Implement modifier keys settings UI.

Add four modifier keys and one reset button.

Bug: 244535460
Test: local test
Change-Id: I45822b0d8391022c17439dc25ab86fe022e9f43f

src/com/android/settings/inputmethod/ModifierKeysResetDialogFragment.java

@@ -0,0 +1,104 @@
+/*
+ * Copyright (C) 2022 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.settings.inputmethod;
+
+import static android.view.WindowManager.LayoutParams.TYPE_SYSTEM_DIALOG;
+
+import android.app.AlertDialog;
+import android.app.Dialog;
+import android.content.Context;
+import android.os.Bundle;
+import android.text.Spannable;
+import android.text.SpannableString;
+import android.text.style.ForegroundColorSpan;
+import android.view.LayoutInflater;
+import android.view.View;
+import android.view.Window;
+import android.widget.Button;
+
+import androidx.fragment.app.DialogFragment;
+import androidx.preference.Preference;
+import androidx.preference.PreferenceScreen;
+
+import com.android.settings.R;
+import com.android.settingslib.Utils;
+
+public class ModifierKeysResetDialogFragment extends DialogFragment {
+    private static final String MODIFIER_KEYS_CAPS_LOCK = "modifier_keys_caps_lock";
+    private static final String MODIFIER_KEYS_CTRL = "modifier_keys_ctrl";
+    private static final String MODIFIER_KEYS_META = "modifier_keys_meta";
+    private static final String MODIFIER_KEYS_ALT = "modifier_keys_alt";
+
+    private PreferenceScreen mScreen;
+    private String[] mKeys = {
+            MODIFIER_KEYS_CAPS_LOCK,
+            MODIFIER_KEYS_CTRL,
+            MODIFIER_KEYS_META,
+            MODIFIER_KEYS_ALT};
+
+    public ModifierKeysResetDialogFragment() {
+    }
+
+    public ModifierKeysResetDialogFragment(PreferenceScreen screen) {
+        mScreen = screen;
+    }
+
+    @Override
+    public Dialog onCreateDialog(Bundle savedInstanceState) {
+        super.onCreateDialog(savedInstanceState);
+        Context mContext = getActivity();
+        View dialoglayout =
+                LayoutInflater.from(mContext).inflate(R.layout.modifier_key_reset_dialog, null);
+        AlertDialog.Builder dialogBuilder = new AlertDialog.Builder(mContext);
+        dialogBuilder.setView(dialoglayout);
+        AlertDialog modifierKeyResetDialog = dialogBuilder.create();
+
+        Button restoreButton = dialoglayout.findViewById(R.id.modifier_key_reset_restore_button);
+        restoreButton.setOnClickListener(v -> {
+            resetToDefault();
+            modifierKeyResetDialog.dismiss();
+        });
+
+        Button cancelButton = dialoglayout.findViewById(R.id.modifier_key_reset_cancel_button);
+        cancelButton.setOnClickListener(v -> {
+            modifierKeyResetDialog.dismiss();
+        });
+
+        final Window window = modifierKeyResetDialog.getWindow();
+        window.setType(TYPE_SYSTEM_DIALOG);
+
+        return modifierKeyResetDialog;
+    }
+
+    private void resetToDefault() {
+        Context mContext = getActivity();
+        for (int i = 0; i < mKeys.length; i++) {
+            Preference preference = mScreen.findPreference(mKeys[i]);
+            Spannable title = new SpannableString(
+                    mContext.getString(R.string.modifier_keys_default_summary));
+            title.setSpan(
+                    new ForegroundColorSpan(getColorOfTextColorSecondary()),
+                    0, title.length(), 0);
+            preference.setSummary(title);
+        }
+        // TODO(b/252812993): clearAllModifierKeyRemappings()
+    }
+
+    private int getColorOfTextColorSecondary() {
+        return Utils.getColorAttrDefaultColor(getActivity(), android.R.attr.textColorSecondary);
+    }
+}