android：上下文菜单 +文件列表视图

Question

我遇到了显示文件夹媒体文件的列表视图的问题...... 我尝试通过可扩展列表视图解决这个问题（消耗性项目应该像上下文菜单一样），但是失败了......所以我决定通过上下文菜单以简单的方式解决这个问题。

列表通过读取文件夹并过滤来获取其项目mp3 & wav - 文件。 现在，上下文菜单应该有选项“播放”、“停止”和“播放”。 “删除” 我想出了如何通过 onListItemClick 使文件播放，但我不太明白如何将选项正确地放入上下文菜单中并将我的列表分配给它。 这是到目前为止的代码。 感谢您提前的帮助。

import android.media.MediaPlayer;
import android.os.Bundle;
import android.widget.TextView;
import java.io.File;
import java.io.FilenameFilter;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;
import java.util.regex.Pattern;
import android.app.AlertDialog;
import android.app.ListActivity;
import android.content.DialogInterface;
import android.util.Log;
import android.view.ContextMenu;
import android.view.MenuInflater;
import android.view.MenuItem;
import android.view.View;
import android.view.ContextMenu.ContextMenuInfo;
import android.widget.ArrayAdapter;
import android.widget.ListView;
import android.widget.Toast;
import android.widget.AdapterView.AdapterContextMenuInfo;

class Mp3WavFilter implements FilenameFilter {
    public boolean accept(File dir, String name) {
        return Pattern.matches(".*\\.(wav|mp3)", name);

    }
}


public class TabAufnahmen extends ListActivity {

    private static final String MEDIA_PATH = new String("/sdcard/Babyaufnahmen/");
    private List<String> songs = new ArrayList<String>();
    private MediaPlayer mp = new MediaPlayer();
    TextView selection;

    ListView list = (ListView)findViewById(R.id.list);

    @Override
    public void onCreate(Bundle icicle) {
        try {
            super.onCreate(icicle);
            setContentView(R.layout.songlist);
            updateSongList();
        } catch (NullPointerException e) {
            Log.v(getString(R.string.app_name), e.getMessage());
        }
    }

    public void updateSongList() {
        File home = new File(MEDIA_PATH);
        if (home.listFiles( new Mp3WavFilter()).length > 0) {
            for (File file : home.listFiles( new Mp3WavFilter())) {
                songs.add(file.getName());
            }


            /*ArrayAdapter<String> songList = new ArrayAdapter<String>(this,R.layout.song_item, songs);
            list.setAdapter(songList);
            //list.setListAdapter(songList);
            registerForContextMenu(list);*/


           /* setListAdapter(new ArrayAdapter<String>(this,android.R.layout.simple_list_item_1, songs));
            selection=(TextView)findViewById(R.id.selection);

            registerForContextMenu(getListView());*/

        }       
    }


/*  @Override
    protected void onListItemClick(ListView l, View v, int position, long id) {
        try {

            mp.reset();
            mp.setDataSource(MEDIA_PATH + songs.get(position));
            mp.prepare();
            mp.start();
        } catch(IOException e) {
            Log.v(getString(R.string.app_name), e.getMessage());
        } 
    }*/




    /*public void onCreateContextMenu(ContextMenu menu, View v, ContextMenuInfo menuInfo) {
        super.onCreateContextMenu(menu, v, menuInfo);
        MenuInflater inflater = getMenuInflater();
        inflater.inflate(R.menu.context_menu, menu);
    }*/


    /*public boolean onContextItemSelected(MenuItem item) {
        AdapterContextMenuInfo info = (AdapterContextMenuInfo) item.getMenuInfo();
        String[] names = getResources().getStringArray(R.array.names);
        switch(item.getItemId()) {
        case R.id.abspielen:
            Toast.makeText(this, "You have chosen the " + getResources().getString(R.string.abspielen) + 
                    " context menu option for " + names[(int)info.id],
                    Toast.LENGTH_SHORT).show();
            return true;
        case R.id.anhalten:
            Toast.makeText(this, "You have chosen the " + getResources().getString(R.string.anhalten) + 
                    " context menu option for " + names[(int)info.id],
                    Toast.LENGTH_SHORT).show();
            return true;
        case R.id.loeschen:
            Toast.makeText(this, "You have chosen the " + getResources().getString(R.string.loeschen) + 
                    " context menu option for " + names[(int)info.id],
                    Toast.LENGTH_SHORT).show();
            return true;
        default:
            return super.onContextItemSelected(item);
        }
    }*/



}

Answer 1

感谢您的帮助，终于弄清楚了。
然而，仍然有一些事情困扰着我..
使用删除时，文件被正确删除，但列表未更新。
另外 - 有什么方法可以定期生成列表吗？

class Mp3WavFilter implements FilenameFilter {
    public boolean accept(File dir, String name) {
        return Pattern.matches(".*\\.(wav|mp3)", name);

    }
}


public class TabAufnahmen extends ListActivity {

    private static final String MEDIA_PATH = new String("/sdcard/Babyaufnahmen/");
    private List<String> songs = new ArrayList<String>();
    private MediaPlayer mp = new MediaPlayer();

    @Override
    public void onCreate(Bundle icicle) {
        try {
            super.onCreate(icicle);
            //setContentView(R.layout.songlist);
            updateSongList();
        } catch (NullPointerException e) {
            Log.v(getString(R.string.app_name), e.getMessage());
        }
    }

    public void updateSongList() {
        File home = new File(MEDIA_PATH);
        if (home.listFiles( new Mp3WavFilter()).length > 0) {
            for (File file : home.listFiles( new Mp3WavFilter())) {
                songs.add(file.getName());
            }

            ArrayAdapter<String> songList = new ArrayAdapter<String>(this,R.layout.song_item,songs);
            this.setListAdapter(songList);
            registerForContextMenu(getListView());
        }       
    }
    //der player
    @Override
    protected void onListItemClick(ListView l, View v, int position, long id) {
        //try {

            mp.reset();
            //mp.setDataSource(MEDIA_PATH + songs.get(position));
            //mp.prepare();
            //mp.start();
        //} catch(IOException e) {
        //  Log.v(getString(R.string.app_name), e.getMessage());
        //} 
    }




    public void onCreateContextMenu(ContextMenu menu, View v, ContextMenuInfo menuInfo) {
        super.onCreateContextMenu(menu, v, menuInfo);
        MenuInflater inflater = getMenuInflater();
        inflater.inflate(R.menu.context_menu, menu);
    }


    public boolean onContextItemSelected(MenuItem item) {
        AdapterContextMenuInfo info = (AdapterContextMenuInfo) item.getMenuInfo();
    //  String[] names = getResources().getStringArray(R.array.);
        switch(item.getItemId()) {
        case R.id.abspielen:
            Toast.makeText(this, "Sie haben " + getResources().getString(R.string.abspielen) + "für die Datei" + getListView().getAdapter().getItem(info.position).toString() + " gewählt",
                    Toast.LENGTH_LONG).show();
            try {

                mp.reset();
                mp.setDataSource(MEDIA_PATH + getListView().getAdapter().getItem(info.position).toString());
                mp.prepare();
                mp.start();
            } catch(IOException e) {
                Log.v(getString(R.string.app_name), e.getMessage());
            } 

            return true;
        case R.id.loeschen:
            Toast.makeText(this, "Sie haben " + getResources().getString(R.string.loeschen) + "für die Datei" + getListView().getAdapter().getItem(info.position).toString() + " gewählt",
                    Toast.LENGTH_SHORT).show();
            File file = new File("/sdcard/Babyaufnahmen/" + getListView().getAdapter().getItem(info.position).toString());
            boolean deleted = file.delete();


            return true;
        default:
            return super.onContextItemSelected(item);

        }
    }



}

Answer 2

如果您想在长按项目后打开上下文菜单，那么您可以在初始化时使用 registerForContextMenu(View) 注册上下文菜单的列表视图。

如果您想在 ItemClick 上打开上下文菜单，则可以使用 openContextMenu 来显示上下文菜单。您还应该为您的视图注册上下文菜单。