1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
|
/*
* Copyright (C) 2014 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.android.systemui.recents.views;
import android.content.Context;
import java.util.Iterator;
import java.util.LinkedList;
/* A view pool to manage more views than we can visibly handle */
public class ViewPool<V, T> {
/* An interface to the consumer of a view pool */
public interface ViewPoolConsumer<V, T> {
public V createView(Context context);
public void prepareViewToEnterPool(V v);
public void prepareViewToLeavePool(V v, T prepareData, boolean isNewView);
public boolean hasPreferredData(V v, T preferredData);
}
Context mContext;
ViewPoolConsumer<V, T> mViewCreator;
LinkedList<V> mPool = new LinkedList<V>();
/** Initializes the pool with a fixed predetermined pool size */
public ViewPool(Context context, ViewPoolConsumer<V, T> viewCreator) {
mContext = context;
mViewCreator = viewCreator;
}
/** Returns a view into the pool */
void returnViewToPool(V v) {
mViewCreator.prepareViewToEnterPool(v);
mPool.push(v);
}
/** Gets a view from the pool and prepares it */
V pickUpViewFromPool(T preferredData, T prepareData) {
V v = null;
boolean isNewView = false;
if (mPool.isEmpty()) {
v = mViewCreator.createView(mContext);
isNewView = true;
} else {
// Try and find a preferred view
Iterator<V> iter = mPool.iterator();
while (iter.hasNext()) {
V vpv = iter.next();
if (mViewCreator.hasPreferredData(vpv, preferredData)) {
v = vpv;
iter.remove();
break;
}
}
// Otherwise, just grab the first view
if (v == null) {
v = mPool.pop();
}
}
mViewCreator.prepareViewToLeavePool(v, prepareData, isNewView);
return v;
}
/** Returns an iterator to the list of the views in the pool. */
Iterator<V> poolViewIterator() {
if (mPool != null) {
return mPool.iterator();
}
return null;
}
}
|
