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1 /*
2  * Copyright (C) 2013 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 
17 package android.support.v7.app;
18 
19 import android.content.Context;
20 import android.content.res.TypedArray;
21 import android.graphics.Color;
22 import android.support.annotation.IntDef;
23 import android.support.v4.graphics.ColorUtils;
24 import android.support.v7.mediarouter.R;
25 import android.util.TypedValue;
26 import android.view.ContextThemeWrapper;
27 import android.view.View;
28 
29 import java.lang.annotation.Retention;
30 import java.lang.annotation.RetentionPolicy;
31 
32 final class MediaRouterThemeHelper {
33     private static final float MIN_CONTRAST = 3.0f;
34 
35     @IntDef({COLOR_DARK_ON_LIGHT_BACKGROUND, COLOR_WHITE_ON_DARK_BACKGROUND})
36     @Retention(RetentionPolicy.SOURCE)
37     private @interface ControllerColorType {}
38 
39     private static final int COLOR_DARK_ON_LIGHT_BACKGROUND = 0xDE000000; /* Opacity of 87% */
40     private static final int COLOR_WHITE_ON_DARK_BACKGROUND = Color.WHITE;
41 
MediaRouterThemeHelper()42     private MediaRouterThemeHelper() {
43     }
44 
45     /**
46      * Creates a themed context based on the explicit style resource or the parent context's default
47      * theme.
48      * <p>
49      * The theme which will be applied on top of the parent {@code context}'s theme is determined
50      * by the primary color defined in the given {@code style}, or in the parent {@code context}.
51      *
52      * @param context the parent context
53      * @param style the resource ID of the style against which to inflate this context, or
54      *              {@code 0} to use the parent {@code context}'s default theme.
55      * @return The themed context.
56      */
createThemedContext(Context context, int style)57     public static Context createThemedContext(Context context, int style) {
58         int theme;
59         if (isLightTheme(context)) {
60             if (getControllerColor(context, style) == COLOR_DARK_ON_LIGHT_BACKGROUND) {
61                 theme = R.style.Theme_MediaRouter_Light;
62             } else {
63                 theme = R.style.Theme_MediaRouter_Light_DarkControlPanel;
64             }
65         } else {
66             if (getControllerColor(context, style) == COLOR_DARK_ON_LIGHT_BACKGROUND) {
67                 theme = R.style.Theme_MediaRouter_LightControlPanel;
68             } else {
69                 theme = R.style.Theme_MediaRouter;
70             }
71         }
72         return new ContextThemeWrapper(context, theme);
73     }
74 
getThemeResource(Context context, int attr)75     public static int getThemeResource(Context context, int attr) {
76         TypedValue value = new TypedValue();
77         return context.getTheme().resolveAttribute(attr, value, true) ? value.resourceId : 0;
78     }
79 
getDisabledAlpha(Context context)80     public static float getDisabledAlpha(Context context) {
81         TypedValue value = new TypedValue();
82         return context.getTheme().resolveAttribute(android.R.attr.disabledAlpha, value, true)
83                 ? value.getFloat() : 0.5f;
84     }
85 
getControllerColor(Context context, int style)86     public static @ControllerColorType int getControllerColor(Context context, int style) {
87         int primaryColor = getThemeColor(context, style,
88                 android.support.v7.appcompat.R.attr.colorPrimary);
89         if (ColorUtils.calculateContrast(COLOR_WHITE_ON_DARK_BACKGROUND, primaryColor)
90                 >= MIN_CONTRAST) {
91             return COLOR_WHITE_ON_DARK_BACKGROUND;
92         }
93         return COLOR_DARK_ON_LIGHT_BACKGROUND;
94     }
95 
getButtonTextColor(Context context)96     public static int getButtonTextColor(Context context) {
97         int primaryColor = getThemeColor(context, 0,
98                 android.support.v7.appcompat.R.attr.colorPrimary);
99         int backgroundColor = getThemeColor(context, 0, android.R.attr.colorBackground);
100 
101         if (ColorUtils.calculateContrast(primaryColor, backgroundColor) < MIN_CONTRAST) {
102             // Default to colorAccent if the contrast ratio is low.
103             return getThemeColor(context, 0, android.support.v7.appcompat.R.attr.colorAccent);
104         }
105         return primaryColor;
106     }
107 
setMediaControlsBackgroundColor( Context context, View mainControls, View groupControls, boolean hasGroup)108     public static void setMediaControlsBackgroundColor(
109             Context context, View mainControls, View groupControls, boolean hasGroup) {
110         int primaryColor = getThemeColor(context, 0,
111                 android.support.v7.appcompat.R.attr.colorPrimary);
112         int primaryDarkColor = getThemeColor(context, 0,
113                 android.support.v7.appcompat.R.attr.colorPrimaryDark);
114         if (hasGroup && getControllerColor(context, 0) == COLOR_DARK_ON_LIGHT_BACKGROUND) {
115             // Instead of showing dark controls in a possibly dark (i.e. the primary dark), model
116             // the white dialog and use the primary color for the group controls.
117             primaryDarkColor = primaryColor;
118             primaryColor = Color.WHITE;
119         }
120         mainControls.setBackgroundColor(primaryColor);
121         groupControls.setBackgroundColor(primaryDarkColor);
122         // Also store the background colors to the view tags. They are used in
123         // setVolumeSliderColor() below.
124         mainControls.setTag(primaryColor);
125         groupControls.setTag(primaryDarkColor);
126     }
127 
setVolumeSliderColor( Context context, MediaRouteVolumeSlider volumeSlider, View backgroundView)128     public static void setVolumeSliderColor(
129             Context context, MediaRouteVolumeSlider volumeSlider, View backgroundView) {
130         int controllerColor = getControllerColor(context, 0);
131         if (Color.alpha(controllerColor) != 0xFF) {
132             // Composite with the background in order not to show the underlying progress bar
133             // through the thumb.
134             int backgroundColor = (int) backgroundView.getTag();
135             controllerColor = ColorUtils.compositeColors(controllerColor, backgroundColor);
136         }
137         volumeSlider.setColor(controllerColor);
138     }
139 
140     // This is copied from {@link AlertDialog#resolveDialogTheme} to pre-evaluate theme in advance.
getAlertDialogResolvedTheme(Context context, int themeResId)141     public static int getAlertDialogResolvedTheme(Context context, int themeResId) {
142         if (themeResId >= 0x01000000) {   // start of real resource IDs.
143             return themeResId;
144         } else {
145             TypedValue outValue = new TypedValue();
146             context.getTheme().resolveAttribute(
147                     android.support.v7.appcompat.R.attr.alertDialogTheme, outValue, true);
148             return outValue.resourceId;
149         }
150     }
151 
isLightTheme(Context context)152     private static boolean isLightTheme(Context context) {
153         TypedValue value = new TypedValue();
154         return context.getTheme().resolveAttribute(
155                 android.support.v7.appcompat.R.attr.isLightTheme, value, true)
156                 && value.data != 0;
157     }
158 
getThemeColor(Context context, int style, int attr)159     private static int getThemeColor(Context context, int style, int attr) {
160         if (style != 0) {
161             int[] attrs = { attr };
162             TypedArray ta = context.obtainStyledAttributes(style, attrs);
163             int color = ta.getColor(0, 0);
164             ta.recycle();
165             if (color != 0) {
166                 return color;
167             }
168         }
169         TypedValue value = new TypedValue();
170         context.getTheme().resolveAttribute(attr, value, true);
171         if (value.resourceId != 0) {
172             return context.getResources().getColor(value.resourceId);
173         }
174         return value.data;
175     }
176 }
177