Question

我试图在Eclipse中创建一个简单的Android Media Player应用程序，播放sdcard中的歌曲。所有歌曲都在屏幕上显示为列表，但在单击时不播放。这是我的MainActivity.java文件：

import java.io.File;
import java.io.FilenameFilter;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;

import android.app.ListActivity;
import android.media.MediaPlayer;
import android.os.Bundle;
import android.os.Environment;
import android.util.Log;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.ListView;




class Mp3Filter implements FilenameFilter {
    public boolean accept(File dir, String name) {
        return (name.endsWith(".mp3"));
    }
}

public class MainActivity extends ListActivity {

    Button stop, play;
    String SD_PATH = Environment.getExternalStorageDirectory().getPath();
    List<String> songs = new ArrayList<String>();
    MediaPlayer mp = new MediaPlayer();

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        updatePlaylist();

        stop = (Button) findViewById(R.id.button1);
        play = (Button) findViewById(R.id.button2);
        play.setVisibility(View.GONE);


        stop.setOnClickListener(new OnClickListener() {

            @Override
            public void onClick(View v) {
                // TODO Auto-generated method stub
                mp.stop();              
            }
        });
        play.setOnClickListener(new OnClickListener() {

            @Override
            public void onClick(View v) {
                // TODO Auto-generated method stub
             mp.pause();
             if(mp.isPlaying()==false){
                 play.setText("Resume");
             }
            }
        });
    }
    @Override
    protected void onListItemClick(ListView l, View v, int position, long id) {
        // TODO Auto-generated method stub
        super.onListItemClick(l, v, position, id);
        try{
            mp.reset();
            mp.setDataSource(SD_PATH + songs.get(position));
            mp.prepare();
            mp.start();
            if(mp.isPlaying()== true){
                play.setText("Pause");
                play.setVisibility(View.VISIBLE);
            }

        } catch(IOException e){
            Log.v(getString(R.string.app_name),e.getMessage());
        }
    }


    private void updatePlaylist() {
        // TODO Auto-generated method stub
        File home = new File(SD_PATH);
        if(home.listFiles( new Mp3Filter()).length > 0){
            for(File file : home.listFiles( new Mp3Filter())) {
                songs.add(file.getName());
            }
            ArrayAdapter<String> songList = new ArrayAdapter<String>(this,R.layout.song_items,songs);
            setListAdapter(songList);
        }
    }


    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.main, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();
        if (id == R.id.action_settings) {
            return true;
        }
        return super.onOptionsItemSelected(item);
    }
}

Activity_Main.xml文件：

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context="com.studs.mediaplayer.MainActivity" >

    <ListView
        android:id="@+id/android:list"
        android:layout_width="match_parent"
        android:layout_height="40dp"
        android:layout_marginBottom="50dp" >
    </ListView>

    <Button
        android:id="@+id/button2"
        style="?android:attr/buttonStyleSmall"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignLeft="@+id/android:list"
        android:layout_alignParentBottom="true"
        android:layout_marginLeft="23dp"
        android:text="@string/pp" />

    <Button
        android:id="@+id/button1"
        style="?android:attr/buttonStyleSmall"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentBottom="true"
        android:layout_alignRight="@+id/android:list"
        android:layout_marginRight="52dp"
        android:text="@string/st" />

</RelativeLayout>

和song_items.xml文件：

<?xml version="1.0" encoding="utf-8"?>
<TextView xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical" >


</TextView>

提前致谢！

Answer 1

你的问题就在这一行

mp.setDataSource(SD_PATH + songs.get(position));

songs.get(position)只是文件的名称，因为文件可能位于SD卡的某个子文件夹中，所以您没有设置正确的数据源..

<强>更新

可能是您可以使用第二个列表

List<String> songsPaths = new ArrayList<String>();

然后更新你的方法

private void updatePlaylist() {
    // TODO Auto-generated method stub
    File home = new File(SD_PATH);
    if(home.listFiles( new Mp3Filter()).length > 0){
        for(File file : home.listFiles( new Mp3Filter())) {
            songs.add(file.getName());
            songsPaths.add(file.getAbsolutePath());
        }
        ArrayAdapter<String> songList = new ArrayAdapter<String>(this,R.layout.song_items,songs);
        setListAdapter(songList);
    }
}

@Override
protected void onListItemClick(ListView l, View v, int position, long id) {
    // TODO Auto-generated method stub
    super.onListItemClick(l, v, position, id);
    try{
        mp.reset();
        mp.setDataSource(songsPaths.get(position));
        mp.prepare();
        mp.start();
        if(mp.isPlaying()== true){
            play.setText("Pause");
            play.setVisibility(View.VISIBLE);
        }

    } catch(IOException e){
        Log.v(getString(R.string.app_name),e.getMessage());
    }
}

歌曲没有播放点击

1 个答案: