1/*
2 * Copyright (C) 2007 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (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.apache.org/licenses/LICENSE-2.0
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
17package com.example.android.apis.view;
18
19import android.app.Activity;
20import android.os.Bundle;
21import android.view.ViewGroup;
22import android.widget.LinearLayout;
23import android.widget.ScrollView;
24
25/**
26 * Demonstrates how a well behaved view with internal selection
27 * ({@link InternalSelectionView}) can cause its parent {@link android.widget.ScrollView}
28 * to scroll to keep the internally interesting rectangle on the screen.
29 *
30 * {@link InternalSelectionView} achieves this by calling {@link android.view.View#requestRectangleOnScreen}
31 * each time its internal selection changes.
32 *
33 * {@link android.widget.ScrollView}, in turn, implements {@link android.view.View#requestRectangleOnScreen}
34 * thereby acheiving the result.  Note that {@link android.widget.ListView} also implements the
35 * method, so views that call {@link android.view.View#requestRectangleOnScreen} that are embedded
36 * within either {@link android.widget.ScrollView}s or {@link android.widget.ListView}s can
37 * expect to keep their internal interesting rectangle visible.
38 */
39public class InternalSelectionScroll extends Activity {
40
41    @Override
42    protected void onCreate(Bundle savedInstanceState) {
43        super.onCreate(savedInstanceState);
44
45        ScrollView sv = new ScrollView(this);
46        ViewGroup.LayoutParams svLp = new ScrollView.LayoutParams(
47                ViewGroup.LayoutParams.MATCH_PARENT,
48                ViewGroup.LayoutParams.WRAP_CONTENT);
49
50        LinearLayout ll = new LinearLayout(this);
51        ll.setLayoutParams(svLp);
52        sv.addView(ll);
53
54        InternalSelectionView isv = new InternalSelectionView(this, 10);
55        int screenHeight = getWindowManager().getDefaultDisplay().getHeight();
56        LinearLayout.LayoutParams llLp = new LinearLayout.LayoutParams(
57                ViewGroup.LayoutParams.MATCH_PARENT,
58                2 * screenHeight);  // 2x screen height to ensure scrolling
59        isv.setLayoutParams(llLp);
60        ll.addView(isv);
61
62        setContentView(sv);
63    }
64}
65