问安卓系统中的SeekBar和媒体播放器

EN

package com.example.recorder;

import java.io.IOException;

import android.app.Activity;
import android.media.MediaPlayer;
import android.media.MediaRecorder;
import android.os.Bundle;
import android.os.Environment;
import android.util.Log;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.SeekBar;
import android.widget.SeekBar.OnSeekBarChangeListener;

public class MainActivity extends Activity implements OnSeekBarChangeListener
{
    private static final String LOG_TAG = "AudioRecordTest";
    private static String mFileName = null;
    private SeekBar seekBar;
    private MediaRecorder mRecorder = null;
    private Button startRecord, startPlaying, stopPlaying;
    private MediaPlayer   mPlayer = null;

    private void onRecord(boolean start) {
        if (start) {
            startRecording();
        } else {
            stopRecording();
        }
    }



    private void startPlaying() {
        if(mPlayer != null && mPlayer.isPlaying()){
            mPlayer.pause();
        } else if(mPlayer != null){
            mPlayer.start();
        }else{
        mPlayer = new MediaPlayer();
        try {

            mPlayer.setDataSource(mFileName);
            mPlayer.prepare();
            mPlayer.start();

        } catch (IOException e) {
            Log.e(LOG_TAG, "prepare() failed");
        }
        }

    }

    private void stopPlaying() {
        mPlayer.release();
        mPlayer = null;
        startPlaying.setText("Start playing");
    }

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

    private void startRecording() {
        mRecorder = new MediaRecorder();
        mRecorder.setAudioSource(MediaRecorder.AudioSource.MIC);
        mRecorder.setOutputFormat(MediaRecorder.OutputFormat.THREE_GPP);
        mRecorder.setOutputFile(mFileName);
        mRecorder.setAudioEncoder(MediaRecorder.AudioEncoder.AMR_NB);

        try {
            mRecorder.prepare();
        } catch (IOException e) {
            Log.e(LOG_TAG, "prepare() failed");
        }

        mRecorder.start();
    }

    private void stopRecording() {
        mRecorder.stop();
        mRecorder.release();
        mRecorder = null;
    }



    public MainActivity() {
        mFileName = Environment.getExternalStorageDirectory().getAbsolutePath();
        mFileName += "/audiorecordtest.3gp";
    }

    @Override
    public void onCreate(Bundle icicle) {
        super.onCreate(icicle);

        setContentView(R.layout.activity_main);

        startPlaying = (Button) findViewById(R.id.buttonStartPlay);
        stopPlaying = (Button) findViewById(R.id.buttonStopPlaying);
        startRecord = (Button) findViewById(R.id.buttonStartRecord);
        seekBar = (SeekBar) findViewById(R.id.seekBar);

        startRecord.setOnClickListener(new OnClickListener() {
            boolean mStartRecording = true;
            @Override
            public void onClick(View v) {
                onRecord(mStartRecording);
                if (mStartRecording) {
                    startRecord.setText("Stop recording");
                } else {
                    startRecord.setText("Start recording");
                }
                mStartRecording = !mStartRecording;

            }
        });  


        startPlaying.setOnClickListener(new OnClickListener() {
            boolean mStartPlaying = true;
            @Override
            public void onClick(View v) {
                //onPlay(mStartPlaying);
                startPlaying();
                if (mStartPlaying) {
                    startPlaying.setText("Stop playing");
                } else {
                    startPlaying.setText("Start playing");
                }
                mStartPlaying = !mStartPlaying;
            }
        });

        stopPlaying.setOnClickListener(new OnClickListener() {
            boolean mStartPlaying = true;
            @Override
            public void onClick(View v) {
                 stopPlaying();

            }
        });


    }

    @Override
    public void onPause() {
        super.onPause();
        if (mRecorder != null) {
            mRecorder.release();
            mRecorder = null;
        }

        if (mPlayer != null) {
            mPlayer.release();
            mPlayer = null;
        }
    }



    @Override
    public void onProgressChanged(SeekBar seekBar, int progress,
            boolean fromUser) {
        if(fromUser){
            mPlayer.seekTo(progress); 
            seekBar.setProgress(progress);
            }
            else{
             // the event was fired from code and you shouldn't call player.seekTo()
            }

    }



    @Override
    public void onStartTrackingTouch(SeekBar seekBar) {
        // TODO Auto-generated method stub

    }



    @Override
    public void onStopTrackingTouch(SeekBar seekBar) {
        // TODO Auto-generated method stub

    }
}