android自定義列表視圖滾動時很慢

球員我的列表視圖出現問題。滾動時，任何人都可以幫助我，它運行的很慢。我的listview是自定義佈局，使用相對3個textview和1個imageview每行，所有內容都從網上檢索。我使用自定義適配器和視圖持有人。android自定義列表視圖滾動時很慢

下面是我如何使用適配器的代碼。

public class MessageList extends ListActivity { 


    @Override 
    public void onCreate(Bundle icicle) { 
    super.onCreate(icicle); 
     setContentView(R.layout.listarticle); 

     loadFeed(link); 
     setListAdapter(new IconAdapter(this)); 

    } 

/* This method load xml file and parse it into message object*/ 
private void loadFeed(String link){ 
    try{ 
     BaseFeedParser parser = new BaseFeedParser(link); 
     messages = parser.parse(); 
     titles = new ArrayList<String>(messages.size()); 
     image = new ArrayList<String>(messages.size()); 
     date_post = new ArrayList<String>(messages.size()); 
     descs = new ArrayList<String>(messages.size()); 
     for (Message msg : messages){ 
     titles.add(msg.getTitle()); 
     image.add(msg.getImageLink().toString()); 
     date_post.add(msg.getDate()); 
     descs.add(msg.getDescription()); 

     } 
     } catch (Throwable t){ 
     Log.e("AndroidNews",t.getMessage(),t); 
    } 
    } 

/*this is my custom baseadapter */ 
class IconAdapter extends BaseAdapter{ 
    private LayoutInflater mInflater; 


    public IconAdapter(Context cxt){ 
    mInflater = LayoutInflater.from(cxt); 


    } 

    public class ViewHolder{ 
    private TextView title; 
    private TextView date; 
    private TextView desc; 
    private ImageView thumb; 
    } 

    public View getView(int positiion, View convertView, ViewGroup parent){ 
    ViewHolder holder; 

    if (convertView==null){ 
    convertView = mInflater.inflate(R.layout.row, null); 

    holder = new ViewHolder(); 

    holder.title = (TextView) convertView.findViewById(R.id.title); 
    holder.date = (TextView) convertView.findViewById(R.id.date); 
    holder.desc = (TextView) convertView.findViewById(R.id.deskripsi); 
    holder.thumb = (ImageView) convertView.findViewById(R.id.thumbnail); 

    convertView.setTag(holder); 
    }else{ 

    holder = (ViewHolder) convertView.getTag(); 
    } 

    holder.title.setText(titles.get(positiion)); 
    holder.date.setText(date_post.get(positiion)); 
    holder.desc.setText(descs.get(positiion).substring(0, 55)+"..."); 
    Drawable draw = LoadImageFromWebOperation(image.get(positiion)); 

    holder.thumb.setImageDrawable(draw); 

    return convertView; 
    } 
    /* this method take image from url that retrieve from xml*/ 
    public Drawable LoadImageFromWebOperation(String url){ 
    try{ 
    InputStream is = (InputStream) new URL(url).getContent(); 
    Drawable d = Drawable.createFromStream(is, "src name"); 
    return d; 
    }catch (Exception e){ 
    Log.d("image", url, e); 
    return null; 
    } 
    } 

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

    @Override 
    public Object getItem(int position) { 
    return messages.get(position); 
    } 

    @Override 
    public long getItemId(int position) { 
    return position; 
    } 

}

來源

2010-12-22 Rahadyanteja

編輯和格式化問題中的代碼以更好地理解您的問題。 – 2010-12-22 07:37:11

thx。我刪除了一些代碼。希望你能理解這個問題 – Rahadyanteja 2010-12-22 07:57:57

@Raha，在你的構造函數中，讓所有的URL請求都存儲在一個數組中，在`getView`中不要再加載它們......這會加快速度。 – st0le 2010-12-22 08:01:41

在這個答案的鏈接看看：Scrolling large lists of Cursor-based adapters is faster than much smaller lists of in-memory adapters

來源

2010-12-22 07:36:50 psychotik

public View getView(int positiion, View convertView, ViewGroup parent){ 
     ... 
     Drawable draw = LoadImageFromWebOperation(image.get(positiion)); 
     ... 
    }

這就是問題所在。你永遠不應該在UI線程中進行聯網。爲這項工作實施一些異步任務。另外，您可以使用traceview http://developer.android.com/guide/developing/tools/traceview.html工具來確定性能瓶頸。

來源

2010-12-22 08:40:18

這是你的問題，就在這裏..

Drawable draw = LoadImageFromWebOperation(image.get(positiion));

而不是在你的getView()使得重複URL請求，請立即您的所有要求，並存儲在Drawables一個數組，然後用裏面的數組getView。這將使其速度更快...

來源

2010-12-22 10:15:35 st0le

Please use View Holder pattern in getview. 

ViewHolder holder = null; 

String fileName = arrfiles.get(position); 
     if (convertView == null) { 
      holder = new ViewHolder(); 
      LayoutInflater inflator = ((Activity) context).getLayoutInflater(); 
      convertView = inflator.inflate(R.layout.unsubmited_row, parent, 
        false); 
      convertView.setClickable(false); 
     } 
     else 
     { 
      holder = (ViewHolder) convertView.getTag(); 
     } 
     holder.txtFileName = (TextView) convertView 
       .findViewById(R.id.txtFileName); 
     holder.txtisActive = (TextView) convertView 
       .findViewById(R.id.txtIsActive); 
     holder.txtFileName.setText(fileName); 
     convertView.setTag(holder);

來源

2014-01-27 10:44:44

android自定義列表視圖滾動時很慢

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