Nav Drawer Under Status Bar Tricks

activity_main.xml

<android.support.v4.widget.DrawerLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:id="@+id/drawer_layout"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:fitsSystemWindows="true">

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:orientation="vertical">

        <android.support.v7.widget.Toolbar 
            android:id="@+id/toolbar_actionbar"
            android:layout_width="match_parent"
            android:layout_height="?actionBarSize"
            app:contentInsetStart="72dp"
            android:elevation="4dp"
            android:background="?colorPrimary"
            app:theme="@style/ThemeOverlay.AppCompat.Dark.ActionBar"
            app:popupTheme="@style/ThemeOverlay.AppCompat.Light"
            tools:ignore="UnusedAttribute,NewApi" />

        <FrameLayout
            android:layout_width="match_parent"
            android:layout_height="match_parent">

            <View
                android:id="@+id/main_shadow"
                android:layout_width="match_parent"
                android:layout_height="5dp"
                android:background="?toolbar_shadow" />

            <FrameLayout
                android:id="@+id/container"
                android:layout_width="match_parent"
                android:layout_height="match_parent" />

        </FrameLayout>

    </LinearLayout>

    <nexbit.icons.moonshine.views.ScrimInsetsFrameLayout
        android:id="@+id/nav_drawer_frame"
        android:layout_width="304dp"
        android:layout_height="match_parent"
        android:layout_gravity="start"
        android:fitsSystemWindows="true"
        app:insetForeground="#40000000">

        <fragment
            android:id="@+id/navigation_drawer"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:name="nexbit.icons.moonshine.fragments.NavigationDrawerFragment"
            android:tag="NAV_DRAWER" />

    </nexbit.icons.moonshine.views.ScrimInsetsFrameLayout>

</android.support.v4.widget.DrawerLayout>

attrs.xml

<?xml version="1.0" encoding="utf-8"?>
<resources>

    <declare-styleable name="ScrimInsetsView">
        <attr name="insetForeground" format="reference|color" />
    </declare-styleable>
    
    <attr name="toolbar_shadow" format="reference" />

</resources>

ScrimInsetsFrameLayout.java

import android.content.Context;
import android.content.res.TypedArray;
import android.graphics.Canvas;
import android.graphics.Rect;
import android.graphics.drawable.Drawable;
import android.support.v4.view.ViewCompat;
import android.util.AttributeSet;
import android.widget.FrameLayout;

/**
 * A layout that draws something in the insets passed to {@link #fitSystemWindows(Rect)}, i.e. the area above UI chrome
 * (status and navigation bars, overlay action bars).
 */
public class ScrimInsetsFrameLayout extends FrameLayout {
    private Drawable mInsetForeground;

    private Rect mInsets;
    private Rect mTempRect = new Rect();
    private OnInsetsCallback mOnInsetsCallback;

    public ScrimInsetsFrameLayout(Context context) {
        super(context);
        init(context, null, 0);
    }

    public ScrimInsetsFrameLayout(Context context, AttributeSet attrs) {
        super(context, attrs);
        init(context, attrs, 0);
    }

    public ScrimInsetsFrameLayout(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);
        init(context, attrs, defStyle);
    }

    private void init(Context context, AttributeSet attrs, int defStyle) {
        final TypedArray a = context.obtainStyledAttributes(attrs,
                R.styleable.ScrimInsetsView, defStyle, 0);
        if (a == null) {
            return;
        }
        mInsetForeground = a.getDrawable(R.styleable.ScrimInsetsView_insetForeground);
        a.recycle();

        setWillNotDraw(true);
    }

    @Override
    protected boolean fitSystemWindows(Rect insets) {
        mInsets = new Rect(insets);
        setWillNotDraw(mInsetForeground == null);
        ViewCompat.postInvalidateOnAnimation(this);
        if (mOnInsetsCallback != null) {
            mOnInsetsCallback.onInsetsChanged(insets);
        }
        return true; // consume insets
    }

    @Override
    public void draw(Canvas canvas) {
        super.draw(canvas);

        int width = getWidth();
        int height = getHeight();
        if (mInsets != null && mInsetForeground != null) {
            int sc = canvas.save();
            canvas.translate(getScrollX(), getScrollY());

            // Top
            mTempRect.set(0, 0, width, mInsets.top);
            mInsetForeground.setBounds(mTempRect);
            mInsetForeground.draw(canvas);

            // Bottom
            mTempRect.set(0, height - mInsets.bottom, width, height);
            mInsetForeground.setBounds(mTempRect);
            mInsetForeground.draw(canvas);

            // Left
            mTempRect.set(0, mInsets.top, mInsets.left, height - mInsets.bottom);
            mInsetForeground.setBounds(mTempRect);
            mInsetForeground.draw(canvas);

            // Right
            mTempRect.set(width - mInsets.right, mInsets.top, width, height - mInsets.bottom);
            mInsetForeground.setBounds(mTempRect);
            mInsetForeground.draw(canvas);

            canvas.restoreToCount(sc);
        }
    }

    @Override
    protected void onAttachedToWindow() {
        super.onAttachedToWindow();
        if (mInsetForeground != null) {
            mInsetForeground.setCallback(this);
        }
    }

    @Override
    protected void onDetachedFromWindow() {
        super.onDetachedFromWindow();
        if (mInsetForeground != null) {
            mInsetForeground.setCallback(null);
        }
    }

    /**
     * Allows the calling container to specify a callback for custom processing when insets change (i.e. when
     * {@link #fitSystemWindows(Rect)} is called. This is useful for setting padding on UI elements based on
     * UI chrome insets (e.g. a Google Map or a ListView). When using with ListView or GridView, remember to set
     * clipToPadding to false.
     */
    public void setOnInsetsCallback(OnInsetsCallback onInsetsCallback) {
        mOnInsetsCallback = onInsetsCallback;
    }

    public static interface OnInsetsCallback {
        public void onInsetsChanged(Rect insets);
    }
}

styles.xml

<!-- PUT IN: /res/values/styles.xml -->

<style name="AppTheme" parent="Theme.AppCompat.Light.NoActionBar">

    <item name="colorPrimary">#3F51B5</item>
    <item name="colorPrimaryDark">#303F9F</item>
    <item name="colorAccent">#E91E63</item>

    <item name="toolbar_shadow">@drawable/toolbar_shadow</item>

</style>

styles2.xml

<!-- PUT IN: /res/values-v21/styles.xml, NOT styles2.xml -->

<style name="AppTheme" parent="Theme.AppCompat.Light.NoActionBar">

    <item name="colorPrimary">#3F51B5</item>
    <item name="colorPrimaryDark">#303F9F</item>
    <item name="colorAccent">#E91E63</item>

    <!-- Elevation will be used instead on API 21+ -->
    <item name="toolbar_shadow">@null</item>

</style>

toolbar_shadow.xml

<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android"
    android:shape="rectangle">
    <gradient
        android:angle="90"
        android:endColor="#34000000"
        android:startColor="@android:color/transparent" />
</shape>