Android video playback (1)

Package cn. c; import java. io. file; import android. app. activity; import android. media. mediaPlayer; import android. media. mediaPlayer. onCompletionListener; import android. media. mediaPlayer. onErrorListener; import android. media. mediaPlayer. onInfoListener; import android. media. mediaPlayer. onPreparedListener; import android. media. mediaPlayer. onSeekCompleteListener; import android. media. mediaPlayer. onVideoSizeChan GedListener; import android. OS. bundle; import android. OS. environment; import android. view. display; import android. view. motionEvent; import android. view. surfaceHolder; import android. view. surfaceView; import android. widget. linearLayout; import android. widget. mediaController; import android. widget. mediaController. mediaPlayerControl;/*** references: http://www.embedu.org/Column/Column503.htm * use MidiaPlayer to play the approximate stream of the video Cheng: * Create A Player Object --> set the source of the video to be played --> * prepare for decoding the video --> start playing --> (pause/restart) the process for stopping playback * defines related methods in MediaPlayer. * after these methods are called, The MediaPlayer can enter different states. * These methods and statuses are well understood. You can refer to them for details. * In addition, after you set the video data source for the video to be played, you need to decode the video (call the prepare () method). * This is a time-consuming operation, to avoid application blocking, * You can use its prepareAsync () method with the OnPreparedListener listener for asynchronous operations. * Note: Only after preparation for MediaPlayer is complete can you start playing the video. * MediaPlayer itself cannot display the video content. It can only control video playback. * if you want to use MediaPlayer to play the video, surfaceVie is also required. W to display the video * and play the video data decoded in the MediaPlayer in SurfaceView. You need to call setDisplay () * in the MediaPlayer to accept a SurfaceHolder object, we can use the SurfaceHolder object corresponding to * SurfaceView for video playback as the parameter *, so that MediaPlayer and SurfaceView are associated. ** MediaPlayer: video playback step * 1. Set the video to be played by the MediaPlayer * mMediaPlayer. setDataSource (path); * 2 set the video output interface of the MediaPlayer * mMediaPlayer. setDisplay (mSurfaceHolder); * 3 MediaPlayer decoding * mMediaPlayer. prepareAsync () combined with * public void OnPrepared (MediaPlayer mediaPlayer) * 4 MediaPlayer starts playing * mediaPlayer. start (); ***/public class MainActivity extends Activity implements OnCompletionListener, OnErrorListener, OnInfoListener, OnPreparedListener, OnSeekCompleteListener, OnVideoSizeChangedListener, SurfaceHolder. callback, MediaPlayerControl {private SurfaceView mSurfaceView; private SurfaceHolder mSurfaceHolder; private MediaController m MediaController; private Display mDisplay; private MediaPlayer mMediaPlayer; int videoWidth = 0; int videoHeight = 0; @ Override public void onCreate (Bundle savedInstanceState) {super. onCreate (savedInstanceState); setContentView (R. layout. main); mDisplay = getWindowManager (). getdefadisplay display (); mSurfaceView = (SurfaceView) findViewById (R. id. surfaceView); mSurfaceHolder = mSurfaceView. getHolder (); // SurfaceH Older is used to manage SurfaceView objects. // how is it managed? Use mSurfaceHolder // to add a callback, that is, addCallback. // This class implements SurfaceHolder. callback interface, so addCallback (this) // In SurfaceHolder. there are three methods in the Callback interface to manage the // SurfaceView object: // surfaceCreated () // surfaceChanged () // surfaceDestroyed () // Overview: surfaceHolder is mainly used to monitor the underlying situation of mSurfaceHolder. addCallback (this); mSurfaceHolder. setType (SurfaceHolder. SURFACE_TYPE_PUSH_BUFFERS); mMediaPlayer = new MediaPlayer (); mMediaPlayer. setOnCompletion Listener (this); mMediaPlayer. setOnErrorListener (this); mMediaPlayer. setOnInfoListener (this); mMediaPlayer. setOnPreparedListener (this); mMediaPlayer. setOnSeekCompleteListener (this); mMediaPlayer. setOnVideoSizeChangedListener (this); String path = Environment. getExternalStorageDirectory (). getPath () + File. separator + "Test_Movie.m4v"; try {// set the video mMediaPlayer to be played by the MediaPlayer. setDataSource (path);} catch (E Xception e) {e. printStackTrace (); finish ();} mMediaController = new MediaController (MainActivity. this) ;}@ Override public boolean onTouchEvent (MotionEvent event) {if (mMediaController. isShowing () {mMediaController. hide ();} else {mMediaController. show ();} return false;} // from SurfaceHolder. callback interface // this method is called when SurfaceView is created. public void surfaceCreated (SurfaceHolder holder) {// sets the video output interface of the MediaPlayer/ /This method is not called when only the audio is displayed but not the video. setDisplay (mSurfaceHolder); try {// prepare for playing and call mMediaPlayer. prepareAsync (); // the overwritten // public void onPrepared (MediaPlayer mp) will be executed. // Note: // you can also call prepare () decoding, but for a synchronous operation mMediaPlayer. prepareAsync ();} catch (Exception e) {e. printStackTrace (); finish () ;}// from SurfaceHolder. callback interface // when the width, height, or other parameters of SurfaceView change, this method is called public void surfaceChanged (SurfaceHolder holder, int format, int Width, int height) {}// from SurfaceHolder. callback interface // when SurfaceView is destroyed, this method is called public void surfaceDestroyed (SurfaceHolder holder) {}// from MediaPlayer. onVideoSizeChangedListener API // call this method when the video width or height changes. public void onVideoSizeChanged (MediaPlayer mp, int width, int height) {}// from MediaPlayer. onSeekCompleteListener interface public void onSeekComplete (MediaPlayer mp) {}// from MediaPlayer. onPreparedListener interface // once this method is called, M The ediaPlayer enters the "ready" // status, ready to start playing. // This can be used to dynamically set the SurfaceView width and height !!! Public void onPrepared (MediaPlayer mediaPlayer) {videoWidth = mediaPlayer. getVideoWidth (); videoHeight = mediaPlayer. getVideoHeight (); if (videoWidth> mDisplay. getWidth () | videoHeight> mDisplay. getHeight () {float heightRatio = (float) videoHeight/(float) mDisplay. getHeight (); float widthRatio = (float) videoWidth/(float) mDisplay. getWidth (); if (heightRatio> 1 | widthRatio> 1) {if (heightRatio> widthRatio) {videoHeight = (int) Math. ceil (float) videoHeight/(float) heightRatio); videoWidth = (int) Math. ceil (float) videoWidth/(float) heightRatio);} else {videoHeight = (int) Math. ceil (float) videoHeight/(float) widthRatio); videoWidth = (int) Math. ceil (float) videoWidth/(float) widthRatio) ;}}// set the width and height of SurfaceView mSurfaceView. setLayoutParams (new LinearLayout. layoutParams (videoWidth, videoHeight); // you can set and use mMediaController only after the MediaPlayer is ready. setMediaPlayer (this); mMediaController. setAnchorView (findViewById (R. id. mainView); mMediaController. setEnabled (true); mMediaController. show (); // MediaPlayer starts playing mediaPlayer. start ();} // from MediaPlayer. onInfoListener interface // This method will be called when specific information about the playing media is displayed or a warning is required. // For example, start buffering, buffer end, and download speed change (this row is awaiting verification)) // Summary: all these Info items are MediaPlayer. public boolean onInfo (MediaPlayer mp, int what, int extra) {if (what = MediaPlayer. MEDIA_INFO_BAD_INTERLEAVING) {// This prompt is displayed when audio and video data are incorrectly staggered. in a // correctly staggered media file, audio and video samples are arranged in sequence so that the video can be played effectively and stably.} if (what = MediaPlayer. MEDIA_INFO_NOT_SEEKABLE) {// This prompt is displayed when the media cannot be correctly located. // This means it may be an online stream} if (what = MediaPlayer. MEDIA_INFO_VIDEO_TRACK_LAGGING) {// This prompt is displayed when the device cannot play the video. // For example, the video is too complex or the bit rate is too high.} if (what = MediaPlayer. MEDIA_INFO_METADATA_UPDATE) {// This prompt will appear when the new metadata is available} if (what = MediaPlayer. MEDIA_INFO_UNKNOWN) {// other unknown message} return false;} // from MediaPlayer. onErrorListener interface // This method will be called when a MediaPlayer error occurs // There are only the following three errors. // conclusion: all these errors are MediaPlayer. MEDIA_ERROR. public boolean onError (MediaPlayer mp, int what, int extra) {if (what = MediaPlayer. MEDIA_ERROR_NOT_VALID_FOR_PROGRESSIVE_PLAYBACK) {System. out. println ("first error");} if (what = MediaPlayer. MEDIA_ERROR_SERVER_DIED) {System. out. println ("second error");} if (what = MediaPlayer. MEDIA_ERROR_UNKNOWN) {System. out. println ("third error");} return false;} // from MediaPlayer. onCompletionListener interface // this method is called when the MediaPlayer finishes playing the file. // you can perform other operations at this time, such as playing the next video public void onCompletion (MediaPlayer mp) {finish () ;}// the following methods are all from the MediaPlayerControl interface public void start () {mMediaPlayer. start ();} public void pause () {if (mMediaPlayer. isPlaying () {mMediaPlayer. pause () ;}} public int getDuration () {return mMediaPlayer. getDuration ();} public int getCurrentPosition () {return mMediaPlayer. getCurrentPosition ();} public void seekTo (int pos) {mMediaPlayer. seekTo (pos);} public boolean isPlaying () {return mMediaPlayer. isPlaying ();} public int getBufferPercentage () {// TODO Auto-generated method stubreturn 0;} public boolean canPause () {return true;} public boolean canSeekBackward () {return true;} public boolean canSeekForward () {return true ;}}