Add elevation/shadow on toolbar for pre-lollipop devices

Question

I updated my android app to the new material design, but I also wanted to add some shadow or elevation to the Toolbar. There seem to be some (hacky) ways of doing it via ima

Answer 1

I have also lost 1 day on this issue, but I finally figured out a way to make it work.

/**
 * Controller for the toolbar which will take care of the drop down shadow also on pre-lollipop devices.
 * 

 * The controller also handles the status bar based on the state of the toolbar.
 * 

 * Created by Negru Ionut Valentin on 20/1/2016.
 */
public class ToolbarController {

    private boolean handleStatusBar = false;
    private boolean showTitle = true;

    /**
     * Call this method in onCreate() method of your Activity or in onCreateView() in Fragment
     *
     * @param view
     *         The view into which to look for the toolbar
     * @param activity
     *         The activity for which setup the toolbar
     *
     * @return The toolbar found and customized or {@code null}
     */
    public Toolbar initToolbar(View view, Activity activity) {
        Toolbar mToolbar = (Toolbar) view.findViewById(R.id.toolbar);

        // Valid and visible toolbar - otherwise ignore
        if (null != mToolbar && mToolbar.getVisibility() == View.VISIBLE) {

            int paddingLeft = mToolbar.getPaddingLeft();
            int paddingRight = mToolbar.getPaddingRight();
            int paddingBottom = mToolbar.getPaddingBottom();
            // Set the top padding of the toolbar to match the status bar height
            int paddingTop = new CynnyContextWrapper(activity).getStatusBarHeight();

            mToolbar.setPadding(paddingLeft, paddingTop, paddingRight, paddingBottom);

            if (Build.VERSION.SDK_INT <= Build.VERSION_CODES.LOLLIPOP) {
                ViewParent parent = mToolbar.getParent();
                if (parent instanceof RelativeLayout) {
                    // Manually create the drop shadow
                    RelativeLayout.LayoutParams params =
                            new RelativeLayout.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT,
                                                            Metrics.convertDpToPixel(4, activity));

                    View dropShadow = new View(activity);
                    dropShadow.setBackgroundResource(R.drawable.toolbar_shadow);

                    params.addRule(RelativeLayout.BELOW, R.id.toolbar);

                    ((RelativeLayout) parent).addView(dropShadow, params);
                }
            }

            if (activity instanceof AppCompatActivity) {
                // Check if the Activity actually support ActionBar with Toolbar and set our custom Toolbar for it
                ((AppCompatActivity) activity).setSupportActionBar(mToolbar);

                // Get the actionbar from the activity
                ActionBar actionBar = ((AppCompatActivity) activity).getSupportActionBar();
                if (null != actionBar) {
                    // If the actionbar is valid, customize it
                    actionBar.setDisplayHomeAsUpEnabled(true);
                    actionBar.setHomeButtonEnabled(true);

                    actionBar.setDisplayShowTitleEnabled(this.showTitle);

                    mToolbar.setNavigationIcon(R.drawable.ic_arrow_back_selector);
                }
            }

            if (this.handleStatusBar) {
                // For showing the status bar
                activity.getWindow().clearFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN);
                activity.getWindow().addFlags(WindowManager.LayoutParams.FLAG_FORCE_NOT_FULLSCREEN);
            }
        } else if (handleStatusBar) {
            // Force hide the status bar
            activity.getWindow().addFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN);
            activity.getWindow().clearFlags(WindowManager.LayoutParams.FLAG_FORCE_NOT_FULLSCREEN);
        }

        return mToolbar;
    }

    /**
     * Set the flag indicating if the controller should handle or not the status bar.
     *
     * @param handleStatusBar
     *         Flag which indicates if the initialization of the toolbar should also update
     *         the status bar state (if two calls are made for the init, the last one will
     *         be taken into consideration).
     *
     * @return The current toolbar controller.
     */
    public ToolbarController setHandleStatusBar(boolean handleStatusBar) {
        this.handleStatusBar = handleStatusBar;

        return this;
    }

    /**
     * Set the flag indicating if the toolbar should show or hide the title.
     *
     * @param showTitle
     *         Flag indicating if the toolbar should also show the title (the title can be changed after the toolbar
     *         initialization)
     *
     * @return The current toolbar controller.
     */
    public ToolbarController setShowTitle(boolean showTitle) {
        this.showTitle = showTitle;

        return this;
    }
}

In the activity you should use this in onCreate() method like this:

// Create and customize the Toolbar controller
new ToolbarController().setHandleStatusBar(true).setShowTitle(true)
                                 .initToolbar(((ViewGroup) findViewById(android.R.id.content)).getChildAt(0),
                                              this);

In the fragment you should use this in onCreateView() method like this:

new ToolbarController().setHandleStatusBar(false).setShowTitle(false).initToolbar(resultView, getActivity());

Do not forget to add you toolbar in the layouts and set it's id with android:id="@id/toolbar". If you want to use another id, you can customize the controller and add another setter method which uses the id you provide.

I have two toolbar layouts created:

v21

other

I use them in may layouts using:

I hope this will help to solve your issue. Also take note this can be optimized further more, but it works for me and I don't want to loose anymore time on this issue.