使用RecyclerView创建动态列表:
当我们创建一个RecyclerView时。适配器我们必须指定ViewHolder,它将绑定到适配器。
public class MyAdapter extends RecyclerView.Adapter<MyAdapter.ViewHolder> {
private String[] mDataset;
public MyAdapter(String[] myDataset) {
mDataset = myDataset;
}
public static class ViewHolder extends RecyclerView.ViewHolder {
public TextView mTextView;
public ViewHolder(TextView v) {
super(v);
mTextView = v;
}
}
@Override
public MyAdapter.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View v = LayoutInflater.from(parent.getContext()).inflate(R.layout.some_layout, parent, false);
//findViewById...
ViewHolder vh = new ViewHolder(v);
return vh;
}
@Override
public void onBindViewHolder(ViewHolder holder, int position) {
holder.mTextView.setText(mDataset[position]);
}
@Override
public int getItemCount() {
return mDataset.length;
}
}
有可能创建多个视图类型的RecyclerView吗?
我推荐汉内斯·多夫曼的这个图书馆。它将所有与特定视图类型相关的逻辑封装在一个名为“AdapterDelegate”的单独对象中。
https://github.com/sockeqwe/AdapterDelegates
public class CatAdapterDelegate extends AdapterDelegate<List<Animal>> {
private LayoutInflater inflater;
public CatAdapterDelegate(Activity activity) {
inflater = activity.getLayoutInflater();
}
@Override public boolean isForViewType(@NonNull List<Animal> items, int position) {
return items.get(position) instanceof Cat;
}
@NonNull @Override public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent) {
return new CatViewHolder(inflater.inflate(R.layout.item_cat, parent, false));
}
@Override public void onBindViewHolder(@NonNull List<Animal> items, int position,
@NonNull RecyclerView.ViewHolder holder, @Nullable List<Object> payloads) {
CatViewHolder vh = (CatViewHolder) holder;
Cat cat = (Cat) items.get(position);
vh.name.setText(cat.getName());
}
static class CatViewHolder extends RecyclerView.ViewHolder {
public TextView name;
public CatViewHolder(View itemView) {
super(itemView);
name = (TextView) itemView.findViewById(R.id.name);
}
}
}
public class AnimalAdapter extends ListDelegationAdapter<List<Animal>> {
public AnimalAdapter(Activity activity, List<Animal> items) {
// DelegatesManager is a protected Field in ListDelegationAdapter
delegatesManager.addDelegate(new CatAdapterDelegate(activity))
.addDelegate(new DogAdapterDelegate(activity))
.addDelegate(new GeckoAdapterDelegate(activity))
.addDelegate(23, new SnakeAdapterDelegate(activity));
// Set the items from super class.
setItems(items);
}
}
使用Kotlin,视图类型的实现变得更加容易。下面是这个light库https://github.com/Link184/KidAdapter的示例
recyclerView.setUp {
withViewType {
withLayoutResId(R.layout.item_int)
withItems(mutableListOf(1, 2, 3, 4, 5, 6))
bind<Int> { // this - is adapter view hoder itemView, it - current item
intName.text = it.toString()
}
}
withViewType("SECOND_STRING_TAG") {
withLayoutResId(R.layout.item_text)
withItems(mutableListOf("eight", "nine", "ten", "eleven", "twelve"))
bind<String> {
stringName.text = it
}
}
}
首先,必须创建两个布局XML文件。之后,在recyclerview适配器中,TYPE_CALL和TYPE_EMAIL是两个静态值,分别为适配器类中的1和2。
现在在Recycler视图Adapter类级别定义两个静态值,例如:private static int TYPE_EMAIL = 2;
现在创建多个视图的视图持有者,如下所示:
class CallViewHolder extends RecyclerView.ViewHolder {
private TextView txtName;
private TextView txtAddress;
CallViewHolder(@NonNull View itemView) {
super(itemView);
txtName = itemView.findViewById(R.id.txtName);
txtAddress = itemView.findViewById(R.id.txtAddress);
}
}
class EmailViewHolder extends RecyclerView.ViewHolder {
private TextView txtName;
private TextView txtAddress;
EmailViewHolder(@NonNull View itemView) {
super(itemView);
txtName = itemView.findViewById(R.id.txtName);
txtAddress = itemView.findViewById(R.id.txtAddress);
}
}
现在在recyclerview适配器的onCreateViewHolder和onBindViewHolder方法中编写如下代码:
@NonNull
@Override
public RecyclerView.ViewHolder onCreateViewHolder(@NonNull ViewGroup viewGroup, int viewType) {
View view;
if (viewType == TYPE_CALL) { // for call layout
view = LayoutInflater.from(context).inflate(R.layout.item_call, viewGroup, false);
return new CallViewHolder(view);
} else { // for email layout
view = LayoutInflater.from(context).inflate(R.layout.item_email, viewGroup, false);
return new EmailViewHolder(view);
}
}
@Override
public void onBindViewHolder(@NonNull RecyclerView.ViewHolder viewHolder, int position) {
if (getItemViewType(position) == TYPE_CALL) {
((CallViewHolder) viewHolder).setCallDetails(employees.get(position));
} else {
((EmailViewHolder) viewHolder).setEmailDetails(employees.get(position));
}
}
你可以使用这个图书馆:https://github.com/vivchar/RendererRecyclerViewAdapter
mRecyclerViewAdapter = new RendererRecyclerViewAdapter(); /* Included from library */
mRecyclerViewAdapter.registerRenderer(new SomeViewRenderer(SomeModel.TYPE, this));
mRecyclerViewAdapter.registerRenderer(...); /* You can use several types of cells */
对于每一个项目,你应该实现一个ViewRenderer, ViewHolder, SomeModel:
ViewHolder -它是回收器视图的一个简单视图持有者。
SomeModel -它是你的模型与ItemModel接口
public class SomeViewRenderer extends ViewRenderer<SomeModel, SomeViewHolder> {
public SomeViewRenderer(final int type, final Context context) {
super(type, context);
}
@Override
public void bindView(@NonNull final SomeModel model, @NonNull final SomeViewHolder holder) {
holder.mTitle.setText(model.getTitle());
}
@NonNull
@Override
public SomeViewHolder createViewHolder(@Nullable final ViewGroup parent) {
return new SomeViewHolder(LayoutInflater.from(getContext()).inflate(R.layout.some_item, parent, false));
}
}
有关更多详细信息,您可以查看文档。