ContextThemeWrapper.java revision f933672168f6deff5e3636584bec735416b5a93b 
1/*
2 * Copyright (C) 2014 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.support.v7.internal.view;
18
19import android.content.Context;
20import android.content.ContextWrapper;
21import android.content.res.Resources;
22import android.support.annotation.StyleRes;
23import android.support.v7.appcompat.R;
24import android.view.LayoutInflater;
25
26/**
27 * A ContextWrapper that allows you to modify the theme from what is in the
28 * wrapped context.
29 *
30 * @hide
31 */
32public class ContextThemeWrapper extends ContextWrapper {
33    private int mThemeResource;
34    private Resources.Theme mTheme;
35    private LayoutInflater mInflater;
36
37    public ContextThemeWrapper(Context base, @StyleRes int themeResId) {
38        super(base);
39        mThemeResource = themeResId;
40    }
41
42    public ContextThemeWrapper(Context base, Resources.Theme theme) {
43        super(base);
44        mTheme = theme;
45    }
46
47    @Override
48    public void setTheme(int resid) {
49        if (mThemeResource != resid) {
50            mThemeResource = resid;
51            initializeTheme();
52        }
53    }
54
55    public int getThemeResId() {
56        return mThemeResource;
57    }
58
59    @Override
60    public Resources.Theme getTheme() {
61        if (mTheme != null) {
62            return mTheme;
63        }
64
65        if (mThemeResource == 0) {
66            mThemeResource = R.style.Theme_AppCompat_Light;
67        }
68        initializeTheme();
69
70        return mTheme;
71    }
72
73    @Override
74    public Object getSystemService(String name) {
75        if (LAYOUT_INFLATER_SERVICE.equals(name)) {
76            if (mInflater == null) {
77                mInflater = LayoutInflater.from(getBaseContext()).cloneInContext(this);
78            }
79            return mInflater;
80        }
81        return getBaseContext().getSystemService(name);
82    }
83
84    /**
85     * Called by {@link #setTheme} and {@link #getTheme} to apply a theme
86     * resource to the current Theme object.  Can override to change the
87     * default (simple) behavior.  This method will not be called in multiple
88     * threads simultaneously.
89     *
90     * @param theme The Theme object being modified.
91     * @param resid The theme style resource being applied to <var>theme</var>.
92     * @param first Set to true if this is the first time a style is being
93     *              applied to <var>theme</var>.
94     */
95    protected void onApplyThemeResource(Resources.Theme theme, int resid, boolean first) {
96        theme.applyStyle(resid, true);
97    }
98
99    private void initializeTheme() {
100        final boolean first = mTheme == null;
101        if (first) {
102            mTheme = getResources().newTheme();
103            Resources.Theme theme = getBaseContext().getTheme();
104            if (theme != null) {
105                mTheme.setTo(theme);
106            }
107        }
108        onApplyThemeResource(mTheme, mThemeResource, first);
109    }
110}
111
112