1 /* 2 * Copyright (C) 2011 The Android Open Source Project 3 * 4 * Licensed under the Eclipse Public License, Version 1.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.eclipse.org/org/documents/epl-v10.php 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 package com.android.ide.common.layout.relative; 17 18 import static com.android.ide.common.layout.LayoutConstants.ANDROID_URI; 19 import static com.android.ide.common.layout.LayoutConstants.ATTR_ID; 20 import static com.android.ide.common.layout.LayoutConstants.VALUE_TRUE; 21 22 import com.android.ide.common.api.Segment; 23 24 /** A match is a potential pairing of two segments with a given {@link ConstraintType}. */ 25 class Match { 26 /** the edge of the dragged node that is matched */ 27 public final Segment with; 28 29 /** the "other" edge that the dragged edge is matched with */ 30 public final Segment edge; 31 32 /** the signed distance between the matched edges */ 33 public final int delta; 34 35 /** the type of constraint this is a match for */ 36 public final ConstraintType type; 37 38 /** whether this {@link Match} results in a cycle */ 39 public boolean cycle; 40 41 /** The associated {@link GuidelineHander} which performed the match */ 42 private final GuidelineHandler mHandler; 43 44 /** 45 * Create a new match. 46 * 47 * @param handler the handler which performed the match 48 * @param edge the "other" edge that the dragged edge is matched with 49 * @param with the edge of the dragged node that is matched 50 * @param type the type of constraint this is a match for 51 * @param delta the signed distance between the matched edges 52 */ Match(GuidelineHandler handler, Segment edge, Segment with, ConstraintType type, int delta)53 public Match(GuidelineHandler handler, Segment edge, Segment with, 54 ConstraintType type, int delta) { 55 mHandler = handler; 56 57 this.edge = edge; 58 this.with = with; 59 this.type = type; 60 this.delta = delta; 61 } 62 63 /** 64 * Returns the XML constraint attribute value for this match 65 * 66 * @param generateId whether an id should be generated if one is missing 67 * @return the XML constraint attribute value for this match 68 */ getConstraint(boolean generateId)69 public String getConstraint(boolean generateId) { 70 if (type.targetParent) { 71 return type.name + '=' + VALUE_TRUE; 72 } else { 73 String id = edge.id; 74 if (id == null || id.length() == -1) { 75 if (!generateId) { 76 // Placeholder to display for the user during dragging 77 id = "<generated>"; 78 } else { 79 // Must generate an id on the fly! 80 // See if it's been set by a different constraint we've already applied 81 // to this same node 82 id = edge.node.getStringAttr(ANDROID_URI, ATTR_ID); 83 if (id == null || id.length() == 0) { 84 id = mHandler.getRulesEngine().getUniqueId(edge.node.getFqcn()); 85 edge.node.setAttribute(ANDROID_URI, ATTR_ID, id); 86 } 87 } 88 } 89 return type.name + '=' + id; 90 } 91 } 92 93 @Override toString()94 public String toString() { 95 return "Match [type=" + type + ", delta=" + delta + ", edge=" + edge 96 + "]"; 97 } 98 }