ViewFlipper.java revision 2b95c2413838c2e2b127ebab8fb4fead7d52e460 
1/*
2 * Copyright (C) 2006 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 android.widget;
18
19import android.content.BroadcastReceiver;
20import android.content.Context;
21import android.content.Intent;
22import android.content.IntentFilter;
23import android.content.res.TypedArray;
24import android.os.Handler;
25import android.os.Message;
26import android.util.AttributeSet;
27import android.util.Log;
28import android.widget.RemoteViews.RemoteView;
29
30/**
31 * Simple {@link ViewAnimator} that will animate between two or more views
32 * that have been added to it.  Only one child is shown at a time.  If
33 * requested, can automatically flip between each child at a regular interval.
34 *
35 * @attr ref android.R.styleable#ViewFlipper_flipInterval
36 * @attr ref android.R.styleable#ViewFlipper_autoStart
37 */
38@RemoteView
39public class ViewFlipper extends ViewAnimator {
40    private static final String TAG = "ViewFlipper";
41    private static final boolean LOGD = false;
42
43    private static final int DEFAULT_INTERVAL = 3000;
44
45    private int mFlipInterval = DEFAULT_INTERVAL;
46    private boolean mAutoStart = false;
47
48    private boolean mRunning = false;
49    private boolean mStarted = false;
50    private boolean mVisible = false;
51    private boolean mUserPresent = true;
52
53    public ViewFlipper(Context context) {
54        super(context);
55    }
56
57    public ViewFlipper(Context context, AttributeSet attrs) {
58        super(context, attrs);
59
60        TypedArray a = context.obtainStyledAttributes(attrs,
61                com.android.internal.R.styleable.ViewFlipper);
62        mFlipInterval = a.getInt(
63                com.android.internal.R.styleable.ViewFlipper_flipInterval, DEFAULT_INTERVAL);
64        mAutoStart = a.getBoolean(
65                com.android.internal.R.styleable.ViewFlipper_autoStart, false);
66        a.recycle();
67    }
68
69    private final BroadcastReceiver mReceiver = new BroadcastReceiver() {
70        @Override
71        public void onReceive(Context context, Intent intent) {
72            final String action = intent.getAction();
73            if (Intent.ACTION_SCREEN_OFF.equals(action)) {
74                mUserPresent = false;
75                updateRunning();
76            } else if (Intent.ACTION_USER_PRESENT.equals(action)) {
77                mUserPresent = true;
78                updateRunning();
79            }
80        }
81    };
82
83    @Override
84    protected void onAttachedToWindow() {
85        super.onAttachedToWindow();
86
87        // Listen for broadcasts related to user-presence
88        final IntentFilter filter = new IntentFilter();
89        filter.addAction(Intent.ACTION_SCREEN_OFF);
90        filter.addAction(Intent.ACTION_USER_PRESENT);
91        getContext().registerReceiver(mReceiver, filter);
92
93        if (mAutoStart) {
94            // Automatically start when requested
95            startFlipping();
96        }
97    }
98
99    @Override
100    protected void onDetachedFromWindow() {
101        super.onDetachedFromWindow();
102        mVisible = false;
103
104        getContext().unregisterReceiver(mReceiver);
105        updateRunning();
106    }
107
108    @Override
109    protected void onWindowVisibilityChanged(int visibility) {
110        super.onWindowVisibilityChanged(visibility);
111        mVisible = visibility == VISIBLE;
112        updateRunning();
113    }
114
115    /**
116     * How long to wait before flipping to the next view
117     *
118     * @param milliseconds
119     *            time in milliseconds
120     */
121    @android.view.RemotableViewMethod
122    public void setFlipInterval(int milliseconds) {
123        mFlipInterval = milliseconds;
124    }
125
126    /**
127     * Start a timer to cycle through child views
128     */
129    public void startFlipping() {
130        mStarted = true;
131        updateRunning();
132    }
133
134    /**
135     * No more flips
136     */
137    public void stopFlipping() {
138        mStarted = false;
139        updateRunning();
140    }
141
142    /**
143     * Internal method to start or stop dispatching flip {@link Message} based
144     * on {@link #mRunning} and {@link #mVisible} state.
145     */
146    private void updateRunning() {
147        boolean running = mVisible && mStarted && mUserPresent;
148        if (running != mRunning) {
149            if (running) {
150                showOnly(mWhichChild);
151                Message msg = mHandler.obtainMessage(FLIP_MSG);
152                mHandler.sendMessageDelayed(msg, mFlipInterval);
153            } else {
154                mHandler.removeMessages(FLIP_MSG);
155            }
156            mRunning = running;
157        }
158        if (LOGD) {
159            Log.d(TAG, "updateRunning() mVisible=" + mVisible + ", mStarted=" + mStarted
160                    + ", mUserPresent=" + mUserPresent + ", mRunning=" + mRunning);
161        }
162    }
163
164    /**
165     * Returns true if the child views are flipping.
166     */
167    public boolean isFlipping() {
168        return mStarted;
169    }
170
171    /**
172     * Set if this view automatically calls {@link #startFlipping()} when it
173     * becomes attached to a window.
174     */
175    public void setAutoStart(boolean autoStart) {
176        mAutoStart = autoStart;
177    }
178
179    /**
180     * Returns true if this view automatically calls {@link #startFlipping()}
181     * when it becomes attached to a window.
182     */
183    public boolean isAutoStart() {
184        return mAutoStart;
185    }
186
187    private final int FLIP_MSG = 1;
188
189    private final Handler mHandler = new Handler() {
190        @Override
191        public void handleMessage(Message msg) {
192            if (msg.what == FLIP_MSG) {
193                if (mRunning) {
194                    showNext();
195                    msg = obtainMessage(FLIP_MSG);
196                    sendMessageDelayed(msg, mFlipInterval);
197                }
198            }
199        }
200    };
201}
202