android音乐播放器(1)

1、主界面专辑图片采用AsyncTask异步加载，并使用了自定义ListView风格对主界面进行布局

/**
  * 异步加载图片 构造方法传入iamgeView和Position 将下载过的图片临时存入HashMap中
  * 通过HashMap中的position判断是否需要启动异步任务进行下载 已经下载过的图片则不再进行下载
  */
 class LoadAlBumIcon extends AsyncTask<URL, Void, Bitmap> {
  private ImageView imageView;
  private int mPosition;

  private LoadAlBumIcon(ImageView imageView, int position) {
   this.imageView = imageView;
   this.mPosition = position;
  }

  @Override
  protected Bitmap doInBackground(URL... params) {
   try {
    // 得到bitmap图片
    InputStream is = params[0].openStream();
    Bitmap bitmap = BitmapFactory.decodeStream(is);
    // 存入HashMap中
    albumIconCache.put(mPosition, bitmap);
    return bitmap;

   } catch (MalformedURLException e) {
    // TODO Auto-generated catch block
    e.printStackTrace();
   } catch (IOException e) {
    e.printStackTrace();
   }
   return null;
  }

  @Override
  protected void onPostExecute(Bitmap result) {
   imageView.setImageBitmap(result);
  }
 }

// 主界面，自定义ListView
  final String[] strs = getResources().getStringArray(R.array.separator);
  final int[] icons = new int[] { R.drawable.no_cd,
    R.drawable.list_search, R.drawable.list_radio,
    R.drawable.list_top, R.drawable.no_cd,
    R.drawable.list_playlist, R.drawable.list_download };
  mListView = (ListView) findViewById(R.id.listView1);
  mListView.setAdapter(new BaseAdapter() {
   //设置全部不可点击
   @Override
   public boolean areAllItemsEnabled() {
    return false;
   }
   //设置是否可以点击ListView中的Item
   @Override
   public boolean isEnabled(int position) {
    if ("Browse Jamendo".equals(strs[position])
      || "My Library".equals(strs[position])) {
     return false;
    } else {
     return true;
    }
   }

   @Override
   public View getView(int position, View convertView, ViewGroup parent) {
    Log.d("String", strs[position]+String.valueOf(position));

    ViewHolder holder = null;
    if (convertView == null) {
     LayoutInflater inflater = LayoutInflater
       .from(MusicPlayerActivity.this);
     View layout = null;
     // 判断是否是分类标题
     if ("Browse Jamendo".equals(strs[position])
       || "My Library".equals(strs[position])) {
      layout = inflater.inflate(R.layout.listtext, null);
      TextView tv = (TextView) layout;
      tv.setText(strs[position]);
     } else {
      layout = inflater.inflate(R.layout.listitem, null);
      holder = new ViewHolder();
      holder.mImage1 = (ImageView) layout
        .findViewById(R.id.imageView1);
      holder.mImage1.setImageResource(icons[position]);
      holder.mText = (TextView) layout
        .findViewById(R.id.textView1);
      holder.mText.setText(strs[position]);
      holder.mImage2 = (ImageView) layout
        .findViewById(R.id.imageView2);

      layout.setTag(holder);
     }
     convertView = layout;
    } else {
     holder = (ViewHolder) convertView.getTag();
    }
    return convertView;
   }

   @Override
   public long getItemId(int position) {
    // TODO Auto-generated method stub
    return 0;
   }

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

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

 

 

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