1 /* 2 * Copyright (C) 2011 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.android.gallery3d.util; 18 19 import android.app.Activity; 20 import android.os.Handler; 21 import android.os.Message; 22 import android.os.SystemClock; 23 24 import java.util.HashMap; 25 import java.util.Map; 26 27 /** 28 * This class manages the visibility of the progress spinner in the action bar for an 29 * Activity. It filters out short-lived appearances of the progress spinner by only 30 * showing the spinner if it hasn't been hidden again before the end of a specified 31 * delay period. It also enforces a minimum display time once the spinner is made visible. 32 * This meant to cut down on the frequent "flashes" of the progress spinner. 33 */ 34 public class SpinnerVisibilitySetter { 35 36 private static final int SHOW_SPINNER_REQUESTED = 0; 37 private static final int HIDE_SPINNER_REQUESTED = 1; 38 private static final int SHOW_SPINNER_DELAY_REACHED = 2; 39 private static final int HIDE_SPINNER_DELAY_REACHED = 3; 40 41 // Amount of time after a show request that the progress spinner is actually made visible. 42 // This means that any show/hide requests that happen subsequently within this period 43 // of time will be ignored. 44 private static final long SPINNER_DISPLAY_DELAY = 1000; 45 46 // The minimum amount of time the progress spinner must be visible before it can be hidden. 47 private static final long MIN_SPINNER_DISPLAY_TIME = 2000; 48 49 private boolean mPendingVisibilityRequest = false; 50 private boolean mActiveVisibilityRequest = false; 51 private long mSpinnerVisibilityStartTime; 52 53 Handler mHandler = new Handler() { 54 55 @Override 56 public void handleMessage(Message msg) { 57 switch(msg.what) { 58 case SHOW_SPINNER_REQUESTED: 59 mPendingVisibilityRequest = true; 60 sendEmptyMessageDelayed(SHOW_SPINNER_DELAY_REACHED, SPINNER_DISPLAY_DELAY); 61 break; 62 case HIDE_SPINNER_REQUESTED: 63 mPendingVisibilityRequest = false; 64 if (!mActiveVisibilityRequest) { 65 // We haven't requested to show the spinner so no need to decide 66 // when to hide it. 67 break; 68 } 69 70 long currTime = SystemClock.uptimeMillis(); 71 if (currTime - mSpinnerVisibilityStartTime > MIN_SPINNER_DISPLAY_TIME) { 72 // The spinner has already been visible longer than the requisite min 73 // display time. Send the hide message immediately. 74 sendEmptyMessage(HIDE_SPINNER_DELAY_REACHED); 75 } else { 76 // The spinner is visible but hasn't been visible for long enough yet. 77 // Send a delayed hide message. 78 sendEmptyMessageAtTime(HIDE_SPINNER_DELAY_REACHED, 79 mSpinnerVisibilityStartTime + MIN_SPINNER_DISPLAY_TIME); 80 } 81 break; 82 case SHOW_SPINNER_DELAY_REACHED: 83 if (mPendingVisibilityRequest) { 84 mPendingVisibilityRequest = false; 85 mActiveVisibilityRequest = true; 86 87 // Even though the spinner isn't visible quite yet, lets set this 88 // here to avoid possible cross-thread synchronization issues. 89 mSpinnerVisibilityStartTime = SystemClock.uptimeMillis(); 90 mActivity.runOnUiThread(new SetProgressVisibilityRunnable(true)); 91 } 92 break; 93 case HIDE_SPINNER_DELAY_REACHED: 94 mActiveVisibilityRequest = false; 95 mActivity.runOnUiThread(new SetProgressVisibilityRunnable(false)); 96 break; 97 } 98 } 99 }; 100 static final Map<Activity, SpinnerVisibilitySetter> sInstanceMap = 101 new HashMap<Activity, SpinnerVisibilitySetter>(); 102 private Activity mActivity; 103 104 private SpinnerVisibilitySetter(Activity activity) { 105 mActivity = activity; 106 } 107 108 public static SpinnerVisibilitySetter getInstance(Activity activity) { 109 synchronized(sInstanceMap) { 110 if (sInstanceMap.get(activity) == null) { 111 sInstanceMap.put(activity, new SpinnerVisibilitySetter(activity)); 112 } 113 return sInstanceMap.get(activity); 114 } 115 } 116 117 public void setSpinnerVisibility(boolean visible) { 118 mHandler.sendEmptyMessage(visible ? SHOW_SPINNER_REQUESTED : HIDE_SPINNER_REQUESTED); 119 } 120 121 private class SetProgressVisibilityRunnable implements Runnable { 122 boolean mVisible; 123 124 public SetProgressVisibilityRunnable(boolean visible) { 125 mVisible = visible; 126 } 127 128 @Override 129 public void run() { 130 mActivity.setProgressBarIndeterminateVisibility(mVisible); 131 } 132 } 133 } 134