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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.ATTR_ORIENTATION;
     23 import static com.android.ide.common.layout.LayoutConstants.FQCN_LINEAR_LAYOUT;
     24 import static com.android.ide.common.layout.LayoutConstants.VALUE_HORIZONTAL;
     25 
     26 import com.android.ide.common.api.DrawingStyle;
     27 import com.android.ide.common.api.DropFeedback;
     28 import com.android.ide.common.api.IDragElement;
     29 import com.android.ide.common.api.IGraphics;
     30 import com.android.ide.common.api.INode;
     31 import com.android.ide.common.api.IViewRule;
     32 import com.android.ide.common.api.InsertType;
     33 import com.android.ide.common.api.Point;
     34 import com.android.ide.common.api.Rect;
     35 
     36 /**
     37  * An {@link IViewRule} for android.widget.HorizontalScrollView.
     38  */
     39 public class HorizontalScrollViewRule extends FrameLayoutRule {
     40 
     41     @Override
     42     public void onChildInserted(INode child, INode parent, InsertType insertType) {
     43         super.onChildInserted(child, parent, insertType);
     44 
     45         // The child of the ScrollView should fill in both directions
     46         String fillParent = getFillParentValueName();
     47         child.setAttribute(ANDROID_URI, ATTR_LAYOUT_WIDTH, fillParent);
     48         child.setAttribute(ANDROID_URI, ATTR_LAYOUT_HEIGHT, fillParent);
     49     }
     50 
     51     @Override
     52     public void onCreate(INode node, INode parent, InsertType insertType) {
     53         super.onCreate(node, parent, insertType);
     54 
     55         if (insertType.isCreate()) {
     56             // Insert a horizontal linear layout which is commonly used with horizontal scrollbars
     57             // as described by the documentation for HorizontalScrollbars.
     58             INode linearLayout = node.appendChild(FQCN_LINEAR_LAYOUT);
     59             linearLayout.setAttribute(ANDROID_URI, ATTR_ORIENTATION,
     60                     VALUE_HORIZONTAL);
     61         }
     62     }
     63 
     64     @Override
     65     public DropFeedback onDropMove(INode targetNode, IDragElement[] elements,
     66             DropFeedback feedback, Point p) {
     67         DropFeedback f = super.onDropMove(targetNode, elements, feedback, p);
     68 
     69         // HorizontalScrollViews only allow a single child
     70         if (targetNode.getChildren().length > 0) {
     71             f.invalidTarget = true;
     72         }
     73         return f;
     74     }
     75 
     76     @Override
     77     protected void drawFeedback(
     78             IGraphics gc,
     79             INode targetNode,
     80             IDragElement[] elements,
     81             DropFeedback feedback) {
     82         if (targetNode.getChildren().length > 0) {
     83             Rect b = targetNode.getBounds();
     84             if (b.isValid()) {
     85                 gc.useStyle(DrawingStyle.DROP_RECIPIENT);
     86                 gc.drawRect(b);
     87             }
     88         } else {
     89             super.drawFeedback(gc, targetNode, elements, feedback);
     90         }
     91     }
     92 }
     93