Android：如何优化 ListView？

Question

我想我已经阅读了其他类似的主题，并且我使用了所有提示，但我在滚动时看到了滞后。我不明白我需要做什么来防止它。我想我错过了一些东西，因为 ListView 滚动不好。

这是我的代码。我正在使用毕加索加载图像。我在这里做错了什么？

public class CustomAdapter extends ArrayAdapter<CustomObjects>
{
    Context context;
    int layoutResourceId;
    List<CustomObjects> data = null;

    public CustomAdapter(Context context, int layoutResourceId, List<Objects> data) {
        super(context, layoutResourceId, data);
        this.layoutResourceId = layoutResourceId;
        this.context = context;
        this.data = data;
    }

    public View getView(int position, View convertView, ViewGroup parent)
    {
        final ViewHolder holder;
        if (convertView == null) {
            holder = new ViewHolder();
            convertView = LayoutInflater.from(getContext()).inflate(layoutResourceId, parent, false);
            holder.img = (ImageView) convertView.findViewById(R.id.objectImage);

            holder.title = (TextView) convertView.findViewById(R.id.title);
            holder.field2 = (TextView) convertView.findViewById(R.id.field2);
            holder.field3 = (TextView) convertView.findViewById(R.id.field3);
            holder.field4 = (TextView) convertView.findViewById(R.id.field4);
            holder.field5 = (TextView) convertView.findViewById(R.id.field5);
            convertView.setTag(holder);
        }else {
            holder = (ViewHolder) convertView.getTag();
        }

        CustomObjects customObject = getItem(position);

        Picasso.with(getActivity())
                .load(customObject.getImgUrl())
                .tag("image") 
                .into(holder.img);              

        holder.title.setText(customObject.getName());
        holder.field2.setText(customObject.getField2());
        holder.field3.setText(customObject.getField3());
        holder.field4.setText(customObject.getField4());
        holder.field5.setText(customObject.getField5());
        return convertView;
    }
}

ViewHolder：

private static class ViewHolder {
    TextView title;
    ImageView img;
    TextView field1;
    TextView field2;
    TextView field3;
    TextView field4;
}

我在滚动时也停止上传图片：

 //Its my ListView (objectsList)
 objectsList.setOnScrollListener(new SampleScrollListener(getActivity()));

 public class SampleScrollListener implements AbsListView.OnScrollListener {
    private final Context context;

    public SampleScrollListener(Context context) {
        this.context = context;
    }

    @Override
    public void onScrollStateChanged(AbsListView view, int scrollState) {
        final Picasso picasso = Picasso.with(context);
        if (scrollState == SCROLL_STATE_IDLE || scrollState == SCROLL_STATE_TOUCH_SCROLL) {
            picasso.resumeTag("image");
        } else {
            picasso.pauseTag("image");
        }
    }

    @Override
    public void onScroll(AbsListView view, int firstVisibleItem, int visibleItemCount,
                         int totalItemCount) {int lastInScreen = firstVisibleItem + visibleItemCount;
        if (lastInScreen == totalItemCount) {
            if(isUploaded == false && isLoading==false) {
                isLoading = true;
               // Async loading of objects
            }
        }

    }
}

还有我的 ListView：

<ListView
    android:layout_marginLeft="0dp"
    android:layout_marginRight="0dp"
    android:paddingRight="0dp"
    android:paddingLeft="0dp"
    android:fastScrollEnabled="false"
    android:layout_marginTop="0dp"
    android:id="@+id/objectsList"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:footerDividersEnabled="false"
    android:scrollingCache="false"
    android:animationCache="false"
    android:smoothScrollbar="true"
    android:divider="@android:color/transparent"
    android:dividerHeight="0dp"
    android:cacheColorHint="#00000000"
    android:clipToPadding="false"
    android:overScrollFooter="@android:color/transparent"/>

Answer 1

我建议你使用Glide：从Picasso 切换很简单，Glide 可以更好地管理内存。滚动不再有延迟。

Answer 2

问题解决了。我刚刚断开了手机与 USB 的连接。我不知道问题的原因。