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>
答案 0 :(得分：2)
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。
答案 1 :(得分：0)
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();