Android example source code file (MediaController.java)

This example Android source code file (MediaController.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Android by Example" ^TM.

Java - Android tags/keywords

android, fade_out, formatter, handler, imagebutton, layoutinflater, mediacontroller, mediaplayercontrol, onseekbarchangelistener, os, override, progressbar, seekbar, show_progress, textview, ui, util, utilities, utils, view

The MediaController.java Android example source code

/*
 * Copyright (C) 2006 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 android.widget;

import android.content.Context;
import android.graphics.PixelFormat;
import android.media.AudioManager;
import android.os.Handler;
import android.os.Message;
import android.util.AttributeSet;
import android.util.Log;
import android.view.Gravity;
import android.view.KeyEvent;
import android.view.LayoutInflater;
import android.view.MotionEvent;
import android.view.View;
import android.view.ViewGroup;
import android.view.Window;
import android.view.WindowManager;
import android.widget.SeekBar.OnSeekBarChangeListener;

import com.android.internal.policy.PolicyManager;

import java.util.Formatter;
import java.util.Locale;

/**
 * A view containing controls for a MediaPlayer. Typically contains the
 * buttons like "Play/Pause", "Rewind", "Fast Forward" and a progress
 * slider. It takes care of synchronizing the controls with the state
 * of the MediaPlayer.
 * <p>
 * The way to use this class is to instantiate it programatically.
 * The MediaController will create a default set of controls
 * and put them in a window floating above your application. Specifically,
 * the controls will float above the view specified with setAnchorView().
 * The window will disappear if left idle for three seconds and reappear
 * when the user touches the anchor view.
 * <p>
 * Functions like show() and hide() have no effect when MediaController
 * is created in an xml layout.
 * 
 * MediaController will hide and
 * show the buttons according to these rules:
 * <ul>
 * <li> The "previous" and "next" buttons are hidden until setPrevNextListeners()
 *   has been called
 * <li> The "previous" and "next" buttons are visible but disabled if
 *   setPrevNextListeners() was called with null listeners
 * <li> The "rewind" and "fastforward" buttons are shown unless requested
 *   otherwise by using the MediaController(Context, boolean) constructor
 *   with the boolean set to false
 * </ul>
 */
public class MediaController extends FrameLayout {

    private MediaPlayerControl  mPlayer;
    private Context             mContext;
    private View                mAnchor;
    private View                mRoot;
    private WindowManager       mWindowManager;
    private Window              mWindow;
    private View                mDecor;
    private ProgressBar         mProgress;
    private TextView            mEndTime, mCurrentTime;
    private boolean             mShowing;
    private boolean             mDragging;
    private static final int    sDefaultTimeout = 3000;
    private static final int    FADE_OUT = 1;
    private static final int    SHOW_PROGRESS = 2;
    private boolean             mUseFastForward;
    private boolean             mFromXml;
    private boolean             mListenersSet;
    private View.OnClickListener mNextListener, mPrevListener;
    StringBuilder               mFormatBuilder;
    Formatter                   mFormatter;
    private ImageButton         mPauseButton;
    private ImageButton         mFfwdButton;
    private ImageButton         mRewButton;
    private ImageButton         mNextButton;
    private ImageButton         mPrevButton;

    public MediaController(Context context, AttributeSet attrs) {
        super(context, attrs);
        mRoot = this;
        mContext = context;
        mUseFastForward = true;
        mFromXml = true;
    }

    @Override
    public void onFinishInflate() {
        if (mRoot != null)
            initControllerView(mRoot);
    }

    public MediaController(Context context, boolean useFastForward) {
        super(context);
        mContext = context;
        mUseFastForward = useFastForward;
        initFloatingWindow();
    }

    public MediaController(Context context) {
        super(context);
        mContext = context;
        mUseFastForward = true;
        initFloatingWindow();
    }

    private void initFloatingWindow() {
        mWindowManager = (WindowManager)mContext.getSystemService(Context.WINDOW_SERVICE);
        mWindow = PolicyManager.makeNewWindow(mContext);
        mWindow.setWindowManager(mWindowManager, null, null);
        mWindow.requestFeature(Window.FEATURE_NO_TITLE);
        mDecor = mWindow.getDecorView();
        mDecor.setOnTouchListener(mTouchListener);
        mWindow.setContentView(this);
        mWindow.setBackgroundDrawableResource(android.R.color.transparent);
        
        // While the media controller is up, the volume control keys should
        // affect the media stream type
        mWindow.setVolumeControlStream(AudioManager.STREAM_MUSIC);

        setFocusable(true);
        setFocusableInTouchMode(true);
        setDescendantFocusability(ViewGroup.FOCUS_AFTER_DESCENDANTS);
        requestFocus();
    }

    private OnTouchListener mTouchListener = new OnTouchListener() {
        public boolean onTouch(View v, MotionEvent event) {
            if (event.getAction() == MotionEvent.ACTION_DOWN) {
                if (mShowing) {
                    hide();
                }
            }
            return false;
        }
    };
    
    public void setMediaPlayer(MediaPlayerControl player) {
        mPlayer = player;
        updatePausePlay();
    }

    /**
     * Set the view that acts as the anchor for the control view.
     * This can for example be a VideoView, or your Activity's main view.
     * @param view The view to which to anchor the controller when it is visible.
     */
    public void setAnchorView(View view) {
        mAnchor = view;

        FrameLayout.LayoutParams frameParams = new FrameLayout.LayoutParams(
                ViewGroup.LayoutParams.MATCH_PARENT,
                ViewGroup.LayoutParams.MATCH_PARENT
        );

        removeAllViews();
        View v = makeControllerView();
        addView(v, frameParams);
    }

    /**
     * Create the view that holds the widgets that control playback.
     * Derived classes can override this to create their own.
     * @return The controller view.
     * @hide This doesn't work as advertised
     */
    protected View makeControllerView() {
        LayoutInflater inflate = (LayoutInflater) mContext.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        mRoot = inflate.inflate(com.android.internal.R.layout.media_controller, null);

        initControllerView(mRoot);

        return mRoot;
    }

    private void initControllerView(View v) {
        mPauseButton = (ImageButton) v.findViewById(com.android.internal.R.id.pause);
        if (mPauseButton != null) {
            mPauseButton.requestFocus();
            mPauseButton.setOnClickListener(mPauseListener);
        }

        mFfwdButton = (ImageButton) v.findViewById(com.android.internal.R.id.ffwd);
        if (mFfwdButton != null) {
            mFfwdButton.setOnClickListener(mFfwdListener);
            if (!mFromXml) {
                mFfwdButton.setVisibility(mUseFastForward ? View.VISIBLE : View.GONE);
            }
        }

        mRewButton = (ImageButton) v.findViewById(com.android.internal.R.id.rew);
        if (mRewButton != null) {
            mRewButton.setOnClickListener(mRewListener);
            if (!mFromXml) {
                mRewButton.setVisibility(mUseFastForward ? View.VISIBLE : View.GONE);
            }
        }

        // By default these are hidden. They will be enabled when setPrevNextListeners() is called 
        mNextButton = (ImageButton) v.findViewById(com.android.internal.R.id.next);
        if (mNextButton != null && !mFromXml && !mListenersSet) {
            mNextButton.setVisibility(View.GONE);
        }
        mPrevButton = (ImageButton) v.findViewById(com.android.internal.R.id.prev);
        if (mPrevButton != null && !mFromXml && !mListenersSet) {
            mPrevButton.setVisibility(View.GONE);
        }

        mProgress = (ProgressBar) v.findViewById(com.android.internal.R.id.mediacontroller_progress);
        if (mProgress != null) {
            if (mProgress instanceof SeekBar) {
                SeekBar seeker = (SeekBar) mProgress;
                seeker.setOnSeekBarChangeListener(mSeekListener);
            }
            mProgress.setMax(1000);
        }

        mEndTime = (TextView) v.findViewById(com.android.internal.R.id.time);
        mCurrentTime = (TextView) v.findViewById(com.android.internal.R.id.time_current);
        mFormatBuilder = new StringBuilder();
        mFormatter = new Formatter(mFormatBuilder, Locale.getDefault());

        installPrevNextListeners();
    }

    /**
     * Show the controller on screen. It will go away
     * automatically after 3 seconds of inactivity.
     */
    public void show() {
        show(sDefaultTimeout);
    }

    /**
     * Disable pause or seek buttons if the stream cannot be paused or seeked.
     * This requires the control interface to be a MediaPlayerControlExt
     */
    private void disableUnsupportedButtons() {
        try {
            if (mPauseButton != null && !mPlayer.canPause()) {
                mPauseButton.setEnabled(false);
            }
            if (mRewButton != null && !mPlayer.canSeekBackward()) {
                mRewButton.setEnabled(false);
            }
            if (mFfwdButton != null && !mPlayer.canSeekForward()) {
                mFfwdButton.setEnabled(false);
            }
        } catch (IncompatibleClassChangeError ex) {
            // We were given an old version of the interface, that doesn't have
            // the canPause/canSeekXYZ methods. This is OK, it just means we
            // assume the media can be paused and seeked, and so we don't disable
            // the buttons.
        }
    }
    
    /**
     * Show the controller on screen. It will go away
     * automatically after 'timeout' milliseconds of inactivity.
     * @param timeout The timeout in milliseconds. Use 0 to show
     * the controller until hide() is called.
     */
    public void show(int timeout) {

        if (!mShowing && mAnchor != null) {
            setProgress();
            if (mPauseButton != null) {
                mPauseButton.requestFocus();
            }
            disableUnsupportedButtons();

            int [] anchorpos = new int[2];
            mAnchor.getLocationOnScreen(anchorpos);

            WindowManager.LayoutParams p = new WindowManager.LayoutParams();
            p.gravity = Gravity.TOP;
            p.width = mAnchor.getWidth();
            p.height = LayoutParams.WRAP_CONTENT;
            p.x = 0;
            p.y = anchorpos[1] + mAnchor.getHeight() - p.height;
            p.format = PixelFormat.TRANSLUCENT;
            p.type = WindowManager.LayoutParams.TYPE_APPLICATION_PANEL;
            p.flags |= WindowManager.LayoutParams.FLAG_ALT_FOCUSABLE_IM;
            p.token = null;
            p.windowAnimations = 0; // android.R.style.DropDownAnimationDown;
            mWindowManager.addView(mDecor, p);
            mShowing = true;
        }
        updatePausePlay();
        
        // cause the progress bar to be updated even if mShowing
        // was already true.  This happens, for example, if we're
        // paused with the progress bar showing the user hits play.
        mHandler.sendEmptyMessage(SHOW_PROGRESS);

        Message msg = mHandler.obtainMessage(FADE_OUT);
        if (timeout != 0) {
            mHandler.removeMessages(FADE_OUT);
            mHandler.sendMessageDelayed(msg, timeout);
        }
    }
    
    public boolean isShowing() {
        return mShowing;
    }

    /**
     * Remove the controller from the screen.
     */
    public void hide() {
        if (mAnchor == null)
            return;

        if (mShowing) {
            try {
                mHandler.removeMessages(SHOW_PROGRESS);
                mWindowManager.removeView(mDecor);
            } catch (IllegalArgumentException ex) {
                Log.w("MediaController", "already removed");
            }
            mShowing = false;
        }
    }

    private Handler mHandler = new Handler() {
        @Override
        public void handleMessage(Message msg) {
            int pos;
            switch (msg.what) {
                case FADE_OUT:
                    hide();
                    break;
                case SHOW_PROGRESS:
                    pos = setProgress();
                    if (!mDragging && mShowing && mPlayer.isPlaying()) {
                        msg = obtainMessage(SHOW_PROGRESS);
                        sendMessageDelayed(msg, 1000 - (pos % 1000));
                    }
                    break;
            }
        }
    };

    private String stringForTime(int timeMs) {
        int totalSeconds = timeMs / 1000;

        int seconds = totalSeconds % 60;
        int minutes = (totalSeconds / 60) % 60;
        int hours   = totalSeconds / 3600;

        mFormatBuilder.setLength(0);
        if (hours > 0) {
            return mFormatter.format("%d:%02d:%02d", hours, minutes, seconds).toString();
        } else {
            return mFormatter.format("%02d:%02d", minutes, seconds).toString();
        }
    }

    private int setProgress() {
        if (mPlayer == null || mDragging) {
            return 0;
        }
        int position = mPlayer.getCurrentPosition();
        int duration = mPlayer.getDuration();
        if (mProgress != null) {
            if (duration > 0) {
                // use long to avoid overflow
                long pos = 1000L * position / duration;
                mProgress.setProgress( (int) pos);
            }
            int percent = mPlayer.getBufferPercentage();
            mProgress.setSecondaryProgress(percent * 10);
        }

        if (mEndTime != null)
            mEndTime.setText(stringForTime(duration));
        if (mCurrentTime != null)
            mCurrentTime.setText(stringForTime(position));

        return position;
    }

    @Override
    public boolean onTouchEvent(MotionEvent event) {
        show(sDefaultTimeout);
        return true;
    }

    @Override
    public boolean onTrackballEvent(MotionEvent ev) {
        show(sDefaultTimeout);
        return false;
    }

    @Override
    public boolean dispatchKeyEvent(KeyEvent event) {
        int keyCode = event.getKeyCode();
        if (event.getRepeatCount() == 0 && event.isDown() && (
                keyCode ==  KeyEvent.KEYCODE_HEADSETHOOK ||
                keyCode ==  KeyEvent.KEYCODE_MEDIA_PLAY_PAUSE ||
                keyCode ==  KeyEvent.KEYCODE_SPACE)) {
            doPauseResume();
            show(sDefaultTimeout);
            if (mPauseButton != null) {
                mPauseButton.requestFocus();
            }
            return true;
        } else if (keyCode ==  KeyEvent.KEYCODE_MEDIA_STOP) {
            if (mPlayer.isPlaying()) {
                mPlayer.pause();
                updatePausePlay();
            }
            return true;
        } else if (keyCode == KeyEvent.KEYCODE_VOLUME_DOWN ||
                keyCode == KeyEvent.KEYCODE_VOLUME_UP) {
            // don't show the controls for volume adjustment
            return super.dispatchKeyEvent(event);
        } else if (keyCode == KeyEvent.KEYCODE_BACK || keyCode == KeyEvent.KEYCODE_MENU) {
            hide();

            return true;
        } else {
            show(sDefaultTimeout);
        }
        return super.dispatchKeyEvent(event);
    }

    private View.OnClickListener mPauseListener = new View.OnClickListener() {
        public void onClick(View v) {
            doPauseResume();
            show(sDefaultTimeout);
        }
    };

    private void updatePausePlay() {
        if (mRoot == null || mPauseButton == null)
            return;

        if (mPlayer.isPlaying()) {
            mPauseButton.setImageResource(com.android.internal.R.drawable.ic_media_pause);
        } else {
            mPauseButton.setImageResource(com.android.internal.R.drawable.ic_media_play);
        }
    }

    private void doPauseResume() {
        if (mPlayer.isPlaying()) {
            mPlayer.pause();
        } else {
            mPlayer.start();
        }
        updatePausePlay();
    }

    // There are two scenarios that can trigger the seekbar listener to trigger:
    //
    // The first is the user using the touchpad to adjust the posititon of the
    // seekbar's thumb. In this case onStartTrackingTouch is called followed by
    // a number of onProgressChanged notifications, concluded by onStopTrackingTouch.
    // We're setting the field "mDragging" to true for the duration of the dragging
    // session to avoid jumps in the position in case of ongoing playback.
    //
    // The second scenario involves the user operating the scroll ball, in this
    // case there WON'T BE onStartTrackingTouch/onStopTrackingTouch notifications,
    // we will simply apply the updated position without suspending regular updates.
    private OnSeekBarChangeListener mSeekListener = new OnSeekBarChangeListener() {
        public void onStartTrackingTouch(SeekBar bar) {
            show(3600000);

            mDragging = true;

            // By removing these pending progress messages we make sure
            // that a) we won't update the progress while the user adjusts
            // the seekbar and b) once the user is done dragging the thumb
            // we will post one of these messages to the queue again and
            // this ensures that there will be exactly one message queued up.
            mHandler.removeMessages(SHOW_PROGRESS);
        }

        public void onProgressChanged(SeekBar bar, int progress, boolean fromuser) {
            if (!fromuser) {
                // We're not interested in programmatically generated changes to
                // the progress bar's position.
                return;
            }

            long duration = mPlayer.getDuration();
            long newposition = (duration * progress) / 1000L;
            mPlayer.seekTo( (int) newposition);
            if (mCurrentTime != null)
                mCurrentTime.setText(stringForTime( (int) newposition));
        }

        public void onStopTrackingTouch(SeekBar bar) {
            mDragging = false;
            setProgress();
            updatePausePlay();
            show(sDefaultTimeout);

            // Ensure that progress is properly updated in the future,
            // the call to show() does not guarantee this because it is a
            // no-op if we are already showing.
            mHandler.sendEmptyMessage(SHOW_PROGRESS);
        }
    };

    @Override
    public void setEnabled(boolean enabled) {
        if (mPauseButton != null) {
            mPauseButton.setEnabled(enabled);
        }
        if (mFfwdButton != null) {
            mFfwdButton.setEnabled(enabled);
        }
        if (mRewButton != null) {
            mRewButton.setEnabled(enabled);
        }
        if (mNextButton != null) {
            mNextButton.setEnabled(enabled && mNextListener != null);
        }
        if (mPrevButton != null) {
            mPrevButton.setEnabled(enabled && mPrevListener != null);
        }
        if (mProgress != null) {
            mProgress.setEnabled(enabled);
        }
        disableUnsupportedButtons();
        super.setEnabled(enabled);
    }

    private View.OnClickListener mRewListener = new View.OnClickListener() {
        public void onClick(View v) {
            int pos = mPlayer.getCurrentPosition();
            pos -= 5000; // milliseconds
            mPlayer.seekTo(pos);
            setProgress();

            show(sDefaultTimeout);
        }
    };

    private View.OnClickListener mFfwdListener = new View.OnClickListener() {
        public void onClick(View v) {
            int pos = mPlayer.getCurrentPosition();
            pos += 15000; // milliseconds
            mPlayer.seekTo(pos);
            setProgress();

            show(sDefaultTimeout);
        }
    };

    private void installPrevNextListeners() {
        if (mNextButton != null) {
            mNextButton.setOnClickListener(mNextListener);
            mNextButton.setEnabled(mNextListener != null);
        }

        if (mPrevButton != null) {
            mPrevButton.setOnClickListener(mPrevListener);
            mPrevButton.setEnabled(mPrevListener != null);
        }
    }

    public void setPrevNextListeners(View.OnClickListener next, View.OnClickListener prev) {
        mNextListener = next;
        mPrevListener = prev;
        mListenersSet = true;

        if (mRoot != null) {
            installPrevNextListeners();
            
            if (mNextButton != null && !mFromXml) {
                mNextButton.setVisibility(View.VISIBLE);
            }
            if (mPrevButton != null && !mFromXml) {
                mPrevButton.setVisibility(View.VISIBLE);
            }
        }
    }

    public interface MediaPlayerControl {
        void    start();
        void    pause();
        int     getDuration();
        int     getCurrentPosition();
        void    seekTo(int pos);
        boolean isPlaying();
        int     getBufferPercentage();
        boolean canPause();
        boolean canSeekBackward();
        boolean canSeekForward();
    }
}