MinTimeProgressView.java revision 9e2d407fdafeb874e640eb84017feaf784309075 
1/**
2 * Copyright (c) 2011, Google Inc.
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 */
16package com.android.mail;
17
18import android.content.Context;
19import android.os.Handler;
20import android.util.AttributeSet;
21import android.view.View;
22import android.widget.ProgressBar;
23
24/**
25 * MinTimeProgressView implements a ProgressBar that waits MIN_DELAY ms to be
26 * dismissed before showing. Once visible, the progress bar will be visible for
27 * at least MIN_SHOW_TIME to avoid "flashes" in the UI when an event could take
28 * a largely variable time to complete (from none, to a user perceivable amount)
29 *
30 * @author mindyp
31 */
32public class MinTimeProgressView extends ProgressBar {
33    private static int sMinShowTime;
34
35    private static int sMinDelay;
36
37    private long mStartTime = -1;
38
39    private final Handler mHandler = new Handler();
40
41    private boolean mDismissed = false;
42
43    public MinTimeProgressView(Context context) {
44        this(context, null);
45    }
46
47    public MinTimeProgressView(Context context, AttributeSet attrs) {
48        super(context, attrs, R.style.MinTimeProgressViewStyle);
49        sMinShowTime = context.getResources()
50            .getInteger(R.integer.html_conv_progress_display_time);
51        sMinDelay = context.getResources()
52            .getInteger(R.integer.html_conv_progress_wait_time);
53    }
54
55    private final Runnable mDelayedHide = new Runnable() {
56        @Override
57        public void run() {
58            MinTimeProgressView.super.setVisibility(View.GONE);
59        }
60    };
61
62    private final Runnable mDelayedShow = new Runnable() {
63        @Override
64        public void run() {
65            if (!mDismissed) {
66                mStartTime = System.currentTimeMillis();
67                MinTimeProgressView.super.setVisibility(View.VISIBLE);
68            }
69        }
70    };
71
72    private void hide() {
73        mDismissed = true;
74        long diff = System.currentTimeMillis() - mStartTime;
75        if (diff >= sMinShowTime || mStartTime == -1) {
76            // The progress spinner has been shown long enough
77            // OR was not shown yet. If it wasn't shown yet,
78            // it will just never be shown.
79            MinTimeProgressView.super.setVisibility(View.GONE);
80        } else {
81            // The progress spinner is shown, but not long enough,
82            // so put a delayed message in to hide it when its been
83            // shown long enough.
84            mHandler.postDelayed(mDelayedHide, sMinShowTime - diff);
85        }
86    }
87
88    private void show() {
89        // Reset the start time.
90        mStartTime = -1;
91        mHandler.postDelayed(mDelayedShow, sMinDelay);
92    }
93
94    @Override
95    public void setVisibility(int visibility) {
96        // Whenever the visibility gets changed, clear dismissed
97        // state.
98        mDismissed = false;
99        switch (visibility) {
100            case View.VISIBLE:
101                show();
102                break;
103            case View.GONE:
104                hide();
105                break;
106            default:
107                super.setVisibility(visibility);
108        }
109    }
110}
111