android - 在 bool 值上更改特定的 ListView 图像

Question

我有一个带有自定义适配器和图像的 ListView。我还为 ListView 中的每个项目分配了声音。例如，当用户单击 ListView 中的第 3 个项目时，我想更改该项目的图像，当用户单击第 15 个项目时，将第 3 项图像更改为旧图像，并更改第 15 个项目的图像等等。我怎样才能做到这一点？这是我的代码:

适配器:

@Override
public View getView(final int position, View convertView, ViewGroup parent){
    View item=convertView;
    HolderActivity holder=null;
    if(item==null){


    LayoutInflater inflater=(LayoutInflater)context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
    item=inflater.inflate(R.layout.generator, parent,false);
    holder=new HolderActivity(item);
    item.setTag(holder);
    }
    else{
        holder=(HolderActivity)item.getTag();
    }

    holder.transfer.setImageResource(transfer[position]);
    holder.myImage.setImageResource(pictures[position]);
    holder.ringName.setText(ringNames[position]);
    holder.ringDesc.setText(descInfo[position]);

    return item;
}

}

然后在主 Activity 中简单的 ItemClickListener

    int[] songPos = { R.raw.position1, R.raw.position2, R.raw.position3,
                R.raw.position4, R.raw.position4, R.raw.position5, R.raw.position6...etc etc




   list.setOnItemClickListener(new OnItemClickListener() {

       @Override
       public void onItemClick(AdapterView<?> parent, View paramAnonymousView, int position, long id) {
           CentralActivity.this.playSound(position);


       }
   });   

private void playSound(int paramInt)
    {
      try
      {
        if ((CentralActivity.playing.booleanValue()) && (CentralActivity.position == paramInt))
        {
         Toast.makeText(CentralActivity.this, "It's Playing", Toast.LENGTH_SHORT).show();
        }
        else
        {
          CentralActivity.mp = MediaPlayer.create(CentralActivity.this, Integer.valueOf(this.songPos[paramInt]).intValue());
          CentralActivity.mp.start();
          CentralActivity.position = paramInt;
          CentralActivity.playing = Boolean.valueOf(true);
          CentralActivity.mp.setOnCompletionListener(new MediaPlayer.OnCompletionListener()
          {
            public void onCompletion(MediaPlayer paramAnonymousMediaPlayer)
            {
              paramAnonymousMediaPlayer.release();
              CentralActivity.playing = Boolean.valueOf(false);
            }
          });
        }
      }
      catch (Exception localException) {}
    }

Answer 1

以下是您的代码应该可以工作的部分:

Activity :

private ArrayAdapter mAdapter; // Make the mAdapter reachable by other methods

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    ...
    // If creating adapter from your activity, send it's context (this):
    mAdapter = new ArrayAdapter(this,...);
    ...
}

private void playSound(int paramInt) {
    try {
        if ((CentralActivity.playing) && (CentralActivity.position == paramInt)) {
            Toast.makeText(CentralActivity.this, "It's Playing", Toast.LENGTH_SHORT).show();
        } else {
            // Set activity variables
            CentralActivity.position = paramInt;
            CentralActivity.playing = true;

            // Update ListView views
            mAdapter.notifyDataSetChanged();

            // Create MP and start playing
            CentralActivity.mp = MediaPlayer.create(CentralActivity.this, Integer.valueOf(this.songPos[paramInt]).intValue());
            CentralActivity.mp.setOnCompletionListener(new MediaPlayer.OnCompletionListener() {
                public void onCompletion(MediaPlayer paramAnonymousMediaPlayer) {
                    paramAnonymousMediaPlayer.release();
                    CentralActivity.playing = false;

                    // Update ListView views
                    mAdapter.notifyDataSetChanged();
                }
            });
            CentralActivity.mp.start();
        }
    } catch (Exception localException) {
        localException.printStackTrace();
    }
}

适配器:

public class CustomAdapter extends ArrayAdapter {

    // Considering CentralActivity is the name of your Activity's class
    private CentralActivity mActivity;

    // Custom adapter's constructor
    public CustomAdapter(Context context, ...) {
        mActivity = (CentralActivity) context;
        ...
    }

    @Override
    public View getView(final int position, View convertView, ViewGroup parent) {
        View item = convertView;
        HolderActivity holder = null;

        if (item == null) {
            LayoutInflater inflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
            item = inflater.inflate(R.layout.generator, parent, false);
            holder = new HolderActivity(item);
            item.setTag(holder);
        } else {
            holder = (HolderActivity) item.getTag();
        }

        if (mActivity.playing && mActivity.position == position) {
            holder.myImage.setImageResource(pauseImageResource);
        } else {
            holder.myImage.setImageResource(pictures[position]);
        }

        holder.transfer.setImageResource(transfer[position]);
        holder.ringName.setText(ringNames[position]);
        holder.ringDesc.setText(descInfo[position]);

        return item;
    }

    ...

}

请注意，您显然需要将 ... 和可能的 CentralActivity 替换为代码中的相应等效项。