DrawerLayout.java

package us.nineworlds.serenity.widgets;

import java.util.ArrayList;

import android.content.Context;
import android.graphics.Rect;
import android.util.AttributeSet;
import android.view.MotionEvent;
import android.view.View;
import android.view.ViewGroup;
import android.view.accessibility.AccessibilityEvent;

/**
 * Fixes focus issues in the base DrawerLayout. This uses code inspired from
 * ViewPager to ensure that focus goes to the right place depending on drawer
 * state, namely first to any opened drawer, and if no drawer is opened to the
 * main content.
 */
public class DrawerLayout extends android.support.v4.widget.DrawerLayout {

	private DrawerListener m_wrappedListener;

	private final DrawerListener m_drawerListener = new DrawerListener() {

		@Override
		public void onDrawerOpened(View drawerView) {
			// if the content has focus, transfer focus to the drawer
			if (getContentView().hasFocus()) {
				drawerView.requestFocus(View.FOCUS_FORWARD);
			}

			if (m_wrappedListener != null) {
				m_wrappedListener.onDrawerOpened(drawerView);
			}
		}

		@Override
		public void onDrawerClosed(View drawerView) {
			if (drawerView.hasFocus()) {
				getContentView().requestFocus(View.FOCUS_FORWARD);
			}

			if (m_wrappedListener != null) {
				m_wrappedListener.onDrawerClosed(drawerView);
			}
		}

		@Override
		public void onDrawerSlide(View drawerView, float slideOffset) {
			if (m_wrappedListener != null) {
				m_wrappedListener.onDrawerSlide(drawerView, slideOffset);
			}
		}

		@Override
		public void onDrawerStateChanged(int newState) {
			if (m_wrappedListener != null) {
				m_wrappedListener.onDrawerStateChanged(newState);
			}
		}

	};

	private static final OnTouchListener s_drawerTouchListener = new OnTouchListener() {

		@Override
		public boolean onTouch(View v, MotionEvent event) {
			// prevent touch events from going through the drawer
			return false;
		}

	};

	private final OnHierarchyChangeListener m_hierarchyChangeListener = new OnHierarchyChangeListener() {

		@Override
		public void onChildViewAdded(View parent, View child) {
			if (DrawerLayout.this == parent && child != getContentView()) {
				child.setOnTouchListener(s_drawerTouchListener);
			}
		}

		@Override
		public void onChildViewRemoved(View parent, View child) {

		}

	};

	public DrawerLayout(Context context) {
		super(context);
		init();
	}

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

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

	private void init() {
		setDescendantFocusability(ViewGroup.FOCUS_AFTER_DESCENDANTS);
		super.setDrawerListener(m_drawerListener);
		setOnHierarchyChangeListener(m_hierarchyChangeListener);
	}

	private View getContentView() {
		return getChildAt(0);
	}

	@Override
	public void setDrawerListener(DrawerListener listener) {
		m_wrappedListener = listener;
	}

	@Override
	public void addFocusables(ArrayList<View> views, int direction,
			int focusableMode) {
		// logic derived from ViewPager

		final int focusableCount = views.size();
		final int descendantFocusability = getDescendantFocusability();

		if (descendantFocusability != FOCUS_BLOCK_DESCENDANTS) {
			boolean opened = false;
			for (int i = 1; i < getChildCount(); i++) {
				final View drawerView = getChildAt(i);
				if (isDrawerOpen(drawerView)) {
					opened = true;
					drawerView.addFocusables(views, direction, focusableMode);
				}
			}

			if (!opened) {
				getContentView().addFocusables(views, direction, focusableMode);
			}
		}

		// we add ourselves (if focusable) in all cases except for when we are
		// FOCUS_AFTER_DESCENDANTS and there are some descendants focusable.
		// this is
		// to avoid the focus search finding layouts when a more precise search
		// among the focusable children would be more interesting.
		if (descendantFocusability != FOCUS_AFTER_DESCENDANTS ||
				// No focusable descendants
				(focusableCount == views.size())) {
			// Note that we can't call the superclass here, because it will
			// add all views in. So we need to do the same thing View does.
			if (!isFocusable()) {
				return;
			}
			if ((focusableMode & FOCUSABLES_TOUCH_MODE) == FOCUSABLES_TOUCH_MODE
					&& isInTouchMode() && !isFocusableInTouchMode()) {
				return;
			}
			if (views != null) {
				views.add(this);
			}
		}
	}

	@Override
	protected boolean onRequestFocusInDescendants(int direction,
			Rect previouslyFocusedRect) {
		boolean opened = false;
		for (int i = 1; i < getChildCount(); i++) {
			final View drawerView = getChildAt(i);
			if (isDrawerOpen(drawerView)) {
				opened = true;
				if (drawerView.requestFocus(direction, previouslyFocusedRect)) {
					return true;
				}
			}
		}

		if (!opened) {
			return getContentView().requestFocus(direction,
					previouslyFocusedRect);
		}

		return false;
	}

	@Override
	public boolean dispatchPopulateAccessibilityEvent(AccessibilityEvent event) {
		boolean opened = false;
		for (int i = 1; i < getChildCount(); i++) {
			final View drawerView = getChildAt(i);
			if (isDrawerOpen(drawerView)) {
				opened = true;
				if (drawerView.dispatchPopulateAccessibilityEvent(event)) {
					return true;
				}
			}
		}

		if (!opened) {
			return getContentView().dispatchPopulateAccessibilityEvent(event);
		}

		return false;
	}

}