机器人 - 确定在ListView

Question

我有一些麻烦，在一个ListView正确识别项目的项目。

有4类，没关系，这是一个很大的代码，以便在第一，我要解释这些类的逻辑。

• 输入ListActivity和初始化其ListView
• 执行AsyncTask其从服务器下载JSON响应，解析它，使用对象填充ListView和设置在适配器而呈现出ProgressDialog
• 的PlaylistItem类包含从单个JSONObject获取数据的方法。它是用来参数以及它的目的ArrayList的
  • 的AsyncTask后完成列表填充项，看起来像|按钮|艺术家（TextView） - 标题（TextView）

UPDATE

解决第1期，但仍无法找出什么地方错了按钮

2）。我在适配器的getView（）方法中为我的按钮设置了一个OnClickListener。要找出按钮是否被正确识别，我什么也没做，只是改变了它的背景。但在某个按钮点击迫使每11或12按钮的背景改变。到目前为止无法弄清楚。

我无法继续获得URL和流音频，直到这些问题都解决了，所以任何帮助是极大的赞赏。我的课程在下面，请问是否看起来不清楚。

AudioList

  public class AudioList extends ListActivity { 
private ListView lv; 
private PlaylistLoader loader; 
private AudioListAdapter adapter; 
@Override 
protected void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
    setContentView(R.layout.activity_audio_list); 
    init(); // initialize the ListView 

    /*--- populate the list with user's audio in case network connection is available ---*/ 
    loader = new PlaylistLoader(this, lv, adapter); 
    if (Utils.isNetworkAvailable(this)) { 
     loader.execute(); 
    } else { 
     APP_CONSTANTS.NO_DATA_CONNECTION(this); 
    } 

} 

@Override 
protected void onResume() { 
    super.onResume(); 
    lv.setOnItemClickListener(new OnItemClickListener() { 
     @Override 
     public void onItemClick(AdapterView<?> arg0, View arg1, int arg2, 
       long arg3) { 

      Toast.makeText(getApplicationContext(), Integer.toString(arg2), 
        Toast.LENGTH_SHORT).show(); 
      } 
    }); 

} 

private void init() { 
    lv = getListView(); 
    lv.setTranscriptMode(0x00000000); 
    lv.setDividerHeight(1); 
    lv.setSmoothScrollbarEnabled(true); 
    lv.setVerticalFadingEdgeEnabled(true); 

} 

PlaylistLoader

 public class PlaylistLoader extends AsyncTask<Void, Void, Void> { 

private JSONObject usersPlaylist, singleJSONItem; 
private JSONArray responseJSONArray; 
private ListView lv; 
private ArrayList<PlaylistItem> playlist; 
private Activity a; 
private PlaylistItem audioList; 
private SharedPreferences prefs; 
private ProgressDialog pd; 
AudioListAdapter adapter; 

public PlaylistLoader(Activity a, ListView lv, AudioListAdapter adapter) { 
    this.lv = lv; 
    this.a = a; 
    this.adapter = adapter; 
} 

@Override 
protected Void doInBackground(Void... arg0) { 
    /*--- create new ArrayList of PlaylistItem Objects ---*/ 
    playlist = new ArrayList<PlaylistItem>(); 
    /*--- get the preferences using context of calling activity ---*/ 
    prefs = PreferenceManager.getDefaultSharedPreferences(a); 
    try { 
     /*--- download the response JSONObject from server // access_token and 
     * user_id come from activity's defaultSharedPreferences ---*/ 
     usersPlaylist = Utils.retrieveJsonObjectFromUrl(new URL(
       APP_CONSTANTS.REQUEST_AUDIO_LIST(prefs)), a); 
     /*--- get the response array from received object ---*/ 
     responseJSONArray = usersPlaylist.getJSONArray("response"); 
     /*--- populate the ArrayList with Objects from the response array ---*/ 
     for (int i = 0; i < responseJSONArray.length(); i++) { 
      singleJSONItem = responseJSONArray.getJSONObject(i); 
      audioList = new PlaylistItem(singleJSONItem); 
      playlist.add(audioList); 

     } 

    } catch (MalformedURLException e) { 
     e.printStackTrace(); 
    } catch (JSONException e) { 
     e.printStackTrace(); 
    } catch (IOException e) { 
     e.printStackTrace(); 
    } 
    return null; 
} 

@Override 
protected void onPreExecute() { 
    super.onPreExecute(); 
    pd = new ProgressDialog(a); 
    pd.setTitle("Please wait"); 
    pd.setMessage("Retrieving audio list..."); 
    pd.show(); 

} 

@Override 
protected void onPostExecute(Void result) { 
    super.onPostExecute(result); 
    lv.setVisibility(View.VISIBLE); 
    pd.dismiss(); 
    /*--- set the adapter passed in constructor as an adapter for passed ListView ---*/ 
    adapter = new AudioListAdapter(a, R.layout.playlist_item, playlist); 
    lv.setAdapter(adapter); 

} 
    } 

AudioListAdapter

  public class AudioListAdapter extends ArrayAdapter<PlaylistItem> { 
private PlaylistItem pl; 
private Context context; 
private int layoutResourceId; 
private PlaylistItem aud; 
private ArrayList<PlaylistItem> data = null; 

public AudioListAdapter(Context context, int layoutResourceId, 
     ArrayList<PlaylistItem> data) { 
    super(context, layoutResourceId, data); 
    this.layoutResourceId = layoutResourceId; 
    this.context = context; 
    this.data = data; 

} 

@Override 
public PlaylistItem getItem(int position) { 
    return super.getItem(position); 
} 

@Override 
public int getCount() { 
    return data.size(); 
} 

@Override 
public int getPosition(PlaylistItem item) { 
    return super.getPosition(item); 
} 

@Override 
public View getView(int position, View convertView, ViewGroup parent) { 

    pl = new PlaylistItem(); 
    aud = getItem(position); 

    if (convertView == null) { 
     LayoutInflater inflater = ((Activity) context).getLayoutInflater(); 
     convertView = inflater.inflate(layoutResourceId, parent, false); 
     pl.btnPlay = (Button) convertView.findViewById(R.id.btn_list_play); 
     pl.imgSaved = (ImageView) convertView 
       .findViewById(R.id.img_list_audio_saved); 
     pl.tvArtist = (TextView) convertView 
       .findViewById(R.id.tvListItemArtist); 
     pl.tvTitle = (TextView) convertView 
       .findViewById(R.id.tvListItemSong); 

     convertView.setTag(pl); 
    } else { 
     pl = (PlaylistItem) convertView.getTag(); 
     pl.btnPlay.setBackgroundResource(R.drawable.list_button_play); 
    } 

    pl.tvArtist.setText(aud.getArtist() + " " + "-"); 
    pl.tvTitle.setText(aud.getTitle()); 

    pl.btnPlay.setOnClickListener(new View.OnClickListener() { 
     @Override 
     public void onClick(View v) { 
      /*--- vibrate if this option is enabled in the preferences ---*/ 
      if (APP_CONSTANTS.isHapticFeedbackEnabled(getContext())) { 
       APP_CONSTANTS.doVibrate(getContext()); 

      } 
     pl.btnPlay.setBackgroundResource(R.drawable.list_button_pause); 

     } 
    }); 

    return convertView; 
} 

PlayListItem

 public class PlaylistItem { 

private String artist, title; 
private JSONObject obj; 
public Button btnPlay; 
public TextView tvArtist, tvTitle; 
public ImageView imgSaved; 
public int duration; 
public int audio_id; 
public String url; 

/*--- the constructor takes a single JSONObject from the response array ---*/ 
public PlaylistItem(JSONObject obj) { 
    this.obj = obj; 
} 

public PlaylistItem() { 
    // default constructor 
} 

/*--- the methods below return values by key from the passed JSONObject ---*/ 

public String getArtist() { 
    try { 
     artist = obj.getString("artist"); 
    } catch (JSONException e) { 

     e.printStackTrace(); 
    } 
    return artist; 

} 

public String getTitle() { 
    try { 
     title = obj.getString("title"); 
    } catch (JSONException e) { 

     e.printStackTrace(); 
    } 
    return title; 
} 

public int getID() { 
    try { 
     audio_id = obj.getInt("aid"); 
    } catch (JSONException e) { 

     e.printStackTrace(); 
    } 
    return audio_id; 
} 

public String getURL() { 
    try { 
     url = obj.getString("url"); 
    } catch (JSONException e) { 

     e.printStackTrace(); 
    } 
    return url; 
} 
    } 

Answer 1

编辑：

试试这个

以自定义选择在绘制 button_play。XML

<?xml version="1.0" encoding="utf-8"?> 
<selector xmlns:android="http://schemas.android.com/apk/res/android"> 

    <item android:drawable="@drawable/pause_button" 
      android:state_selected="true" /> 
    <item android:drawable="@drawable/play_button" /> 
</selector> 

Modifty适配器这样

public class AudioListAdapter extends ArrayAdapter<PlaylistItem> { 
private PlaylistItem pl; 
private Context context; 
private int layoutResourceId; 
private PlaylistItem aud; 
private ArrayList<PlaylistItem> data = null; 
Button previous; 

public AudioListAdapter(Context context, int layoutResourceId, 
     ArrayList<PlaylistItem> data) { 
    super(context, layoutResourceId, data); 
    this.layoutResourceId = layoutResourceId; 
    previous=new Button(context); 
    this.context = context; 
    this.data = data; 

} 

.... 
.... 

@Override 
public View getView(int position, View convertView, ViewGroup parent) { 

    pl = new PlaylistItem(); 
    aud = getItem(position); 

    if (convertView == null) { 
     LayoutInflater inflater = ((Activity) context).getLayoutInflater(); 
     convertView = inflater.inflate(layoutResourceId, parent, false); 
     pl.btnPlay = (Button) convertView.findViewById(R.id.btn_list_play); 
pl.btnPlay.setBackGroundResouce(R.drawable.button_play); //you can set here or in xml 

     pl.imgSaved = (ImageView) convertView 
       .findViewById(R.id.img_list_audio_saved); 
     pl.tvArtist = (TextView) convertView 
       .findViewById(R.id.tvListItemArtist); 
     pl.tvTitle = (TextView) convertView 
       .findViewById(R.id.tvListItemSong); 

     convertView.setTag(pl); 
    } else { 
     pl = (PlaylistItem) convertView.getTag(); 
    } 


    pl.tvArtist.setText(aud.getArtist() + " " + "-"); 
    pl.tvTitle.setText(aud.getTitle()); 

    pl.btnPlay.setOnClickListener(new View.OnClickListener() { 
     @Override 
     public void onClick(View v) { 
      /*--- vibrate if this option is enabled in the preferences ---*/ 
      if (APP_CONSTANTS.isHapticFeedbackEnabled(getContext())) { 
       APP_CONSTANTS.doVibrate(getContext()); 
      } 
       //for some reason, the background gets changed for every 11th or 12th button in the list 
      Button current=((Button)v); 
       current.setSelected(true); 
       previous.setSelected(false); 
       previous=current; 
     } 
    }); 

    return convertView; 
} 

    } 

---

之所以你的按钮，列表项无法点击，因为你的名单有一个重点项目按钮，所以你需要setFocusable为= FALSE你的按钮。 尝试在xml中为您的按钮设置focusable = false。如果它不为你工作不是做这样的

在你行的xml文件

1.设置可聚焦=真为你的按钮。 2.在同一组android:descendantFocusability="blocksDescendants"为您的父项目（即您的意见所在的父布局）。

在为按钮设置onclickListener之后，在getView（）方法中，为按钮设置focusable false。 它肯定会有效。我希望这会帮助你..

Answer 2

但是点击某个按钮强制每改变第11或第12个按钮的背景。到目前为止无法弄清楚。

你在与ListViews回收行布局的方式作斗争。
可以这样想：如果你有一个有10000行的ListView，但只能在屏幕上显示9个ListView，那么创建10,000个独特的布局是没有意义的。这只是浪费资源，而不是ListView创建〜10个布局并重用它们。

解决方案：将每行恢复为重用时的默认状态。在getView()添加：

} else { 
    pl = (PlaylistItem) convertView.getTag(); 
    pl.btnPlay.setBackgroundResource(R.drawable.list_button_play); 
    // I guessed at the resource's name   ^^^^^^^^^^^^^^^^ 
} 

（你也可以做一些小的改动，以加快你的代码举例来说，你只需要一个OnClickListener，因为它们都含有相同的代码，使之成为一个类变量，并通过这一点。 ）