Activity which let's you easily color toolbar, its back button and overflow menu items

EasyColorableActivity.java

import android.annotation.SuppressLint;
import android.content.res.Resources;
import android.content.res.TypedArray;
import android.graphics.Color;
import android.graphics.PorterDuff;
import android.graphics.drawable.Drawable;
import android.os.Build;
import android.os.Bundle;
import android.support.annotation.ColorInt;
import android.support.annotation.NonNull;
import android.support.annotation.Nullable;
import android.support.design.widget.AppBarLayout;
import android.support.design.widget.CollapsingToolbarLayout;
import android.support.v4.content.ContextCompat;
import android.support.v7.app.ActionBar;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.AppCompatImageView;
import android.support.v7.widget.AppCompatTextView;
import android.support.v7.widget.Toolbar;
import android.text.SpannableString;
import android.text.style.ForegroundColorSpan;
import android.view.Gravity;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;
import android.view.ViewTreeObserver;
import android.view.Window;
import android.view.WindowManager;
import android.widget.LinearLayout;

import java.util.ArrayList;

/**
 * {@link android.app.Activity} which supports quick and easy customizations.
 * <p>
 * Needs a {@link Toolbar} and optionally a {@link CollapsingToolbarLayout}
 * <p>
 * Created by Tobias Schürg on 14.11.2016.
 */

public abstract class EasyColorableActivity extends AppCompatActivity {

    private Toolbar toolbar;

    @Nullable private CollapsingToolbarLayout collapsingToolbarLayout;
    @Nullable private AppBarLayout            appbarLayout;
    private           Integer                 foregroundColor;

    @Override
    protected void onPostCreate(@Nullable Bundle savedInstanceState) {
        super.onPostCreate(savedInstanceState);
        getTopView(); // make sure view is set up correctly
    }

    @NonNull
    private View getTopView() {
        if (toolbar != null) {
            return toolbar;
        } else if (collapsingToolbarLayout != null) {
            return collapsingToolbarLayout;
        } else {
            throw new NullPointerException(
                "No toolbar set! Call setToolbar(toolbar) or setToolbar(collapsingToolbarLayout) during onCreate");
        }
    }

    /**
     * For the use with just a 'simple' {@link Toolbar}
     */
    protected void setToolbar(@NonNull Toolbar toolbar) {
        setToolbar(toolbar, null, null);
    }

    /**
     * For the use with a collapsing toolbar.
     */
    protected void setToolbar(@NonNull Toolbar toolbar, CollapsingToolbarLayout collapsingToolbarLayout, AppBarLayout appBarLayout) {
        this.toolbar = toolbar;
        this.collapsingToolbarLayout = collapsingToolbarLayout;
        this.appbarLayout = appBarLayout;
    }

    protected void setBarBackgroundColor(@ColorInt int color) {
        // status bar
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
            Window window = getWindow();
            window.addFlags(WindowManager.LayoutParams.FLAG_DRAWS_SYSTEM_BAR_BACKGROUNDS);
            window.setStatusBarColor(ColorHelper.darken(color));
        }

        // actionbar
        if (appbarLayout != null) {
            appbarLayout.setBackgroundColor(color);
        } else {
            toolbar.setBackgroundColor(color);
        }

        setSupportActionBar(toolbar);
        ActionBar actionbar = getSupportActionBar();
        if (actionbar != null) {
            actionbar.setHomeButtonEnabled(true);
            actionbar.setDisplayHomeAsUpEnabled(true);
        }
    }

    @SuppressLint("PrivateResource")
    protected void setBarForegroundColor(@ColorInt int color) {
        foregroundColor = color;
        if (collapsingToolbarLayout != null) {
            collapsingToolbarLayout.setCollapsedTitleTextColor(color);
        } else if (toolbar != null) {
            toolbar.setTitleTextColor(color);
        }

        ActionBar actionbar = getSupportActionBar();
        if (actionbar != null) {
            Drawable upArrow = ContextCompat.getDrawable(this, android.support.v7.appcompat.R.drawable.abc_ic_ab_back_material);
            upArrow.setColorFilter(color, PorterDuff.Mode.SRC_ATOP);
            actionbar.setHomeAsUpIndicator(upArrow);
        }

        setOverflowButtonColor(color);
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        for (int i = 0; i < menu.size(); i++) {
            final MenuItem item = menu.getItem(i);
            final CharSequence itemTitle = item.getTitle();
            SpannableString s = new SpannableString(itemTitle);
            s.setSpan(new ForegroundColorSpan(Color.DKGRAY), 0, s.length(), 0);
            item.setTitle(s);

            AppCompatTextView tv = new AppCompatTextView(getApplicationContext());
            LinearLayout.LayoutParams params = new LinearLayout
                    .LayoutParams(LinearLayout.LayoutParams.MATCH_PARENT,
                                  LinearLayout.LayoutParams.MATCH_PARENT,
                                  1f);
            tv.setPadding(dpToPx(8), 0, dpToPx(8), 0);
            tv.setLayoutParams(params);
            tv.setGravity(Gravity.CENTER);
            tv.setText(itemTitle.toString());
            tv.setTextAppearance(this, android.R.style.TextAppearance_DeviceDefault_Widget_ActionBar_Menu);
            tv.setTextColor(foregroundColor);
            tv.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    onOptionsItemSelected(item);
                }
            });
            addRippleEffect(tv);
            item.setActionView(tv);
        }
        return super.onCreateOptionsMenu(menu);
    }

    private void addRippleEffect(View view) {
        int[] attrs = new int[]{R.attr.selectableItemBackgroundBorderless};
        TypedArray typedArray = obtainStyledAttributes(attrs);
        Drawable drawable = typedArray.getDrawable(0);
        view.setBackground(drawable);
        typedArray.recycle();
        view.setClickable(true);
        view.setFocusable(true);
    }

    /**
     * Changes the color of the overflow dots.
     * Great cinema ^^
     * Based on http://stackoverflow.com/a/36278375/570168
     */
    public void setOverflowButtonColor(final int color) {
        @SuppressLint("PrivateResource") final String overflowDescription = getString(R.string.abc_action_menu_overflow_description);
        final ViewGroup decorView = (ViewGroup) getWindow().getDecorView();
        final ViewTreeObserver viewTreeObserver = decorView.getViewTreeObserver();
        viewTreeObserver.addOnGlobalLayoutListener(new ViewTreeObserver.OnGlobalLayoutListener() {
            @Override
            public void onGlobalLayout() {
                final ArrayList<View> outViews = new ArrayList<>();
                decorView.findViewsWithText(outViews, overflowDescription, View.FIND_VIEWS_WITH_CONTENT_DESCRIPTION);
                if (outViews.isEmpty()) {
                    return;
                }
                for (View outView : outViews) {
                    AppCompatImageView overflow = (AppCompatImageView) outView;
                    overflow.setColorFilter(color);
                }
            }
        });
    }

    public static int dpToPx(int dp) {
        return (int) (dp * Resources.getSystem().getDisplayMetrics().density);
    }

}