PreferenceCategory.java

/*
 * Copyright (C) 2015 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 android.support.v7.preference;

import android.content.Context;
import android.support.v4.content.res.TypedArrayUtils;
import android.support.v4.view.accessibility.AccessibilityNodeInfoCompat;
import android.support.v4.view.accessibility.AccessibilityNodeInfoCompat.CollectionItemInfoCompat;
import android.util.AttributeSet;

/**
 * Used to group {@link Preference} objects and provide a disabled title above
 * the group.
 *
 * <div class="special reference">
 * <h3>Developer Guides</h3>
 * <p>For information about building a settings UI with Preferences,
 * read the <a href="{@docRoot}guide/topics/ui/settings.html">Settings</a>
 * guide.</p>
 * </div>
 */
public class PreferenceCategory extends PreferenceGroup {
    private static final String TAG = "PreferenceCategory";

    public PreferenceCategory(
            Context context, AttributeSet attrs, int defStyleAttr, int defStyleRes) {
        super(context, attrs, defStyleAttr, defStyleRes);
    }

    public PreferenceCategory(Context context, AttributeSet attrs, int defStyleAttr) {
        this(context, attrs, defStyleAttr, 0);
    }

    public PreferenceCategory(Context context, AttributeSet attrs) {
        this(context, attrs, TypedArrayUtils.getAttr(context, R.attr.preferenceCategoryStyle,
                android.R.attr.preferenceCategoryStyle));
    }

    public PreferenceCategory(Context context) {
        this(context, null);
    }

    @Override
    protected boolean onPrepareAddPreference(Preference preference) {
        if (preference instanceof PreferenceCategory) {
            throw new IllegalArgumentException(
                    "Cannot add a " + TAG + " directly to a " + TAG);
        }

        return super.onPrepareAddPreference(preference);
    }

    @Override
    public boolean isEnabled() {
        return false;
    }

    @Override
    public boolean shouldDisableDependents() {
        return !super.isEnabled();
    }

    @Override
    public void onInitializeAccessibilityNodeInfo(AccessibilityNodeInfoCompat info) {
        super.onInitializeAccessibilityNodeInfo(info);

        CollectionItemInfoCompat existingItemInfo = info.getCollectionItemInfo();
        if (existingItemInfo == null) {
            return;
        }

        final CollectionItemInfoCompat newItemInfo = CollectionItemInfoCompat.obtain(
                existingItemInfo.getRowIndex(),
                existingItemInfo.getRowSpan(),
                existingItemInfo.getColumnIndex(),
                existingItemInfo.getColumnSpan(),
                true /* heading */,
                existingItemInfo.isSelected());
        info.setCollectionItemInfo(newItemInfo);
    }
}