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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.SdkConstants.ANDROID_URI;
     20 import static com.android.SdkConstants.ATTR_LAYOUT_HEIGHT;
     21 import static com.android.SdkConstants.ATTR_LAYOUT_WIDTH;
     22 import static com.android.SdkConstants.ATTR_ORIENTATION;
     23 import static com.android.SdkConstants.FQCN_LINEAR_LAYOUT;
     24 import static com.android.SdkConstants.VALUE_VERTICAL;
     25 
     26 import com.android.annotations.NonNull;
     27 import com.android.annotations.Nullable;
     28 import com.android.ide.common.api.DrawingStyle;
     29 import com.android.ide.common.api.DropFeedback;
     30 import com.android.ide.common.api.IDragElement;
     31 import com.android.ide.common.api.IGraphics;
     32 import com.android.ide.common.api.INode;
     33 import com.android.ide.common.api.IViewRule;
     34 import com.android.ide.common.api.InsertType;
     35 import com.android.ide.common.api.Point;
     36 import com.android.ide.common.api.Rect;
     37 
     38 /**
     39  * An {@link IViewRule} for android.widget.ScrollView.
     40  */
     41 public class ScrollViewRule extends FrameLayoutRule {
     42 
     43     @Override
     44     public void onChildInserted(@NonNull INode child, @NonNull INode parent,
     45             @NonNull InsertType insertType) {
     46         super.onChildInserted(child, parent, insertType);
     47 
     48         // The child of the ScrollView should fill in both directions
     49         String fillParent = getFillParentValueName();
     50         child.setAttribute(ANDROID_URI, ATTR_LAYOUT_WIDTH, fillParent);
     51         child.setAttribute(ANDROID_URI, ATTR_LAYOUT_HEIGHT, fillParent);
     52     }
     53 
     54     @Override
     55     public void onCreate(@NonNull INode node, @NonNull INode parent,
     56             @NonNull InsertType insertType) {
     57         super.onCreate(node, parent, insertType);
     58 
     59         if (insertType.isCreate()) {
     60             // Insert a default linear layout (which will in turn be registered as
     61             // a child of this node and the create child method above will set its
     62             // fill parent attributes, its id, etc.
     63             INode linear = node.appendChild(FQCN_LINEAR_LAYOUT);
     64             linear.setAttribute(ANDROID_URI, ATTR_ORIENTATION, VALUE_VERTICAL);
     65         }
     66     }
     67 
     68     @Override
     69     public DropFeedback onDropMove(@NonNull INode targetNode, @NonNull IDragElement[] elements,
     70             @Nullable DropFeedback feedback, @NonNull Point p) {
     71         DropFeedback f = super.onDropMove(targetNode, elements, feedback, p);
     72 
     73         // ScrollViews only allow a single child
     74         if (targetNode.getChildren().length > 0) {
     75             f.invalidTarget = true;
     76         }
     77         return f;
     78     }
     79 
     80     @Override
     81     protected void drawFeedback(
     82             IGraphics gc,
     83             INode targetNode,
     84             IDragElement[] elements,
     85             DropFeedback feedback) {
     86         if (targetNode.getChildren().length > 0) {
     87             Rect b = targetNode.getBounds();
     88             if (b.isValid()) {
     89                 gc.useStyle(DrawingStyle.DROP_RECIPIENT);
     90                 gc.drawRect(b);
     91             }
     92         } else {
     93             super.drawFeedback(gc, targetNode, elements, feedback);
     94         }
     95     }
     96 }
     97