Drawer positioning and layout is controlled using the android:layout_gravity
+ * attribute on child views corresponding to which side of the view you want the drawer
+ * to emerge from: left or right. (Or start/end on platform versions that support layout direction.)
+ *
To use a DrawerLayout, position your primary content view as the first child with
+ * a width and height of match_parent. Add drawers as child views after the main
+ * content view and set the layout_gravity appropriately. Drawers commonly use
+ * match_parent for height with a fixed width.
{@link DrawerListener} can be used to monitor the state and motion of drawer views. + * Avoid performing expensive operations such as layout during animation as it can cause + * stuttering; try to perform expensive operations during the {@link #STATE_IDLE} state. + * {@link SimpleDrawerListener} offers default/no-op implementations of each callback method.
+ * + *As per the Android Design + * guide, any drawers positioned to the left/start should + * always contain content for navigating around the application, whereas any drawers + * positioned to the right/end should always contain actions to take on the current content. + * This preserves the same navigation left, actions right structure present in the Action Bar + * and elsewhere.
+ * + *For more information about how to use DrawerLayout, read Creating a Navigation + * Drawer.
+ */ +@SuppressLint("RtlHardcoded") +public class DrawerLayout extends ViewGroup { + private static final String TAG = "DrawerLayout"; + + @IntDef({STATE_IDLE, STATE_DRAGGING, STATE_SETTLING}) + @Retention(RetentionPolicy.SOURCE) + private @interface State {} + + /** + * Indicates that any drawers are in an idle, settled state. No animation is in progress. + */ + public static final int STATE_IDLE = ViewDragHelper.STATE_IDLE; + + /** + * Indicates that a drawer is currently being dragged by the user. + */ + public static final int STATE_DRAGGING = ViewDragHelper.STATE_DRAGGING; + + /** + * Indicates that a drawer is in the process of settling to a final position. + */ + public static final int STATE_SETTLING = ViewDragHelper.STATE_SETTLING; + + @IntDef({LOCK_MODE_UNLOCKED, LOCK_MODE_LOCKED_CLOSED, LOCK_MODE_LOCKED_OPEN}) + @Retention(RetentionPolicy.SOURCE) + private @interface LockMode {} + + /** + * The drawer is unlocked. + */ + public static final int LOCK_MODE_UNLOCKED = 0; + + /** + * The drawer is locked closed. The user may not open it, though + * the app may open it programmatically. + */ + public static final int LOCK_MODE_LOCKED_CLOSED = 1; + + /** + * The drawer is locked open. The user may not close it, though the app + * may close it programmatically. + */ + public static final int LOCK_MODE_LOCKED_OPEN = 2; + + @IntDef({Gravity.LEFT, Gravity.RIGHT, GravityCompat.START, GravityCompat.END}) + @Retention(RetentionPolicy.SOURCE) + private @interface EdgeGravity {} + + + private static final int MIN_DRAWER_MARGIN = 64; // dp + + private static final int DEFAULT_SCRIM_COLOR = 0x99000000; + + /** + * Length of time to delay before peeking the drawer. + */ + private static final int PEEK_DELAY = 160; // ms + + /** + * Minimum velocity that will be detected as a fling + */ + private static final int MIN_FLING_VELOCITY = 400; // dips per second + + /** + * Experimental feature. + */ + private static final boolean ALLOW_EDGE_LOCK = false; + + private static final boolean CHILDREN_DISALLOW_INTERCEPT = true; + + private static final float TOUCH_SLOP_SENSITIVITY = 1.f; + + private static final int[] LAYOUT_ATTRS = new int[] { + android.R.attr.layout_gravity + }; + + /** Whether we can use NO_HIDE_DESCENDANTS accessibility importance. */ + private static final boolean CAN_HIDE_DESCENDANTS = Build.VERSION.SDK_INT >= 19; + + private final ChildAccessibilityDelegate mChildAccessibilityDelegate = + new ChildAccessibilityDelegate(); + + private int mMinDrawerMargin; + + private int mScrimColor = DEFAULT_SCRIM_COLOR; + private float mScrimOpacity; + private Paint mScrimPaint = new Paint(); + + private final ViewDragHelper mLeftDragger; + private final ViewDragHelper mRightDragger; + private final ViewDragCallback mLeftCallback; + private final ViewDragCallback mRightCallback; + private int mDrawerState; + private boolean mInLayout; + private boolean mFirstLayout = true; + private int mLockModeLeft; + private int mLockModeRight; + private boolean mChildrenCanceledTouch; + + private DrawerListener mListener; + + private float mInitialMotionX; + private float mInitialMotionY; + + private Drawable mShadowLeft; + private Drawable mShadowRight; + + private CharSequence mTitleLeft; + private CharSequence mTitleRight; + + /** + * Listener for monitoring events about drawers. + */ + public interface DrawerListener { + /** + * Called when a drawer's position changes. + * @param drawerView The child view that was moved + * @param slideOffset The new offset of this drawer within its range, from 0-1 + */ + void onDrawerSlide(View drawerView, float slideOffset); + + /** + * Called when a drawer has settled in a completely open state. + * The drawer is interactive at this point. + * + * @param drawerView Drawer view that is now open + */ + void onDrawerOpened(View drawerView); + + /** + * Called when a drawer has settled in a completely closed state. + * + * @param drawerView Drawer view that is now closed + */ + void onDrawerClosed(View drawerView); + + /** + * Called when the drawer motion state changes. The new state will + * be one of {@link #STATE_IDLE}, {@link #STATE_DRAGGING} or {@link #STATE_SETTLING}. + * + * @param newState The new drawer motion state + */ + void onDrawerStateChanged(@State int newState); + } + + /** + * Stub/no-op implementations of all methods of {@link DrawerListener}. + * Override this if you only care about a few of the available callback methods. + */ + public static abstract class SimpleDrawerListener implements DrawerListener { + @Override + public void onDrawerSlide(View drawerView, float slideOffset) { + } + + @Override + public void onDrawerOpened(View drawerView) { + } + + @Override + public void onDrawerClosed(View drawerView) { + } + + @Override + public void onDrawerStateChanged(int newState) { + } + } + + public DrawerLayout(Context context) { + this(context, null); + } + + public DrawerLayout(Context context, AttributeSet attrs) { + this(context, attrs, 0); + } + + public DrawerLayout(Context context, AttributeSet attrs, int defStyle) { + super(context, attrs, defStyle); + setDescendantFocusability(ViewGroup.FOCUS_AFTER_DESCENDANTS); + final float density = getResources().getDisplayMetrics().density; + mMinDrawerMargin = (int) (MIN_DRAWER_MARGIN * density + 0.5f); + final float minVel = MIN_FLING_VELOCITY * density; + + mLeftCallback = new ViewDragCallback(Gravity.LEFT); + mRightCallback = new ViewDragCallback(Gravity.RIGHT); + + mLeftDragger = ViewDragHelper.create(this, TOUCH_SLOP_SENSITIVITY, mLeftCallback); + mLeftDragger.setEdgeTrackingEnabled(ViewDragHelper.EDGE_LEFT); + mLeftDragger.setMinVelocity(minVel); + mLeftCallback.setDragger(mLeftDragger); + + mRightDragger = ViewDragHelper.create(this, TOUCH_SLOP_SENSITIVITY, mRightCallback); + mRightDragger.setEdgeTrackingEnabled(ViewDragHelper.EDGE_RIGHT); + mRightDragger.setMinVelocity(minVel); + mRightCallback.setDragger(mRightDragger); + + // So that we can catch the back button + setFocusableInTouchMode(true); + + ViewCompat.setImportantForAccessibility(this, ViewCompat.IMPORTANT_FOR_ACCESSIBILITY_YES); + + ViewCompat.setAccessibilityDelegate(this, new AccessibilityDelegate()); + ViewGroupCompat.setMotionEventSplittingEnabled(this, false); + } + + /** + * Set a simple drawable used for the left or right shadow. + * The drawable provided must have a nonzero intrinsic width. + * + * @param shadowDrawable Shadow drawable to use at the edge of a drawer + * @param gravity Which drawer the shadow should apply to + */ + public void setDrawerShadow(Drawable shadowDrawable, @EdgeGravity int gravity) { + /* + * TODO Someone someday might want to set more complex drawables here. + * They're probably nuts, but we might want to consider registering callbacks, + * setting states, etc. properly. + */ + + final int absGravity = GravityCompat.getAbsoluteGravity(gravity, ViewCompat.getLayoutDirection(this)); + if ((absGravity & Gravity.LEFT) == Gravity.LEFT) { + mShadowLeft = shadowDrawable; + invalidate(); + } + if ((absGravity & Gravity.RIGHT) == Gravity.RIGHT) { + mShadowRight = shadowDrawable; + invalidate(); + } + } + + /** + * Set a simple drawable used for the left or right shadow. + * The drawable provided must have a nonzero intrinsic width. + * + * @param resId Resource id of a shadow drawable to use at the edge of a drawer + * @param gravity Which drawer the shadow should apply to + */ + public void setDrawerShadow(@DrawableRes int resId, @EdgeGravity int gravity) { + setDrawerShadow(getResources().getDrawable(resId), gravity); + } + + /** + * Set a color to use for the scrim that obscures primary content while a drawer is open. + * + * @param color Color to use in 0xAARRGGBB format. + */ + public void setScrimColor(int color) { + mScrimColor = color; + invalidate(); + } + + /** + * Set a listener to be notified of drawer events. + * + * @param listener Listener to notify when drawer events occur + * @see DrawerListener + */ + public void setDrawerListener(DrawerListener listener) { + mListener = listener; + } + + /** + * Enable or disable interaction with all drawers. + * + *This allows the application to restrict the user's ability to open or close + * any drawer within this layout. DrawerLayout will still respond to calls to + * {@link #openDrawer(int)}, {@link #closeDrawer(int)} and friends if a drawer is locked.
+ * + *Locking drawers open or closed will implicitly open or close + * any drawers as appropriate.
+ * + * @param lockMode The new lock mode for the given drawer. One of {@link #LOCK_MODE_UNLOCKED}, + * {@link #LOCK_MODE_LOCKED_CLOSED} or {@link #LOCK_MODE_LOCKED_OPEN}. + */ + public void setDrawerLockMode(@LockMode int lockMode) { + setDrawerLockMode(lockMode, Gravity.LEFT); + setDrawerLockMode(lockMode, Gravity.RIGHT); + } + + /** + * Enable or disable interaction with the given drawer. + * + *This allows the application to restrict the user's ability to open or close + * the given drawer. DrawerLayout will still respond to calls to {@link #openDrawer(int)}, + * {@link #closeDrawer(int)} and friends if a drawer is locked.
+ * + *Locking a drawer open or closed will implicitly open or close + * that drawer as appropriate.
+ * + * @param lockMode The new lock mode for the given drawer. One of {@link #LOCK_MODE_UNLOCKED}, + * {@link #LOCK_MODE_LOCKED_CLOSED} or {@link #LOCK_MODE_LOCKED_OPEN}. + * @param edgeGravity Gravity.LEFT, RIGHT, START or END. + * Expresses which drawer to change the mode for. + * + * @see #LOCK_MODE_UNLOCKED + * @see #LOCK_MODE_LOCKED_CLOSED + * @see #LOCK_MODE_LOCKED_OPEN + */ + public void setDrawerLockMode(@LockMode int lockMode, @EdgeGravity int edgeGravity) { + final int absGravity = GravityCompat.getAbsoluteGravity(edgeGravity, ViewCompat.getLayoutDirection(this)); + if (absGravity == Gravity.LEFT) { + mLockModeLeft = lockMode; + } else if (absGravity == Gravity.RIGHT) { + mLockModeRight = lockMode; + } + if (lockMode != LOCK_MODE_UNLOCKED) { + // Cancel interaction in progress + final ViewDragHelper helper = absGravity == Gravity.LEFT ? mLeftDragger : mRightDragger; + helper.cancel(); + } + switch (lockMode) { + case LOCK_MODE_LOCKED_OPEN: + final View toOpen = findDrawerWithGravity(absGravity); + if (toOpen != null) { + openDrawer(toOpen); + } + break; + case LOCK_MODE_LOCKED_CLOSED: + final View toClose = findDrawerWithGravity(absGravity); + if (toClose != null) { + closeDrawer(toClose); + } + break; + // default: do nothing + } + } + + /** + * Enable or disable interaction with the given drawer. + * + *This allows the application to restrict the user's ability to open or close + * the given drawer. DrawerLayout will still respond to calls to {@link #openDrawer(int)}, + * {@link #closeDrawer(int)} and friends if a drawer is locked.
+ * + *Locking a drawer open or closed will implicitly open or close + * that drawer as appropriate.
+ * + * @param lockMode The new lock mode for the given drawer. One of {@link #LOCK_MODE_UNLOCKED}, + * {@link #LOCK_MODE_LOCKED_CLOSED} or {@link #LOCK_MODE_LOCKED_OPEN}. + * @param drawerView The drawer view to change the lock mode for + * + * @see #LOCK_MODE_UNLOCKED + * @see #LOCK_MODE_LOCKED_CLOSED + * @see #LOCK_MODE_LOCKED_OPEN + */ + public void setDrawerLockMode(@LockMode int lockMode, View drawerView) { + if (!isDrawerView(drawerView)) { + throw new IllegalArgumentException("View " + drawerView + " is not a " + + "drawer with appropriate layout_gravity"); + } + final int gravity = ((LayoutParams) drawerView.getLayoutParams()).gravity; + //noinspection ResourceType + setDrawerLockMode(lockMode, gravity); + } + + /** + * Check the lock mode of the drawer with the given gravity. + * + * @param edgeGravity Gravity of the drawer to check + * @return one of {@link #LOCK_MODE_UNLOCKED}, {@link #LOCK_MODE_LOCKED_CLOSED} or + * {@link #LOCK_MODE_LOCKED_OPEN}. + */ + @LockMode + public int getDrawerLockMode(@EdgeGravity int edgeGravity) { + final int absGravity = GravityCompat.getAbsoluteGravity(edgeGravity, ViewCompat.getLayoutDirection(this)); + if (absGravity == Gravity.LEFT) { + return mLockModeLeft; + } else if (absGravity == Gravity.RIGHT) { + return mLockModeRight; + } + return LOCK_MODE_UNLOCKED; + } + + /** + * Check the lock mode of the given drawer view. + * + * @param drawerView Drawer view to check lock mode + * @return one of {@link #LOCK_MODE_UNLOCKED}, {@link #LOCK_MODE_LOCKED_CLOSED} or + * {@link #LOCK_MODE_LOCKED_OPEN}. + */ + @LockMode + public int getDrawerLockMode(View drawerView) { + final int absGravity = getDrawerViewAbsoluteGravity(drawerView); + if (absGravity == Gravity.LEFT) { + return mLockModeLeft; + } else if (absGravity == Gravity.RIGHT) { + return mLockModeRight; + } + return LOCK_MODE_UNLOCKED; + } + + /** + * Sets the title of the drawer with the given gravity. + *
+ * When accessibility is turned on, this is the title that will be used to
+ * identify the drawer to the active accessibility service.
+ *
+ * @param edgeGravity Gravity.LEFT, RIGHT, START or END. Expresses which
+ * drawer to set the title for.
+ * @param title The title for the drawer.
+ */
+ public void setDrawerTitle(@EdgeGravity int edgeGravity, CharSequence title) {
+ final int absGravity = GravityCompat.getAbsoluteGravity(edgeGravity, ViewCompat.getLayoutDirection(this));
+ if (absGravity == Gravity.LEFT) {
+ mTitleLeft = title;
+ } else if (absGravity == Gravity.RIGHT) {
+ mTitleRight = title;
+ }
+ }
+
+ /**
+ * Returns the title of the drawer with the given gravity.
+ *
+ * @param edgeGravity Gravity.LEFT, RIGHT, START or END. Expresses which
+ * drawer to return the title for.
+ * @return The title of the drawer, or null if none set.
+ * @see #setDrawerTitle(int, CharSequence)
+ */
+ @Nullable
+ public CharSequence getDrawerTitle(@EdgeGravity int edgeGravity) {
+ final int absGravity = GravityCompat.getAbsoluteGravity(edgeGravity, ViewCompat.getLayoutDirection(this));
+ if (absGravity == Gravity.LEFT) {
+ return mTitleLeft;
+ } else if (absGravity == Gravity.RIGHT) {
+ return mTitleRight;
+ }
+ return null;
+ }
+
+ /**
+ * Resolve the shared state of all drawers from the component ViewDragHelpers.
+ * Should be called whenever a ViewDragHelper's state changes.
+ */
+ void updateDrawerState(int forGravity, @State int activeState, View activeDrawer) {
+ final int leftState = mLeftDragger.getViewDragState();
+ final int rightState = mRightDragger.getViewDragState();
+
+ final int state;
+ if (leftState == STATE_DRAGGING || rightState == STATE_DRAGGING) {
+ state = STATE_DRAGGING;
+ } else if (leftState == STATE_SETTLING || rightState == STATE_SETTLING) {
+ state = STATE_SETTLING;
+ } else {
+ state = STATE_IDLE;
+ }
+
+ if (activeDrawer != null && activeState == STATE_IDLE) {
+ final LayoutParams lp = (LayoutParams) activeDrawer.getLayoutParams();
+ if (lp.onScreen == 0) {
+ dispatchOnDrawerClosed(activeDrawer);
+ } else if (lp.onScreen == 1) {
+ dispatchOnDrawerOpened(activeDrawer);
+ }
+ }
+
+ if (state != mDrawerState) {
+ mDrawerState = state;
+
+ if (mListener != null) {
+ mListener.onDrawerStateChanged(state);
+ }
+ }
+ }
+
+ void dispatchOnDrawerClosed(View drawerView) {
+ final LayoutParams lp = (LayoutParams) drawerView.getLayoutParams();
+ if (lp.knownOpen) {
+ lp.knownOpen = false;
+ if (mListener != null) {
+ mListener.onDrawerClosed(drawerView);
+ }
+
+ updateChildrenImportantForAccessibility(drawerView, false);
+
+ // Only send WINDOW_STATE_CHANGE if the host has window focus. This
+ // may change if support for multiple foreground windows (e.g. IME)
+ // improves.
+ if (hasWindowFocus()) {
+ final View rootView = getRootView();
+ if (rootView != null) {
+ rootView.sendAccessibilityEvent(AccessibilityEvent.TYPE_WINDOW_STATE_CHANGED);
+ }
+ }
+ }
+ }
+
+ void dispatchOnDrawerOpened(View drawerView) {
+ final LayoutParams lp = (LayoutParams) drawerView.getLayoutParams();
+ if (!lp.knownOpen) {
+ lp.knownOpen = true;
+ if (mListener != null) {
+ mListener.onDrawerOpened(drawerView);
+ }
+
+ updateChildrenImportantForAccessibility(drawerView, true);
+
+ // Only send WINDOW_STATE_CHANGE if the host has window focus.
+ if (hasWindowFocus()) {
+ sendAccessibilityEvent(AccessibilityEvent.TYPE_WINDOW_STATE_CHANGED);
+ }
+
+ drawerView.requestFocus();
+ }
+ }
+
+ private void updateChildrenImportantForAccessibility(View drawerView, boolean isDrawerOpen) {
+ final int childCount = getChildCount();
+ for (int i = 0; i < childCount; i++) {
+ final View child = getChildAt(i);
+ if (!isDrawerOpen && !isDrawerView(child)
+ || isDrawerOpen && child == drawerView) {
+ // Drawer is closed and this is a content view or this is an
+ // open drawer view, so it should be visible.
+ ViewCompat.setImportantForAccessibility(child, ViewCompat.IMPORTANT_FOR_ACCESSIBILITY_YES);
+ } else {
+ ViewCompat.setImportantForAccessibility(child, ViewCompat.IMPORTANT_FOR_ACCESSIBILITY_NO_HIDE_DESCENDANTS);
+ }
+ }
+ }
+
+ void dispatchOnDrawerSlide(View drawerView, float slideOffset) {
+ if (mListener != null) {
+ mListener.onDrawerSlide(drawerView, slideOffset);
+ }
+ }
+
+ void setDrawerViewOffset(View drawerView, float slideOffset) {
+ final LayoutParams lp = (LayoutParams) drawerView.getLayoutParams();
+ if (slideOffset == lp.onScreen) {
+ return;
+ }
+
+ lp.onScreen = slideOffset;
+ dispatchOnDrawerSlide(drawerView, slideOffset);
+ }
+
+ float getDrawerViewOffset(View drawerView) {
+ return ((LayoutParams) drawerView.getLayoutParams()).onScreen;
+ }
+
+ /**
+ * @return the absolute gravity of the child drawerView, resolved according
+ * to the current layout direction
+ */
+ int getDrawerViewAbsoluteGravity(View drawerView) {
+ final int gravity = ((LayoutParams) drawerView.getLayoutParams()).gravity;
+ return GravityCompat.getAbsoluteGravity(gravity, ViewCompat.getLayoutDirection(this));
+ }
+
+ boolean checkDrawerViewAbsoluteGravity(View drawerView, int checkFor) {
+ final int absGravity = getDrawerViewAbsoluteGravity(drawerView);
+ return (absGravity & checkFor) == checkFor;
+ }
+
+ View findOpenDrawer() {
+ final int childCount = getChildCount();
+ for (int i = 0; i < childCount; i++) {
+ final View child = getChildAt(i);
+ if (((LayoutParams) child.getLayoutParams()).knownOpen) {
+ return child;
+ }
+ }
+ return null;
+ }
+
+ /**
+ * @param gravity the gravity of the child to return. If specified as a
+ * relative value, it will be resolved
+ * according to the current
+ * layout direction.
+ * @return the drawer with the specified gravity
+ */
+ View findDrawerWithGravity(int gravity) {
+ final int absHorizGravity = GravityCompat.getAbsoluteGravity(gravity, ViewCompat.getLayoutDirection(this)) & Gravity.HORIZONTAL_GRAVITY_MASK;
+ final int childCount = getChildCount();
+ for (int i = 0; i < childCount; i++) {
+ final View child = getChildAt(i);
+ final int childAbsGravity = getDrawerViewAbsoluteGravity(child);
+ if ((childAbsGravity & Gravity.HORIZONTAL_GRAVITY_MASK) == absHorizGravity) {
+ return child;
+ }
+ }
+ return null;
+ }
+
+ /**
+ * Simple gravity to string - only supports LEFT and RIGHT for debugging output.
+ *
+ * @param gravity Absolute gravity value
+ * @return LEFT or RIGHT as appropriate, or a hex string
+ */
+ static String gravityToString(@EdgeGravity int gravity) {
+ if ((gravity & Gravity.LEFT) == Gravity.LEFT) {
+ return "LEFT";
+ }
+ if ((gravity & Gravity.RIGHT) == Gravity.RIGHT) {
+ return "RIGHT";
+ }
+ return Integer.toHexString(gravity);
+ }
+
+ @SuppressWarnings("deprecation")
+ @Override
+ protected boolean fitSystemWindows(@NonNull Rect insets) {
+ int fitPaddingTop = insets.top;
+ int fitPaddingBottom = insets.bottom;
+
+ int count = getChildCount();
+ for (int i = 0; i < count; i++) {
+ View child = getChildAt(i);
+ if (child instanceof FitPaddingImpl) {
+ ((FitPaddingImpl) child).onFitPadding(0 ,fitPaddingTop, 0, fitPaddingBottom);
+ }
+ }
+
+ insets.set(insets.left, 0 , insets.right, 0);
+ return super.fitSystemWindows(insets);
+ }
+
+ @Override
+ protected void onDetachedFromWindow() {
+ super.onDetachedFromWindow();
+ mFirstLayout = true;
+ }
+
+ @Override
+ protected void onAttachedToWindow() {
+ super.onAttachedToWindow();
+ mFirstLayout = true;
+ }
+
+ @Override
+ protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
+ int widthMode = MeasureSpec.getMode(widthMeasureSpec);
+ int heightMode = MeasureSpec.getMode(heightMeasureSpec);
+ int widthSize = MeasureSpec.getSize(widthMeasureSpec);
+ int heightSize = MeasureSpec.getSize(heightMeasureSpec);
+
+ if (widthMode != MeasureSpec.EXACTLY || heightMode != MeasureSpec.EXACTLY) {
+ if (isInEditMode()) {
+ // Don't crash the layout editor. Consume all of the space if specified
+ // or pick a magic number from thin air otherwise.
+ // TODO Better communication with tools of this bogus state.
+ // It will crash on a real device.
+ if (widthMode == MeasureSpec.AT_MOST) {
+ widthMode = MeasureSpec.EXACTLY;
+ } else if (widthMode == MeasureSpec.UNSPECIFIED) {
+ widthMode = MeasureSpec.EXACTLY;
+ widthSize = 300;
+ }
+ if (heightMode == MeasureSpec.AT_MOST) {
+ heightMode = MeasureSpec.EXACTLY;
+ }
+ else if (heightMode == MeasureSpec.UNSPECIFIED) {
+ heightMode = MeasureSpec.EXACTLY;
+ heightSize = 300;
+ }
+ } else {
+ throw new IllegalArgumentException(
+ "DrawerLayout must be measured with MeasureSpec.EXACTLY.");
+ }
+ }
+
+ setMeasuredDimension(widthSize, heightSize);
+
+ // Gravity value for each drawer we've seen. Only one of each permitted.
+ int foundDrawers = 0;
+ final int childCount = getChildCount();
+ for (int i = 0; i < childCount; i++) {
+ final View child = getChildAt(i);
+
+ if (child.getVisibility() == GONE) {
+ continue;
+ }
+
+ final LayoutParams lp = (LayoutParams) child.getLayoutParams();
+
+ if (isContentView(child)) {
+ // Content views get measured at exactly the layout's size.
+ final int contentWidthSpec = MeasureSpec.makeMeasureSpec(
+ widthSize - lp.leftMargin - lp.rightMargin, MeasureSpec.EXACTLY);
+ final int contentHeightSpec = MeasureSpec.makeMeasureSpec(
+ heightSize - lp.topMargin - lp.bottomMargin, MeasureSpec.EXACTLY);
+ child.measure(contentWidthSpec, contentHeightSpec);
+ } else if (isDrawerView(child)) {
+ final int childGravity =
+ getDrawerViewAbsoluteGravity(child) & Gravity.HORIZONTAL_GRAVITY_MASK;
+ if ((foundDrawers & childGravity) != 0) {
+ //noinspection ResourceType
+ throw new IllegalStateException("Child drawer has absolute gravity " +
+ gravityToString(childGravity) + " but this " + TAG + " already has a " +
+ "drawer view along that edge");
+ }
+ final int drawerWidthSpec = getChildMeasureSpec(widthMeasureSpec,
+ mMinDrawerMargin + lp.leftMargin + lp.rightMargin,
+ lp.width);
+ final int drawerHeightSpec = getChildMeasureSpec(heightMeasureSpec,
+ lp.topMargin + lp.bottomMargin,
+ lp.height);
+ child.measure(drawerWidthSpec, drawerHeightSpec);
+ } else {
+ throw new IllegalStateException("Child " + child + " at index " + i +
+ " does not have a valid layout_gravity - must be Gravity.LEFT, " +
+ "Gravity.RIGHT or Gravity.NO_GRAVITY");
+ }
+ }
+ }
+
+ @Override
+ protected void onLayout(boolean changed, int l, int t, int r, int b) {
+ mInLayout = true;
+ final int width = r - l;
+ final int childCount = getChildCount();
+ for (int i = 0; i < childCount; i++) {
+ final View child = getChildAt(i);
+
+ if (child.getVisibility() == GONE) {
+ continue;
+ }
+
+ final LayoutParams lp = (LayoutParams) child.getLayoutParams();
+
+ if (isContentView(child)) {
+ child.layout(lp.leftMargin, lp.topMargin,
+ lp.leftMargin + child.getMeasuredWidth(),
+ lp.topMargin + child.getMeasuredHeight());
+ } else { // Drawer, if it wasn't onMeasure would have thrown an exception.
+ final int childWidth = child.getMeasuredWidth();
+ final int childHeight = child.getMeasuredHeight();
+ int childLeft;
+
+ final float newOffset;
+ if (checkDrawerViewAbsoluteGravity(child, Gravity.LEFT)) {
+ childLeft = -childWidth + (int) (childWidth * lp.onScreen);
+ newOffset = (float) (childWidth + childLeft) / childWidth;
+ } else { // Right; onMeasure checked for us.
+ childLeft = width - (int) (childWidth * lp.onScreen);
+ newOffset = (float) (width - childLeft) / childWidth;
+ }
+
+ final boolean changeOffset = newOffset != lp.onScreen;
+
+ final int vgrav = lp.gravity & Gravity.VERTICAL_GRAVITY_MASK;
+
+ switch (vgrav) {
+ default:
+ case Gravity.TOP: {
+ child.layout(childLeft, lp.topMargin, childLeft + childWidth,
+ lp.topMargin + childHeight);
+ break;
+ }
+
+ case Gravity.BOTTOM: {
+ final int height = b - t;
+ child.layout(childLeft,
+ height - lp.bottomMargin - child.getMeasuredHeight(),
+ childLeft + childWidth,
+ height - lp.bottomMargin);
+ break;
+ }
+
+ case Gravity.CENTER_VERTICAL: {
+ final int height = b - t;
+ int childTop = (height - childHeight) / 2;
+
+ // Offset for margins. If things don't fit right because of
+ // bad measurement before, oh well.
+ if (childTop < lp.topMargin) {
+ childTop = lp.topMargin;
+ } else if (childTop + childHeight > height - lp.bottomMargin) {
+ childTop = height - lp.bottomMargin - childHeight;
+ }
+ child.layout(childLeft, childTop, childLeft + childWidth,
+ childTop + childHeight);
+ break;
+ }
+ }
+
+ if (changeOffset) {
+ setDrawerViewOffset(child, newOffset);
+ }
+
+ final int newVisibility = lp.onScreen > 0 ? VISIBLE : INVISIBLE;
+ if (child.getVisibility() != newVisibility) {
+ child.setVisibility(newVisibility);
+ }
+ }
+ }
+ mInLayout = false;
+ mFirstLayout = false;
+ }
+
+ @Override
+ public void requestLayout() {
+ if (!mInLayout) {
+ super.requestLayout();
+ }
+ }
+
+ @Override
+ public void computeScroll() {
+ final int childCount = getChildCount();
+ float scrimOpacity = 0;
+ for (int i = 0; i < childCount; i++) {
+ final float onscreen = ((LayoutParams) getChildAt(i).getLayoutParams()).onScreen;
+ scrimOpacity = Math.max(scrimOpacity, onscreen);
+ }
+ mScrimOpacity = scrimOpacity;
+
+ // "|" used on purpose; both need to run.
+ if (mLeftDragger.continueSettling(true) | mRightDragger.continueSettling(true)) {
+ ViewCompat.postInvalidateOnAnimation(this);
+ }
+ }
+
+ private static boolean hasOpaqueBackground(View v) {
+ final Drawable bg = v.getBackground();
+ return bg != null && bg.getOpacity() == PixelFormat.OPAQUE;
+ }
+
+ @Override
+ protected boolean drawChild(@NonNull Canvas canvas, @NonNull View child, long drawingTime) {
+ final int height = getHeight();
+ final boolean drawingContent = isContentView(child);
+ int clipLeft = 0, clipRight = getWidth();
+
+ final int restoreCount = canvas.save();
+ if (drawingContent) {
+ final int childCount = getChildCount();
+ for (int i = 0; i < childCount; i++) {
+ final View v = getChildAt(i);
+ if (v == child || v.getVisibility() != VISIBLE ||
+ !hasOpaqueBackground(v) || !isDrawerView(v) ||
+ v.getHeight() < height) {
+ continue;
+ }
+
+ if (checkDrawerViewAbsoluteGravity(v, Gravity.LEFT)) {
+ final int vright = v.getRight();
+ if (vright > clipLeft) clipLeft = vright;
+ } else {
+ final int vleft = v.getLeft();
+ if (vleft < clipRight) clipRight = vleft;
+ }
+ }
+ canvas.clipRect(clipLeft, 0, clipRight, getHeight());
+ }
+ final boolean result = super.drawChild(canvas, child, drawingTime);
+ canvas.restoreToCount(restoreCount);
+
+ if (mScrimOpacity > 0 && drawingContent) {
+ final int baseAlpha = (mScrimColor & 0xff000000) >>> 24;
+ final int imag = (int) (baseAlpha * mScrimOpacity);
+ final int color = imag << 24 | (mScrimColor & 0xffffff);
+ mScrimPaint.setColor(color);
+
+ canvas.drawRect(clipLeft, 0, clipRight, getHeight(), mScrimPaint);
+ } else if (mShadowLeft != null && checkDrawerViewAbsoluteGravity(child, Gravity.LEFT)) {
+ final int shadowWidth = mShadowLeft.getIntrinsicWidth();
+ final int childRight = child.getRight();
+ final int drawerPeekDistance = mLeftDragger.getEdgeSize();
+ final float alpha =
+ Math.max(0, Math.min((float) childRight / drawerPeekDistance, 1.f));
+ mShadowLeft.setBounds(childRight, child.getTop(),
+ childRight + shadowWidth, child.getBottom());
+ mShadowLeft.setAlpha((int) (0xff * alpha));
+ mShadowLeft.draw(canvas);
+ } else if (mShadowRight != null && checkDrawerViewAbsoluteGravity(child, Gravity.RIGHT)) {
+ final int shadowWidth = mShadowRight.getIntrinsicWidth();
+ final int childLeft = child.getLeft();
+ final int showing = getWidth() - childLeft;
+ final int drawerPeekDistance = mRightDragger.getEdgeSize();
+ final float alpha =
+ Math.max(0, Math.min((float) showing / drawerPeekDistance, 1.f));
+ mShadowRight.setBounds(childLeft - shadowWidth, child.getTop(),
+ childLeft, child.getBottom());
+ mShadowRight.setAlpha((int) (0xff * alpha));
+ mShadowRight.draw(canvas);
+ }
+ return result;
+ }
+
+ boolean isContentView(View child) {
+ return ((LayoutParams) child.getLayoutParams()).gravity == Gravity.NO_GRAVITY;
+ }
+
+ boolean isDrawerView(View child) {
+ final int gravity = ((LayoutParams) child.getLayoutParams()).gravity;
+ final int absGravity = GravityCompat.getAbsoluteGravity(gravity, ViewCompat.getLayoutDirection(child));
+ return (absGravity & (Gravity.LEFT | Gravity.RIGHT)) != 0;
+ }
+
+ @Override
+ public boolean onInterceptTouchEvent(MotionEvent ev) {
+ final int action = MotionEventCompat.getActionMasked(ev);
+
+ // "|" used deliberately here; both methods should be invoked.
+ final boolean interceptForDrag = mLeftDragger.shouldInterceptTouchEvent(ev) |
+ mRightDragger.shouldInterceptTouchEvent(ev);
+
+ boolean interceptForTap = false;
+
+ switch (action) {
+ case MotionEvent.ACTION_DOWN: {
+ final float x = ev.getX();
+ final float y = ev.getY();
+ mInitialMotionX = x;
+ mInitialMotionY = y;
+ if (mScrimOpacity > 0) {
+ final View child = mLeftDragger.findTopChildUnder((int) x, (int) y);
+ if (child != null && isContentView(child)) {
+ interceptForTap = true;
+ }
+ }
+ mChildrenCanceledTouch = false;
+ break;
+ }
+
+ case MotionEvent.ACTION_MOVE: {
+ // If we cross the touch slop, don't perform the delayed peek for an edge touch.
+ if (mLeftDragger.checkTouchSlop(ViewDragHelper.DIRECTION_ALL)) {
+ mLeftCallback.removeCallbacks();
+ mRightCallback.removeCallbacks();
+ }
+ break;
+ }
+
+ case MotionEvent.ACTION_CANCEL:
+ case MotionEvent.ACTION_UP: {
+ closeDrawers(true);
+ mChildrenCanceledTouch = false;
+ }
+ }
+
+ return interceptForDrag || interceptForTap || hasPeekingDrawer() || mChildrenCanceledTouch;
+ }
+
+ @Override
+ public boolean onTouchEvent(@NonNull MotionEvent ev) {
+ mLeftDragger.processTouchEvent(ev);
+ mRightDragger.processTouchEvent(ev);
+
+ final int action = ev.getAction();
+ boolean wantTouchEvents = true;
+
+ switch (action & MotionEventCompat.ACTION_MASK) {
+ case MotionEvent.ACTION_DOWN: {
+ final float x = ev.getX();
+ final float y = ev.getY();
+ mInitialMotionX = x;
+ mInitialMotionY = y;
+ mChildrenCanceledTouch = false;
+ break;
+ }
+
+ case MotionEvent.ACTION_UP: {
+ final float x = ev.getX();
+ final float y = ev.getY();
+ boolean peekingOnly = true;
+ final View touchedView = mLeftDragger.findTopChildUnder((int) x, (int) y);
+ if (touchedView != null && isContentView(touchedView)) {
+ final float dx = x - mInitialMotionX;
+ final float dy = y - mInitialMotionY;
+ final int slop = mLeftDragger.getTouchSlop();
+ if (dx * dx + dy * dy < slop * slop) {
+ // Taps close a dimmed open drawer but only if it isn't locked open.
+ final View openDrawer = findOpenDrawer();
+ if (openDrawer != null) {
+ peekingOnly = getDrawerLockMode(openDrawer) == LOCK_MODE_LOCKED_OPEN;
+ }
+ }
+ }
+ closeDrawers(peekingOnly);
+ break;
+ }
+
+ case MotionEvent.ACTION_CANCEL: {
+ closeDrawers(true);
+ mChildrenCanceledTouch = false;
+ break;
+ }
+ }
+
+ return wantTouchEvents;
+ }
+
+ @Override
+ public void requestDisallowInterceptTouchEvent(boolean disallowIntercept) {
+ if (CHILDREN_DISALLOW_INTERCEPT ||
+ (!mLeftDragger.isEdgeTouched(ViewDragHelper.EDGE_LEFT) &&
+ !mRightDragger.isEdgeTouched(ViewDragHelper.EDGE_RIGHT))) {
+ // If we have an edge touch we want to skip this and track it for later instead.
+ super.requestDisallowInterceptTouchEvent(disallowIntercept);
+ }
+ if (disallowIntercept) {
+ closeDrawers(true);
+ }
+ }
+
+ /**
+ * Close all currently open drawer views by animating them out of view.
+ */
+ public void closeDrawers() {
+ closeDrawers(false);
+ }
+
+ void closeDrawers(boolean peekingOnly) {
+ boolean needsInvalidate = false;
+ final int childCount = getChildCount();
+ for (int i = 0; i < childCount; i++) {
+ final View child = getChildAt(i);
+ final LayoutParams lp = (LayoutParams) child.getLayoutParams();
+
+ if (!isDrawerView(child) || (peekingOnly && !lp.isPeeking)) {
+ continue;
+ }
+
+ final int childWidth = child.getWidth();
+
+ if (checkDrawerViewAbsoluteGravity(child, Gravity.LEFT)) {
+ needsInvalidate |= mLeftDragger.smoothSlideViewTo(child,
+ -childWidth, child.getTop());
+ } else {
+ needsInvalidate |= mRightDragger.smoothSlideViewTo(child,
+ getWidth(), child.getTop());
+ }
+
+ lp.isPeeking = false;
+ }
+
+ mLeftCallback.removeCallbacks();
+ mRightCallback.removeCallbacks();
+
+ if (needsInvalidate) {
+ invalidate();
+ }
+ }
+
+ /**
+ * Open the specified drawer view by animating it into view.
+ *
+ * @param drawerView Drawer view to open
+ */
+ public void openDrawer(View drawerView) {
+ if (!isDrawerView(drawerView)) {
+ throw new IllegalArgumentException("View " + drawerView + " is not a sliding drawer");
+ }
+
+ if (mFirstLayout) {
+ final LayoutParams lp = (LayoutParams) drawerView.getLayoutParams();
+ lp.onScreen = 1.f;
+ lp.knownOpen = true;
+
+ updateChildrenImportantForAccessibility(drawerView, true);
+ } else {
+ if (checkDrawerViewAbsoluteGravity(drawerView, Gravity.LEFT)) {
+ mLeftDragger.smoothSlideViewTo(drawerView, 0, drawerView.getTop());
+ } else {
+ mRightDragger.smoothSlideViewTo(drawerView, getWidth() - drawerView.getWidth(),
+ drawerView.getTop());
+ }
+ }
+ invalidate();
+ }
+
+ /**
+ * Open the specified drawer by animating it out of view.
+ *
+ * @param gravity Gravity.LEFT to move the left drawer or Gravity.RIGHT for the right.
+ * GravityCompat.START or GravityCompat.END may also be used.
+ */
+ public void openDrawer(@EdgeGravity int gravity) {
+ final View drawerView = findDrawerWithGravity(gravity);
+ if (drawerView == null) {
+ throw new IllegalArgumentException("No drawer view found with gravity " +
+ gravityToString(gravity));
+ }
+ openDrawer(drawerView);
+ }
+
+ /**
+ * Close the specified drawer view by animating it into view.
+ *
+ * @param drawerView Drawer view to close
+ */
+ public void closeDrawer(View drawerView) {
+ if (!isDrawerView(drawerView)) {
+ throw new IllegalArgumentException("View " + drawerView + " is not a sliding drawer");
+ }
+
+ if (mFirstLayout) {
+ final LayoutParams lp = (LayoutParams) drawerView.getLayoutParams();
+ lp.onScreen = 0.f;
+ lp.knownOpen = false;
+ } else {
+ if (checkDrawerViewAbsoluteGravity(drawerView, Gravity.LEFT)) {
+ mLeftDragger.smoothSlideViewTo(drawerView, -drawerView.getWidth(),
+ drawerView.getTop());
+ } else {
+ mRightDragger.smoothSlideViewTo(drawerView, getWidth(), drawerView.getTop());
+ }
+ }
+ invalidate();
+ }
+
+ /**
+ * Close the specified drawer by animating it out of view.
+ *
+ * @param gravity Gravity.LEFT to move the left drawer or Gravity.RIGHT for the right.
+ * GravityCompat.START or GravityCompat.END may also be used.
+ */
+ public void closeDrawer(@EdgeGravity int gravity) {
+ final View drawerView = findDrawerWithGravity(gravity);
+ if (drawerView == null) {
+ throw new IllegalArgumentException("No drawer view found with gravity " +
+ gravityToString(gravity));
+ }
+ closeDrawer(drawerView);
+ }
+
+ /**
+ * Check if the given drawer view is currently in an open state.
+ * To be considered "open" the drawer must have settled into its fully
+ * visible state. To check for partial visibility use
+ * {@link #isDrawerVisible(View)}.
+ *
+ * @param drawer Drawer view to check
+ * @return true if the given drawer view is in an open state
+ * @see #isDrawerVisible(View)
+ */
+ public boolean isDrawerOpen(View drawer) {
+ if (!isDrawerView(drawer)) {
+ throw new IllegalArgumentException("View " + drawer + " is not a drawer");
+ }
+ return ((LayoutParams) drawer.getLayoutParams()).knownOpen;
+ }
+
+ /**
+ * Check if the given drawer view is currently in an open state.
+ * To be considered "open" the drawer must have settled into its fully
+ * visible state. If there is no drawer with the given gravity this method
+ * will return false.
+ *
+ * @param drawerGravity Gravity of the drawer to check
+ * @return true if the given drawer view is in an open state
+ */
+ public boolean isDrawerOpen(@EdgeGravity int drawerGravity) {
+ final View drawerView = findDrawerWithGravity(drawerGravity);
+ if (drawerView != null) {
+ return isDrawerOpen(drawerView);
+ }
+ return false;
+ }
+
+ /**
+ * Check if a given drawer view is currently visible on-screen. The drawer
+ * may be only peeking onto the screen, fully extended, or anywhere inbetween.
+ *
+ * @param drawer Drawer view to check
+ * @return true if the given drawer is visible on-screen
+ * @see #isDrawerOpen(View)
+ */
+ public boolean isDrawerVisible(View drawer) {
+ if (!isDrawerView(drawer)) {
+ throw new IllegalArgumentException("View " + drawer + " is not a drawer");
+ }
+ return ((LayoutParams) drawer.getLayoutParams()).onScreen > 0;
+ }
+
+ /**
+ * Check if a given drawer view is currently visible on-screen. The drawer
+ * may be only peeking onto the screen, fully extended, or anywhere in between.
+ * If there is no drawer with the given gravity this method will return false.
+ *
+ * @param drawerGravity Gravity of the drawer to check
+ * @return true if the given drawer is visible on-screen
+ */
+ public boolean isDrawerVisible(@EdgeGravity int drawerGravity) {
+ final View drawerView = findDrawerWithGravity(drawerGravity);
+ return drawerView != null && isDrawerVisible(drawerView);
+ }
+
+ private boolean hasPeekingDrawer() {
+ final int childCount = getChildCount();
+ for (int i = 0; i < childCount; i++) {
+ final LayoutParams lp = (LayoutParams) getChildAt(i).getLayoutParams();
+ if (lp.isPeeking) {
+ return true;
+ }
+ }
+ return false;
+ }
+
+ @Override
+ protected ViewGroup.LayoutParams generateDefaultLayoutParams() {
+ return new LayoutParams(LayoutParams.FILL_PARENT, LayoutParams.FILL_PARENT);
+ }
+
+ @Override
+ protected ViewGroup.LayoutParams generateLayoutParams(ViewGroup.LayoutParams p) {
+ return p instanceof LayoutParams
+ ? new LayoutParams((LayoutParams) p)
+ : p instanceof MarginLayoutParams
+ ? new LayoutParams((MarginLayoutParams) p)
+ : new LayoutParams(p);
+ }
+
+ @Override
+ protected boolean checkLayoutParams(ViewGroup.LayoutParams p) {
+ return p instanceof LayoutParams && super.checkLayoutParams(p);
+ }
+
+ @Override
+ public ViewGroup.LayoutParams generateLayoutParams(AttributeSet attrs) {
+ return new LayoutParams(getContext(), attrs);
+ }
+
+ private boolean hasVisibleDrawer() {
+ return findVisibleDrawer() != null;
+ }
+
+ private View findVisibleDrawer() {
+ final int childCount = getChildCount();
+ for (int i = 0; i < childCount; i++) {
+ final View child = getChildAt(i);
+ if (isDrawerView(child) && isDrawerVisible(child)) {
+ return child;
+ }
+ }
+ return null;
+ }
+
+ void cancelChildViewTouch() {
+ // Cancel child touches
+ if (!mChildrenCanceledTouch) {
+ final long now = SystemClock.uptimeMillis();
+ final MotionEvent cancelEvent = MotionEvent.obtain(now, now,
+ MotionEvent.ACTION_CANCEL, 0.0f, 0.0f, 0);
+ final int childCount = getChildCount();
+ for (int i = 0; i < childCount; i++) {
+ getChildAt(i).dispatchTouchEvent(cancelEvent);
+ }
+ cancelEvent.recycle();
+ mChildrenCanceledTouch = true;
+ }
+ }
+
+ @Override
+ public boolean onKeyDown(int keyCode, @NonNull KeyEvent event) {
+ if (keyCode == KeyEvent.KEYCODE_BACK && hasVisibleDrawer()) {
+ KeyEventCompat.startTracking(event);
+ return true;
+ }
+ return super.onKeyDown(keyCode, event);
+ }
+
+ @Override
+ public boolean onKeyUp(int keyCode, KeyEvent event) {
+ if (keyCode == KeyEvent.KEYCODE_BACK) {
+ final View visibleDrawer = findVisibleDrawer();
+ if (visibleDrawer != null && getDrawerLockMode(visibleDrawer) == LOCK_MODE_UNLOCKED) {
+ closeDrawers();
+ }
+ return visibleDrawer != null;
+ }
+ return super.onKeyUp(keyCode, event);
+ }
+
+ @Override
+ protected void onRestoreInstanceState(Parcelable state) {
+ final SavedState ss = (SavedState) state;
+ super.onRestoreInstanceState(ss.getSuperState());
+
+ if (ss.openDrawerGravity != Gravity.NO_GRAVITY) {
+ final View toOpen = findDrawerWithGravity(ss.openDrawerGravity);
+ if (toOpen != null) {
+ openDrawer(toOpen);
+ }
+ }
+
+ setDrawerLockMode(ss.lockModeLeft, Gravity.LEFT);
+ setDrawerLockMode(ss.lockModeRight, Gravity.RIGHT);
+ }
+
+ @Override
+ protected Parcelable onSaveInstanceState() {
+ final Parcelable superState = super.onSaveInstanceState();
+ final SavedState ss = new SavedState(superState);
+
+ final View openDrawer = findOpenDrawer();
+ if (openDrawer != null) {
+ ss.openDrawerGravity = ((LayoutParams) openDrawer.getLayoutParams()).gravity;
+ }
+
+ ss.lockModeLeft = mLockModeLeft;
+ ss.lockModeRight = mLockModeRight;
+
+ return ss;
+ }
+
+ @Override
+ public void addView(View child, int index, ViewGroup.LayoutParams params) {
+ super.addView(child, index, params);
+
+ final View openDrawer = findOpenDrawer();
+ if (openDrawer != null || isDrawerView(child)) {
+ // A drawer is already open or the new view is a drawer, so the
+ // new view should start out hidden.
+ ViewCompat.setImportantForAccessibility(child, ViewCompat.IMPORTANT_FOR_ACCESSIBILITY_NO_HIDE_DESCENDANTS);
+ } else {
+ // Otherwise this is a content view and no drawer is open, so the
+ // new view should start out visible.
+ ViewCompat.setImportantForAccessibility(child, ViewCompat.IMPORTANT_FOR_ACCESSIBILITY_YES);
+ }
+
+ // We only need a delegate here if the framework doesn't understand
+ // NO_HIDE_DESCENDANTS importance.
+ if (!CAN_HIDE_DESCENDANTS) {
+ ViewCompat.setAccessibilityDelegate(child, mChildAccessibilityDelegate);
+ }
+ }
+
+ private static boolean includeChildForAccessibility(View child) {
+ // If the child is not important for accessibility we make
+ // sure this hides the entire subtree rooted at it as the
+ // IMPORTANT_FOR_ACCESSIBILITY_NO_HIDE_DESCENDATS is not
+ // supported on older platforms but we want to hide the entire
+ // content and not opened drawers if a drawer is opened.
+ return ViewCompat.getImportantForAccessibility(child)
+ != ViewCompat.IMPORTANT_FOR_ACCESSIBILITY_NO_HIDE_DESCENDANTS
+ && ViewCompat.getImportantForAccessibility(child)
+ != ViewCompat.IMPORTANT_FOR_ACCESSIBILITY_NO;
+ }
+
+ /**
+ * State persisted across instances
+ */
+ protected static class SavedState extends BaseSavedState {
+ int openDrawerGravity = Gravity.NO_GRAVITY;
+ int lockModeLeft = LOCK_MODE_UNLOCKED;
+ int lockModeRight = LOCK_MODE_UNLOCKED;
+
+ public SavedState(Parcel in) {
+ super(in);
+ openDrawerGravity = in.readInt();
+ }
+
+ public SavedState(Parcelable superState) {
+ super(superState);
+ }
+
+ @Override
+ public void writeToParcel(Parcel dest, int flags) {
+ super.writeToParcel(dest, flags);
+ dest.writeInt(openDrawerGravity);
+ }
+
+ public static final Creator