Developing multimedia software MediaPlayer on Android

In the previous article, we introduced how to build an Eclipse Android development environment under Ubuntu. Now we will introduce how to develop the MediaPlayer multimedia software on the Android platform. MediaPlayer can be used to play videos, audio, and streaming media. The lifecycle of MediaPlayer is as follows:

 

From the MediaPlayer lifecycle diagram, we can see that using MediaPlayer is not very complex.

The simplest process is initialization-> resrt ()-> setDataSource ()-> prepare ()-> start ()-> ...... You only need a few simple steps to play the audio file.

Let's take a look at an example of playing audio. Let's look at the code and comments ......

1: private Handler handler = new Handler (){ 2:  3: public void handleMessage(Message msg) { 4: // update the progress bar 5: progressBar.setProgress(progressState); 6: }; 7: }; 8:  9: /** 10: * Play 11: * 12: * @param filePath 13: * file path 14: */ 15: private void playMusic(String filePath) { 16: try { 17: progressState = 0; 18: progressBar.setProgress(0); 19: // Reset 20: mediaPlayer.reset(); 21: // set the data source 22: mediaPlayer.setDataSource(filePath); 23: // prepare for playing 24: mediaPlayer.prepare(); 25: // obtain the playback duration 26: length = mediaPlayer.getDuration(); 27: progressBar.setMax(length / 1000); 28: // play 29: mediaPlayer.start(); 30: new Thread(new ProcessBarRefresh()).start(); 31: // set the listener after playing 32: mediaPlayer.setOnCompletionListener(new OnCompletionListener() { 33: @Override 34: public void onCompletion(MediaPlayer mp) { 35: nextMusic(); 36: } 37: }); 38:  39: } catch (Exception e) { 40: displayToast(e.getMessage()); 41: } 42: } 43: 44: /** 45: * update progress bar 46: * @ author Zhang hanguo 47: */ 48: class ProcessBarRefresh implements Runnable{ 49:  50: @Override 51: public void run() { 52: while(isPlaying){ 53: progressState = mediaPlayer.getCurrentPosition()/1000; 54: handler.sendMessage(handler.obtainMessage()); 55: } 56: } 57: 58: }

 

 

The above is just a simple example. To develop a player, you must pay attention to a lot of details in addition to the UI.

In Android, music playback is a background process. When the above Code calls onStop ()-> onCreate (), the playlist will be repeatedly loaded, resulting in duplicate playlists. This requires onSaveIntanceState (). In this way, when initializing the playlist in onCreate (), you can first determine whether the Bundle is empty and whether the playlist can be obtained. If not, you can re-initialize the playlist.

In addition, Android also provides a Provider property object such as MediaStore for our development and utilization.