SystemUiHelper

/*

• Copyright (C) 2014 The Android Open Source Project
• Licensed under the Apache License, Version 2.0 (the "License");
• you may not use this file except in compliance with the License.
• You may obtain a copy of the License at

•  http://www.apache.org/licenses/LICENSE-2.0
  

• Unless required by applicable law or agreed to in writing, software
• distributed under the License is distributed on an "AS IS" BASIS,
• WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
• See the License for the specific language governing permissions and
• limitations under the License. */

package com.example.android.systemuivis;

import android.app.Activity; import android.os.Build; import android.os.Handler; import android.os.Looper; import android.view.WindowManager;

/**

• Helper for controlling the visibility of the System UI across the various API levels. To use

• this API, instantiate an instance of this class with the required level. The level specifies the

• extent to which the System UI's visibility is changed when you call {@link #hide()}

• or {@link #toggle()}. */ public final class SystemUiHelper {

  /**

  • In this level, the helper will toggle low profile mode. */ public static final int LEVEL_LOW_PROFILE = 0;

  /**

  • In this level, the helper will toggle the visibility of the status bar.
  • If there is a navigation bar, it will toggle low profile mode. */ public static final int LEVEL_HIDE_STATUS_BAR = 1;

  /**

  • In this level, the helper will toggle the visibility of the navigation bar
  • (if present and if possible) and status bar. In cases where the navigation
  • bar is present but cannot be hidden, it will toggle low profile mode. */ public static final int LEVEL_LEAN_BACK = 2;

  /**

  • In this level, the helper will toggle the visibility of the navigation bar
  • (if present and if possible) and status bar, in an immersive mode. This means that the app
  • will continue to receive all touch events. The user can reveal the system bars with an
  • inward swipe along the region where the system bars normally appear.

  • The {@link #FLAG_IMMERSIVE_STICKY} flag can be used to control how the system bars are

  • displayed. */ public static final int LEVEL_IMMERSIVE = 3;

  /**

  • When this flag is set, the
  • {@link android.view.WindowManager.LayoutParams#FLAG_LAYOUT_IN_SCREEN}
  • flag will be set on older devices, making the status bar "float" on top
  • of the activity layout. This is most useful when there are no controls at
  • the top of the activity layout.
  • This flag isn't used on newer devices because the <a
  • href="http://developer.android.com/design/patterns/actionbar.html">action
  • bar, the most important structural element of an Android app, should
  • be visible and not obscured by the system UI. */ public static final int FLAG_LAYOUT_IN_SCREEN_OLDER_DEVICES = 0x1;

  /**

  • Used with {@link #LEVEL_IMMERSIVE}. When this flag is set, an inward swipe in the system
  • bars areas will cause the system bars to temporarily appear in a semi-transparent state,
  • but no flags are cleared, and your system UI visibility change listeners are not triggered.
  • The bars automatically hide again after a short delay, or if the user interacts with the
  • middle of the screen. */ public static final int FLAG_IMMERSIVE_STICKY = 0x2;

  private static final String LOG_TAG = SystemUiHelper.class.getSimpleName();

  private final SystemUiHelperImpl mImpl;

  private final Handler mHandler; private final Runnable mHideRunnable;

  /**

  • Construct a new SystemUiHelper.
  • @param activity The Activity who's system UI should be changed
  • @param level The level of hiding. Should be either {@link #LEVEL_LOW_PROFILE},

  •          {@link #LEVEL_HIDE_STATUS_BAR}, {@link #LEVEL_LEAN_BACK} or
    

  •          {@link #LEVEL_IMMERSIVE}
    

  • @param flags Additional options. See {@link #FLAG_LAYOUT_IN_SCREEN_OLDER_DEVICES} and

  •          {@link #FLAG_IMMERSIVE_STICKY}
    

  */ public SystemUiHelper(Activity activity, int level, int flags) { this(activity, level, flags, null); }

  /**

  • Construct a new SystemUiHelper.

  • @param activity The Activity who's system UI should be changed

  • @param level The level of hiding. Should be either {@link #LEVEL_LOW_PROFILE},

  •          {@link #LEVEL_HIDE_STATUS_BAR}, {@link #LEVEL_LEAN_BACK} or
    

  •          {@link #LEVEL_IMMERSIVE}
    

  • @param flags Additional options. See {@link #FLAG_LAYOUT_IN_SCREEN_OLDER_DEVICES} and

  •          {@link #FLAG_IMMERSIVE_STICKY}
    

  • @param listener A listener which is called when the system visibility is changed */ public SystemUiHelper(Activity activity, int level, int flags, OnVisibilityChangeListener listener) {

    mHandler = new Handler(Looper.getMainLooper()); mHideRunnable = new HideRunnable();

    // Create impl if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.KITKAT) { mImpl = new SystemUiHelperImplKK(activity, level, flags, listener); } else if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN) { mImpl = new SystemUiHelperImplJB(activity, level, flags, listener); } else if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.ICE_CREAM_SANDWICH) { mImpl = new SystemUiHelperImplICS(activity, level, flags, listener); } else if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.HONEYCOMB) { mImpl = new SystemUiHelperImplHC(activity, level, flags, listener); } else { mImpl = new SystemUiHelperImplBase(activity, level, flags, listener); } }

  /**

  • @return true if the system UI is currently showing. What this means depends on the mode this

  •     {@link android.example.android.systemuivis.SystemUiHelper} was instantiated with.
    

  */ public boolean isShowing() { return mImpl.isShowing(); }

  /**

  • Show the system UI. What this means depends on the mode this {@link android.example.android.systemuivis.SystemUiHelper} was
  • instantiated with.

  • Any currently queued delayed hide requests will be removed.

  */ public void show() { // Ensure that any currently queued hide calls are removed removeQueuedRunnables();

   mImpl.show();
  

  }

  /**

  • Hide the system UI. What this means depends on the mode this {@link android.example.android.systemuivis.SystemUiHelper} was
  • instantiated with.

  • Any currently queued delayed hide requests will be removed.

  */ public void hide() { // Ensure that any currently queued hide calls are removed removeQueuedRunnables();

   mImpl.hide();
  

  }

  /**

  • Request that the system UI is hidden after a delay.

  • Any currently queued delayed hide requests will be removed.

  • @param delayMillis The delay (in milliseconds) until the Runnable

  •    will be executed.
    

  */ public void delayHide(long delayMillis) { // Ensure that any currently queued hide calls are removed removeQueuedRunnables();

   mHandler.postDelayed(mHideRunnable, delayMillis);
  

  }

  /**

  • Toggle whether the system UI is displayed. */ public void toggle() { if (mImpl.isShowing()) { mImpl.hide(); } else { mImpl.show(); } }

  private void removeQueuedRunnables() { // Ensure that any currently queued hide calls are removed mHandler.removeCallbacks(mHideRunnable); }

  /**

  • A callback interface used to listen for system UI visibility changes. / public interface OnVisibilityChangeListener { /*
    • Called when the system UI visibility has changed.
    • @param visible True if the system UI is visible. */ public void onVisibilityChange(boolean visible); }

  static abstract class SystemUiHelperImpl {

   final Activity mActivity;
   final int mLevel;
   final int mFlags;
   final OnVisibilityChangeListener mOnVisibilityChangeListener;
  
   boolean mIsShowing = true;
  
   SystemUiHelperImpl(Activity activity, int level, int flags,
           OnVisibilityChangeListener onVisibilityChangeListener) {
       mActivity = activity;
       mLevel = level;
       mFlags = flags;
       mOnVisibilityChangeListener = onVisibilityChangeListener;
   }
  
   abstract void show();
   abstract void hide();
  
   boolean isShowing() {
       return mIsShowing;
   }
  
   void setIsShowing(boolean isShowing) {
       mIsShowing = isShowing;
  
       if (mOnVisibilityChangeListener != null) {
           mOnVisibilityChangeListener.onVisibilityChange(mIsShowing);
       }
   }
  

  }

  /**

  • Base implementation. Used on API level 10 and below. */ static class SystemUiHelperImplBase extends SystemUiHelperImpl {

    SystemUiHelperImplBase(Activity activity, int level, int flags, OnVisibilityChangeListener onVisibilityChangeListener) { super(activity, level, flags, onVisibilityChangeListener);

     if ((mFlags & SystemUiHelper.FLAG_LAYOUT_IN_SCREEN_OLDER_DEVICES) != 0) {
         mActivity.getWindow().addFlags(
                 WindowManager.LayoutParams.FLAG_LAYOUT_IN_SCREEN
                         | WindowManager.LayoutParams.FLAG_LAYOUT_NO_LIMITS);
     }
    

    }

    @Override void show() { if (mLevel > SystemUiHelper.LEVEL_LOW_PROFILE) { mActivity.getWindow().clearFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN); setIsShowing(true); } }

    @Override void hide() { if (mLevel > SystemUiHelper.LEVEL_LOW_PROFILE) { mActivity.getWindow().addFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN); setIsShowing(false); } } }

  private class HideRunnable implements Runnable { @Override public void run() { hide(); } }

}