使用 2 种不同的布局重用 Android Listview 中的视图 [英] Reusing views in Android Listview with 2 different layouts

问题描述

我了解到，为了最大限度地提高 Android 列表视图的效率，您应该只拥有适合屏幕所需的膨胀行"视图.一旦视图移出屏幕，您应该在 getView 方法中重用它，检查 convertView 是否为空.

I've learned that to maximize efficiency with Android listviews, you should only have as many inflated 'row' views as are needed to fit on the screen. Once a view has moved off the screen, you should reuse it in your getView method, checking if convertView is null or not.

但是，当列表需要 2 种不同的布局时，如何实现这个想法?假设它是一个订单列表，1 个布局用于已完成的订单，另一个布局用于处理中的订单.

However, how can you implement this idea when you need 2 different layouts for the list? Lets say its a list of orders and 1 layout is for completed orders and the other layout is for in process orders.

这是我的代码使用的想法的示例教程.就我而言，我将有 2 行布局:R.layout.listview_item_product_complete 和 R.layout.listview_item_product_inprocess

This is an example tutorial of the idea my code is using. In my case, I would have 2 row layouts: R.layout.listview_item_product_complete and R.layout.listview_item_product_inprocess

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

ViewHolder holder = null;

if (convertView == null) {
    holder = new ViewHolder();
    if(getItemViewType(position) == COMPLETE_TYPE_INDEX) {
        convertView = mInflator.inflate(R.layout.listview_item_product_complete, null);
        holder.mNameTextView = (TextView) convertView.findViewById(R.list.text_complete);
        holder.mImgImageView = (ImageView) convertView.findViewById(R.list.img_complete);
    }
    else { // must be INPROCESS_TYPE_INDEX
        convertView = mInflator.inflate(R.layout.listview_item_product_inprocess, null);
        holder.mNameTextView = (TextView) convertView.findViewById(R.list.text_inprocess);
        holder.mImgImageView = (ImageView) convertView.findViewById(R.list.img_inprocess);
    }
    convertView.setTag(holder);
} else {
    holder = (ViewHolder) convertView.getTag();
}
    thisOrder = (Order) myOrders.getOrderList().get(position);
    // If using different views for each type, use an if statement to test for type, like above
    holder.mNameTextView.setText(thisOrder.getNameValue());
    holder.mImgImageView.setImageResource(thisOrder.getIconValue());
    return convertView;
}

public static class ViewHolder {
    public TextView mNameTextView;
    public ImageView mImgImageView;
}

推荐答案

你需要让适配器的视图回收器知道有不止一种布局，以及如何为每一行区分这两种布局.只需覆盖这些方法:

You need to let the adapter's view recycler know that there is more than one layout and how to distinguish between the two for each row. Simply override these methods:

@Override
public int getItemViewType(int position) {
    // Define a way to determine which layout to use, here it's just evens and odds.
    return position % 2;
}

@Override
public int getViewTypeCount() {
    return 2; // Count of different layouts
}

<小时>

在getView()中加入getItemViewType()，像这样:

if (convertView == null) {
    // You can move this line into your constructor, the inflater service won't change.
    mInflater = (LayoutInflater) mContext.getSystemService(LAYOUT_INFLATER_SERVICE);
    if(getItemViewType(position) == 0)
        convertView = mInflater.inflate(R.layout.listview_item_product_complete, parent, false);
    else
        convertView = mInflater.inflate(R.layout.listview_item_product_inprocess, parent, false);
    // etc, etc...

在 Google Talks 上观看 Android 的 Romain Guy 讨论视图回收器.

Watch Android's Romain Guy discuss the view recycler at Google Talks.

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