MP3播放器源码 Android

package cn.itcast.mp3; import java.io.File; import java.io.IOException; import android.app.Activity; import android.media.MediaPlayer; import android.os.Bundle; import android.os.Environment; import android.util.Log; import android.view.View; import android.widget.Button; import android.widget.EditText; import android.widget.Toast; public class MainActivity extends Activity { private static final String TAG = "MainActivity"; private EditText filenameText; private String filename; private MediaPlayer mediaPlayer; private int position; @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); mediaPlayer = new MediaPlayer(); ButtonClickListener listener = new ButtonClickListener(); Button playButton = (Button)this.findViewById(R.id.play); Button pauseButton = (Button)this.findViewById(R.id.pause); Button resetButton = (Button)this.findViewById(R.id.reset); Button stopButton = (Button)this.findViewById(R.id.stop); filenameText = (EditText)this.findViewById(R.id.filename); playButton.setOnClickListener(listener); pauseButton.setOnClickListener(listener); resetButton.setOnClickListener(listener); stopButton.setOnClickListener(listener); } @Override protected void onResume() { if(position>0 && filename!=null){ File file = new File(Environment.getExternalStorageDirectory(), filename); try { play(file); mediaPlayer.seekTo(position); position = 0; } catch (IOException e) { Log.e(TAG, e.toString()); } } super.onResume(); } @Override protected void onPause() { if(mediaPlayer.isPlaying()){ position = mediaPlayer.getCurrentPosition(); mediaPlayer.stop(); } super.onPause(); } @Override protected void onDestroy() { if(mediaPlayer!=null) mediaPlayer.release(); super.onDestroy(); } private final class ButtonClickListener implements View.OnClickListener{ @Override public void onClick(View v) { filename = filenameText.getText().toString(); if(Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED)){ File file = new File(Environment.getExternalStorageDirectory(), filename); if(file.exists()){ try { switch (v.getId()) { case R.id.play: play(file); break; case R.id.pause: if(mediaPlayer.isPlaying()){ mediaPlayer.pause(); ((Button)v).setText(R.string.continues); }else{ mediaPlayer.start();//继续播放 ((Button)v).setText(R.string.pause); } break; case R.id.reset: if(mediaPlayer.isPlaying()){ mediaPlayer.seekTo(0); }else{ play(file); } break; case R.id.stop: if(mediaPlayer.isPlaying()) mediaPlayer.stop(); break; } } catch (Exception e) { Log.e(TAG, e.toString()); } }else{ Toast.makeText(MainActivity.this, R.string.noexist, 1).show(); } }else{ Toast.makeText(MainActivity.this, R.string.SDCarderror, 1).show(); } } } private void play(File file) throws IOException { mediaPlayer.reset(); mediaPlayer.setDataSource(file.getAbsolutePath()); mediaPlayer.prepare(); mediaPlayer.start(); } }