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 17 package com.example.android.visualgamecontroller.util; 18 19 import android.app.Activity; 20 import android.os.Build; 21 import android.view.View; 22 23 /** 24 * A utility class that helps with showing and hiding system UI such as the 25 * status bar and navigation/system bar. This class uses backward-compatibility 26 * techniques described in <a href= 27 * "http://developer.android.com/training/backward-compatible-ui/index.html"> 28 * Creating Backward-Compatible UIs</a> to ensure that devices running any 29 * version of Android OS are supported. More specifically, there are separate 30 * implementations of this abstract class: for newer devices, 31 * {@link #getInstance} will return a {@link SystemUiHiderHoneycomb} instance, 32 * while on older devices {@link #getInstance} will return a 33 * {@link SystemUiHiderBase} instance. 34 * <p> 35 * For more on system bars, see <a href= 36 * "http://developer.android.com/design/get-started/ui-overview.html#system-bars" 37 * > System Bars</a>. 38 * 39 * @see android.view.View#setSystemUiVisibility(int) 40 * @see android.view.WindowManager.LayoutParams#FLAG_FULLSCREEN 41 */ 42 public abstract class SystemUiHider { 43 /** 44 * When this flag is set, the 45 * {@link android.view.WindowManager.LayoutParams#FLAG_LAYOUT_IN_SCREEN} 46 * flag will be set on older devices, making the status bar "float" on top 47 * of the activity layout. This is most useful when there are no controls at 48 * the top of the activity layout. 49 * <p> 50 * This flag isn't used on newer devices because the <a 51 * href="http://developer.android.com/design/patterns/actionbar.html">action 52 * bar</a>, the most important structural element of an Android app, should 53 * be visible and not obscured by the system UI. 54 */ 55 public static final int FLAG_LAYOUT_IN_SCREEN_OLDER_DEVICES = 0x1; 56 57 /** 58 * When this flag is set, {@link #show()} and {@link #hide()} will toggle 59 * the visibility of the status bar. If there is a navigation bar, show and 60 * hide will toggle low profile mode. 61 */ 62 public static final int FLAG_FULLSCREEN = 0x2; 63 64 /** 65 * When this flag is set, {@link #show()} and {@link #hide()} will toggle 66 * the visibility of the navigation bar, if it's present on the device and 67 * the device allows hiding it. In cases where the navigation bar is present 68 * but cannot be hidden, show and hide will toggle low profile mode. 69 */ 70 public static final int FLAG_HIDE_NAVIGATION = FLAG_FULLSCREEN | 0x4; 71 72 /** 73 * The activity associated with this UI hider object. 74 */ 75 protected Activity mActivity; 76 77 /** 78 * The view on which {@link View#setSystemUiVisibility(int)} will be called. 79 */ 80 protected View mAnchorView; 81 82 /** 83 * The current UI hider flags. 84 * 85 * @see #FLAG_FULLSCREEN 86 * @see #FLAG_HIDE_NAVIGATION 87 * @see #FLAG_LAYOUT_IN_SCREEN_OLDER_DEVICES 88 */ 89 protected int mFlags; 90 91 /** 92 * The current visibility callback. 93 */ 94 protected OnVisibilityChangeListener mOnVisibilityChangeListener = sDummyListener; 95 96 /** 97 * Creates and returns an instance of {@link SystemUiHider} that is 98 * appropriate for this device. The object will be either a 99 * {@link SystemUiHiderBase} or {@link SystemUiHiderHoneycomb} depending on 100 * the device. 101 * 102 * @param activity The activity whose window's system UI should be 103 * controlled by this class. 104 * @param anchorView The view on which 105 * {@link View#setSystemUiVisibility(int)} will be called. 106 * @param flags Either 0 or any combination of {@link #FLAG_FULLSCREEN}, 107 * {@link #FLAG_HIDE_NAVIGATION}, and 108 * {@link #FLAG_LAYOUT_IN_SCREEN_OLDER_DEVICES}. 109 */ getInstance(Activity activity, View anchorView, int flags)110 public static SystemUiHider getInstance(Activity activity, View anchorView, int flags) { 111 if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.HONEYCOMB) { 112 return new SystemUiHiderHoneycomb(activity, anchorView, flags); 113 } else { 114 return new SystemUiHiderBase(activity, anchorView, flags); 115 } 116 } 117 SystemUiHider(Activity activity, View anchorView, int flags)118 protected SystemUiHider(Activity activity, View anchorView, int flags) { 119 mActivity = activity; 120 mAnchorView = anchorView; 121 mFlags = flags; 122 } 123 124 /** 125 * Sets up the system UI hider. Should be called from 126 * {@link Activity#onCreate}. 127 */ setup()128 public abstract void setup(); 129 130 /** 131 * Returns whether or not the system UI is visible. 132 */ isVisible()133 public abstract boolean isVisible(); 134 135 /** 136 * Hide the system UI. 137 */ hide()138 public abstract void hide(); 139 140 /** 141 * Show the system UI. 142 */ show()143 public abstract void show(); 144 145 /** 146 * Toggle the visibility of the system UI. 147 */ toggle()148 public void toggle() { 149 if (isVisible()) { 150 hide(); 151 } else { 152 show(); 153 } 154 } 155 156 /** 157 * Registers a callback, to be triggered when the system UI visibility 158 * changes. 159 */ setOnVisibilityChangeListener(OnVisibilityChangeListener listener)160 public void setOnVisibilityChangeListener(OnVisibilityChangeListener listener) { 161 if (listener == null) { 162 listener = sDummyListener; 163 } 164 165 mOnVisibilityChangeListener = listener; 166 } 167 168 /** 169 * A dummy no-op callback for use when there is no other listener set. 170 */ 171 private static OnVisibilityChangeListener sDummyListener = new OnVisibilityChangeListener() { 172 @Override 173 public void onVisibilityChange(boolean visible) { 174 } 175 }; 176 177 /** 178 * A callback interface used to listen for system UI visibility changes. 179 */ 180 public interface OnVisibilityChangeListener { 181 /** 182 * Called when the system UI visibility has changed. 183 * 184 * @param visible True if the system UI is visible. 185 */ onVisibilityChange(boolean visible)186 public void onVisibilityChange(boolean visible); 187 } 188 } 189