RotationPolicy.java revision 6090995951c6e2e4dcf38102f01793f8a94166e1 
1/*
2 * Copyright (C) 2012 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.android.internal.view;
18
19import android.content.Context;
20import android.content.pm.PackageManager;
21import android.database.ContentObserver;
22import android.net.Uri;
23import android.os.AsyncTask;
24import android.os.Handler;
25import android.os.RemoteException;
26import android.os.UserHandle;
27import android.provider.Settings;
28import android.util.Log;
29import android.view.IWindowManager;
30import android.view.Surface;
31import android.view.WindowManagerGlobal;
32
33/**
34 * Provides helper functions for configuring the display rotation policy.
35 */
36public final class RotationPolicy {
37    private static final String TAG = "RotationPolicy";
38
39    private RotationPolicy() {
40    }
41
42    /**
43     * Gets whether the device supports rotation. In general such a
44     * device has an accelerometer and has the portrait and landscape
45     * features.
46     *
47     * @param context Context for accessing system resources.
48     * @return Whether the device supports rotation.
49     */
50    public static boolean isRotationSupported(Context context) {
51        PackageManager pm = context.getPackageManager();
52        return pm.hasSystemFeature(PackageManager.FEATURE_SENSOR_ACCELEROMETER)
53                && pm.hasSystemFeature(PackageManager.FEATURE_SCREEN_PORTRAIT)
54                && pm.hasSystemFeature(PackageManager.FEATURE_SCREEN_LANDSCAPE);
55    }
56
57    /**
58     * Returns true if the device supports the rotation-lock toggle feature
59     * in the system UI or system bar.
60     *
61     * When the rotation-lock toggle is supported, the "auto-rotate screen" option in
62     * Display settings should be hidden, but it should remain available in Accessibility
63     * settings.
64     */
65    public static boolean isRotationLockToggleSupported(Context context) {
66        return isRotationSupported(context)
67                && context.getResources().getConfiguration().smallestScreenWidthDp >= 600;
68    }
69
70    /**
71     * Returns true if the rotation-lock toggle should be shown in the UI.
72     */
73    public static boolean isRotationLockToggleVisible(Context context) {
74        return isRotationLockToggleSupported(context) &&
75                Settings.System.getIntForUser(context.getContentResolver(),
76                        Settings.System.HIDE_ROTATION_LOCK_TOGGLE_FOR_ACCESSIBILITY, 0,
77                        UserHandle.USER_CURRENT) == 0;
78    }
79
80    /**
81     * Returns true if rotation lock is enabled.
82     */
83    public static boolean isRotationLocked(Context context) {
84        return Settings.System.getIntForUser(context.getContentResolver(),
85                Settings.System.ACCELEROMETER_ROTATION, 0, UserHandle.USER_CURRENT) == 0;
86    }
87
88    /**
89     * Enables or disables rotation lock.
90     *
91     * Should be used by the rotation lock toggle.
92     */
93    public static void setRotationLock(Context context, final boolean enabled) {
94        Settings.System.putIntForUser(context.getContentResolver(),
95                Settings.System.HIDE_ROTATION_LOCK_TOGGLE_FOR_ACCESSIBILITY, 0,
96                UserHandle.USER_CURRENT);
97
98        AsyncTask.execute(new Runnable() {
99            @Override
100            public void run() {
101                try {
102                    IWindowManager wm = WindowManagerGlobal.getWindowManagerService();
103                    if (enabled) {
104                        wm.freezeRotation(-1);
105                    } else {
106                        wm.thawRotation();
107                    }
108                } catch (RemoteException exc) {
109                    Log.w(TAG, "Unable to save auto-rotate setting");
110                }
111            }
112        });
113    }
114
115    /**
116     * Enables or disables rotation lock and adjusts whether the rotation lock toggle
117     * should be hidden for accessibility purposes.
118     *
119     * Should be used by Display settings and Accessibility settings.
120     */
121    public static void setRotationLockForAccessibility(Context context, final boolean enabled) {
122        Settings.System.putIntForUser(context.getContentResolver(),
123                Settings.System.HIDE_ROTATION_LOCK_TOGGLE_FOR_ACCESSIBILITY, enabled ? 1 : 0,
124                        UserHandle.USER_CURRENT);
125
126        AsyncTask.execute(new Runnable() {
127            @Override
128            public void run() {
129                try {
130                    IWindowManager wm = WindowManagerGlobal.getWindowManagerService();
131                    if (enabled) {
132                        wm.freezeRotation(Surface.ROTATION_0);
133                    } else {
134                        wm.thawRotation();
135                    }
136                } catch (RemoteException exc) {
137                    Log.w(TAG, "Unable to save auto-rotate setting");
138                }
139            }
140        });
141    }
142
143    /**
144     * Registers a listener for rotation policy changes affecting the caller's user
145     */
146    public static void registerRotationPolicyListener(Context context,
147            RotationPolicyListener listener) {
148        registerRotationPolicyListener(context, listener, UserHandle.getCallingUserId());
149    }
150
151    /**
152     * Registers a listener for rotation policy changes affecting a specific user,
153     * or USER_ALL for all users.
154     */
155    public static void registerRotationPolicyListener(Context context,
156            RotationPolicyListener listener, int userHandle) {
157        context.getContentResolver().registerContentObserver(Settings.System.getUriFor(
158                Settings.System.ACCELEROMETER_ROTATION),
159                false, listener.mObserver, userHandle);
160        context.getContentResolver().registerContentObserver(Settings.System.getUriFor(
161                Settings.System.HIDE_ROTATION_LOCK_TOGGLE_FOR_ACCESSIBILITY),
162                false, listener.mObserver, userHandle);
163    }
164
165    /**
166     * Unregisters a listener for rotation policy changes.
167     */
168    public static void unregisterRotationPolicyListener(Context context,
169            RotationPolicyListener listener) {
170        context.getContentResolver().unregisterContentObserver(listener.mObserver);
171    }
172
173    /**
174     * Listener that is invoked whenever a change occurs that might affect the rotation policy.
175     */
176    public static abstract class RotationPolicyListener {
177        final ContentObserver mObserver = new ContentObserver(new Handler()) {
178            public void onChange(boolean selfChange, Uri uri) {
179                RotationPolicyListener.this.onChange();
180            }
181        };
182
183        public abstract void onChange();
184    }
185}