/*
* Copyright (C) 2011 The Android Open Source Project
*
* Licensed under the Eclipse Public License, Version 1.0 (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.eclipse.org/org/documents/epl-v10.php
*
* 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 com.android.ide.common.layout.relative;
import static com.android.ide.common.api.MarginType.NO_MARGIN;
import static com.android.ide.common.api.MarginType.WITHOUT_MARGIN;
import static com.android.ide.common.api.MarginType.WITH_MARGIN;
import static com.android.ide.common.api.SegmentType.BASELINE;
import static com.android.ide.common.api.SegmentType.BOTTOM;
import static com.android.ide.common.api.SegmentType.CENTER_HORIZONTAL;
import static com.android.ide.common.api.SegmentType.CENTER_VERTICAL;
import static com.android.ide.common.api.SegmentType.LEFT;
import static com.android.ide.common.api.SegmentType.RIGHT;
import static com.android.ide.common.api.SegmentType.TOP;
import static com.android.ide.common.layout.BaseLayoutRule.getMaxMatchDistance;
import static com.android.SdkConstants.ATTR_ID;
import static com.android.SdkConstants.ATTR_LAYOUT_ABOVE;
import static com.android.SdkConstants.ATTR_LAYOUT_ALIGN_BASELINE;
import static com.android.SdkConstants.ATTR_LAYOUT_ALIGN_BOTTOM;
import static com.android.SdkConstants.ATTR_LAYOUT_ALIGN_LEFT;
import static com.android.SdkConstants.ATTR_LAYOUT_ALIGN_PARENT_BOTTOM;
import static com.android.SdkConstants.ATTR_LAYOUT_ALIGN_PARENT_LEFT;
import static com.android.SdkConstants.ATTR_LAYOUT_ALIGN_PARENT_RIGHT;
import static com.android.SdkConstants.ATTR_LAYOUT_ALIGN_PARENT_TOP;
import static com.android.SdkConstants.ATTR_LAYOUT_ALIGN_RIGHT;
import static com.android.SdkConstants.ATTR_LAYOUT_ALIGN_TOP;
import static com.android.SdkConstants.ATTR_LAYOUT_BELOW;
import static com.android.SdkConstants.ATTR_LAYOUT_CENTER_HORIZONTAL;
import static com.android.SdkConstants.ATTR_LAYOUT_CENTER_IN_PARENT;
import static com.android.SdkConstants.ATTR_LAYOUT_CENTER_VERTICAL;
import static com.android.SdkConstants.ATTR_LAYOUT_MARGIN_BOTTOM;
import static com.android.SdkConstants.ATTR_LAYOUT_MARGIN_LEFT;
import static com.android.SdkConstants.ATTR_LAYOUT_MARGIN_RIGHT;
import static com.android.SdkConstants.ATTR_LAYOUT_MARGIN_TOP;
import static com.android.SdkConstants.ATTR_LAYOUT_TO_LEFT_OF;
import static com.android.SdkConstants.ATTR_LAYOUT_TO_RIGHT_OF;
import static com.android.SdkConstants.VALUE_N_DP;
import static com.android.SdkConstants.VALUE_TRUE;
import static com.android.ide.common.layout.relative.ConstraintType.ALIGN_BASELINE;
import static java.lang.Math.abs;
import com.android.SdkConstants;
import static com.android.SdkConstants.ANDROID_URI;
import com.android.ide.common.api.DropFeedback;
import com.android.ide.common.api.IClientRulesEngine;
import com.android.ide.common.api.INode;
import com.android.ide.common.api.Margins;
import com.android.ide.common.api.Rect;
import com.android.ide.common.api.Segment;
import com.android.ide.common.api.SegmentType;
import com.android.ide.common.layout.BaseLayoutRule;
import com.android.ide.common.layout.relative.DependencyGraph.Constraint;
import com.android.ide.common.layout.relative.DependencyGraph.ViewData;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.Comparator;
import java.util.List;
import java.util.Set;
/**
* The {@link GuidelineHandler} class keeps track of state related to a guideline operation
* like move and resize, and performs various constraint computations.
*/
public class GuidelineHandler {
/**
* A dependency graph for the relative layout recording constraint relationships
*/
protected DependencyGraph mDependencyGraph;
/** The RelativeLayout we are moving/resizing within */
public INode layout;
/** The set of nodes being dragged (may be null) */
protected Collection<INode> mDraggedNodes;
/** The bounds of the primary child node being dragged */
protected Rect mBounds;
/** Whether the left edge is being moved/resized */
protected boolean mMoveLeft;
/** Whether the right edge is being moved/resized */
protected boolean mMoveRight;
/** Whether the top edge is being moved/resized */
protected boolean mMoveTop;
/** Whether the bottom edge is being moved/resized */
protected boolean mMoveBottom;
/**
* Whether the drop/move/resize position should be snapped (which can be turned off
* with a modifier key during the operation)
*/
protected boolean mSnap = true;
/**
* The set of nodes which depend on the currently selected nodes, including
* transitively, through horizontal constraints (a "horizontal constraint"
* is a constraint between two horizontal edges)
*/
protected Set<INode> mHorizontalDeps;
/**
* The set of nodes which depend on the currently selected nodes, including
* transitively, through vertical constraints (a "vertical constraint"
* is a constraint between two vertical edges)
*/
protected Set<INode> mVerticalDeps;
/** The current list of constraints which result in a horizontal cycle (if applicable) */
protected List<Constraint> mHorizontalCycle;
/** The current list of constraints which result in a vertical cycle (if applicable) */
protected List<Constraint> mVerticalCycle;
/**
* All horizontal segments in the relative layout - top and bottom edges, baseline
* edges, and top and bottom edges offset by the applicable margins in each direction
*/
protected List<Segment> mHorizontalEdges;
/**
* All vertical segments in the relative layout - left and right edges, and left and
* right edges offset by the applicable margins in each direction
*/
protected List<Segment> mVerticalEdges;
/**
* All center vertical segments in the relative layout. These are kept separate since
* they only match other center edges.
*/
protected List<Segment> mCenterVertEdges;
/**
* All center horizontal segments in the relative layout. These are kept separate
* since they only match other center edges.
*/
protected List<Segment> mCenterHorizEdges;
/**
* Suggestions for horizontal matches. There could be more than one, but all matches
* will be equidistant from the current position (as well as in the same direction,
* which means that you can't have one match 5 pixels to the left and one match 5
* pixels to the right since it would be impossible to snap to fit with both; you can
* however have multiple matches all 5 pixels to the left.)
* <p
* The best vertical match will be found in {@link #mCurrentTopMatch} or
* {@link #mCurrentBottomMatch}.
*/
protected List<Match> mHorizontalSuggestions;
/**
* Suggestions for vertical matches.
* <p
* The best vertical match will be found in {@link #mCurrentLeftMatch} or
* {@link #mCurrentRightMatch}.
*/
protected List<Match> mVerticalSuggestions;
/**
* The current match on the left edge, or null if no match or if the left edge is not
* being moved or resized.
*/
protected Match mCurrentLeftMatch;
/**
* The current match on the top edge, or null if no match or if the top edge is not
* being moved or resized.
*/
protected Match mCurrentTopMatch;
/**
* The current match on the right edge, or null if no match or if the right edge is
* not being moved or resized.
*/
protected Match mCurrentRightMatch;
/**
* The current match on the bottom edge, or null if no match or if the bottom edge is
* not being moved or resized.
*/
protected Match mCurrentBottomMatch;
/**
* The amount of margin to add to the top edge, or 0
*/
protected int mTopMargin;
/**
* The amount of margin to add to the bottom edge, or 0
*/
protected int mBottomMargin;
/**
* The amount of margin to add to the left edge, or 0
*/
protected int mLeftMargin;
/**
* The amount of margin to add to the right edge, or 0
*/
protected int mRightMargin;
/**
* The associated rules engine
*/
protected IClientRulesEngine mRulesEngine;
/**
* Construct a new {@link GuidelineHandler} for the given relative layout.
*
* @param layout the RelativeLayout to handle
*/
GuidelineHandler(INode layout, IClientRulesEngine rulesEngine) {
this.layout = layout;
mRulesEngine = rulesEngine;
mHorizontalEdges = new ArrayList<Segment>();
mVerticalEdges = new ArrayList<Segment>();
mCenterVertEdges = new ArrayList<Segment>();
mCenterHorizEdges = new ArrayList<Segment>();
mDependencyGraph = new DependencyGraph(layout);
}
/**
* Returns true if the handler has any suggestions to offer
*
* @return true if the handler has any suggestions to offer
*/
public boolean haveSuggestions() {
return mCurrentLeftMatch != null || mCurrentTopMatch != null
|| mCurrentRightMatch != null || mCurrentBottomMatch != null;
}
/**
* Returns the closest match.
*
* @return the closest match, or null if nothing matched
*/
protected Match pickBestMatch(List<Match> matches) {
int alternatives = matches.size();
if (alternatives == 0) {
return null;
} else if (alternatives == 1) {
Match match = matches.get(0);
return match;
} else {
assert alternatives > 1;
Collections.sort(matches, new MatchComparator());
return matches.get(0);
}
}
private boolean checkCycle(DropFeedback feedback, Match match, boolean vertical) {
if (match != null && match.cycle) {
for (INode node : mDraggedNodes) {
INode from = match.edge.node;
assert match.with.node == null || match.with.node == node;
INode to = node;
List<Constraint> path = mDependencyGraph.getPathTo(from, to, vertical);
if (path != null) {
if (vertical) {
mVerticalCycle = path;
} else {
mHorizontalCycle = path;
}
String desc = Constraint.describePath(path,
match.type.name, match.edge.id);
feedback.errorMessage = "Constraint creates a cycle: " + desc;
return true;
}
}
}
return false;
}
/**
* Checks for any cycles in the dependencies
*
* @param feedback the drop feedback state
*/
public void checkCycles(DropFeedback feedback) {
// Deliberate short circuit evaluation -- only list the first cycle
feedback.errorMessage = null;
mHorizontalCycle = null;
mVerticalCycle = null;
if (checkCycle(feedback, mCurrentTopMatch, true /* vertical */)
|| checkCycle(feedback, mCurrentBottomMatch, true)) {
}
if (checkCycle(feedback, mCurrentLeftMatch, false)
|| checkCycle(feedback, mCurrentRightMatch, false)) {
}
}
/** Records the matchable outside edges for the given node to the potential match list */
protected void addBounds(INode node, String id,
boolean addHorizontal, boolean addVertical) {
Rect b = node.getBounds();
Margins margins = node.getMargins();
if (addHorizontal) {
if (margins.top != 0) {
mHorizontalEdges.add(new Segment(b.y, b.x, b.x2(), node, id, TOP, WITHOUT_MARGIN));
mHorizontalEdges.add(new Segment(b.y - margins.top, b.x, b.x2(), node, id,
TOP, WITH_MARGIN));
} else {
mHorizontalEdges.add(new Segment(b.y, b.x, b.x2(), node, id, TOP, NO_MARGIN));
}
if (margins.bottom != 0) {
mHorizontalEdges.add(new Segment(b.y2(), b.x, b.x2(), node, id, BOTTOM,
WITHOUT_MARGIN));
mHorizontalEdges.add(new Segment(b.y2() + margins.bottom, b.x, b.x2(), node,
id, BOTTOM, WITH_MARGIN));
} else {
mHorizontalEdges.add(new Segment(b.y2(), b.x, b.x2(), node, id,
BOTTOM, NO_MARGIN));
}
}
if (addVertical) {
if (margins.left != 0) {
mVerticalEdges.add(new Segment(b.x, b.y, b.y2(), node, id, LEFT, WITHOUT_MARGIN));
mVerticalEdges.add(new Segment(b.x - margins.left, b.y, b.y2(), node, id, LEFT,
WITH_MARGIN));
} else {
mVerticalEdges.add(new Segment(b.x, b.y, b.y2(), node, id, LEFT, NO_MARGIN));
}
if (margins.right != 0) {
mVerticalEdges.add(new Segment(b.x2(), b.y, b.y2(), node, id,
RIGHT, WITHOUT_MARGIN));
mVerticalEdges.add(new Segment(b.x2() + margins.right, b.y, b.y2(), node, id,
RIGHT, WITH_MARGIN));
} else {
mVerticalEdges.add(new Segment(b.x2(), b.y, b.y2(), node, id,
RIGHT, NO_MARGIN));
}
}
}
/** Records the center edges for the given node to the potential match list */
protected void addCenter(INode node, String id,
boolean addHorizontal, boolean addVertical) {
Rect b = node.getBounds();
if (addHorizontal) {
mCenterHorizEdges.add(new Segment(b.centerY(), b.x, b.x2(),
node, id, CENTER_HORIZONTAL, NO_MARGIN));
}
if (addVertical) {
mCenterVertEdges.add(new Segment(b.centerX(), b.y, b.y2(),
node, id, CENTER_VERTICAL, NO_MARGIN));
}
}
/** Records the baseline edge for the given node to the potential match list */
protected int addBaseLine(INode node, String id) {
int baselineY = node.getBaseline();
if (baselineY != -1) {
Rect b = node.getBounds();
mHorizontalEdges.add(new Segment(b.y + baselineY, b.x, b.x2(), node, id, BASELINE,
NO_MARGIN));
}
return baselineY;
}
protected void snapVertical(Segment vEdge, int x, Rect newBounds) {
newBounds.x = x;
}
protected void snapHorizontal(Segment hEdge, int y, Rect newBounds) {
newBounds.y = y;
}
/**
* Returns whether two edge types are compatible. For example, we only match the
* center of one object with the center of another.
*
* @param edge the first edge type to compare
* @param dragged the second edge type to compare the first one with
* @param delta the delta between the two edge locations
* @return true if the two edge types can be compatibly matched
*/
protected boolean isEdgeTypeCompatible(SegmentType edge, SegmentType dragged, int delta) {
if (Math.abs(delta) > BaseLayoutRule.getMaxMatchDistance()) {
if (dragged == LEFT || dragged == TOP) {
if (delta > 0) {
return false;
}
} else {
if (delta < 0) {
return false;
}
}
}
switch (edge) {
case BOTTOM:
case TOP:
return dragged == TOP || dragged == BOTTOM;
case LEFT:
case RIGHT:
return dragged == LEFT || dragged == RIGHT;
// Center horizontal, center vertical and Baseline only matches the same
// type, and only within the matching distance -- no margins!
case BASELINE:
case CENTER_HORIZONTAL:
case CENTER_VERTICAL:
return dragged == edge && Math.abs(delta) < getMaxMatchDistance();
default: assert false : edge;
}
return false;
}
/**
* Finds the closest matching segments among the given list of edges for the given
* dragged edge, and returns these as a list of matches
*/
protected List<Match> findClosest(Segment draggedEdge, List<Segment> edges) {
List<Match> closest = new ArrayList<Match>();
addClosest(draggedEdge, edges, closest);
return closest;
}
protected void addClosest(Segment draggedEdge, List<Segment> edges,
List<Match> closest) {
int at = draggedEdge.at;
int closestDelta = closest.size() > 0 ? closest.get(0).delta : Integer.MAX_VALUE;
int closestDistance = abs(closestDelta);
for (Segment edge : edges) {
assert draggedEdge.edgeType.isHorizontal() == edge.edgeType.isHorizontal();
int delta = edge.at - at;
int distance = abs(delta);
if (distance > closestDistance) {
continue;
}
if (!isEdgeTypeCompatible(edge.edgeType, draggedEdge.edgeType, delta)) {
continue;
}
boolean withParent = edge.node == layout;
ConstraintType type = ConstraintType.forMatch(withParent,
draggedEdge.edgeType, edge.edgeType);
if (type == null) {
continue;
}
// Ensure that the edge match is compatible; for example, a "below"
// constraint can only apply to the margin bounds and a "bottom"
// constraint can only apply to the non-margin bounds.
if (type.relativeToMargin && edge.marginType == WITHOUT_MARGIN) {
continue;
} else if (!type.relativeToMargin && edge.marginType == WITH_MARGIN) {
continue;
}
Match match = new Match(this, edge, draggedEdge, type, delta);
if (distance < closestDistance) {
closest.clear();
closestDistance = distance;
closestDelta = delta;
} else if (delta * closestDelta < 0) {
// They have different signs, e.g. the matches are equal but
// on opposite sides; can't accept them both
continue;
}
closest.add(match);
}
}
protected void clearSuggestions() {
mHorizontalSuggestions = mVerticalSuggestions = null;
mCurrentLeftMatch = mCurrentRightMatch = null;
mCurrentTopMatch = mCurrentBottomMatch = null;
}
/**
* Given a node, apply the suggestions by expressing them as relative layout param
* values
*
* @param n the node to apply constraints to
*/
public void applyConstraints(INode n) {
// Process each edge separately
String centerBoth = n.getStringAttr(ANDROID_URI, ATTR_LAYOUT_CENTER_IN_PARENT);
if (centerBoth != null && centerBoth.equals(VALUE_TRUE)) {
n.setAttribute(ANDROID_URI, ATTR_LAYOUT_CENTER_IN_PARENT, null);
// If you had a center-in-both-directions attribute, and you're
// only resizing in one dimension, then leave the other dimension
// centered, e.g. if you have centerInParent and apply alignLeft,
// then you should end up with alignLeft and centerVertically
if (mCurrentTopMatch == null && mCurrentBottomMatch == null) {
n.setAttribute(ANDROID_URI, ATTR_LAYOUT_CENTER_VERTICAL, VALUE_TRUE);
}
if (mCurrentLeftMatch == null && mCurrentRightMatch == null) {
n.setAttribute(ANDROID_URI, ATTR_LAYOUT_CENTER_HORIZONTAL, VALUE_TRUE);
}
}
if (mMoveTop) {
// Remove top attachments
n.setAttribute(ANDROID_URI, ATTR_LAYOUT_ALIGN_PARENT_TOP, null);
n.setAttribute(ANDROID_URI, ATTR_LAYOUT_ALIGN_TOP, null);
n.setAttribute(ANDROID_URI, ATTR_LAYOUT_BELOW, null);
n.setAttribute(ANDROID_URI, ATTR_LAYOUT_CENTER_VERTICAL, null);
n.setAttribute(ANDROID_URI, ATTR_LAYOUT_ALIGN_BASELINE, null);
}
if (mMoveBottom) {
// Remove bottom attachments
n.setAttribute(ANDROID_URI, ATTR_LAYOUT_ALIGN_PARENT_BOTTOM, null);
n.setAttribute(ANDROID_URI, ATTR_LAYOUT_ALIGN_BOTTOM, null);
n.setAttribute(ANDROID_URI, ATTR_LAYOUT_ABOVE, null);
n.setAttribute(ANDROID_URI, ATTR_LAYOUT_CENTER_VERTICAL, null);
n.setAttribute(ANDROID_URI, ATTR_LAYOUT_ALIGN_BASELINE, null);
}
if (mMoveLeft) {
// Remove left attachments
n.setAttribute(ANDROID_URI, ATTR_LAYOUT_ALIGN_PARENT_LEFT, null);
n.setAttribute(ANDROID_URI, ATTR_LAYOUT_ALIGN_LEFT, null);
n.setAttribute(ANDROID_URI, ATTR_LAYOUT_TO_RIGHT_OF, null);
n.setAttribute(ANDROID_URI, ATTR_LAYOUT_CENTER_HORIZONTAL, null);
}
if (mMoveRight) {
// Remove right attachments
n.setAttribute(ANDROID_URI, ATTR_LAYOUT_ALIGN_PARENT_RIGHT, null);
n.setAttribute(ANDROID_URI, ATTR_LAYOUT_ALIGN_RIGHT, null);
n.setAttribute(ANDROID_URI, ATTR_LAYOUT_TO_LEFT_OF, null);
n.setAttribute(ANDROID_URI, ATTR_LAYOUT_CENTER_HORIZONTAL, null);
}
if (mMoveTop && mCurrentTopMatch != null) {
applyConstraint(n, mCurrentTopMatch.getConstraint(true /* generateId */));
if (mCurrentTopMatch.type == ALIGN_BASELINE) {
// HACK! WORKAROUND! Baseline doesn't provide a new bottom edge for attachments
String c = mCurrentTopMatch.getConstraint(true);
c = c.replace(ATTR_LAYOUT_ALIGN_BASELINE, ATTR_LAYOUT_ALIGN_BOTTOM);
applyConstraint(n, c);
}
}
if (mMoveBottom && mCurrentBottomMatch != null) {
applyConstraint(n, mCurrentBottomMatch.getConstraint(true));
}
if (mMoveLeft && mCurrentLeftMatch != null) {
applyConstraint(n, mCurrentLeftMatch.getConstraint(true));
}
if (mMoveRight && mCurrentRightMatch != null) {
applyConstraint(n, mCurrentRightMatch.getConstraint(true));
}
if (mMoveLeft) {
applyMargin(n, ATTR_LAYOUT_MARGIN_LEFT, mLeftMargin);
}
if (mMoveRight) {
applyMargin(n, ATTR_LAYOUT_MARGIN_RIGHT, mRightMargin);
}
if (mMoveTop) {
applyMargin(n, ATTR_LAYOUT_MARGIN_TOP, mTopMargin);
}
if (mMoveBottom) {
applyMargin(n, ATTR_LAYOUT_MARGIN_BOTTOM, mBottomMargin);
}
}
private void applyConstraint(INode n, String constraint) {
assert constraint.contains("=") : constraint;
String name = constraint.substring(0, constraint.indexOf('='));
String value = constraint.substring(constraint.indexOf('=') + 1);
n.setAttribute(ANDROID_URI, name, value);
}
private void applyMargin(INode n, String marginAttribute, int margin) {
if (margin > 0) {
int dp = mRulesEngine.pxToDp(margin);
n.setAttribute(ANDROID_URI, marginAttribute, String.format(VALUE_N_DP, dp));
} else if (n.getStringAttr(ANDROID_URI, marginAttribute) != null) {
// Clear out existing margin
n.setAttribute(ANDROID_URI, marginAttribute, null);
}
}
private void removeRelativeParams(INode node) {
for (ConstraintType type : ConstraintType.values()) {
node.setAttribute(ANDROID_URI, type.name, null);
}
node.setAttribute(ANDROID_URI,ATTR_LAYOUT_MARGIN_LEFT, null);
node.setAttribute(ANDROID_URI,ATTR_LAYOUT_MARGIN_RIGHT, null);
node.setAttribute(ANDROID_URI,ATTR_LAYOUT_MARGIN_TOP, null);
node.setAttribute(ANDROID_URI,ATTR_LAYOUT_MARGIN_BOTTOM, null);
}
/**
* Attach the new child to the previous node
* @param previous the previous child
* @param node the new child to attach it to
*/
public void attachPrevious(INode previous, INode node) {
removeRelativeParams(node);
String id = previous.getStringAttr(ANDROID_URI, ATTR_ID);
if (id == null) {
return;
}
if (mCurrentTopMatch != null || mCurrentBottomMatch != null) {
// Attaching the top: arrange below, and for bottom arrange above
node.setAttribute(ANDROID_URI,
mCurrentTopMatch != null ? ATTR_LAYOUT_BELOW : ATTR_LAYOUT_ABOVE, id);
// Apply same left/right constraints as the parent
if (mCurrentLeftMatch != null) {
applyConstraint(node, mCurrentLeftMatch.getConstraint(true));
applyMargin(node, ATTR_LAYOUT_MARGIN_LEFT, mLeftMargin);
} else if (mCurrentRightMatch != null) {
applyConstraint(node, mCurrentRightMatch.getConstraint(true));
applyMargin(node, ATTR_LAYOUT_MARGIN_RIGHT, mRightMargin);
}
} else if (mCurrentLeftMatch != null || mCurrentRightMatch != null) {
node.setAttribute(ANDROID_URI,
mCurrentLeftMatch != null ? ATTR_LAYOUT_TO_RIGHT_OF : ATTR_LAYOUT_TO_LEFT_OF,
id);
// Apply same top/bottom constraints as the parent
if (mCurrentTopMatch != null) {
applyConstraint(node, mCurrentTopMatch.getConstraint(true));
applyMargin(node, ATTR_LAYOUT_MARGIN_TOP, mTopMargin);
} else if (mCurrentBottomMatch != null) {
applyConstraint(node, mCurrentBottomMatch.getConstraint(true));
applyMargin(node, ATTR_LAYOUT_MARGIN_BOTTOM, mBottomMargin);
}
} else {
return;
}
}
/** Breaks any cycles detected by the handler */
public void removeCycles() {
if (mHorizontalCycle != null) {
removeCycles(mHorizontalDeps);
}
if (mVerticalCycle != null) {
removeCycles(mVerticalDeps);
}
}
private void removeCycles(Set<INode> deps) {
for (INode node : mDraggedNodes) {
ViewData view = mDependencyGraph.getView(node);
if (view != null) {
for (Constraint constraint : view.dependedOnBy) {
// For now, remove ALL constraints pointing to this node in this orientation.
// Later refine this to be smarter. (We can't JUST remove the constraints
// identified in the cycle since there could be multiple.)
constraint.from.node.setAttribute(ANDROID_URI, constraint.type.name, null);
}
}
}
}
/**
* Comparator used to sort matches such that the first match is the most desirable
* match (where we prefer attaching to parent bounds, we avoid matches that lead to a
* cycle, we prefer constraints on closer widgets rather than ones further away, and
* so on.)
* <p>
* There are a number of sorting criteria. One of them is the distance between the
* matched edges. We may end up with multiple matches that are the same distance. In
* that case we look at the orientation; on the left side, prefer left-oriented
* attachments, and on the right-side prefer right-oriented attachments. For example,
* consider the following scenario:
*
* <pre>
* +--------------------+-------------------------+
* | Attached on left | |
* +--------------------+ |
* | |
* | +-----+ |
* | | A | |
* | +-----+ |
* | |
* | +-------------------------+
* | | Attached on right |
* +--------------------+-------------------------+
* </pre>
*
* Here, dragging the left edge should attach to the top left attached view, whereas
* in the following layout dragging the right edge would attach to the bottom view:
*
* <pre>
* +--------------------------+-------------------+
* | Attached on left | |
* +--------------------------+ |
* | |
* | +-----+ |
* | | A | |
* | +-----+ |
* | |
* | +-------------------+
* | | Attached on right |
* +--------------------------+-------------------+
*
* </pre>
*
* </ul>
*/
private final class MatchComparator implements Comparator<Match> {
@Override
public int compare(Match m1, Match m2) {
// Always prefer matching parent bounds
int parent1 = m1.edge.node == layout ? -1 : 1;
int parent2 = m2.edge.node == layout ? -1 : 1;
// unless it's a center bound -- those should always get lowest priority since
// they overlap with other usually more interesting edges near the center of
// the layout.
if (m1.edge.edgeType == CENTER_HORIZONTAL
|| m1.edge.edgeType == CENTER_VERTICAL) {
parent1 = 2;
}
if (m2.edge.edgeType == CENTER_HORIZONTAL
|| m2.edge.edgeType == CENTER_VERTICAL) {
parent2 = 2;
}
if (parent1 != parent2) {
return parent1 - parent2;
}
// Avoid matching edges that would lead to a cycle
if (m1.edge.edgeType.isHorizontal()) {
int cycle1 = mHorizontalDeps.contains(m1.edge.node) ? 1 : -1;
int cycle2 = mHorizontalDeps.contains(m2.edge.node) ? 1 : -1;
if (cycle1 != cycle2) {
return cycle1 - cycle2;
}
} else {
int cycle1 = mVerticalDeps.contains(m1.edge.node) ? 1 : -1;
int cycle2 = mVerticalDeps.contains(m2.edge.node) ? 1 : -1;
if (cycle1 != cycle2) {
return cycle1 - cycle2;
}
}
// TODO: Sort by minimum depth -- do we have the depth anywhere?
// Prefer nodes that are closer
int distance1, distance2;
if (m1.edge.to <= m1.with.from) {
distance1 = m1.with.from - m1.edge.to;
} else if (m1.edge.from >= m1.with.to) {
distance1 = m1.edge.from - m1.with.to;
} else {
// Some kind of overlap - not sure how to prioritize these yet...
distance1 = 0;
}
if (m2.edge.to <= m2.with.from) {
distance2 = m2.with.from - m2.edge.to;
} else if (m2.edge.from >= m2.with.to) {
distance2 = m2.edge.from - m2.with.to;
} else {
// Some kind of overlap - not sure how to prioritize these yet...
distance2 = 0;
}
if (distance1 != distance2) {
return distance1 - distance2;
}
// Prefer matching on baseline
int baseline1 = (m1.edge.edgeType == BASELINE) ? -1 : 1;
int baseline2 = (m2.edge.edgeType == BASELINE) ? -1 : 1;
if (baseline1 != baseline2) {
return baseline1 - baseline2;
}
// Prefer matching top/left edges before matching bottom/right edges
int orientation1 = (m1.with.edgeType == LEFT ||
m1.with.edgeType == TOP) ? -1 : 1;
int orientation2 = (m2.with.edgeType == LEFT ||
m2.with.edgeType == TOP) ? -1 : 1;
if (orientation1 != orientation2) {
return orientation1 - orientation2;
}
// Prefer opposite-matching over same-matching.
// In other words, if we have the choice of matching
// our left edge with another element's left edge,
// or matching our left edge with another element's right
// edge, prefer the right edge since that
// The two matches have identical distance; try to sort by
// orientation
int edgeType1 = (m1.edge.edgeType != m1.with.edgeType) ? -1 : 1;
int edgeType2 = (m2.edge.edgeType != m2.with.edgeType) ? -1 : 1;
if (edgeType1 != edgeType2) {
return edgeType1 - edgeType2;
}
return 0;
}
}
/**
* Returns the {@link IClientRulesEngine} IDE callback
*
* @return the {@link IClientRulesEngine} IDE callback, never null
*/
public IClientRulesEngine getRulesEngine() {
return mRulesEngine;
}
}