xref: /frameworks/base/core/java/android/widget/Toolbar.java

/*
 * Copyright (C) 2014 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.widget;

import android.annotation.NonNull;
import android.content.Context;
import android.content.res.TypedArray;
import android.graphics.drawable.Drawable;
import android.os.Parcel;
import android.os.Parcelable;
import android.text.TextUtils;
import android.util.AttributeSet;
import android.view.Gravity;
import android.view.Menu;
import android.view.MenuInflater;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewDebug;
import android.view.ViewGroup;
import com.android.internal.R;

import java.util.ArrayList;
import java.util.List;

/**
 * A standard toolbar for use within application content.
 *
 * <p>A Toolbar is a generalization of {@link android.app.ActionBar action bars} for use
 * within application layouts. While an action bar is traditionally part of an
 * {@link android.app.Activity Activity's} opaque window decor controlled by the framework,
 * a Toolbar may be placed at any arbitrary level of nesting within a view hierarchy.
 * An application may choose to designate a Toolbar as the action bar for an Activity
 * using the {@link android.app.Activity#setActionBar(Toolbar) setActionBar()} method.</p>
 *
 * <p>Toolbar supports a more focused feature set than ActionBar. From start to end, a toolbar
 * may contain a combination of the following optional elements:
 *
 * <ul>
 *     <li><em>A navigation button.</em> This may be an Up arrow, navigation menu toggle, close,
 *     collapse, done or another glyph of the app's choosing. This button should always be used
 *     to access other navigational destinations within the container of the Toolbar and
 *     its signified content or otherwise leave the current context signified by the Toolbar.</li>
 *     <li><em>A branded logo image.</em> This may extend to the height of the bar and can be
 *     arbitrarily wide.</li>
 *     <li><em>A title and subtitle.</em> The title should be a signpost for the Toolbar's current
 *     position in the navigation hierarchy and the content contained there. The subtitle,
 *     if present should indicate any extended information about the current content.
 *     If an app uses a logo image it should strongly consider omitting a title and subtitle.</li>
 *     <li><em>One or more custom views.</em> The application may add arbitrary child views
 *     to the Toolbar. They will appear at this position within the layout. If a child view's
 *     {@link LayoutParams} indicates a {@link Gravity} value of
 *     {@link Gravity#CENTER_HORIZONTAL CENTER_HORIZONTAL} the view will attempt to center
 *     within the available space remaining in the Toolbar after all other elements have been
 *     measured.</li>
 *     <li><em>An {@link ActionMenuView action menu}.</em> The menu of actions will pin to the
 *     end of the Toolbar offering a few
 *     <a href="http://developer.android.com/design/patterns/actionbar.html#ActionButtons">
 *         frequent, important or typical</a> actions along with an optional overflow menu for
 *         additional actions.</li>
 * </ul>
 * </p>
 *
 * <p>In modern Android UIs developers should lean more on a visually distinct color scheme for
 * toolbars than on their application icon. The use of application icon plus title as a standard
 * layout is discouraged on API 21 devices and newer.</p>
 */
public class Toolbar extends ViewGroup {
    private ActionMenuView mMenuView;
    private TextView mTitleTextView;
    private TextView mSubtitleTextView;
    private ImageButton mNavButtonView;
    private ImageView mLogoView;

    private int mTitleTextAppearance;
    private int mSubtitleTextAppearance;
    private int mTitleMarginStart;
    private int mTitleMarginEnd;
    private int mTitleMarginTop;
    private int mTitleMarginBottom;

    private int mGravity = Gravity.START | Gravity.CENTER_VERTICAL;

    private CharSequence mTitleText;
    private CharSequence mSubtitleText;

    // Clear me after use.
    private final ArrayList<View> mTempViews = new ArrayList<View>();

    private OnMenuItemClickListener mOnMenuItemClickListener;

    private final ActionMenuView.OnMenuItemClickListener mMenuViewItemClickListener =
            new ActionMenuView.OnMenuItemClickListener() {
                @Override
                public boolean onMenuItemClick(MenuItem item) {
                    if (mOnMenuItemClickListener != null) {
                        return mOnMenuItemClickListener.onMenuItemClick(item);
                    }
                    return false;
                }
            };

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

    public Toolbar(Context context, AttributeSet attrs) {
        this(context, attrs, com.android.internal.R.attr.toolbarStyle);
    }

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

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

        final TypedArray a = context.obtainStyledAttributes(attrs, R.styleable.Toolbar,
                defStyleAttr, defStyleRes);

        mTitleTextAppearance = a.getResourceId(R.styleable.Toolbar_titleTextAppearance, 0);
        mSubtitleTextAppearance = a.getResourceId(R.styleable.Toolbar_subtitleTextAppearance, 0);
        mGravity = a.getInteger(R.styleable.Toolbar_gravity, mGravity);
        mTitleMarginStart = mTitleMarginEnd = Math.max(0, a.getDimensionPixelOffset(
                R.styleable.Toolbar_titleMargins, -1));

        final int marginStart = a.getDimensionPixelOffset(R.styleable.Toolbar_titleMarginStart, -1);
        if (marginStart >= 0) {
            mTitleMarginStart = marginStart;
        }

        final int marginEnd = a.getDimensionPixelOffset(R.styleable.Toolbar_titleMarginEnd, -1);
        if (marginEnd >= 0) {
            mTitleMarginEnd = marginEnd;
        }

        final int marginTop = a.getDimensionPixelOffset(R.styleable.Toolbar_titleMarginTop, -1);
        if (marginTop >= 0) {
            mTitleMarginTop = marginTop;
        }

        final int marginBottom = a.getDimensionPixelOffset(R.styleable.Toolbar_titleMarginBottom,
                -1);
        if (marginBottom >= 0) {
            mTitleMarginBottom = marginBottom;
        }

        final CharSequence title = a.getText(R.styleable.Toolbar_title);
        if (!TextUtils.isEmpty(title)) {
            setTitle(title);
        }

        final CharSequence subtitle = a.getText(R.styleable.Toolbar_subtitle);
        if (!TextUtils.isEmpty(subtitle)) {
            setSubtitle(title);
        }
        a.recycle();
    }

    /**
     * Set a logo drawable from a resource id.
     *
     * <p>This drawable should generally take the place of title text. The logo cannot be
     * clicked. Apps using a logo should also supply a description using
     * {@link #setLogoDescription(int)}.</p>
     *
     * @param resId ID of a drawable resource
     */
    public void setLogo(int resId) {
        setLogo(getContext().getDrawable(resId));
    }

    /**
     * Set a logo drawable.
     *
     * <p>This drawable should generally take the place of title text. The logo cannot be
     * clicked. Apps using a logo should also supply a description using
     * {@link #setLogoDescription(int)}.</p>
     *
     * @param drawable Drawable to use as a logo
     */
    public void setLogo(Drawable drawable) {
        if (drawable != null) {
            if (mLogoView == null) {
                mLogoView = new ImageView(getContext());
            }
            if (mLogoView.getParent() == null) {
                addSystemView(mLogoView);
            }
        } else if (mLogoView != null && mLogoView.getParent() != null) {
            removeView(mLogoView);
        }
        if (mLogoView != null) {
            mLogoView.setImageDrawable(drawable);
        }
    }

    /**
     * Return the current logo drawable.
     *
     * @return The current logo drawable
     * @see #setLogo(int)
     * @see #setLogo(android.graphics.drawable.Drawable)
     */
    public Drawable getLogo() {
        return mLogoView != null ? mLogoView.getDrawable() : null;
    }

    /**
     * Set a description of the toolbar's logo.
     *
     * <p>This description will be used for accessibility or other similar descriptions
     * of the UI.</p>
     *
     * @param resId String resource id
     */
    public void setLogoDescription(int resId) {
        setLogoDescription(getContext().getText(resId));
    }

    /**
     * Set a description of the toolbar's logo.
     *
     * <p>This description will be used for accessibility or other similar descriptions
     * of the UI.</p>
     *
     * @param description Description to set
     */
    public void setLogoDescription(CharSequence description) {
        if (!TextUtils.isEmpty(description) && mLogoView == null) {
            mLogoView = new ImageView(getContext());
        }
        if (mLogoView != null) {
            mLogoView.setContentDescription(description);
        }
    }

    /**
     * Return the description of the toolbar's logo.
     *
     * @return A description of the logo
     */
    public CharSequence getLogoDescription() {
        return mLogoView != null ? mLogoView.getContentDescription() : null;
    }

    /**
     * Return the current title displayed in the toolbar.
     *
     * @return The current title
     */
    public CharSequence getTitle() {
        return mTitleText;
    }

    /**
     * Set the title of this toolbar.
     *
     * <p>A title should be used as the anchor for a section of content. It should
     * describe or name the content being viewed.</p>
     *
     * @param resId Resource ID of a string to set as the title
     */
    public void setTitle(int resId) {
        setTitle(getContext().getText(resId));
    }

    /**
     * Set the title of this toolbar.
     *
     * <p>A title should be used as the anchor for a section of content. It should
     * describe or name the content being viewed.</p>
     *
     * @param title Title to set
     */
    public void setTitle(CharSequence title) {
        if (!TextUtils.isEmpty(title)) {
            if (mTitleTextView == null) {
                final Context context = getContext();
                mTitleTextView = new TextView(context);
                mTitleTextView.setTextAppearance(context, mTitleTextAppearance);
            }
            if (mTitleTextView.getParent() == null) {
                addSystemView(mTitleTextView);
            }
        } else if (mTitleTextView != null && mTitleTextView.getParent() != null) {
            removeView(mTitleTextView);
        }
        if (mTitleTextView != null) {
            mTitleTextView.setText(title);
        }
        mTitleText = title;
    }

    /**
     * Return the subtitle of this toolbar.
     *
     * @return The current subtitle
     */
    public CharSequence getSubtitle() {
        return mSubtitleText;
    }

    /**
     * Set the subtitle of this toolbar.
     *
     * <p>Subtitles should express extended information about the current content.</p>
     *
     * @param resId String resource ID
     */
    public void setSubtitle(int resId) {
        setSubtitle(getContext().getText(resId));
    }

    /**
     * Set the subtitle of this toolbar.
     *
     * <p>Subtitles should express extended information about the current content.</p>
     *
     * @param subtitle Subtitle to set
     */
    public void setSubtitle(CharSequence subtitle) {
        if (!TextUtils.isEmpty(subtitle)) {
            if (mSubtitleTextView == null) {
                final Context context = getContext();
                mSubtitleTextView = new TextView(context);
                mSubtitleTextView.setTextAppearance(context, mSubtitleTextAppearance);
            }
            if (mSubtitleTextView.getParent() == null) {
                addSystemView(mSubtitleTextView);
            }
        } else if (mSubtitleTextView != null && mSubtitleTextView.getParent() != null) {
            removeView(mSubtitleTextView);
        }
        if (mSubtitleTextView != null) {
            mSubtitleTextView.setText(subtitle);
        }
        mSubtitleText = subtitle;
    }

    /**
     * Set the icon to use for the toolbar's navigation button.
     *
     * <p>The navigation button appears at the start of the toolbar if present. Setting an icon
     * will make the navigation button visible.</p>
     *
     * <p>If you use a navigation icon you should also set a description for its action using
     * {@link #setNavigationDescription(int)}. This is used for accessibility and tooltips.</p>
     *
     * @param resId Resource ID of a drawable to set
     */
    public void setNavigationIcon(int resId) {
        setNavigationIcon(getContext().getDrawable(resId));
    }

    /**
     * Set the icon to use for the toolbar's navigation button.
     *
     * <p>The navigation button appears at the start of the toolbar if present. Setting an icon
     * will make the navigation button visible.</p>
     *
     * <p>If you use a navigation icon you should also set a description for its action using
     * {@link #setNavigationDescription(int)}. This is used for accessibility and tooltips.</p>
     *
     * @param icon Drawable to set
     */
    public void setNavigationIcon(Drawable icon) {
        if (icon != null) {
            ensureNavButtonView();
            if (mNavButtonView.getParent() == null) {
                addSystemView(mNavButtonView);
            }
        } else if (mNavButtonView != null && mNavButtonView.getParent() != null) {
            removeView(mNavButtonView);
        }
        if (mNavButtonView != null) {
            mNavButtonView.setImageDrawable(icon);
        }
    }

    /**
     * Return the current drawable used as the navigation icon.
     *
     * @return The navigation icon drawable
     */
    public Drawable getNavigationIcon() {
        return mNavButtonView != null ? mNavButtonView.getDrawable() : null;
    }

    /**
     * Set a description for the navigation button.
     *
     * <p>This description string is used for accessibility, tooltips and other facilities
     * to improve discoverability.</p>
     *
     * @param resId Resource ID of a string to set
     */
    public void setNavigationDescription(int resId) {
        setNavigationDescription(getContext().getText(resId));
    }

    /**
     * Set a description for the navigation button.
     *
     * <p>This description string is used for accessibility, tooltips and other facilities
     * to improve discoverability.</p>
     *
     * @param description String to set as the description
     */
    public void setNavigationDescription(CharSequence description) {
        if (!TextUtils.isEmpty(description)) {
            ensureNavButtonView();
        }
        if (mNavButtonView != null) {
            mNavButtonView.setContentDescription(description);
        }
    }

    /**
     * Set a listener to respond to navigation events.
     *
     * <p>This listener will be called whenever the user clicks the navigation button
     * at the start of the toolbar. An icon must be set for the navigation button to appear.</p>
     *
     * @param listener Listener to set
     * @see #setNavigationIcon(android.graphics.drawable.Drawable)
     */
    public void setNavigationOnClickListener(OnClickListener listener) {
        ensureNavButtonView();
        mNavButtonView.setOnClickListener(listener);
    }

    /**
     * Return the Menu shown in the toolbar.
     *
     * <p>Applications that wish to populate the toolbar's menu can do so from here. To use
     * an XML menu resource, use {@link #inflateMenu(int)}.</p>
     *
     * @return The toolbar's Menu
     */
    public Menu getMenu() {
        if (mMenuView == null) {
            mMenuView = new ActionMenuView(getContext());
            mMenuView.setOnMenuItemClickListener(mMenuViewItemClickListener);
            addSystemView(mMenuView);
        }
        return mMenuView.getMenu();
    }

    private MenuInflater getMenuInflater() {
        return new MenuInflater(getContext());
    }

    /**
     * Inflate a menu resource into this toolbar.
     *
     * <p>Inflate an XML menu resource into this toolbar. Existing items in the menu will not
     * be modified or removed.</p>
     *
     * @param resId ID of a menu resource to inflate
     */
    public void inflateMenu(int resId) {
        getMenuInflater().inflate(resId, getMenu());
    }

    /**
     * Set a listener to respond to menu item click events.
     *
     * <p>This listener will be invoked whenever a user selects a menu item from
     * the action buttons presented at the end of the toolbar or the associated overflow.</p>
     *
     * @param listener Listener to set
     */
    public void setOnMenuItemClickListener(OnMenuItemClickListener listener) {
        mOnMenuItemClickListener = listener;
    }

    private void ensureNavButtonView() {
        if (mNavButtonView == null) {
            mNavButtonView = new ImageButton(getContext(), null, R.attr.borderlessButtonStyle);
        }
    }

    private void addSystemView(View v) {
        final LayoutParams lp = new LayoutParams(LayoutParams.WRAP_CONTENT,
                LayoutParams.WRAP_CONTENT);
        lp.mViewType = LayoutParams.SYSTEM;
        addView(v, lp);
    }

    @Override
    protected Parcelable onSaveInstanceState() {
        SavedState state = new SavedState(super.onSaveInstanceState());
        return state;
    }

    @Override
    protected void onRestoreInstanceState(Parcelable state) {
        final SavedState ss = (SavedState) state;
        super.onRestoreInstanceState(ss.getSuperState());
    }

    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        int width = 0;
        int height = 0;
        int childState = 0;

        // System views measure first.

        if (shouldLayout(mNavButtonView)) {
            measureChildWithMargins(mNavButtonView, widthMeasureSpec, width, heightMeasureSpec, 0);
            width += mNavButtonView.getMeasuredWidth() + getHorizontalMargins(mNavButtonView);
            height = Math.max(height, mNavButtonView.getMeasuredHeight() +
                    getVerticalMargins(mNavButtonView));
            childState = combineMeasuredStates(childState, mNavButtonView.getMeasuredState());
        }

        if (shouldLayout(mMenuView)) {
            measureChildWithMargins(mMenuView, widthMeasureSpec, width, heightMeasureSpec, 0);
            width += mMenuView.getMeasuredWidth() + getHorizontalMargins(mMenuView);
            height = Math.max(height, mMenuView.getMeasuredHeight() +
                    getVerticalMargins(mMenuView));
            childState = combineMeasuredStates(childState, mMenuView.getMeasuredState());
        }

        if (shouldLayout(mLogoView)) {
            measureChildWithMargins(mLogoView, widthMeasureSpec, width, heightMeasureSpec, 0);
            width += mLogoView.getMeasuredWidth() + getHorizontalMargins(mLogoView);
            height = Math.max(height, mLogoView.getMeasuredHeight() +
                    getVerticalMargins(mLogoView));
            childState = combineMeasuredStates(childState, mLogoView.getMeasuredState());
        }

        int titleWidth = 0;
        int titleHeight = 0;
        final int titleVertMargins = mTitleMarginTop + mTitleMarginBottom;
        final int titleHorizMargins = mTitleMarginStart + mTitleMarginEnd;
        if (shouldLayout(mTitleTextView)) {
            measureChildWithMargins(mTitleTextView, widthMeasureSpec, width + titleHorizMargins,
                    heightMeasureSpec, titleVertMargins);
            titleWidth = mTitleTextView.getMeasuredWidth() + getHorizontalMargins(mTitleTextView);
            titleHeight = mTitleTextView.getMeasuredHeight() + getVerticalMargins(mTitleTextView);
            childState = combineMeasuredStates(childState, mTitleTextView.getMeasuredState());
        }
        if (shouldLayout(mSubtitleTextView)) {
            measureChildWithMargins(mSubtitleTextView, widthMeasureSpec, width + titleHorizMargins,
                    heightMeasureSpec, titleHeight + titleVertMargins);
            titleWidth = Math.max(titleWidth, mSubtitleTextView.getMeasuredWidth() +
                    getHorizontalMargins(mSubtitleTextView));
            titleHeight += mSubtitleTextView.getMeasuredHeight() +
                    getVerticalMargins(mSubtitleTextView);
            childState = combineMeasuredStates(childState, mSubtitleTextView.getMeasuredState());
        }

        width += titleWidth;
        height = Math.max(height, titleHeight);

        final int childCount = getChildCount();
        for (int i = 0; i < childCount; i++) {
            final View child = getChildAt(i);
            final LayoutParams lp = (LayoutParams) child.getLayoutParams();
            if (lp.mViewType == LayoutParams.SYSTEM || !shouldLayout(child)) {
                // We already got all system views above. Skip them and GONE views.
                continue;
            }

            measureChildWithMargins(child, widthMeasureSpec, width, heightMeasureSpec, 0);
            width += child.getMeasuredWidth() + getHorizontalMargins(child);
            height = Math.max(height, child.getMeasuredHeight() + getVerticalMargins(child));
            childState = combineMeasuredStates(childState, child.getMeasuredState());
        }

        // Measurement already took padding into account for available space for the children,
        // add it in for the final size.
        width += getPaddingLeft() + getPaddingRight();
        height += getPaddingTop() + getPaddingBottom();

        final int measuredWidth = resolveSizeAndState(
                Math.max(width, getSuggestedMinimumWidth()),
                widthMeasureSpec, childState & MEASURED_STATE_MASK);
        final int measuredHeight = resolveSizeAndState(
                Math.max(height, getSuggestedMinimumHeight()),
                heightMeasureSpec, childState << MEASURED_HEIGHT_STATE_SHIFT);
        setMeasuredDimension(measuredWidth, measuredHeight);
    }

    @Override
    protected void onLayout(boolean changed, int l, int t, int r, int b) {
        final boolean isRtl = getLayoutDirection() == LAYOUT_DIRECTION_RTL;
        final int width = getWidth();
        final int height = getHeight();
        final int paddingLeft = getPaddingLeft();
        final int paddingRight = getPaddingRight();
        final int paddingTop = getPaddingTop();
        final int paddingBottom = getPaddingBottom();
        int left = paddingLeft;
        int right = width - paddingRight;

        if (shouldLayout(mNavButtonView)) {
            if (isRtl) {
                right = layoutChildRight(mNavButtonView, right);
            } else {
                left = layoutChildLeft(mNavButtonView, left);
            }
        }

        if (shouldLayout(mMenuView)) {
            if (isRtl) {
                left = layoutChildLeft(mMenuView, left);
            } else {
                right = layoutChildRight(mMenuView, right);
            }
        }

        if (shouldLayout(mLogoView)) {
            if (isRtl) {
                right = layoutChildRight(mLogoView, right);
            } else {
                left = layoutChildLeft(mLogoView, left);
            }
        }

        final boolean layoutTitle = shouldLayout(mTitleTextView);
        final boolean layoutSubtitle = shouldLayout(mSubtitleTextView);
        int titleHeight = 0;
        if (layoutTitle) {
            final LayoutParams lp = (LayoutParams) mTitleTextView.getLayoutParams();
            titleHeight += lp.topMargin + mTitleTextView.getMeasuredHeight() + lp.bottomMargin;
        }
        if (layoutSubtitle) {
            final LayoutParams lp = (LayoutParams) mSubtitleTextView.getLayoutParams();
            titleHeight += lp.bottomMargin + mTitleTextView.getMeasuredHeight() + lp.bottomMargin;
        }

        if (layoutTitle || layoutSubtitle) {
            int titleTop;
            switch (mGravity & Gravity.VERTICAL_GRAVITY_MASK) {
                case Gravity.TOP:
                    titleTop = getPaddingTop();
                    break;
                default:
                case Gravity.CENTER_VERTICAL:
                    final View child = layoutTitle ? mTitleTextView : mSubtitleTextView;
                    final LayoutParams lp = (LayoutParams) child.getLayoutParams();
                    final int space = height - paddingTop - paddingBottom;
                    int spaceAbove = (space - titleHeight) / 2;
                    if (spaceAbove < lp.topMargin + mTitleMarginTop) {
                        spaceAbove = lp.topMargin + mTitleMarginTop;
                    } else {
                        final int spaceBelow = height - paddingBottom - titleHeight -
                                spaceAbove - paddingTop;
                        if (spaceBelow < lp.bottomMargin + mTitleMarginBottom) {
                            spaceAbove = Math.max(0, spaceAbove -
                                    (lp.bottomMargin + mTitleMarginBottom - spaceBelow));
                        }
                    }
                    titleTop = paddingTop + spaceAbove;
                    break;
                case Gravity.BOTTOM:
                    titleTop = height - paddingBottom - titleHeight;
                    break;
            }
            if (isRtl) {
                int titleRight = right;
                int subtitleRight = right;
                titleTop += mTitleMarginTop;
                if (layoutTitle) {
                    final LayoutParams lp = (LayoutParams) mTitleTextView.getLayoutParams();
                    titleRight -= lp.rightMargin + mTitleMarginStart;
                    titleTop += lp.topMargin;
                    final int titleLeft = titleRight - mTitleTextView.getMeasuredWidth();
                    final int titleBottom = titleTop + mTitleTextView.getMeasuredHeight();
                    mTitleTextView.layout(titleLeft, titleTop, titleRight, titleBottom);
                    titleRight = titleLeft - lp.leftMargin - mTitleMarginEnd;
                    titleTop = titleBottom + lp.bottomMargin;
                }
                if (layoutSubtitle) {
                    final LayoutParams lp = (LayoutParams) mSubtitleTextView.getLayoutParams();
                    subtitleRight -= lp.rightMargin + mTitleMarginStart;
                    titleTop += lp.topMargin;
                    final int subtitleLeft = subtitleRight - mSubtitleTextView.getMeasuredWidth();
                    final int subtitleBottom = titleTop + mSubtitleTextView.getMeasuredHeight();
                    mSubtitleTextView.layout(subtitleLeft, titleTop, subtitleRight, subtitleBottom);
                    subtitleRight = subtitleRight - lp.leftMargin - mTitleMarginEnd;
                    titleTop = subtitleBottom + lp.bottomMargin;
                }
                right = Math.max(titleRight, subtitleRight);
            } else {
                int titleLeft = left;
                int subtitleLeft = left;
                titleTop += mTitleMarginTop;
                if (layoutTitle) {
                    final LayoutParams lp = (LayoutParams) mTitleTextView.getLayoutParams();
                    titleLeft += lp.leftMargin + mTitleMarginStart;
                    titleTop += lp.topMargin;
                    final int titleRight = titleLeft + mTitleTextView.getMeasuredWidth();
                    final int titleBottom = titleTop + mTitleTextView.getMeasuredHeight();
                    mTitleTextView.layout(titleLeft, titleTop, titleRight, titleBottom);
                    titleLeft = titleRight + lp.rightMargin + mTitleMarginEnd;
                    titleTop = titleBottom + lp.bottomMargin;
                }
                if (layoutSubtitle) {
                    final LayoutParams lp = (LayoutParams) mSubtitleTextView.getLayoutParams();
                    subtitleLeft += lp.leftMargin + mTitleMarginStart;
                    titleTop += lp.topMargin;
                    final int subtitleRight = subtitleLeft + mSubtitleTextView.getMeasuredWidth();
                    final int subtitleBottom = titleTop + mSubtitleTextView.getMeasuredHeight();
                    mSubtitleTextView.layout(subtitleLeft, titleTop, subtitleRight, subtitleBottom);
                    subtitleLeft = subtitleRight + lp.rightMargin + mTitleMarginEnd;
                    titleTop = subtitleBottom + lp.bottomMargin;
                }
                left = Math.max(titleLeft, subtitleLeft);
            }
        }

        // Get all remaining children sorted for layout. This is all prepared
        // such that absolute layout direction can be used below.

        addCustomViewsWithGravity(mTempViews, Gravity.LEFT);
        final int leftViewsCount = mTempViews.size();
        for (int i = 0; i < leftViewsCount; i++) {
            left = layoutChildLeft(getChildAt(i), left);
        }

        addCustomViewsWithGravity(mTempViews, Gravity.RIGHT);
        final int rightViewsCount = mTempViews.size();
        for (int i = 0; i < rightViewsCount; i++) {
            right = layoutChildRight(getChildAt(i), right);
        }

        // Centered views try to center with respect to the whole bar, but views pinned
        // to the left or right can push the mass of centered views to one side or the other.
        addCustomViewsWithGravity(mTempViews, Gravity.CENTER);
        final int centerViewsWidth = getViewListMeasuredWidth(mTempViews);
        final int parentCenter = paddingLeft + (width - paddingLeft - paddingRight) / 2;
        final int halfCenterViewsWidth = centerViewsWidth / 2;
        int centerLeft = parentCenter - halfCenterViewsWidth;
        final int centerRight = centerLeft + centerViewsWidth;
        if (centerLeft < left) {
            centerLeft = left;
        } else if (centerRight > right) {
            centerLeft -= centerRight - right;
        }

        final int centerViewsCount = mTempViews.size();
        for (int i = 0; i < centerViewsCount; i++) {
            centerLeft = layoutChildLeft(getChildAt(i), centerLeft);
        }
        mTempViews.clear();
    }

    private int getViewListMeasuredWidth(List<View> views) {
        int width = 0;
        final int count = views.size();
        for (int i = 0; i < count; i++) {
            final View v = views.get(i);
            final LayoutParams lp = (LayoutParams) v.getLayoutParams();
            width += lp.leftMargin + v.getMeasuredWidth() + lp.rightMargin;
        }
        return width;
    }

    private int layoutChildLeft(View child, int left) {
        final LayoutParams lp = (LayoutParams) child.getLayoutParams();
        left += lp.leftMargin;
        int top = getChildTop(child);
        child.layout(left, top, left + child.getMeasuredWidth(), top + child.getMeasuredHeight());
        left += lp.rightMargin;
        return left;
    }

    private int layoutChildRight(View child, int right) {
        final LayoutParams lp = (LayoutParams) child.getLayoutParams();
        right -= lp.rightMargin;
        int top = getChildTop(child);
        child.layout(right - child.getMeasuredWidth(), top, right, top + child.getMeasuredHeight());
        right -= lp.leftMargin;
        return right;
    }

    private int getChildTop(View child) {
        final LayoutParams lp = (LayoutParams) child.getLayoutParams();
        switch (getChildVerticalGravity(lp.gravity)) {
            case Gravity.TOP:
                return getPaddingTop();

            case Gravity.BOTTOM:
                return getPaddingBottom() - child.getMeasuredHeight() - lp.bottomMargin;

            default:
            case Gravity.CENTER_VERTICAL:
                final int paddingTop = getPaddingTop();
                final int paddingBottom = getPaddingBottom();
                final int height = getHeight();
                final int childHeight = child.getMeasuredHeight();
                final int space = height - paddingTop - paddingBottom;
                int spaceAbove = (space - childHeight) / 2;
                if (spaceAbove < lp.topMargin) {
                    spaceAbove = lp.topMargin;
                } else {
                    final int spaceBelow = height - paddingBottom - childHeight -
                            spaceAbove - paddingTop;
                    if (spaceBelow < lp.bottomMargin) {
                        spaceAbove = Math.max(0, spaceAbove - (lp.bottomMargin - spaceBelow));
                    }
                }
                return paddingTop + spaceAbove;
        }
    }

    private int getChildVerticalGravity(int gravity) {
        final int vgrav = gravity & Gravity.VERTICAL_GRAVITY_MASK;
        switch (vgrav) {
            case Gravity.TOP:
            case Gravity.BOTTOM:
            case Gravity.CENTER_VERTICAL:
                return vgrav;
            default:
                return mGravity & Gravity.VERTICAL_GRAVITY_MASK;
        }
    }

    /**
     * Prepare a list of non-SYSTEM child views. If the layout direction is RTL
     * this will be in reverse child order.
     *
     * @param views List to populate. It will be cleared before use.
     * @param gravity Horizontal gravity to match against
     */
    private void addCustomViewsWithGravity(List<View> views, int gravity) {
        final boolean isRtl = getLayoutDirection() == LAYOUT_DIRECTION_RTL;
        final int childCount = getChildCount();
        final int absGrav = Gravity.getAbsoluteGravity(gravity, getLayoutDirection());

        views.clear();

        if (isRtl) {
            for (int i = childCount - 1; i >= 0; i--) {
                final View child = getChildAt(i);
                final LayoutParams lp = (LayoutParams) child.getLayoutParams();
                if (lp.mViewType != LayoutParams.SYSTEM && shouldLayout(child) &&
                        getChildHorizontalGravity(lp.gravity) == absGrav) {
                    views.add(child);
                }

            }
        } else {
            for (int i = 0; i < childCount; i++) {
                final View child = getChildAt(i);
                final LayoutParams lp = (LayoutParams) child.getLayoutParams();
                if (lp.mViewType != LayoutParams.SYSTEM && shouldLayout(child) &&
                        getChildHorizontalGravity(lp.gravity) == absGrav) {
                    views.add(child);
                }
            }
        }
    }

    private int getChildHorizontalGravity(int gravity) {
        final int ld = getLayoutDirection();
        final int absGrav = Gravity.getAbsoluteGravity(gravity, ld);
        final int hGrav = absGrav & Gravity.HORIZONTAL_GRAVITY_MASK;
        switch (hGrav) {
            case Gravity.LEFT:
            case Gravity.RIGHT:
            case Gravity.CENTER_HORIZONTAL:
                return hGrav;
            default:
                return ld == LAYOUT_DIRECTION_RTL ? Gravity.RIGHT : Gravity.LEFT;
        }
    }

    private boolean shouldLayout(View view) {
        return view != null && view.getParent() == this && view.getVisibility() != GONE;
    }

    private int getHorizontalMargins(View v) {
        final MarginLayoutParams mlp = (MarginLayoutParams) v.getLayoutParams();
        return mlp.getMarginStart() + mlp.getMarginEnd();
    }

    private int getVerticalMargins(View v) {
        final MarginLayoutParams mlp = (MarginLayoutParams) v.getLayoutParams();
        return mlp.topMargin + mlp.bottomMargin;
    }

    @Override
    public ViewGroup.LayoutParams generateLayoutParams(AttributeSet attrs) {
        return super.generateLayoutParams(attrs);
    }

    @Override
    protected ViewGroup.LayoutParams generateLayoutParams(ViewGroup.LayoutParams p) {
        if (p instanceof LayoutParams) {
            return new LayoutParams((LayoutParams) p);
        } else if (p instanceof MarginLayoutParams) {
            return new LayoutParams((MarginLayoutParams) p);
        } else {
            return new LayoutParams(p);
        }
    }

    @Override
    protected ViewGroup.LayoutParams generateDefaultLayoutParams() {
        return new LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT);
    }

    @Override
    protected boolean checkLayoutParams(ViewGroup.LayoutParams p) {
        return super.checkLayoutParams(p) && p instanceof LayoutParams;
    }

    private static boolean isCustomView(View child) {
        return ((LayoutParams) child.getLayoutParams()).mViewType == LayoutParams.CUSTOM;
    }

    /**
     * Interface responsible for receiving menu item click events if the items themselves
     * do not have individual item click listeners.
     */
    public interface OnMenuItemClickListener {
        /**
         * This method will be invoked when a menu item is clicked if the item itself did
         * not already handle the event.
         *
         * @param item {@link MenuItem} that was clicked
         * @return <code>true</code> if the event was handled, <code>false</code> otherwise.
         */
        public boolean onMenuItemClick(MenuItem item);
    }

    /**
     * Layout information for child views of Toolbars.
     *
     * @attr ref android.R.styleable#Toolbar_LayoutParams_layout_gravity
     */
    public static class LayoutParams extends MarginLayoutParams {
        /**
         * Gravity for the view associated with these LayoutParams.
         *
         * @see android.view.Gravity
         */
        @ViewDebug.ExportedProperty(category = "layout", mapping = {
                @ViewDebug.IntToString(from =  -1,                       to = "NONE"),
                @ViewDebug.IntToString(from = Gravity.NO_GRAVITY,        to = "NONE"),
                @ViewDebug.IntToString(from = Gravity.TOP,               to = "TOP"),
                @ViewDebug.IntToString(from = Gravity.BOTTOM,            to = "BOTTOM"),
                @ViewDebug.IntToString(from = Gravity.LEFT,              to = "LEFT"),
                @ViewDebug.IntToString(from = Gravity.RIGHT,             to = "RIGHT"),
                @ViewDebug.IntToString(from = Gravity.START,             to = "START"),
                @ViewDebug.IntToString(from = Gravity.END,               to = "END"),
                @ViewDebug.IntToString(from = Gravity.CENTER_VERTICAL,   to = "CENTER_VERTICAL"),
                @ViewDebug.IntToString(from = Gravity.FILL_VERTICAL,     to = "FILL_VERTICAL"),
                @ViewDebug.IntToString(from = Gravity.CENTER_HORIZONTAL, to = "CENTER_HORIZONTAL"),
                @ViewDebug.IntToString(from = Gravity.FILL_HORIZONTAL,   to = "FILL_HORIZONTAL"),
                @ViewDebug.IntToString(from = Gravity.CENTER,            to = "CENTER"),
                @ViewDebug.IntToString(from = Gravity.FILL,              to = "FILL")
        })
        public int gravity = Gravity.NO_GRAVITY;

        static final int CUSTOM = 0;
        static final int SYSTEM = 1;

        int mViewType = CUSTOM;

        public LayoutParams(@NonNull Context c, AttributeSet attrs) {
            super(c, attrs);

            TypedArray a = c.obtainStyledAttributes(attrs,
                    com.android.internal.R.styleable.Toolbar_LayoutParams);
            gravity = a.getInt(
                    com.android.internal.R.styleable.Toolbar_LayoutParams_layout_gravity,
                    Gravity.NO_GRAVITY);
            a.recycle();
        }

        public LayoutParams(int width, int height) {
            super(width, height);
            this.gravity = Gravity.CENTER_VERTICAL | Gravity.START;
        }

        public LayoutParams(int width, int height, int gravity) {
            super(width, height);
            this.gravity = gravity;
        }

        public LayoutParams(int gravity) {
            this(WRAP_CONTENT, MATCH_PARENT, gravity);
        }

        public LayoutParams(LayoutParams source) {
            super(source);

            this.gravity = source.gravity;
        }

        public LayoutParams(MarginLayoutParams source) {
            super(source);
        }

        public LayoutParams(ViewGroup.LayoutParams source) {
            super(source);
        }
    }

    static class SavedState extends BaseSavedState {
        public SavedState(Parcel source) {
            super(source);
        }

        public SavedState(Parcelable superState) {
            super(superState);
        }

        @Override
        public void writeToParcel(Parcel out, int flags) {
            super.writeToParcel(out, flags);
        }

        public static final Creator<SavedState> CREATOR = new Creator<SavedState>() {

            @Override
            public SavedState createFromParcel(Parcel source) {
                return new SavedState(source);
            }

            @Override
            public SavedState[] newArray(int size) {
                return new SavedState[size];
            }
        };
    }
}