16

我正在尝试将Android 的数据绑定功能与自定义适配器和 ListView 一起使用。我无法覆盖自定义适配器的getView方法:

public class ChecksAdapter extends ArrayAdapter<Check> {

    public ChecksAdapter(Context context, ObservableList<Check> checks) {
        super(context, R.layout.check, checks);
    }

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        CheckBinding binding = DataBindingUtil.inflate(
                LayoutInflater.from(getContext()),
                R.layout.check, parent, false);
        binding.setCheck(this.getItem(position));

        // Return what?
    }
    
}

所以我的问题是:

  • 我从哪里得到View我应该返回的元素?或者换句话说,如何将对象绑定到膨胀/转换的视图?
  • convertView使用数据绑定时如何重用?
  • 这是实现这一点的正确方法吗?该指南对 ListViews 不是很清楚

这是指南中 ListViews 的唯一参考:

如果您在 ListView 或 RecyclerView 适配器中使用数据绑定项,您可能更喜欢使用:

   ListItemBinding binding = ListItemBinding.inflate(layoutInflater, viewGroup, false);
   //or
   ListItemBinding binding = DataBindingUtil.inflate(layoutInflater, R.layout.list_item, viewGroup, false);
4

6 回答 6

25

您应该执行以下操作以实现平滑滚动..

@Override
public View getView(int position, View convertView, ViewGroup parent) {
    CheckBinding binding;
    if(convertView == null) {
        binding = DataBindingUtil.inflate(
                LayoutInflater.from(getContext()),
                R.layout.check, parent, false);
        convertView = binding.getRoot();
    }
    else {
        binding = (CheckBinding) convertView.getTag();
    }

    binding.setCheck(this.getItem(position));
    convertView.setTag(binding);
    return convertView;
}
于 2016-03-23T10:11:12.227 回答
11

根据这个,你应该返回binding.getRoot()

View getRoot ()

返回与 Binding 关联的布局文件中最外层的 View。如果此绑定用于合并布局文件,则将返回合并标记中的第一个根。

于 2015-11-26T17:23:32.460 回答
3

为了完成这里是 kotlin 变体:

    val binding = convertView?.tag as? CheckBinding ?: CheckBinding.inflate(layoutInflater, parent, false)
    binding.check = this.getItem(position)
    binding.root.tag = binding

    return binding.root
于 2017-11-24T13:46:47.577 回答
2

推荐方式

使用生成的 Binding 类而不是 DataBindingUtil 类。请参阅文档。

如果您在 、 或 适配器中使用数据绑定项FragmentListViewRecyclerView可能更喜欢使用inflate()绑定类的方法

利用

binding = CheckBinding.inflate(this, parent, false);

代替

binding = DataBindingUtil.inflate(
                LayoutInflater.from(getContext()),
                R.layout.check, parent, false);

其他代码将与@sergi 相同

@Override
public View getView(int position, View convertView, ViewGroup parent) {
    CheckBinding binding;
    if(convertView == null) {
        binding = CheckBinding.inflate(this, parent, false);
        convertView = binding.getRoot();
    }
    else {
        binding = (CheckBinding) convertView.getTag();
    }

    binding.setCheck(this.getItem(position));
    convertView.setTag(binding);
    return convertView;
}
于 2018-08-07T06:08:01.943 回答
0

DataBindingUtil 会将 ViewDataBinding 对象保存到 view.tag 中,以便您稍后通过 DataBindingUtil.getBinding(convertView) 检索它

@Override
public View getView(int position, View convertView, ViewGroup parent) {
    return getViewForResource(mResourceId, position, convertView, parent);
}

@Override
public View getDropDownView(int position, View convertView, ViewGroup parent) {
    return getViewForResource(mDropDownResourceId, position, convertView, parent);
}

public View getViewForResource(int resourceId, int position, View convertView, ViewGroup parent) {
    final ViewDataBinding binding = (convertView != null) ? DataBindingUtil.getBinding(convertView) : DataBindingUtil.inflate(mLayoutInflater, resourceId, parent, false);
    binding.setVariable(BR.viewModel, getItem(position));
    return binding.getRoot();
}
于 2020-11-11T06:23:04.967 回答
0
ItemTickFilterBinding mFilterBinding;

    if (convertView==null) {
        mFilterBinding= DataBindingUtil.inflate(
                LayoutInflater.from(mContext),
                R.layout.item_tick_filter, parent, false);
        convertView.setTag(mFilterBinding);
    }
    else {
        mFilterBinding=(ItemTickFilterBinding)convertView.getTag();
    }
于 2017-03-15T12:05:58.673 回答