我是一名业余Android应用程序开发人员，现在正在为我们的音乐学校开发Android应用程序。
Now I'm in the stage to load a mp3 file in an android Media Player, play or stop each song in the list view when the user clicks play or stop button.
![enter image description here][1]
[1]: http://i.stack.imgur.com/jUbOB.png
I have stored the mp3 files in res/raw folder. And I have created a class called Song to create data for each of the songs.
Below is the XML file to fill each item in the list view
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/tvViewSample"
android:layout_width="match_parent"
android:layout_height="match_parent" >
<ImageView
android:id="@+id/imgFilmPoster"
android:layout_width="75sp"
android:layout_height="75sp"
android:layout_alignParentLeft="true"
android:layout_alignParentTop="true"
android:src="@drawable/abc_ab_bottom_solid_dark_holo" />
<TextView
android:id="@+id/tvSongName"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignLeft="@+id/tvFilmName"
android:layout_below="@+id/tvFilmName"
android:text="@string/dummy"
android:textAppearance="?android:attr/textAppearanceSmall" />
<TextView
android:id="@+id/tvYearReleased"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignLeft="@+id/tvSongName"
android:layout_below="@+id/tvSongName"
android:text="@string/dummy"
android:textAppearance="?android:attr/textAppearanceSmall" />
<TextView
android:id="@+id/tvPrice"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignLeft="@+id/tvYearReleased"
android:layout_below="@+id/tvYearReleased"
android:text="@string/dummy"
android:textAppearance="?android:attr/textAppearanceSmall" />
<TextView
android:id="@+id/tvFilmName"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentTop="true"
android:layout_marginLeft="14dp"
android:layout_toRightOf="@+id/imgFilmPoster"
android:focusable="true"
android:text="@string/dummy"
android:textAppearance="?android:attr/textAppearanceSmall" />
<ImageView
android:id="@+id/imgAddCart"
android:layout_width="35sp"
android:layout_height="35sp"
android:contentDescription="@string/add_to_cart"
android:layout_alignTop="@+id/imgView"
android:layout_toRightOf="@+id/imgView"
android:src="@drawable/add_to_cart"
android:tag = "@string/add_to_cart" />
<ImageView
android:id="@+id/imgView"
android:layout_width="35sp"
android:layout_height="35sp"
android:layout_below="@+id/imgFilmPoster"
android:layout_marginTop="14dp"
android:layout_toRightOf="@+id/imgPlay"
android:src="@drawable/view_icon" />
<ImageView
android:id="@+id/imgPlay"
android:layout_width="35sp"
android:layout_height="35sp"
android:layout_alignLeft="@+id/tvPrice"
android:layout_alignTop="@+id/imgView"
android:contentDescription="@string/play_mp3"
android:src="@drawable/play" />
</RelativeLayout>
Below is the XML file to display the list view
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="#F8AE9F"
android:orientation="vertical" >
<TextView
android:id="@+id/textView1"
style="@style/aboutComposer"
android:layout_width="wrap_content"
android:layout_height="45sp"
android:layout_alignParentTop="true"
android:layout_centerHorizontal="true"
android:gravity="center_vertical|center_horizontal"
android:text="@string/msv_songs"
android:textAppearance="?android:attr/textAppearanceSmall" />
<TextView
android:id="@+id/tvCartTotal"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_below="@+id/textView1"
android:layout_centerHorizontal="true"
android:text="@string/cart_total"
android:textAppearance="?android:attr/textAppearanceMedium" />
<ImageView
android:id="@+id/imageView1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_below="@+id/tvCartTotal"
android:layout_centerHorizontal="true"
android:layout_marginTop="14dp"
android:src="@drawable/icon_pay_now" />
<ListView
android:id="@+id/lstMSVSongs"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_below="@+id/imageView1"
android:layout_centerHorizontal="true"
android:layout_marginTop="16dp"
android:focusable="false" >
</ListView>
</RelativeLayout>
Song.class文件
package com.srindroid.indianmusicsheets;
public class Song {
private int filmImageID;
private String movieName;
private String songName;
private String yearReleased;
private int songPrice;
private int sampleSheetMusicID;
private int mp3File;
private int sheetMusicID;
public Song(int filmImageID, String movieName, String songName,
String yearReleased, int songPrice, int mp3File) {
super();
this.filmImageID = filmImageID;
this.movieName = movieName;
this.songName = songName;
this.yearReleased = yearReleased;
this.songPrice = songPrice;
this.mp3File = mp3File;
}
public int getFilmImageID() {
return filmImageID;
}
public String getMovieName() {
return movieName;
}
public String getSongName() {
return songName;
}
public String getYearReleased() {
return yearReleased;
}
public int getSongPrice() {
return songPrice;
}
public int getmp3File() {
return mp3File;
}
public void setFilmImageID(int filmImageID) {
this.filmImageID = filmImageID;
}
public void setMovieName(String movieName) {
this.movieName = movieName;
}
public void setSongName(String songName) {
this.songName = songName;
}
public void setYearReleased(String yearReleased) {
this.yearReleased = yearReleased;
}
public void setSongPrice(int songPrice) {
this.songPrice = songPrice;
}
public void setSampleSheetMusicID(int sampleSheetMusicID) {
this.sampleSheetMusicID = sampleSheetMusicID;
}
public void setMp3File(int mp3File) {
this.mp3File = mp3File;
}
public void setSheetMusicID(int sheetMusicID) {
this.sheetMusicID = sheetMusicID;
}
}
MsvSongs.class文件
package com.srindroid.indianmusicsheets;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;
import android.app.Activity;
import android.media.MediaPlayer;
import android.os.Bundle;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.widget.ImageView;
import android.widget.ListView;
import android.widget.TextView;
import android.widget.Toast;
import com.srindroid.indianmusicsheets.R.drawable;
public class MsvSongs extends Activity {
int cart_total;
MediaPlayer mp3Player = null;
private List<Song> msvSongs = new ArrayList<Song>();
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.msv_music_sheets);
populateSongsList();
populateSongsListView();
}
private void populateSongsList() {
msvSongs.add(new Song(R.drawable.ayirathil_oruvan,"Aayirathil Oruvan","Aadho Andha Paravai Pola","1975",250,R.raw.adho_andha_paravai_pola));
msvSongs.add(new Song(R.drawable.server_sundaram,"Server Sundaram","Avalukku Enna Azhagiya Mugam","1964",175,R.raw.avalukkenna_azhagiamugham));
}
private void populateSongsListView() {
ArrayAdapter<Song> msvSongs = new MSVSongsAdapter();
ListView songsList = (ListView) findViewById(R.id.lstMSVSongs);
songsList.setAdapter(msvSongs);
}
private class MSVSongsAdapter extends ArrayAdapter<Song>{
public MSVSongsAdapter(){
super(MsvSongs.this, R.layout.songs_view, msvSongs);
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
View itemView = convertView;
if(itemView == null){
itemView = getLayoutInflater().inflate(R.layout.songs_view, parent, false);
}
for(int i=0;i<msvSongs.size();i++){
//Find a song to display
final Song currentSong = msvSongs.get(position);
//Fill the FilmPoster View
ImageView filmPoster = (ImageView)itemView.findViewById(R.id.imgFilmPoster);
filmPoster.setImageResource(currentSong.getFilmImageID());
//Fill the FilmName View
TextView filmName = (TextView)itemView.findViewById(R.id.tvFilmName);
filmName.setText(currentSong.getMovieName());
//Fill the SongName View
TextView songName = (TextView)itemView.findViewById(R.id.tvSongName);
songName.setText(currentSong.getSongName());
//Fill the YearReleased View
TextView yearReleased = (TextView)itemView.findViewById(R.id.tvYearReleased);
yearReleased.setText(currentSong.getYearReleased());
//Fill the Price View
TextView songPrice = (TextView)itemView.findViewById(R.id.tvPrice);
songPrice.setText("Rs. "+currentSong.getSongPrice());
//Fill the Play MP3 View
final ImageView viewMP3 = (ImageView)itemView.findViewById(R.id.imgPlay);
viewMP3.setOnClickListener(new View.OnClickListener() {
**@Override
public void onClick(View v) {
String contentDesc = (String) viewMP3.getContentDescription();
if(contentDesc.contains("Play")){
mp3Player = MediaPlayer.create(MsvSongs.this, currentSong.getmp3File());
mp3Player.start();
viewMP3.setImageResource(drawable.stop);
viewMP3.setContentDescription("Stop MP3");
Toast.makeText(MsvSongs.this, "Playing MP3", Toast.LENGTH_SHORT).show();
}else{
mp3Player.pause();
mp3Player.stop();
viewMP3.setImageResource(drawable.play);
viewMP3.setContentDescription("Play MP3");
Toast.makeText(MsvSongs.this, "Stopping MP3", Toast.LENGTH_SHORT).show();
}
}
});**
//Fill the View Sample View
ImageView viewSample = (ImageView)itemView.findViewById(R.id.imgView);
viewSample.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
Toast.makeText(MsvSongs.this, R.raw.he_is_a_pirate, Toast.LENGTH_LONG).show();
}
});
//Fill the Add To Cart View
final ImageView viewCart = (ImageView)itemView.findViewById(R.id.imgAddCart);
final TextView cartTotal = (TextView) findViewById(R.id.tvCartTotal);
viewCart.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
String contentDesc = (String) viewCart.getContentDescription();
if(contentDesc.contains("Add")){
viewCart.setImageResource(drawable.remove_from_cart);
viewCart.setContentDescription("Remove From Cart");
cart_total=cart_total+(currentSong.getSongPrice());
cartTotal.setText("Your cart total is Rs. "+cart_total);
}else{
viewCart.setImageResource(drawable.add_to_cart);
viewCart.setContentDescription("Add To Cart");
cart_total=cart_total-(currentSong.getSongPrice());
cartTotal.setText("Your cart total is Rs. "+cart_total);
}
}
});
}
return itemView;
}
}
}
现在我面对上述代码的问题是，当用户点击第一首歌曲的“播放”按钮时，媒体播放器会按预期播放。并且当用户点击第二首歌曲的“播放”按钮时，媒体播放器在不停止第一首歌曲的情况下播放它。我使用了mp3Player.isPlaying（），即使正在播放这首歌，也总是返回FALSE。
你能帮帮我吗？
以下是我为在列表视图中播放或停止每首歌而编写的代码
最终ImageView viewMP3 =（ImageView）itemView.findViewById（R.id.imgPlay）;
viewMP3.setOnClickListener（new View.OnClickListener（）{
**@Override
public void onClick(View v) {
String contentDesc = (String) viewMP3.getContentDescription();
if(contentDesc.contains("Play")){
mp3Player = MediaPlayer.create(MsvSongs.this, currentSong.getmp3File());
mp3Player.start();
viewMP3.setImageResource(drawable.stop);
viewMP3.setContentDescription("Stop MP3");
Toast.makeText(MsvSongs.this, "Playing MP3", Toast.LENGTH_SHORT).show();
}else{
mp3Player.pause();
mp3Player.stop();
viewMP3.setImageResource(drawable.play);
viewMP3.setContentDescription("Play MP3");
Toast.makeText(MsvSongs.this, "Stopping MP3", Toast.LENGTH_SHORT).show();
}
}
});*
答案 0 :(得分：0)
抱歉，我没有看到您在代码中的任何位置使用mp3player.isPlaying（）。你删除了吗？
您似乎正在测试与ImageView相关的歌曲是否正在播放。创建MediaPlayer时，不会检查是否正在播放另一首歌曲。
试试：
if(contentDesc.contains("Play")){
if (mp3Player != null && mp3Player.isPlaying()) {
mp3Player.pause();
mp3Player.stop();
mp3Player.release();
}
mp3Player = MediaPlayer.create(MsvSongs.this, currentSong.getmp3File());
mp3Player.start();
...
}else{
mp3Player.pause();
mp3Player.stop();
mp3Player.release();
}
在制作新的MediaPlayer之前，请不要忘记释放它。