android - 如何自动更改对下一个列表项的关注

Question

我正在编写音频播放器应用程序，其中我必须在新歌曲开始时自动将焦点更改为下一个列表项，我可以播放下一首歌曲但无法突出显示该歌曲。

<ListView
        android:id="@+id/list_slidermenu"        
        android:layout_height="0dp"
        android:layout_width="match_parent"
        android:layout_weight="8"       
        android:layout_gravity="start"
        android:scrollbars="none"
        android:fastScrollEnabled="true"
        android:choiceMode="singleChoice"
        android:listSelector="@drawable/list_selector"
        />

点击监听器上的 ListView:

     listview.setOnItemClickListener(new OnItemClickListener() {

        @Override
        public void onItemClick(AdapterView<?> arg0, View view, int position,
                long id) {
            // TODO Auto-generated method stub                          

            positionGlobal = position;  

            strNURL = audiosArrayList.get(positionGlobal).getUrl().toString();
            strNTITLE = audiosArrayList.get(positionGlobal).getTitle().toString();

            if(mediaPlayer!=null && mediaPlayer.isPlaying())
                try {
                    mediaPlayer.stop();
                  } catch (Exception e) { 

                  }
                play();
                textTrack.setText(strNTITLE);
            }
        });                         
    }

自动切换下一首歌曲的方法

public void next() {

   if (positionGlobal == (audiosArrayList.size()-1)) {                 
        positionGlobal = 0;             
        strNURL = audiosArrayList.get(positionGlobal).getUrl().toString();
        strNTITLE = audiosArrayList.get(positionGlobal).getTitle().toString();

        current_position = 0;
        mediaPlayer.seekTo(current_position);
        if(mediaPlayer!=null && mediaPlayer.isPlaying())
                try {
                    mediaPlayer.stop();
                  } catch (Exception e) { 
               }
            play();
            textTrack.setText(strNTITLE);
       } 

   else if(positionGlobal < audiosArrayList.size()) {

    positionGlobal = positionGlobal+1;   

    strNURL = audiosArrayList.get(positionGlobal).getUrl().toString();
    strNTITLE = audiosArrayList.get(positionGlobal).getTitle().toString();

    current_position = 0;
    mediaPlayer.seekTo(current_position);
    if(mediaPlayer!=null && mediaPlayer.isPlaying())
            try {
                mediaPlayer.stop();
              } catch (Exception e) { 
           }
        play();
        textTrack.setText(strNTITLE);
    }
}

适配器类:

public class AudioAdapter extends BaseAdapter {
    ArrayList<Audio> actorList;
    LayoutInflater vi;
    int Resource;
    ViewHolder holder;
    Context context;

    public AudioAdapter(Context context, int resource, ArrayList<Audio> objects) {
        this.context = context;
        this.vi = (LayoutInflater) context
                .getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        this.Resource = resource;
        this.actorList = objects;
    }

    @Override
    public int getCount() {
        // TODO Auto-generated method stub
        return actorList.size();
    }

    @Override
    public Object getItem(int position) {
        // TODO Auto-generated method stub
        return actorList.get(position);
    }

    @Override
    public long getItemId(int position) {
        // TODO Auto-generated method stub
        return position;
    }

    @Override
    public View getView(final int position, View convertView, ViewGroup parent) {
        // convert view = design
        View v = convertView;
        if (v == null) {
            holder = new ViewHolder();
            v = vi.inflate(Resource, null);
            holder.tvName = (TextView) v.findViewById(R.id.title);

            v.setTag(holder);
        } else {
            holder = (ViewHolder) v.getTag();
        }       
            holder.tvName.setText(actorList.get(position).getTitle());      


        return v;

    }

    static class ViewHolder {
        public TextView tvName;

    }

}

Answer 1

您可以通过以下步骤列表实现此目的:

1. 通过跟踪 Adapter 中的当前选择来设置所选项目
2. 执行项目点击
3. 滚动到所选项目:smoothScrollToPosition(int position)

代码 fragment :

mediaPlayer.setOnCompletionListener(new OnCompletionListener() {
    @Override
    public void onCompletion(MediaPlayer mp) {
        // First set next position in positionGlobal   

        //highlight ListItem
        audioAdapter.setSelectedItem(position);

        // Then perform Click
        listview.performItemClick(listview, positionGlobal, listview.getItemIdAtPosition(positionGlobal));

        // Scroll to selected position
        listview.smoothScrollToPosition(positionGlobal);
    }
});

Adapter 类如下所示:

public AudioAdapter(Context context, int resource, ArrayList<Audio> objects) {
    public void setSelectedItem(int selectedItem) {
        this.selectedItem = selectedItem;
        notifyDataSetChange();
    }
    @Override
    public View getView(final int position, View convertView, ViewGroup parent){
          // convert view = design
          View v = convertView;
          // Your code

          // set selected Item
          if(position == selectedItem) {
            // you can define your own color of selected item here
          v.setBackgroundColor(StringUtils.getColorFromResources(R.color.light_blue));
        } else {
            // you can define your own default selector here
            v.setBackground(StringUtils.getDrawableFromResources(R.drawable.abs__list_selector_holo_light));
        }
     }
 }

希望能帮到你