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      1 /*
      2  * Copyright (C) 2011 Google Inc.
      3  * Licensed to The Android Open Source Project.
      4  *
      5  * Licensed under the Apache License, Version 2.0 (the "License");
      6  * you may not use this file except in compliance with the License.
      7  * You may obtain a copy of the License at
      8  *
      9  *      http://www.apache.org/licenses/LICENSE-2.0
     10  *
     11  * Unless required by applicable law or agreed to in writing, software
     12  * distributed under the License is distributed on an "AS IS" BASIS,
     13  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     14  * See the License for the specific language governing permissions and
     15  * limitations under the License.
     16  */
     17 
     18 package com.android.mail.browse;
     19 
     20 import android.content.Context;
     21 import android.util.AttributeSet;
     22 import android.view.View;
     23 
     24 import com.android.mail.browse.ScrollNotifier.ScrollListener;
     25 
     26 /**
     27  * An overlay to sit on top of WebView, message headers, and snap header to display scrollbars.
     28  * It has to sit on top of all other views that compose the conversation so that the scrollbars are
     29  * not obscured.
     30  *
     31  */
     32 public class ScrollIndicatorsView extends View implements ScrollListener {
     33 
     34     private ScrollNotifier mSource;
     35 
     36     public ScrollIndicatorsView(Context context) {
     37         super(context);
     38     }
     39 
     40     public ScrollIndicatorsView(Context context, AttributeSet attrs) {
     41         super(context, attrs);
     42     }
     43 
     44     public void setSourceView(ScrollNotifier notifier) {
     45         mSource = notifier;
     46         mSource.addScrollListener(this);
     47     }
     48 
     49     @Override
     50     protected int computeVerticalScrollRange() {
     51         return mSource.computeVerticalScrollRange();
     52     }
     53 
     54     @Override
     55     protected int computeVerticalScrollOffset() {
     56         return mSource.computeVerticalScrollOffset();
     57     }
     58 
     59     @Override
     60     protected int computeVerticalScrollExtent() {
     61         return mSource.computeVerticalScrollExtent();
     62     }
     63 
     64     @Override
     65     protected int computeHorizontalScrollRange() {
     66         return mSource.computeHorizontalScrollRange();
     67     }
     68 
     69     @Override
     70     protected int computeHorizontalScrollOffset() {
     71         return mSource.computeHorizontalScrollOffset();
     72     }
     73 
     74     @Override
     75     protected int computeHorizontalScrollExtent() {
     76         return mSource.computeHorizontalScrollExtent();
     77     }
     78 
     79     @Override
     80     public void onNotifierScroll(int top) {
     81         awakenScrollBars();
     82     }
     83 }
     84