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      1 /*
      2  * Copyright (C) 2010 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 
     17 package com.android.ide.common.layout;
     18 
     19 import static com.android.ide.common.layout.LayoutConstants.ANDROID_URI;
     20 import static com.android.ide.common.layout.LayoutConstants.ATTR_LAYOUT_HEIGHT;
     21 import static com.android.ide.common.layout.LayoutConstants.ATTR_LAYOUT_WIDTH;
     22 import static com.android.ide.common.layout.LayoutConstants.FQCN_LINEAR_LAYOUT;
     23 
     24 import com.android.ide.common.api.DrawingStyle;
     25 import com.android.ide.common.api.DropFeedback;
     26 import com.android.ide.common.api.IDragElement;
     27 import com.android.ide.common.api.IGraphics;
     28 import com.android.ide.common.api.INode;
     29 import com.android.ide.common.api.IViewRule;
     30 import com.android.ide.common.api.InsertType;
     31 import com.android.ide.common.api.Point;
     32 import com.android.ide.common.api.Rect;
     33 
     34 /**
     35  * An {@link IViewRule} for android.widget.ScrollView.
     36  */
     37 public class ScrollViewRule extends FrameLayoutRule {
     38 
     39     @Override
     40     public void onChildInserted(INode child, INode parent, InsertType insertType) {
     41         super.onChildInserted(child, parent, insertType);
     42 
     43         // The child of the ScrollView should fill in both directions
     44         String fillParent = getFillParentValueName();
     45         child.setAttribute(ANDROID_URI, ATTR_LAYOUT_WIDTH, fillParent);
     46         child.setAttribute(ANDROID_URI, ATTR_LAYOUT_HEIGHT, fillParent);
     47     }
     48 
     49     @Override
     50     public void onCreate(INode node, INode parent, InsertType insertType) {
     51         super.onCreate(node, parent, insertType);
     52 
     53         if (insertType.isCreate()) {
     54             // Insert a default linear layout (which will in turn be registered as
     55             // a child of this node and the create child method above will set its
     56             // fill parent attributes, its id, etc.
     57             node.appendChild(FQCN_LINEAR_LAYOUT);
     58         }
     59     }
     60 
     61     @Override
     62     public DropFeedback onDropMove(INode targetNode, IDragElement[] elements,
     63             DropFeedback feedback, Point p) {
     64         DropFeedback f = super.onDropMove(targetNode, elements, feedback, p);
     65 
     66         // ScrollViews only allow a single child
     67         if (targetNode.getChildren().length > 0) {
     68             f.invalidTarget = true;
     69         }
     70         return f;
     71     }
     72 
     73     @Override
     74     protected void drawFeedback(
     75             IGraphics gc,
     76             INode targetNode,
     77             IDragElement[] elements,
     78             DropFeedback feedback) {
     79         if (targetNode.getChildren().length > 0) {
     80             Rect b = targetNode.getBounds();
     81             if (b.isValid()) {
     82                 gc.useStyle(DrawingStyle.DROP_RECIPIENT);
     83                 gc.drawRect(b);
     84             }
     85         } else {
     86             super.drawFeedback(gc, targetNode, elements, feedback);
     87         }
     88     }
     89 }
     90