Initial Contribution

1 files changed, 950 insertions, 0 deletions

diff --git a/core/java/android/widget/RelativeLayout.java b/core/java/android/widget/RelativeLayout.java
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+++ b/core/java/android/widget/RelativeLayout.java
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+/*
+ * Copyright (C) 2006 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package android.widget;
+
+import android.content.Context;
+import android.content.res.TypedArray;
+import android.util.AttributeSet;
+import android.view.View;
+import android.view.ViewGroup;
+import android.view.Gravity;
+import android.widget.RemoteViews.RemoteView;
+import android.graphics.Rect;
+import com.android.internal.R;
+
+
+/**
+ * A Layout where the positions of the children can be described in relation to each other or to the
+ * parent. For the sake of efficiency, the relations between views are evaluated in one pass, so if
+ * view Y is dependent on the position of view X, make sure the view X comes first in the layout.
+ * 
+ * <p>
+ * Note that you cannot have a circular dependency between the size of the RelativeLayout and the
+ * position of its children. For example, you cannot have a RelativeLayout whose height is set to
+ * {@link android.view.ViewGroup.LayoutParams#WRAP_CONTENT WRAP_CONTENT} and a child set to
+ * {@link #ALIGN_PARENT_BOTTOM}.
+ * </p>
+ * 
+ * <p>
+ * Also see {@link android.widget.RelativeLayout.LayoutParams RelativeLayout.LayoutParams} for
+ * layout attributes
+ * </p>
+ * 
+ * @attr ref android.R.styleable#RelativeLayout_gravity
+ * @attr ref android.R.styleable#RelativeLayout_ignoreGravity
+ */
+@RemoteView
+public class RelativeLayout extends ViewGroup {
+    public static final int TRUE = -1;
+
+    /**
+     * Rule that aligns a child's right edge with another child's left edge.
+     */
+    public static final int LEFT_OF                  = 0;
+    /**
+     * Rule that aligns a child's left edge with another child's right edge.
+     */
+    public static final int RIGHT_OF                 = 1;
+    /**
+     * Rule that aligns a child's bottom edge with another child's top edge.
+     */
+    public static final int ABOVE                    = 2;
+    /**
+     * Rule that aligns a child's top edge with another child's bottom edge.
+     */
+    public static final int BELOW                    = 3;
+
+    /**
+     * Rule that aligns a child's baseline with another child's baseline.
+     */
+    public static final int ALIGN_BASELINE           = 4;
+    /**
+     * Rule that aligns a child's left edge with another child's left edge.
+     */
+    public static final int ALIGN_LEFT               = 5;
+    /**
+     * Rule that aligns a child's top edge with another child's top edge.
+     */
+    public static final int ALIGN_TOP                = 6;
+    /**
+     * Rule that aligns a child's right edge with another child's right edge.
+     */
+    public static final int ALIGN_RIGHT              = 7;
+    /**
+     * Rule that aligns a child's bottom edge with another child's bottom edge.
+     */
+    public static final int ALIGN_BOTTOM             = 8;
+
+    /**
+     * Rule that aligns the child's left edge with its RelativeLayout
+     * parent's left edge.
+     */
+    public static final int ALIGN_PARENT_LEFT        = 9;
+    /**
+     * Rule that aligns the child's top edge with its RelativeLayout
+     * parent's top edge.
+     */
+    public static final int ALIGN_PARENT_TOP         = 10;
+    /**
+     * Rule that aligns the child's right edge with its RelativeLayout
+     * parent's right edge.
+     */
+    public static final int ALIGN_PARENT_RIGHT       = 11;
+    /**
+     * Rule that aligns the child's bottom edge with its RelativeLayout
+     * parent's bottom edge.
+     */
+    public static final int ALIGN_PARENT_BOTTOM      = 12;
+
+    /**
+     * Rule that centers the child with respect to the bounds of its
+     * RelativeLayout parent.
+     */
+    public static final int CENTER_IN_PARENT         = 13;
+    /**
+     * Rule that centers the child horizontally with respect to the
+     * bounds of its RelativeLayout parent.
+     */
+    public static final int CENTER_HORIZONTAL        = 14;
+    /**
+     * Rule that centers the child vertically with respect to the
+     * bounds of its RelativeLayout parent.
+     */
+    public static final int CENTER_VERTICAL          = 15;
+
+    private static final int VERB_COUNT              = 16;
+
+    private View mBaselineView = null;
+    private boolean mHasBaselineAlignedChild;
+
+    private int mGravity = Gravity.LEFT | Gravity.TOP;
+    private final Rect mContentBounds = new Rect();
+    private final Rect mSelfBounds = new Rect();
+    private int mIgnoreGravity;
+
+    public RelativeLayout(Context context) {
+        super(context);
+    }
+
+    public RelativeLayout(Context context, AttributeSet attrs) {
+        super(context, attrs);
+        initFromAttributes(context, attrs);
+    }
+
+    public RelativeLayout(Context context, AttributeSet attrs, int defStyle) {
+        super(context, attrs, defStyle);
+        initFromAttributes(context, attrs);
+    }
+
+    private void initFromAttributes(Context context, AttributeSet attrs) {
+        TypedArray a = context.obtainStyledAttributes(attrs, R.styleable.RelativeLayout);
+        mIgnoreGravity = a.getResourceId(R.styleable.RelativeLayout_ignoreGravity, 0);
+        mGravity = a.getInt(R.styleable.RelativeLayout_gravity, mGravity);
+        a.recycle();
+    }
+
+    /**
+     * Defines which View is ignored when the gravity is applied. This setting has no
+     * effect if the gravity is <code>Gravity.LEFT | Gravity.TOP</code>.
+     *
+     * @param viewId The id of the View to be ignored by gravity, or 0 if no View
+     *        should be ignored.
+     *
+     * @see #setGravity(int)
+     *
+     * @attr ref android.R.styleable#RelativeLayout_ignoreGravity
+     */
+    public void setIgnoreGravity(int viewId) {
+        mIgnoreGravity = viewId;
+    }
+
+    /**
+     * Describes how the child views are positioned. Defaults to
+     * <code>Gravity.LEFT | Gravity.TOP</code>.
+     *
+     * @param gravity See {@link android.view.Gravity}
+     *
+     * @see #setHorizontalGravity(int)
+     * @see #setVerticalGravity(int)
+     *
+     * @attr ref android.R.styleable#RelativeLayout_gravity
+     */
+    public void setGravity(int gravity) {
+        if (mGravity != gravity) {
+            if ((gravity & Gravity.HORIZONTAL_GRAVITY_MASK) == 0) {
+                gravity |= Gravity.LEFT;
+            }
+
+            if ((gravity & Gravity.VERTICAL_GRAVITY_MASK) == 0) {
+                gravity |= Gravity.TOP;
+            }
+
+            mGravity = gravity;
+            requestLayout();
+        }
+    }
+
+    public void setHorizontalGravity(int horizontalGravity) {
+        final int gravity = horizontalGravity & Gravity.HORIZONTAL_GRAVITY_MASK;
+        if ((mGravity & Gravity.HORIZONTAL_GRAVITY_MASK) != gravity) {
+            mGravity = (mGravity & ~Gravity.HORIZONTAL_GRAVITY_MASK) | gravity;
+            requestLayout();
+        }
+    }
+
+    public void setVerticalGravity(int verticalGravity) {
+        final int gravity = verticalGravity & Gravity.VERTICAL_GRAVITY_MASK;
+        if ((mGravity & Gravity.VERTICAL_GRAVITY_MASK) != gravity) {
+            mGravity = (mGravity & ~Gravity.VERTICAL_GRAVITY_MASK) | gravity;
+            requestLayout();
+        }
+    }
+
+    @Override
+    public int getBaseline() {
+        return mBaselineView != null ? mBaselineView.getBaseline() : super.getBaseline();
+    }
+
+    @Override
+    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
+        int myWidth = -1;
+        int myHeight = -1;
+
+        int width = 0;
+        int height = 0;
+
+        int widthMode = MeasureSpec.getMode(widthMeasureSpec);
+        int heightMode = MeasureSpec.getMode(heightMeasureSpec);
+        int widthSize = MeasureSpec.getSize(widthMeasureSpec);
+        int heightSize = MeasureSpec.getSize(heightMeasureSpec);
+
+        // Record our dimensions if they are known;
+        if (widthMode != MeasureSpec.UNSPECIFIED) {
+            myWidth = widthSize;
+        }
+
+        if (heightMode != MeasureSpec.UNSPECIFIED) {
+            myHeight = heightSize;
+        }
+
+        if (widthMode == MeasureSpec.EXACTLY) {
+            width = myWidth;
+        }
+
+        if (heightMode == MeasureSpec.EXACTLY) {
+            height = myHeight;
+        }
+
+        int len = this.getChildCount();
+        mHasBaselineAlignedChild = false;
+
+        View ignore = null;
+        int gravity = mGravity & Gravity.HORIZONTAL_GRAVITY_MASK;
+        final boolean horizontalGravity = gravity != Gravity.LEFT && gravity != 0;
+        gravity = mGravity & Gravity.VERTICAL_GRAVITY_MASK;
+        final boolean verticalGravity = gravity != Gravity.TOP && gravity != 0;
+
+        int left = Integer.MAX_VALUE;
+        int top = Integer.MAX_VALUE;
+        int right = Integer.MIN_VALUE;
+        int bottom = Integer.MIN_VALUE;
+
+        if ((horizontalGravity || verticalGravity) && mIgnoreGravity != 0) {
+            ignore = findViewById(mIgnoreGravity);
+        }
+
+        for (int i = 0; i < len; i++) {
+            View child = getChildAt(i);
+            if (child.getVisibility() != GONE) {
+                LayoutParams params = (LayoutParams) child.getLayoutParams();
+                applySizeRules(params, myWidth, myHeight);
+                measureChild(child, params, myWidth, myHeight);
+                positionChild(child, params, myWidth, myHeight);
+
+                if (widthMode != MeasureSpec.EXACTLY) {
+                    width = Math.max(width, params.mRight);
+                }
+                if (heightMode != MeasureSpec.EXACTLY) {
+                    height = Math.max(height, params.mBottom);
+                }
+
+                if (child != ignore || verticalGravity) {
+                    left = Math.min(left, params.mLeft - params.leftMargin);
+                    top = Math.min(top, params.mTop - params.topMargin);
+                }
+
+                if (child != ignore || horizontalGravity) {
+                    right = Math.max(right, params.mRight + params.rightMargin);
+                    bottom = Math.max(bottom, params.mBottom + params.bottomMargin);
+                }
+            }
+        }
+
+        if (mHasBaselineAlignedChild) {
+            for (int i = 0; i < len; i++) {
+                View child = getChildAt(i);
+                if (child.getVisibility() != GONE) {
+                    LayoutParams params = (LayoutParams) child.getLayoutParams();
+                    alignBaseline(child, params);
+
+                    if (child != ignore || verticalGravity) {
+                    left = Math.min(left, params.mLeft - params.leftMargin);
+                    top = Math.min(top, params.mTop - params.topMargin);
+                    }
+
+                    if (child != ignore || horizontalGravity) {
+                        right = Math.max(right, params.mRight + params.rightMargin);
+                        bottom = Math.max(bottom, params.mBottom + params.bottomMargin);
+                    }
+                }
+            }
+        }
+
+        if (widthMode != MeasureSpec.EXACTLY) {
+            // Width already has left padding in it since it was calculated by looking at 
+            // the right of each child view
+            width += mPaddingRight;
+
+            if (mLayoutParams.width >= 0) {
+                width = Math.max(width, mLayoutParams.width);
+            }
+
+            width = Math.max(width, getSuggestedMinimumWidth());
+            width = resolveSize(width, widthMeasureSpec);
+        }
+        if (heightMode != MeasureSpec.EXACTLY) {
+            // Height already has top padding in it since it was calculated by looking at 
+            // the bottom of each child view
+            height += mPaddingBottom;
+
+            if (mLayoutParams.height >= 0) {
+                height = Math.max(height, mLayoutParams.height);
+            }
+
+            height = Math.max(height, getSuggestedMinimumHeight());
+            height = resolveSize(height, heightMeasureSpec);
+        }
+
+        if (horizontalGravity || verticalGravity) {
+            final Rect selfBounds = mSelfBounds;
+            selfBounds.set(mPaddingLeft, mPaddingTop, width - mPaddingRight,
+                    height - mPaddingBottom);
+
+            final Rect contentBounds = mContentBounds;
+            Gravity.apply(mGravity, right - left, bottom - top, selfBounds, contentBounds);
+
+            final int horizontalOffset = contentBounds.left - left;
+            final int verticalOffset = contentBounds.top - top;
+            if (horizontalOffset != 0 || verticalOffset != 0) {
+                for (int i = 0; i < len; i++) {
+                    View child = getChildAt(i);
+                    if (child.getVisibility() != GONE && child != ignore) {
+                        LayoutParams params = (LayoutParams) child.getLayoutParams();
+                        params.mLeft += horizontalOffset;
+                        params.mRight += horizontalOffset;
+                        params.mTop += verticalOffset;
+                        params.mBottom += verticalOffset;
+                    }
+                }
+            }
+        }
+
+        setMeasuredDimension(width, height);
+    }
+
+    private void alignBaseline(View child, LayoutParams params) {
+        int[] rules = params.getRules();
+        int anchorBaseline = getRelatedViewBaseline(rules, ALIGN_BASELINE);
+
+        if (anchorBaseline != -1) {
+            LayoutParams anchorParams = getRelatedViewParams(rules, ALIGN_BASELINE);
+            if (anchorParams != null) {
+                int offset = anchorParams.mTop + anchorBaseline;
+                int baseline = child.getBaseline();
+                if (baseline != -1) {
+                    offset -= baseline;
+                }
+                int height = params.mBottom - params.mTop;
+                params.mTop = offset;
+                params.mBottom = params.mTop + height;
+            }
+        }
+
+        if (mBaselineView == null) {
+            mBaselineView = child;
+        } else {
+            LayoutParams lp = (LayoutParams) mBaselineView.getLayoutParams();
+            if (params.mTop < lp.mTop || (params.mTop == lp.mTop && params.mLeft < lp.mLeft)) {
+                mBaselineView = child;
+            }
+        }
+    }
+
+    /**
+     * Measure a child. The child should have left, top, right and bottom information
+     * stored in its LayoutParams. If any of these values is -1 it means that the view
+     * can extend up to the corresponding edge.
+     *
+     * @param child Child to measure
+     * @param params LayoutParams associated with child
+     * @param myWidth Width of the the RelativeLayout
+     * @param myHeight Height of the RelativeLayout
+     */
+    private void measureChild(View child, LayoutParams params, int myWidth,
+            int myHeight) {
+
+        int childWidthMeasureSpec = getChildMeasureSpec(params.mLeft,
+                params.mRight, params.width,
+                params.leftMargin, params.rightMargin,
+                mPaddingLeft, mPaddingRight,
+                myWidth);
+        int childHeightMeasureSpec = getChildMeasureSpec(params.mTop,
+                params.mBottom, params.height,
+                params.topMargin, params.bottomMargin,
+                mPaddingTop, mPaddingBottom,
+                myHeight);
+        child.measure(childWidthMeasureSpec, childHeightMeasureSpec);
+    }
+
+    /**
+     * Get a measure spec that accounts for all of the constraints on this view.
+     * This includes size contstraints imposed by the RelativeLayout as well as
+     * the View's desired dimension.
+     *
+     * @param childStart The left or top field of the child's layout params
+     * @param childEnd The right or bottom field of the child's layout params
+     * @param childSize The child's desired size (the width or height field of
+     *        the child's layout params)
+     * @param startMargin The left or top margin
+     * @param endMargin The right or bottom margin
+     * @param startPadding mPaddingLeft or mPaddingTop
+     * @param endPadding mPaddingRight or mPaddingBottom
+     * @param mySize The width or height of this view (the RelativeLayout)
+     * @return MeasureSpec for the child
+     */
+    private int getChildMeasureSpec(int childStart, int childEnd,
+            int childSize, int startMargin, int endMargin, int startPadding,
+            int endPadding, int mySize) {
+        int childSpecMode = 0;
+        int childSpecSize = 0;
+
+        // Figure out start and end bounds.
+        int tempStart = childStart;
+        int tempEnd = childEnd;
+
+        // If the view did not express a layout constraint for an edge, use
+        // view's margins and our padding
+        if (tempStart < 0) {
+            tempStart = startPadding + startMargin;
+        }
+        if (tempEnd < 0) {
+            tempEnd = mySize - endPadding - endMargin;
+        }
+
+        // Figure out maximum size available to this view
+        int maxAvailable = tempEnd - tempStart;
+
+        if (childStart >= 0 && childEnd >= 0) {
+            // Constraints fixed both edges, so child must be an exact size
+            childSpecMode = MeasureSpec.EXACTLY;
+            childSpecSize = maxAvailable;
+        } else {
+            if (childSize >= 0) {
+                // Child wanted an exact size. Give as much as possible
+                childSpecMode = MeasureSpec.EXACTLY;
+
+                if (maxAvailable >= 0) {
+                    // We have a maxmum size in this dimension.
+                    childSpecSize = Math.min(maxAvailable, childSize);
+                } else {
+                    // We can grow in this dimension.
+                    childSpecSize = childSize;
+                }
+            } else if (childSize == LayoutParams.FILL_PARENT) {
+                // Child wanted to be as big as possible. Give all availble
+                // space
+                childSpecMode = MeasureSpec.EXACTLY;
+                childSpecSize = maxAvailable;
+            } else if (childSize == LayoutParams.WRAP_CONTENT) {
+                // Child wants to wrap content. Use AT_MOST
+                // to communicate available space if we know
+                // our max size
+                if (maxAvailable >= 0) {
+                    // We have a maxmum size in this dimension.
+                    childSpecMode = MeasureSpec.AT_MOST;
+                    childSpecSize = maxAvailable;
+                } else {
+                    // We can grow in this dimension. Child can be as big as it
+                    // wants
+                    childSpecMode = MeasureSpec.UNSPECIFIED;
+                    childSpecSize = 0;
+                }
+            }
+        }
+
+        return MeasureSpec.makeMeasureSpec(childSpecSize, childSpecMode);
+    }
+
+    /**
+     * After the child has been measured, assign it a position. Some views may
+     * already have final values for l,t,r,b. Others may have one or both edges
+     * unfixed (i.e. set to -1) in each dimension. These will get positioned
+     * based on which edge is fixed, the view's desired dimension, and whether
+     * or not it is centered.
+     *
+     * @param child Child to position
+     * @param params LayoutParams associated with child
+     * @param myWidth Width of the the RelativeLayout
+     * @param myHeight Height of the RelativeLayout
+     */
+    private void positionChild(View child, LayoutParams params, int myWidth, int myHeight) {
+        int[] rules = params.getRules();
+
+        if (params.mLeft < 0 && params.mRight >= 0) {
+            // Right is fixed, but left varies
+            params.mLeft = params.mRight - child.getMeasuredWidth();
+        } else if (params.mLeft >= 0 && params.mRight < 0) {
+            // Left is fixed, but right varies
+            params.mRight = params.mLeft + child.getMeasuredWidth();
+        } else if (params.mLeft < 0 && params.mRight < 0) {
+            // Both left and right vary
+            if (0 != rules[CENTER_IN_PARENT] || 0 != rules[CENTER_HORIZONTAL]) {
+                centerHorizontal(child, params, myWidth);
+            } else {
+                params.mLeft = mPaddingLeft + params.leftMargin;
+                params.mRight = params.mLeft + child.getMeasuredWidth();
+            }
+        }
+
+        if (params.mTop < 0 && params.mBottom >= 0) {
+            // Bottom is fixed, but top varies
+            params.mTop = params.mBottom - child.getMeasuredHeight();
+        } else if (params.mTop >= 0 && params.mBottom < 0) {
+            // Top is fixed, but bottom varies
+            params.mBottom = params.mTop + child.getMeasuredHeight();
+        } else if (params.mTop < 0 && params.mBottom < 0) {
+            // Both top and bottom vary
+            if (0 != rules[CENTER_IN_PARENT] || 0 != rules[CENTER_VERTICAL]) {
+                centerVertical(child, params, myHeight);
+            } else {
+                params.mTop = mPaddingTop + params.topMargin;
+                params.mBottom = params.mTop + child.getMeasuredHeight();
+            }
+        }
+    }
+
+    /**
+     * Set l,t,r,b values in the LayoutParams for one view based on its layout rules.
+     * Big assumption #1: All antecedents of this view have been sized & positioned
+     * Big assumption #2: The dimensions of the parent view (the RelativeLayout)
+     * are already known if they are needed.
+     *
+     * @param childParams LayoutParams for the view being positioned
+     * @param myWidth Width of the the RelativeLayout
+     * @param myHeight Height of the RelativeLayout
+     */
+    private void applySizeRules(LayoutParams childParams, int myWidth, int myHeight) {
+        int[] rules = childParams.getRules();
+        RelativeLayout.LayoutParams anchorParams;
+
+        // -1 indicated a "soft requirement" in that direction. For example:
+        // left=10, right=-1 means the view must start at 10, but can go as far as it wants to the right
+        // left =-1, right=10 means the view must end at 10, but can go as far as it wants to the left
+        // left=10, right=20 means the left and right ends are both fixed
+        childParams.mLeft = -1;
+        childParams.mRight = -1;
+
+        anchorParams = getRelatedViewParams(rules, LEFT_OF);
+        if (anchorParams != null) {
+            childParams.mRight = anchorParams.mLeft - (anchorParams.leftMargin +
+                    childParams.rightMargin);
+        } else if (childParams.alignWithParent && rules[LEFT_OF] != 0) {
+            if (myWidth >= 0) {
+                childParams.mRight = myWidth - mPaddingRight - childParams.rightMargin;
+            } else {
+                // FIXME uh oh...
+            }
+        }
+
+        anchorParams = getRelatedViewParams(rules, RIGHT_OF);
+        if (anchorParams != null) {
+            childParams.mLeft = anchorParams.mRight + (anchorParams.rightMargin +
+                    childParams.leftMargin);
+        } else if (childParams.alignWithParent && rules[RIGHT_OF] != 0) {
+            childParams.mLeft = mPaddingLeft + childParams.leftMargin;
+        }
+
+        anchorParams = getRelatedViewParams(rules, ALIGN_LEFT);
+        if (anchorParams != null) {
+            childParams.mLeft = anchorParams.mLeft + childParams.leftMargin;
+        } else if (childParams.alignWithParent && rules[ALIGN_LEFT] != 0) {
+            childParams.mLeft = mPaddingLeft + childParams.leftMargin;
+        }
+
+        anchorParams = getRelatedViewParams(rules, ALIGN_RIGHT);
+        if (anchorParams != null) {
+            childParams.mRight = anchorParams.mRight - childParams.rightMargin;
+        } else if (childParams.alignWithParent && rules[ALIGN_RIGHT] != 0) {
+            if (myWidth >= 0) {
+                childParams.mRight = myWidth - mPaddingRight - childParams.rightMargin;
+            } else {
+                // FIXME uh oh...
+            }
+        }
+
+        if (0 != rules[ALIGN_PARENT_LEFT]) {
+            childParams.mLeft = mPaddingLeft + childParams.leftMargin;
+        }
+
+        if (0 != rules[ALIGN_PARENT_RIGHT]) {
+            if (myWidth >= 0) {
+                childParams.mRight = myWidth - mPaddingRight - childParams.rightMargin;
+            } else {
+                // FIXME uh oh...
+            }
+        }
+
+        childParams.mTop = -1;
+        childParams.mBottom = -1;
+
+        anchorParams = getRelatedViewParams(rules, ABOVE);
+        if (anchorParams != null) {
+            childParams.mBottom = anchorParams.mTop - (anchorParams.topMargin +
+                    childParams.bottomMargin);
+        } else if (childParams.alignWithParent && rules[ABOVE] != 0) {
+            if (myHeight >= 0) {
+                childParams.mBottom = myHeight - mPaddingBottom - childParams.bottomMargin;
+            } else {
+                // FIXME uh oh...
+            }
+        }
+
+        anchorParams = getRelatedViewParams(rules, BELOW);
+        if (anchorParams != null) {
+            childParams.mTop = anchorParams.mBottom + (anchorParams.bottomMargin +
+                    childParams.topMargin);
+        } else if (childParams.alignWithParent && rules[BELOW] != 0) {
+            childParams.mTop = mPaddingTop + childParams.topMargin;
+        }
+
+        anchorParams = getRelatedViewParams(rules, ALIGN_TOP);
+        if (anchorParams != null) {
+            childParams.mTop = anchorParams.mTop + childParams.topMargin;
+        } else if (childParams.alignWithParent && rules[ALIGN_TOP] != 0) {
+            childParams.mTop = mPaddingTop + childParams.topMargin;
+        }
+
+        anchorParams = getRelatedViewParams(rules, ALIGN_BOTTOM);
+        if (anchorParams != null) {
+            childParams.mBottom = anchorParams.mBottom - childParams.bottomMargin;
+        } else if (childParams.alignWithParent && rules[ALIGN_BOTTOM] != 0) {
+            if (myHeight >= 0) {
+                childParams.mBottom = myHeight - mPaddingBottom - childParams.bottomMargin;
+            } else {
+                // FIXME uh oh...
+            }
+        }
+
+        if (0 != rules[ALIGN_PARENT_TOP]) {
+            childParams.mTop = mPaddingTop + childParams.topMargin;
+        }
+
+        if (0 != rules[ALIGN_PARENT_BOTTOM]) {
+            if (myHeight >= 0) {
+                childParams.mBottom = myHeight - mPaddingBottom - childParams.bottomMargin;
+            } else {
+                // FIXME uh oh...
+            }
+        }
+
+        if (rules[ALIGN_BASELINE] != 0) {
+            mHasBaselineAlignedChild = true;
+        }
+    }
+
+    private View getRelatedView(int[] rules, int relation) {
+        int id = rules[relation];
+        if (id != 0) {
+            View v = findViewById(id);
+            if (v == null) {
+                return null;
+            }
+
+            // Find the first non-GONE view up the chain
+            while (v.getVisibility() == View.GONE) {
+                rules = ((LayoutParams) v.getLayoutParams()).getRules();
+                v = v.findViewById(rules[relation]);
+                if (v == null) {
+                    return null;
+                }
+            }
+
+            return v;
+        }
+
+        return null;
+    }
+
+    private LayoutParams getRelatedViewParams(int[] rules, int relation) {
+        View v = getRelatedView(rules, relation);
+        if (v != null) {
+            ViewGroup.LayoutParams params = v.getLayoutParams();
+            if (params instanceof LayoutParams) {
+                return (LayoutParams) v.getLayoutParams();
+            }
+        }
+        return null;
+    }
+
+    private int getRelatedViewBaseline(int[] rules, int relation) {
+        View v = getRelatedView(rules, relation);
+        if (v != null) {
+            return v.getBaseline();
+        }
+        return -1;
+    }
+
+    private void centerHorizontal(View child, LayoutParams params, int myWidth) {
+        int childWidth = child.getMeasuredWidth();
+        int left = (myWidth - childWidth) / 2;
+
+        params.mLeft = left;
+        params.mRight = left + childWidth;
+    }
+
+    private void centerVertical(View child, LayoutParams params, int myHeight) {
+        int childHeight = child.getMeasuredHeight();
+        int top = (myHeight - childHeight) / 2;
+
+        params.mTop = top;
+        params.mBottom = top + childHeight;
+    }
+
+    @Override
+    protected void onLayout(boolean changed, int l, int t, int r, int b) {
+        //  The layout has actually already been performed and the positions
+        //  cached.  Apply the cached values to the children.
+        int count = getChildCount();
+
+        for (int i = 0; i < count; i++) {
+            View child = getChildAt(i);
+            if (child.getVisibility() != GONE) {
+                RelativeLayout.LayoutParams st =
+                        (RelativeLayout.LayoutParams) child.getLayoutParams();
+                child.layout(st.mLeft, st.mTop, st.mRight, st.mBottom);
+
+            }
+        }
+    }
+
+    @Override
+    public LayoutParams generateLayoutParams(AttributeSet attrs) {
+        return new RelativeLayout.LayoutParams(getContext(), attrs);
+    }
+
+    /**
+     * Returns a set of layout parameters with a width of
+     * {@link android.view.ViewGroup.LayoutParams#WRAP_CONTENT},
+     * a height of {@link android.view.ViewGroup.LayoutParams#WRAP_CONTENT} and no spanning.
+     */
+    @Override
+    protected ViewGroup.LayoutParams generateDefaultLayoutParams() {
+        return new LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT);
+    }
+
+    // Override to allow type-checking of LayoutParams.
+    @Override
+    protected boolean checkLayoutParams(ViewGroup.LayoutParams p) {
+        return p instanceof RelativeLayout.LayoutParams;
+    }
+
+    @Override
+    protected ViewGroup.LayoutParams generateLayoutParams(ViewGroup.LayoutParams p) {
+        return new LayoutParams(p);
+    }
+
+    /**
+     * Per-child layout information associated with RelativeLayout.
+     *
+     * @attr ref android.R.styleable#RelativeLayout_Layout_layout_alignWithParentIfMissing
+     * @attr ref android.R.styleable#RelativeLayout_Layout_layout_toLeftOf
+     * @attr ref android.R.styleable#RelativeLayout_Layout_layout_toRightOf
+     * @attr ref android.R.styleable#RelativeLayout_Layout_layout_above
+     * @attr ref android.R.styleable#RelativeLayout_Layout_layout_below
+     * @attr ref android.R.styleable#RelativeLayout_Layout_layout_alignBaseline
+     * @attr ref android.R.styleable#RelativeLayout_Layout_layout_alignLeft
+     * @attr ref android.R.styleable#RelativeLayout_Layout_layout_alignTop
+     * @attr ref android.R.styleable#RelativeLayout_Layout_layout_alignRight
+     * @attr ref android.R.styleable#RelativeLayout_Layout_layout_alignBottom
+     * @attr ref android.R.styleable#RelativeLayout_Layout_layout_alignParentLeft
+     * @attr ref android.R.styleable#RelativeLayout_Layout_layout_alignParentTop
+     * @attr ref android.R.styleable#RelativeLayout_Layout_layout_alignParentRight
+     * @attr ref android.R.styleable#RelativeLayout_Layout_layout_alignParentBottom
+     * @attr ref android.R.styleable#RelativeLayout_Layout_layout_centerInParent
+     * @attr ref android.R.styleable#RelativeLayout_Layout_layout_centerHorizontal
+     * @attr ref android.R.styleable#RelativeLayout_Layout_layout_centerVertical
+     */
+    public static class LayoutParams extends ViewGroup.MarginLayoutParams {
+        private int[] mRules = new int[VERB_COUNT];
+        private int mLeft, mTop, mRight, mBottom;
+
+        /**
+         * When true, uses the parent as the anchor if the anchor doesn't exist or if
+         * the anchor's visibility is GONE.
+         */
+        public boolean alignWithParent;
+
+        public LayoutParams(Context c, AttributeSet attrs) {
+            super(c, attrs);
+
+            TypedArray a = c.obtainStyledAttributes(attrs,
+                    com.android.internal.R.styleable.RelativeLayout_Layout);
+
+            final int[] rules = mRules;
+
+            final int N = a.getIndexCount();
+            for (int i = 0; i < N; i++) {
+                int attr = a.getIndex(i);
+                switch (attr) {
+                    case com.android.internal.R.styleable.RelativeLayout_Layout_layout_alignWithParentIfMissing:
+                        alignWithParent = a.getBoolean(attr, false);
+                        break;
+                    case com.android.internal.R.styleable.RelativeLayout_Layout_layout_toLeftOf:
+                        rules[LEFT_OF] = a.getResourceId(attr, 0);
+                        break;
+                    case com.android.internal.R.styleable.RelativeLayout_Layout_layout_toRightOf:
+                        rules[RIGHT_OF] = a.getResourceId(attr, 0);
+                        break;
+                    case com.android.internal.R.styleable.RelativeLayout_Layout_layout_above:
+                        rules[ABOVE] = a.getResourceId(attr, 0);
+                        break;
+                    case com.android.internal.R.styleable.RelativeLayout_Layout_layout_below:
+                        rules[BELOW] = a.getResourceId(attr, 0);
+                        break;
+                    case com.android.internal.R.styleable.RelativeLayout_Layout_layout_alignBaseline:
+                        rules[ALIGN_BASELINE] = a.getResourceId(attr, 0);
+                        break;
+                    case com.android.internal.R.styleable.RelativeLayout_Layout_layout_alignLeft:
+                        rules[ALIGN_LEFT] = a.getResourceId(attr, 0);
+                        break;
+                    case com.android.internal.R.styleable.RelativeLayout_Layout_layout_alignTop:
+                        rules[ALIGN_TOP] = a.getResourceId(attr, 0);
+                        break;
+                    case com.android.internal.R.styleable.RelativeLayout_Layout_layout_alignRight:
+                        rules[ALIGN_RIGHT] = a.getResourceId(attr, 0);
+                        break;
+                    case com.android.internal.R.styleable.RelativeLayout_Layout_layout_alignBottom:
+                        rules[ALIGN_BOTTOM] = a.getResourceId(attr, 0);
+                        break;
+                    case com.android.internal.R.styleable.RelativeLayout_Layout_layout_alignParentLeft:
+                        rules[ALIGN_PARENT_LEFT] = a.getBoolean(attr, false) ? TRUE : 0;
+                        break;
+                    case com.android.internal.R.styleable.RelativeLayout_Layout_layout_alignParentTop:
+                        rules[ALIGN_PARENT_TOP] = a.getBoolean(attr, false) ? TRUE : 0;
+                        break;
+                    case com.android.internal.R.styleable.RelativeLayout_Layout_layout_alignParentRight:
+                        rules[ALIGN_PARENT_RIGHT] = a.getBoolean(attr, false) ? TRUE : 0;
+                        break;
+                    case com.android.internal.R.styleable.RelativeLayout_Layout_layout_alignParentBottom:
+                        rules[ALIGN_PARENT_BOTTOM] = a.getBoolean(attr, false) ? TRUE : 0;
+                        break;
+                    case com.android.internal.R.styleable.RelativeLayout_Layout_layout_centerInParent:
+                        rules[CENTER_IN_PARENT] = a.getBoolean(attr, false) ? TRUE : 0;
+                        break;
+                    case com.android.internal.R.styleable.RelativeLayout_Layout_layout_centerHorizontal:
+                        rules[CENTER_HORIZONTAL] = a.getBoolean(attr, false) ? TRUE : 0;
+                        break;
+                    case com.android.internal.R.styleable.RelativeLayout_Layout_layout_centerVertical:
+                        rules[CENTER_VERTICAL] = a.getBoolean(attr, false) ? TRUE : 0;
+                       break;
+                }
+            }
+
+            a.recycle();
+        }
+
+        public LayoutParams(int w, int h) {
+            super(w, h);
+        }
+
+        /**
+         * {@inheritDoc}
+         */
+        public LayoutParams(ViewGroup.LayoutParams source) {
+            super(source);
+        }
+
+        /**
+         * {@inheritDoc}
+         */
+        public LayoutParams(ViewGroup.MarginLayoutParams source) {
+            super(source);
+        }
+
+        @Override
+        public String debug(String output) {
+            return output + "ViewGroup.LayoutParams={ width=" + sizeToString(width) +
+                    ", height=" + sizeToString(height) + " }";
+        }
+
+        /**
+         * Adds a layout rule to be interpreted by the RelativeLayout. This
+         * method should only be used for constraints that don't refer to another sibling
+         * (e.g., CENTER_IN_PARENT) or take a boolean value ({@link RelativeLayout#TRUE}
+         * for true or - for false). To specify a verb that takes a subject, use
+         * {@link #addRule(int, int)} instead.
+         *
+         * @param verb One of the verbs defined by
+         *        {@link android.widget.RelativeLayout RelativeLayout}, such as
+         *        ALIGN_WITH_PARENT_LEFT.
+         * @see #addRule(int, int)
+         */
+        public void addRule(int verb) {
+            mRules[verb] = TRUE;
+        }
+
+        /**
+         * Adds a layout rule to be interpreted by the RelativeLayout. Use this for
+         * verbs that take a target, such as a sibling (ALIGN_RIGHT) or a boolean
+         * value (VISIBLE).
+         *
+         * @param verb One of the verbs defined by
+         *        {@link android.widget.RelativeLayout RelativeLayout}, such as
+         *         ALIGN_WITH_PARENT_LEFT.
+         * @param anchor The id of another view to use as an anchor,
+         *        or a boolean value(represented as {@link RelativeLayout#TRUE})
+         *        for true or 0 for false).  For verbs that don't refer to another sibling
+         *        (for example, ALIGN_WITH_PARENT_BOTTOM) just use -1.
+         * @see #addRule(int)
+         */
+        public void addRule(int verb, int anchor) {
+            mRules[verb] = anchor;
+        }
+
+        /**
+         * Retrieves a complete list of all supported rules, where the index is the rule
+         * verb, and the element value is the value specified, or "false" if it was never
+         * set.
+         *
+         * @return the supported rules
+         * @see #addRule(int, int)
+         */
+        public int[] getRules() {
+            return mRules;
+        }
+    }
+}