【Android开发】媒体之音乐播放器

可以对音乐文件实现播放、暂停、重播和停止功能。退出应用和回到桌面时音乐停止。

主界面：

主界面配置文件mian.xml:

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/container"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    tools:context="com.example.musicplay.MainActivity" >
    <TextView
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:text="@string/filename" />
    <EditText
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:layout_weight="0.00"
        android:background="#B0C4DE"
        android:text="Payphone.mp3"
        android:id="@+id/filename" />
    <LinearLayout
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:orientation="horizontal"
         >
        <Button
            android:id="@+id/playbutton"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:onClick="mediaplay"
            android:text="@string/playbutton" />
        <Button
            android:id="@+id/pausebutton"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:onClick="mediaplay"
            android:text="@string/pausebutton" />
        <Button
            android:id="@+id/resetbutton"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:onClick="mediaplay"
            android:text="@string/resetbutton" />
        <Button
            android:id="@+id/stopbutton"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:onClick="mediaplay"
            android:text="@string/stopbutton" />
    </LinearLayout>
</LinearLayout>

主界面的Activity
MainActivity.java:

package com.example.musicplay;
import java.io.File;
import android.app.Activity;
import android.content.Context;
import android.media.MediaPlayer;
import android.media.MediaPlayer.OnPreparedListener;
import android.os.Bundle;
import android.os.Environment;
import android.telephony.PhoneStateListener;
import android.telephony.TelephonyManager;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;
public class MainActivity extends Activity {
 private EditText nameText;
 private String path;
 private int position;
 private MediaPlayer mediaplayer;
 private boolean pause;
 protected void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  setContentView(R.layout.activity_main);
  nameText=(EditText) this.findViewById(R.id.filename);
  mediaplayer=new MediaPlayer();

 }
 
  //以下方法会造成只要应用在后台音乐都会停止播放
 @Override
 //当应用不在前台时，停止播放
 protected void onPause() {
  if(mediaplayer.isPlaying()){
   position=mediaplayer.getCurrentPosition();
   mediaplayer.stop();
  }
  super.onPause();
 }
 
 @Override
 protected void onResume() {
  if(position>0&&path!=null){
   play();
   mediaplayer.seekTo(position);
   position=0;
  }
  super.onResume();
 }
 @Override
 protected void onDestroy() {
  mediaplayer.release();
  mediaplayer=null;
  super.onDestroy();
 }
 public void mediaplay(View v){
  switch (v.getId()) {
  case R.id.playbutton:
   String filename=nameText.getText().toString();
   //Environment.getExternalStorageDirectory()检查外部存储设备的可用性
   File audio=new File(Environment.getExternalStorageDirectory(),filename);
   if(audio.exists()){
    //获取SDCard目录,2.2的时候为:/mnt/sdcart  2.1的时候为：/sdcard，所以使用静态方法得到路径会好一点。   
    path=audio.getAbsolutePath();
    play();
   }
   else{
    path=null;
    Toast.makeText(getApplicationContext(), R.string.error, 1).show();
   }
   break;
   
  case R.id.pausebutton:
   if(mediaplayer.isPlaying()){
    mediaplayer.pause();
    pause=true;
    ((Button)v).setText(R.string.continues);
   }else{
    if(pause){
     mediaplayer.start();
     pause=false;
     ((Button)v).setText(R.string.pausebutton);
    }
   }
   break;
   
  case R.id.resetbutton:
   if(mediaplayer.isPlaying()){
    mediaplayer.seekTo(0);//从开始位置播放
   }else{
    if(path!=null){
     play();
    }
   }
   break;
   
  case R.id.stopbutton:
   if(mediaplayer.isPlaying()){
    mediaplayer.stop();
   }
   break;
   
  default:
   break;
  }
 }
 private void play() {
  try {
   mediaplayer.reset();//把各项参数恢复到初始化状态
   mediaplayer.setDataSource(path);
   mediaplayer.prepare();//进行缓冲
   //设置缓冲监听器
   mediaplayer.setOnPreparedListener(new OnPreparedListener() {
    
    //缓冲完毕后调用onPrepared方法
    public void onPrepared(MediaPlayer mp) {
     // 里面写缓冲完要干的事
     mediaplayer.start();
    }
   });
  } catch (Exception e) {
   e.printStackTrace();
  }
 }
}

转载请注明出处！程序猿之洞：http://blog.csdn.net/acmman