2 * Copyright (C) 2009 The Android Open Source Project
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
8 * http://www.eclipse.org/org/documents/epl-v10.php
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.
17 package com.android.ide.eclipse.adt.gscripts;
19 import java.util.ArrayList;
20 import java.util.LinkedHashMap;
25 * An {@link IViewRule} describes the GLE rules that apply to a given Layout or View object
26 * in the Graphical Layout Editor (GLE).
28 * Such a rule is implemented using a Groovy script located in the
29 * com.android.ide.eclipse.adt.internal.editors.layout.gre package or in a
30 * projects' /gscript folder for custom views.
32 * The Groovy script must be named using the fully qualified class name of the View or Layout,
33 * e.g. "android.widget.LinearLayout.groovy". If the rule engine can't find a groovy script
34 * for a given element, it will use the closest matching parent (e.g. View instead of ViewGroup).
36 * Rule instances are stateless. They are created once per View class to handle and are shared
37 * across platforms or editor instances. As such, rules methods should never cache editor-specific
38 * arguments that they might receive.
40 public interface IViewRule {
43 * This method is called by the rule engine when the script is first loaded.
44 * It gives the rule a chance to initialize itself.
46 * @param fqcn The fully qualified class name of the Layout or View that will be managed by
47 * this rule. This can be cached as it will never change for the lifetime of this rule
48 * instance. This may or may not match the script's filename as it may be the fqcn of a
49 * class derived from the one this rule can handle.
50 * @return True if this rule can handle the given FQCN. False if the rule can't handle the
51 * given FQCN, in which case the rule engine will find another rule matching a parent clas.
53 boolean onInitialize(String fqcn);
56 * This method is called by the rules engine just before the script is unloaded.
61 * Returns the class name to display when an element is selected in the GLE.
63 * If null is returned, the GLE will automatically shorten the class name using its
64 * own heuristic, which is to keep the first 2 package components and the class name.
65 * The class name is the <code>fqcn</code> argument that was given
66 * to {@link #onInitialize(String)}.
68 * @return Null for the default behavior or a shortened string.
70 String getDisplayName();
73 // ==== XML Creation ====
77 * Returns the default attributes that a new XML element of this type should have
78 * when added to an XML layout file. Note that these defaults can be overridden by the
79 * specific code performing the insertion.
81 * @return A map of attribute:values for a new element of this type. Can be null or empty.
83 Map<?, ?> getDefaultAttributes();
87 // ==== Drag'n'drop support ====
91 * Called when a drop operation starts, whilst the d'n'd is dragging the cursor over the
92 * views. The purpose of the drop operation will be to create a new element.
94 * Drop targets that can't accept child views should always return null, in which case
95 * the rule engine will ask the parent view (typically a layout).
97 * Drop targets that can accept child views must return a non-empty list of drop zones,
98 * customized to the actual bounds of the target.
99 * The drop zones will be visually shown to the user. Once the user releases the mouse
100 * in one of the drop zone, the dropAccept/dropFinish methods will be called.
102 * Note that at this stage, the drop operation does not offer a way to know what is going
103 * to be dropped. We just know it's a view descriptor, typically from the layout palette,
104 * but we don't know which view class yet.
106 * @param targetNode The XML view that is currently the target of the drop.
107 * @return Null or an empty list if the rule rejects the drop, or a list of usable drop zones.
109 ArrayList<DropZone> dropStart(INodeProxy targetNode);
112 * Called after the user selects to drop the given source into one of the drop zones.
114 * This method should use the methods from the {@link INodeProxy} to actually create the
115 * new XML matching the source descriptor.
117 * @param sourceFqcn The FQCN of the view being dropped.
118 * @param targetNode The XML view that is currently the target of the drop.
119 * @param selectedZone One of the drop zones returned by {@link #dropStart(INodeProxy)}.
120 * @param where The location, in the selected zone, of the drop.
124 INodeProxy targetNode,
125 DropZone selectedZone,
128 ArrayList<DropZone> moveStart(INodeProxy sourceNode, INodeProxy targetNode, boolean copy);
129 void moveFinish(INodeProxy sourceNode, INodeProxy targetNode, boolean copy, DropZone selectedZone);