chrome/android/java/src/org/chromium/chrome/browser/toolbar/HomeButton.java

// Copyright 2018 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

package org.chromium.chrome.browser.toolbar;

import android.content.Context;
import android.content.res.ColorStateList;
import android.support.v4.content.ContextCompat;
import android.util.AttributeSet;
import android.view.ContextMenu;
import android.view.ContextMenu.ContextMenuInfo;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.View.OnCreateContextMenuListener;

import org.chromium.base.ApiCompatibilityUtils;
import org.chromium.chrome.R;
import org.chromium.chrome.browser.ActivityTabProvider;
import org.chromium.chrome.browser.ActivityTabProvider.ActivityTabTabObserver;
import org.chromium.chrome.browser.ThemeColorProvider;
import org.chromium.chrome.browser.ThemeColorProvider.TintObserver;
import org.chromium.chrome.browser.ntp.NewTabPage;
import org.chromium.chrome.browser.partnercustomizations.HomepageManager;
import org.chromium.chrome.browser.tab.Tab;
import org.chromium.chrome.browser.util.FeatureUtilities;
import org.chromium.ui.widget.ChromeImageButton;

/**
 * The home button.
 */
public class HomeButton extends ChromeImageButton
        implements TintObserver, OnCreateContextMenuListener, MenuItem.OnMenuItemClickListener,
                   HomepageManager.HomepageStateListener {
    private static final int ID_REMOVE = 0;

    /** A provider that notifies components when the theme color changes.*/
    private ThemeColorProvider mThemeColorProvider;

    /** The {@link ActivityTabTabObserver} used to know when the active page changed. */
    private ActivityTabTabObserver mActivityTabTabObserver;

    /** The {@link ActivityTabProvider} used to know if the active tab is on the NTP. */
    private ActivityTabProvider mActivityTabProvider;

    public HomeButton(Context context, AttributeSet attrs) {
        super(context, attrs);

        final int homeButtonIcon = FeatureUtilities.isNewTabPageButtonEnabled()
                ? R.drawable.ic_home
                : R.drawable.btn_toolbar_home;
        setImageDrawable(ContextCompat.getDrawable(context, homeButtonIcon));
        if (!FeatureUtilities.isNewTabPageButtonEnabled()
                && !FeatureUtilities.isBottomToolbarEnabled()) {
            setOnCreateContextMenuListener(this);
        }

        HomepageManager.getInstance().addListener(this);
    }

    public void destroy() {
        if (mThemeColorProvider != null) {
            mThemeColorProvider.removeTintObserver(this);
            mThemeColorProvider = null;
        }

        if (mActivityTabTabObserver != null) {
            mActivityTabTabObserver.destroy();
            mActivityTabTabObserver = null;
        }

        HomepageManager.getInstance().removeListener(this);
    }

    public void setThemeColorProvider(ThemeColorProvider themeColorProvider) {
        mThemeColorProvider = themeColorProvider;
        mThemeColorProvider.addTintObserver(this);
    }

    @Override
    public void onTintChanged(ColorStateList tint, boolean useLight) {
        ApiCompatibilityUtils.setImageTintList(this, tint);
    }

    @Override
    public void onCreateContextMenu(ContextMenu menu, View v, ContextMenuInfo menuInfo) {
        menu.add(Menu.NONE, ID_REMOVE, Menu.NONE, R.string.remove).setOnMenuItemClickListener(this);
    }

    @Override
    public boolean onMenuItemClick(MenuItem item) {
        assert item.getItemId() == ID_REMOVE;
        HomepageManager.getInstance().setPrefHomepageEnabled(false);
        return true;
    }

    @Override
    public void onHomepageStateUpdated() {
        updateButtonEnabledState();
    }

    public void setActivityTabProvider(ActivityTabProvider activityTabProvider) {
        mActivityTabProvider = activityTabProvider;
        mActivityTabTabObserver = new ActivityTabTabObserver(activityTabProvider) {
            @Override
            public void onObservingDifferentTab(Tab tab) {
                if (tab == null) return;
                updateButtonEnabledState();
            }

            @Override
            public void onUpdateUrl(Tab tab, String url) {
                updateButtonEnabledState();
            }
        };
    }

    private void updateButtonEnabledState() {
        if (FeatureUtilities.isNewTabPageButtonEnabled() || !HomepageManager.isHomepageEnabled()) {
            setEnabled(!isActiveTabNTP());
        } else {
            setEnabled(true);
        }
    }

    private boolean isActiveTabNTP() {
        if (mActivityTabProvider == null) return false;
        return NewTabPage.isNTPUrl(mActivityTabProvider.getActivityTab().getUrl());
    }
}