Android 与自定义适配器的数据绑定

Question

我正在尝试将 Android's Data Binding features 与自定义适配器和 ListView 结合使用。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：

我从哪里获得我应该返回的 View 元素？或者换句话说，如何将对象绑定到 inflated/converted 视图？
如何在使用数据绑定时重用 convertView？
这是实现它的正确方法吗？ ListViews上的攻略不是很清楚

这是指南中对 ListView 的唯一参考：

If you are using data binding items inside a ListView or RecyclerView adapter, you may prefer to use:
   ListItemBinding binding = ListItemBinding.inflate(layoutInflater, viewGroup, false);
   //or
   ListItemBinding binding = DataBindingUtil.inflate(layoutInflater, R.layout.list_item, viewGroup, false);

Answer 1

根据this，你应该return binding.getRoot()。

View getRoot ()

Returns the outermost View in the layout file associated with the Binding. If this binding is for a merge layout file, this will return the first root in the merge tag.

Answer 2

尽管如此，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;
}

Answer 3

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();
    }

Answer 4

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

Answer 5

使用

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

而不是

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

其他代码与@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;
}

Answer 6

DataBindingUtil 会将 ViewDataBinding 对象保存到 view.tag，因此您稍后可以通过 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();
}

Android 与自定义适配器的数据绑定

Android data binding with custom adapter

android

android-databinding

推荐方式

使用

而不是