1/*
2 * Copyright (C) 2006 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 android.view;
18
19import android.content.Context;
20import android.content.ContextWrapper;
21import android.content.res.Resources;
22import android.os.Build;
23
24/**
25 * A ContextWrapper that allows you to modify the theme from what is in the
26 * wrapped context.
27 */
28public class ContextThemeWrapper extends ContextWrapper {
29    private Context mBase;
30    private int mThemeResource;
31    private Resources.Theme mTheme;
32    private LayoutInflater mInflater;
33
34    public ContextThemeWrapper() {
35        super(null);
36    }
37
38    public ContextThemeWrapper(Context base, int themeres) {
39        super(base);
40        mBase = base;
41        mThemeResource = themeres;
42    }
43
44    @Override protected void attachBaseContext(Context newBase) {
45        super.attachBaseContext(newBase);
46        mBase = newBase;
47    }
48
49    @Override public void setTheme(int resid) {
50        mThemeResource = resid;
51        initializeTheme();
52    }
53
54    /** @hide */
55    @Override
56    public int getThemeResId() {
57        return mThemeResource;
58    }
59
60    @Override public Resources.Theme getTheme() {
61        if (mTheme != null) {
62            return mTheme;
63        }
64
65        mThemeResource = Resources.selectDefaultTheme(mThemeResource,
66                getApplicationInfo().targetSdkVersion);
67        initializeTheme();
68
69        return mTheme;
70    }
71
72    @Override public Object getSystemService(String name) {
73        if (LAYOUT_INFLATER_SERVICE.equals(name)) {
74            if (mInflater == null) {
75                mInflater = LayoutInflater.from(mBase).cloneInContext(this);
76            }
77            return mInflater;
78        }
79        return mBase.getSystemService(name);
80    }
81
82    /**
83     * Called by {@link #setTheme} and {@link #getTheme} to apply a theme
84     * resource to the current Theme object.  Can override to change the
85     * default (simple) behavior.  This method will not be called in multiple
86     * threads simultaneously.
87     *
88     * @param theme The Theme object being modified.
89     * @param resid The theme style resource being applied to <var>theme</var>.
90     * @param first Set to true if this is the first time a style is being
91     *              applied to <var>theme</var>.
92     */
93    protected void onApplyThemeResource(Resources.Theme theme, int resid, boolean first) {
94        theme.applyStyle(resid, true);
95    }
96
97    private void initializeTheme() {
98        final boolean first = mTheme == null;
99        if (first) {
100            mTheme = getResources().newTheme();
101            Resources.Theme theme = mBase.getTheme();
102            if (theme != null) {
103                mTheme.setTo(theme);
104            }
105        }
106        onApplyThemeResource(mTheme, mThemeResource, first);
107    }
108}
109
110