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?
您可以通过使getItemViewType()返回该位置的预期viewType值来处理multipleViewTypes RecyclerAdapter。
我准备了一个MultipleViewTypeAdapter用于构造一个MCQ列表的考试，它可能抛出一个可能有两个或多个有效答案(复选框选项)和一个单一答案问题(单选按钮选项)的问题。
为此，我从API响应中获得问题的类型，并使用它来决定我必须为该问题显示哪个视图。
public class MultiViewTypeAdapter extends RecyclerView.Adapter {
Context mContext;
ArrayList<Question> dataSet;
ArrayList<String> questions;
private Object radiobuttontype1;
//Viewholder to display Questions with checkboxes
public static class Checkboxtype2 extends RecyclerView.ViewHolder {
ImageView imgclockcheck;
CheckBox checkbox;
public Checkboxtype2(@NonNull View itemView) {
super(itemView);
imgclockcheck = (ImageView) itemView.findViewById(R.id.clockout_cbox_image);
checkbox = (CheckBox) itemView.findViewById(R.id.clockout_cbox);
}
}
//Viewholder to display Questions with radiobuttons
public static class Radiobuttontype1 extends RecyclerView.ViewHolder {
ImageView clockout_imageradiobutton;
RadioButton clockout_radiobutton;
TextView sample;
public radiobuttontype1(View itemView) {
super(itemView);
clockout_imageradiobutton = (ImageView) itemView.findViewById(R.id.clockout_imageradiobutton);
clockout_radiobutton = (RadioButton) itemView.findViewById(R.id.clockout_radiobutton);
sample = (TextView) itemView.findViewById(R.id.sample);
}
}
public MultiViewTypeAdapter(ArrayList<QueDatum> data, Context context) {
this.dataSet = data;
this.mContext = context;
}
@NonNull
@Override
public RecyclerView.ViewHolder onCreateViewHolder(@NonNull ViewGroup viewGroup, int viewType) {
if (viewType.equalsIgnoreCase("1")) {
View view = LayoutInflater.from(viewGroup.getContext()).inflate(R.layout.clockout_radio_list_row, viewGroup, false);
return new radiobuttontype1(view);
} else if (viewType.equalsIgnoreCase("2")) {
View view = LayoutInflater.from(viewGroup.getContext()).inflate(R.layout.clockout_cbox_list_row, viewGroup, false);
view.setHorizontalFadingEdgeEnabled(true);
return new Checkboxtype2(view);
} else if (viewType.equalsIgnoreCase("3")) {
View view = LayoutInflater.from(viewGroup.getContext()).inflate(R.layout.clockout_radio_list_row, viewGroup, false);
return new Radiobuttontype1(view);
} else if (viewType.equalsIgnoreCase("4")) {
View view = LayoutInflater.from(viewGroup.getContext()).inflate(R.layout.clockout_radio_list_row, viewGroup, false);
return new Radiobuttontype1(view);
} else if (viewType.equalsIgnoreCase("5")) {
View view = LayoutInflater.from(viewGroup.getContext()).inflate(R.layout.clockout_radio_list_row, viewGroup, false);
return new Radiobuttontype1(view);
}
return null;
}
@Override
public void onBindViewHolder(@NonNull RecyclerView.ViewHolder viewHolder, int viewType) {
if (viewType.equalsIgnoreCase("1")) {
options = dataSet.get(i).getOptions();
question = dataSet.get(i).getQuestion();
image = options.get(i).getValue();
((radiobuttontype1) viewHolder).clockout_radiobutton.setChecked(false);
((radiobuttontype1) viewHolder).sample.setText(question);
//Loading image bitmap in the ViewHolder's View
Picasso.with(mContext)
.load(image)
.into(((radiobuttontype1) viewHolder).clockout_imageradiobutton);
} else if (viewType.equalsIgnoreCase("2")) {
options = (ArrayList<Clockout_questions_Option>) dataSet.get(i).getOptions();
question = dataSet.get(i).getQuestion();
image = options.get(i).getValue();
//Loading image bitmap in the ViewHolder's View
Picasso.with(mContext)
.load(image)
.into(((Checkboxtype2) viewHolder).imgclockcheck);
} else if (viewType.equalsIgnoreCase("3")) {
//Fit data to viewHolder for ViewType 3
} else if (viewType.equalsIgnoreCase("4")) {
//Fit data to viewHolder for ViewType 4
} else if (viewType.equalsIgnoreCase("5")) {
//Fit data to viewHolder for ViewType 5
}
}
@Override
public int getItemCount() {
return dataSet.size();
}
/**
* Returns viewType for that position by picking the viewType value from the
* dataset
*/
@Override
public int getItemViewType(int position) {
return dataSet.get(position).getViewType();
}
}
你可以避免在onBindViewHolder()中基于多个条件的viewHolder数据填充，通过为不同位置的viewHolder中相似的视图分配相同的id。
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));
}
}
是的，这是可能的。只需实现getItemViewType()，并照顾onCreateViewHolder()中的viewType参数。
所以你可以这样做:
public class MyAdapter extends RecyclerView.Adapter<RecyclerView.ViewHolder> {
class ViewHolder0 extends RecyclerView.ViewHolder {
...
public ViewHolder0(View itemView){
...
}
}
class ViewHolder2 extends RecyclerView.ViewHolder {
...
public ViewHolder2(View itemView){
...
}
@Override
public int getItemViewType(int position) {
// Just as an example, return 0 or 2 depending on position
// Note that unlike in ListView adapters, types don't have to be contiguous
return position % 2 * 2;
}
@Override
public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
switch (viewType) {
case 0: return new ViewHolder0(...);
case 2: return new ViewHolder2(...);
...
}
}
@Override
public void onBindViewHolder(final RecyclerView.ViewHolder holder, final int position) {
switch (holder.getItemViewType()) {
case 0:
ViewHolder0 viewHolder0 = (ViewHolder0)holder;
...
break;
case 2:
ViewHolder2 viewHolder2 = (ViewHolder2)holder;
...
break;
}
}
}
我是这样做的。我传递了“fragmentType”，并创建了两个ViewHolders，在此基础上，我在一个适配器中相应地分类了我的布局，可以有不同的布局和布局管理器
private Context mContext;
protected IOnLoyaltyCardCategoriesItemClicked mListener;
private String fragmentType;
private View view;
public LoyaltyCardsCategoriesRecyclerViewAdapter(Context context, IOnLoyaltyCardCategoriesItemClicked itemListener, String fragmentType) {
this.mContext = context;
this.mListener = itemListener;
this.fragmentType = fragmentType;
}
public class LoyaltyCardCategoriesFragmentViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener {
private ImageView lc_categories_iv;
private TextView lc_categories_name_tv;
private int pos;
public LoyaltyCardCategoriesFragmentViewHolder(View v) {
super(v);
view.setOnClickListener(this);
lc_categories_iv = (ImageView) v.findViewById(R.id.lc_categories_iv);
lc_categories_name_tv = (TextView) v.findViewById(R.id.lc_categories_name_tv);
}
public void setData(int pos) {
this.pos = pos;
lc_categories_iv.setImageResource(R.mipmap.ic_launcher);
lc_categories_name_tv.setText("Loyalty Card Categories");
}
@Override
public void onClick(View view) {
if (mListener != null) {
mListener.onLoyaltyCardCategoriesItemClicked(pos);
}
}
}
public class MyLoyaltyCardsFragmentTagViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener {
public ImageButton lc_categories_btn;
private int pos;
public MyLoyaltyCardsFragmentTagViewHolder(View v) {
super(v);
lc_categories_btn = (ImageButton) v.findViewById(R.id.lc_categories_btn);
lc_categories_btn.setOnClickListener(this);
}
public void setData(int pos) {
this.pos = pos;
lc_categories_btn.setImageResource(R.mipmap.ic_launcher);
}
@Override
public void onClick(View view) {
if (mListener != null) {
mListener.onLoyaltyCardCategoriesItemClicked(pos);
}
}
}
@NonNull
@Override
public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
if (fragmentType.equalsIgnoreCase(Constants.LoyaltyCardCategoriesFragmentTag)) {
view = LayoutInflater.from(mContext).inflate(R.layout.loyalty_cards_categories_frag_item, parent, false);
return new LoyaltyCardCategoriesFragmentViewHolder(view);
} else if (fragmentType.equalsIgnoreCase(Constants.MyLoyaltyCardsFragmentTag)) {
view = LayoutInflater.from(mContext).inflate(R.layout.my_loyalty_cards_categories_frag_item, parent, false);
return new MyLoyaltyCardsFragmentTagViewHolder(view);
} else {
return null;
}
}
@Override
public void onBindViewHolder(@NonNull RecyclerView.ViewHolder holder, int position) {
if (fragmentType.equalsIgnoreCase(Constants.LoyaltyCardCategoriesFragmentTag)) {
((LoyaltyCardCategoriesFragmentViewHolder) holder).setData(position);
} else if (fragmentType.equalsIgnoreCase(Constants.MyLoyaltyCardsFragmentTag)) {
((MyLoyaltyCardsFragmentTagViewHolder) holder).setData(position);
}
}
@Override
public int getItemCount() {
return 7;
}
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。
虽然选择的答案是正确的，但我只是想进一步阐述它。我发现一个有用的自定义适配器为多种视图类型在RecyclerView。
它的Kotlin版本在这里。
自定义适配器如下:
public class CustomAdapter extends RecyclerView.Adapter<RecyclerView.ViewHolder> {
private final Context context;
ArrayList<String> list; // ArrayList of your Data Model
final int VIEW_TYPE_ONE = 1;
final int VIEW_TYPE_TWO = 2;
public CustomAdapter(Context context, ArrayList<String> list) { // you can pass other parameters in constructor
this.context = context;
this.list = list;
}
private class ViewHolder1 extends RecyclerView.ViewHolder {
TextView yourView;
ViewHolder1(final View itemView) {
super(itemView);
yourView = itemView.findViewById(R.id.yourView); // Initialize your All views prensent in list items
}
void bind(int position) {
// This method will be called anytime a list item is created or update its data
// Do your stuff here
yourView.setText(list.get(position));
}
}
private class ViewHolder2 extends RecyclerView.ViewHolder {
TextView yourView;
ViewHolder2(final View itemView) {
super(itemView);
yourView = itemView.findViewById(R.id.yourView); // Initialize your All views prensent in list items
}
void bind(int position) {
// This method will be called anytime a list item is created or update its data
//Do your stuff here
yourView.setText(list.get(position));
}
}
@Override
public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
if (viewType == VIEW_TYPE_ONE) {
return new ViewHolder1(LayoutInflater.from(context).inflate(R.layout.your_list_item_1, parent, false));
}
//if its not VIEW_TYPE_ONE then its VIEW_TYPE_TWO
return new ViewHolder2(LayoutInflater.from(context).inflate(R.layout.your_list_item_2, parent, false));
}
@Override
public void onBindViewHolder(RecyclerView.ViewHolder holder, int position) {
if (list.get(position).type == Something) { // Put your condition, according to your requirements
((ViewHolder1) holder).bind(position);
} else {
((ViewHolder2) holder).bind(position);
}
}
@Override
public int getItemCount() {
return list.size();
}
@Override
public int getItemViewType(int position) {
// Here you can get decide from your model's ArrayList, which type of view you need to load. Like
if (list.get(position).type == Something) { // Put your condition, according to your requirements
return VIEW_TYPE_ONE;
}
return VIEW_TYPE_TWO;
}
}
