我是android开发的新手。我刚开始通过查看 Android SDK 中给出的代码示例来创建自己的媒体播放器应用程序。当我尝试播放本地媒体文件 (m.3gp) 时，我收到 IOException error :: error(1,-4)。请有人在这方面帮助我。
这是我的代码。
package com.mediaPlayer;
import java.io.IOException;
import android.app.Activity;
import android.app.AlertDialog;
import android.content.DialogInterface;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.media.MediaPlayer;
import android.media.MediaPlayer.OnBufferingUpdateListener;
import android.media.MediaPlayer.OnCompletionListener;
import android.media.MediaPlayer.OnPreparedListener;
import android.media.MediaPlayer.OnVideoSizeChangedListener;
import android.view.SurfaceHolder;
import android.util.Log;
public class MediaPlayer1 extends Activity implements OnBufferingUpdateListener, OnCompletionListener,OnPreparedListener, OnVideoSizeChangedListener,SurfaceHolder.Callback {
private static final String TAG = "MediaPlayerByMangesh";
// Widgets in the application
private Button btnPlay;
private Button btnPause;
private Button btnStop;
private MediaPlayer mMediaPlayer;
private String path = "m.3gp";
private SurfaceHolder holder;
private int mVideoWidth;
private int mVideoHeight;
private boolean mIsVideoSizeKnown = false;
private boolean mIsVideoReadyToBePlayed = false;
// For the id of radio button selected
private int radioCheckedId = -1;
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
Log.d(TAG, "Entered OnCreate:");
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
Log.d(TAG, "Creatinging Buttons:");
btnPlay = (Button) findViewById(R.id.btnPlay);
btnPause = (Button) findViewById(R.id.btnPause);
// On app load, the Pause button is disabled
btnPause.setEnabled(false);
btnStop = (Button) findViewById(R.id.btnStop);
btnStop.setEnabled(false);
/*
* Attach a OnCheckedChangeListener to the radio group to monitor radio
* buttons selected by user
*/
Log.d(TAG, "Watching for Click");
/* Attach listener to the Calculate and Reset buttons */
btnPlay.setOnClickListener(mClickListener);
btnPause.setOnClickListener(mClickListener);
btnStop.setOnClickListener(mClickListener);
}
/*
* ClickListener for the Calculate and Reset buttons. Depending on the
* button clicked, the corresponding method is called.
*/
private OnClickListener mClickListener = new OnClickListener() {
@Override
public void onClick(View v) {
switch (v.getId()) {
case R.id.btnPlay:
Log.d(TAG, "Clicked Play Button");
Log.d(TAG, "Calling Play Function");
Play();
break;
case R.id.btnPause:
Pause();
break;
case R.id.btnStop:
Stop();
break;
}
}
};
/**
* Play the Video.
*/
private void Play() {
// Create a new media player and set the listeners
mMediaPlayer = new MediaPlayer();
Log.d(TAG, "Entered Play function:");
try
{
mMediaPlayer.setDataSource(path);
}
catch(IOException ie)
{
Log.d(TAG, "IO Exception:" + path);
}
mMediaPlayer.setDisplay(holder);
try
{
mMediaPlayer.prepare();
}
catch(IOException ie)
{
Log.d(TAG, "IO Exception:" + path);
}
mMediaPlayer.setOnBufferingUpdateListener(this);
mMediaPlayer.setOnCompletionListener(this);
mMediaPlayer.setOnPreparedListener(this);
//mMediaPlayer.setOnVideoSizeChangedListener(this);
//mMediaPlayer.setAudioStreamType(AudioManager.STREAM_MUSIC);
}
public void onBufferingUpdate(MediaPlayer arg0, int percent) {
Log.d(TAG, "onBufferingUpdate percent:" + percent);
}
public void onCompletion(MediaPlayer arg0) {
Log.d(TAG, "onCompletion called");
}
public void onVideoSizeChanged(MediaPlayer mp, int width, int height) {
Log.v(TAG, "onVideoSizeChanged called");
if (width == 0 || height == 0) {
Log.e(TAG, "invalid video width(" + width + ") or height(" + height + ")");
return;
}
mIsVideoSizeKnown = true;
mVideoWidth = width;
mVideoHeight = height;
if (mIsVideoReadyToBePlayed && mIsVideoSizeKnown) {
startVideoPlayback();
}
}
public void onPrepared(MediaPlayer mediaplayer) {
Log.d(TAG, "onPrepared called");
mIsVideoReadyToBePlayed = true;
if (mIsVideoReadyToBePlayed && mIsVideoSizeKnown) {
startVideoPlayback();
}
}
public void surfaceChanged(SurfaceHolder surfaceholder, int i, int j, int k) {
Log.d(TAG, "surfaceChanged called");
}
public void surfaceDestroyed(SurfaceHolder surfaceholder) {
Log.d(TAG, "surfaceDestroyed called");
}
public void surfaceCreated(SurfaceHolder holder) {
Log.d(TAG, "surfaceCreated called");
Play();
}
private void startVideoPlayback() {
Log.v(TAG, "startVideoPlayback");
holder.setFixedSize(176, 144);
mMediaPlayer.start();
}
/**
* Pause the Video
*/
private void Pause() {
;
/*
* If all fields are populated with valid values, then proceed to
* calculate the tips
*/
}
/**
* Stop the Video.
*/
private void Stop() {
;
/*
* If all fields are populated with valid values, then proceed to
* calculate the tips
*/
}
/**
* Shows the error message in an alert dialog
*
* @param errorMessage
* String the error message to show
* @param fieldId
* the Id of the field which caused the error. This is required
* so that the focus can be set on that field once the dialog is
* dismissed.
*/
private void showErrorAlert(String errorMessage, final int fieldId) {
new AlertDialog.Builder(this).setTitle("Error")
.setMessage(errorMessage).setNeutralButton("Close",
new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog,
int which) {
findViewById(fieldId).requestFocus();
}
}).show();
}
}
谢谢， Mangesh Kumar K.