Question

我是初学者，当我将音乐文件添加到Sd卡时，我的音乐应用中的列表视图不会更新，直到我重新启动设备或我的genymotion模拟器。而歌曲也在玩耍。

这是我的主要Acivity.java代码：

package com.techdsk.musicdsk.musicdsk;


        import android.app.Activity;
        import android.content.Context;
        import android.graphics.Bitmap;
        import android.graphics.PorterDuff.Mode;
        import android.graphics.drawable.BitmapDrawable;
        import android.os.Bundle;
        import android.os.Handler;
        import android.os.Message;
        import android.view.View;
        import android.view.View.OnClickListener;
        import android.widget.Button;
        import android.widget.LinearLayout;
        import android.widget.ProgressBar;
        import android.widget.TextView;
        import com.techdsk.musicdsk.musicdsk.controls.Controls;
        import com.techdsk.musicdsk.musicdsk.service.SongService;
        import com.techdsk.musicdsk.musicdsk.util.PlayerConstants;
        import com.techdsk.musicdsk.musicdsk.util.UtilFunctions;

public class AudioPlayerActivity extends Activity {

    Button btnBack;
    static Button btnPause;
    Button btnNext;
    static Button btnPlay;
    static TextView textNowPlaying;
    static TextView textAlbumArtist;
    static TextView textComposer;
    static LinearLayout linearLayoutPlayer;
    ProgressBar progressBar;
    static Context context;
    TextView textBufferDuration, textDuration;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        getActionBar().hide();
        setContentView(R.layout.audio_player);
        context = this;
        init();
    }

    private void init() {
        getViews();
        setListeners();
        progressBar.getProgressDrawable().setColorFilter(getResources().getColor(R.color.white), Mode.SRC_IN);
        PlayerConstants.PROGRESSBAR_HANDLER = new Handler(){
            @Override
            public void handleMessage(Message msg){
                Integer i[] = (Integer[])msg.obj;
                textBufferDuration.setText(UtilFunctions.getDuration(i[0]));
                textDuration.setText(UtilFunctions.getDuration(i[1]));
                progressBar.setProgress(i[2]);
            }
        };
    }

    private void setListeners() {
        btnBack.setOnClickListener(new OnClickListener() {
            @Override
            public void onClick(View v) {
                Controls.previousControl(getApplicationContext());
            }
        });

        btnPause.setOnClickListener(new OnClickListener() {
            @Override
            public void onClick(View v) {
                Controls.pauseControl(getApplicationContext());
            }
        });

        btnPlay.setOnClickListener(new OnClickListener() {

            @Override
            public void onClick(View v) {
                Controls.playControl(getApplicationContext());
            }
        });

        btnNext.setOnClickListener(new OnClickListener() {
            @Override
            public void onClick(View v) {
                Controls.nextControl(getApplicationContext());
            }
        });
    }

    public static void changeUI(){
        updateUI();
        changeButton();
    }

    private void getViews() {
        btnBack = (Button) findViewById(R.id.btnBack);
        btnPause = (Button) findViewById(R.id.btnPause);
        btnNext = (Button) findViewById(R.id.btnNext);
        btnPlay = (Button) findViewById(R.id.btnPlay);
        textNowPlaying = (TextView) findViewById(R.id.textNowPlaying);
        linearLayoutPlayer = (LinearLayout) findViewById(R.id.linearLayoutPlayer);
        textAlbumArtist = (TextView) findViewById(R.id.textAlbumArtist);
        textComposer = (TextView) findViewById(R.id.textComposer);
        progressBar = (ProgressBar) findViewById(R.id.progressBar);
        textBufferDuration = (TextView) findViewById(R.id.textBufferDuration);
        textDuration = (TextView) findViewById(R.id.textDuration);
        textNowPlaying.setSelected(true);
        textAlbumArtist.setSelected(true);
    }

    @Override
    protected void onResume() {
        super.onResume();
        boolean isServiceRunning = UtilFunctions.isServiceRunning(SongService.class.getName(), getApplicationContext());
        if (isServiceRunning) {
            updateUI();
        }
        changeButton();
    }

    public static void changeButton() {
        if(PlayerConstants.SONG_PAUSED){
            btnPause.setVisibility(View.GONE);
            btnPlay.setVisibility(View.VISIBLE);
        }else{
            btnPause.setVisibility(View.VISIBLE);
            btnPlay.setVisibility(View.GONE);
        }
    }

    private static void updateUI() {
        try{
            String songName = PlayerConstants.SONGS_LIST.get(PlayerConstants.SONG_NUMBER).getTitle();
            String artist = PlayerConstants.SONGS_LIST.get(PlayerConstants.SONG_NUMBER).getArtist();
            String album = PlayerConstants.SONGS_LIST.get(PlayerConstants.SONG_NUMBER).getAlbum();
            String composer = PlayerConstants.SONGS_LIST.get(PlayerConstants.SONG_NUMBER).getComposer();
            textNowPlaying.setText(songName);
            textAlbumArtist.setText(artist + " - " + album);
            if(composer != null && composer.length() > 0){
                textComposer.setVisibility(View.VISIBLE);
                textComposer.setText(composer);
            }else{
                textComposer.setVisibility(View.GONE);
            }
        }catch(Exception e){
            e.printStackTrace();
        }
        try{
            long albumId = PlayerConstants.SONGS_LIST.get(PlayerConstants.SONG_NUMBER).getAlbumId();
            Bitmap albumArt = UtilFunctions.getAlbumart(context, albumId);
            if(albumArt != null){
                linearLayoutPlayer.setBackgroundDrawable(new BitmapDrawable(albumArt));
            }else{
                linearLayoutPlayer.setBackgroundDrawable(new BitmapDrawable(UtilFunctions.getDefaultAlbumArt(context)));
            }
        }catch(Exception e){
            e.printStackTrace();
        }
    }
}

这是我的Audioplayer Activity.java代码：

package com.techdsk.musicdsk.musicdsk.adapter;

import java.util.ArrayList;
import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.widget.TextView;
import com.techdsk.musicdsk.musicdsk.R;
import com.techdsk.musicdsk.musicdsk.util.MediaItem;
import com.techdsk.musicdsk.musicdsk.util.UtilFunctions;

public class CustomAdapter extends ArrayAdapter<MediaItem>{

    ArrayList<MediaItem> listOfSongs;
    Context context;
    LayoutInflater inflator;

    public CustomAdapter(Context context, int resource, ArrayList<MediaItem> listOfSongs) {
        super(context, resource, listOfSongs);
        this.listOfSongs = listOfSongs;
        this.context = context;
        inflator = LayoutInflater.from(context);
    }

    private class ViewHolder{
        TextView textViewSongName, textViewArtist, textViewDuration;
    }

    ViewHolder holder;

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        View myView = convertView;
        if(convertView == null){
            myView = inflator.inflate(R.layout.custom_list, parent, false);
            holder = new ViewHolder();
            holder.textViewSongName = (TextView) myView.findViewById(R.id.textViewSongName);
            holder.textViewArtist = (TextView) myView.findViewById(R.id.textViewArtist);
            holder.textViewDuration = (TextView) myView.findViewById(R.id.textViewDuration);
            myView.setTag(holder);
        }else{
            holder = (ViewHolder)myView.getTag();
        }
        MediaItem detail = listOfSongs.get(position);
        holder.textViewSongName.setText(detail.toString());
        holder.textViewArtist.setText(detail.getAlbum() + " - " + detail.getArtist());
        holder.textViewDuration.setText(UtilFunctions.getDuration(detail.getDuration()));
        return myView;
    }
}

自定义适配器.java代码：

 <RelativeLayout
    android:layout_height="50dp"
    android:layout_width="fill_parent"
    android:orientation="horizontal"
    android:gravity="end"
    android:padding="5dp">

    <ImageButton
        android:id="@+id/bt_template"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:src="@drawable/ic_launcher"
        android:scaleType="fitCenter"
        android:background="#ffffffff"
        android:layout_alignParentLeft="true"
        android:contentDescription="Choose template"/>

    <ImageButton
        android:id="@+id/bt_captureImage"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:src="@drawable/ic_launcher"
        android:scaleType="fitCenter"
        android:layout_toRightOf="@id/bt_template"
        android:background="#ffffffff"
        android:contentDescription="Choose template"/>

    <Button

        android:layout_margin="0dp"
        android:layout_height="fill_parent"
        android:layout_width="wrap_content"
        android:text="send"
        android:layout_alignParentRight="true"
        android:id="@+id/bt_send" />

</RelativeLayout>

Answer 1

添加文件时，可以使用NotifyDatasetChanged（）。这将告诉您的适配器刷新其数据。因此，在添加新文件后更新源数组时，可以调用NotifyDatasetChanged（）方法。

作为Ex。如果你的适配器中有一个名为Add（）的方法，那么。

public void Add (item e){
items.add (e);
NotifyDatasetChanged();
}

将刷新您的数据。

Answer 2

您的列表未获得更新，因为它未被告知数据更改，

ADW中的文档解释了：

notifyDataSetChanged（）通知附加的观察者基础数据已更改，任何视图都反映数据集应该刷新自己。

<强>解决方案

通知您的适配器：

customAdapter.notifyDataSetChanged();

Android列表视图未更新

2 个答案: