setInputMethodLocked(id, getSelectedInputMethodSubtypeId(id));//設置當前輸入法為默認輸入法。
??????????? } catch (IllegalArgumentException e) {
??????????????? Slog.w(TAG, "Unknown input method from prefs: " + id, e);
??????????????? mCurMethodId = null;
??????????????? unbindCurrentMethodLocked(true);
??????????? }
??????????? mShortcutInputMethodsAndSubtypes.clear();
??????? } else {
??????????? // There is no longer an input method set, so stop any current one.
??????????? mCurMethodId = null;
??????????? unbindCurrentMethodLocked(true);
??????? }
??? }

系統語言改變時，輸入法變成默認輸入法分析