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?
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。
下面的代码不是伪代码。我已经测试过了，它对我很有效。
我想在我的recyclerview中创建一个headerview，然后在用户可以点击的标题下面显示一个图片列表。
我在我的代码中使用了一些开关，不知道这是否是最有效的方法，所以请随意给出您的评论:
public class ViewHolder extends RecyclerView.ViewHolder{
//These are the general elements in the RecyclerView
public TextView place;
public ImageView pics;
//This is the Header on the Recycler (viewType = 0)
public TextView name, description;
//This constructor would switch what to findViewBy according to the type of viewType
public ViewHolder(View v, int viewType) {
super(v);
if (viewType == 0) {
name = (TextView) v.findViewById(R.id.name);
decsription = (TextView) v.findViewById(R.id.description);
} else if (viewType == 1) {
place = (TextView) v.findViewById(R.id.place);
pics = (ImageView) v.findViewById(R.id.pics);
}
}
}
@Override
public ViewHolder onCreateViewHolder(ViewGroup parent,
int viewType)
{
View v;
ViewHolder vh;
// create a new view
switch (viewType) {
case 0: //This would be the header view in my Recycler
v = LayoutInflater.from(parent.getContext())
.inflate(R.layout.recyclerview_welcome, parent, false);
vh = new ViewHolder(v,viewType);
return vh;
default: //This would be the normal list with the pictures of the places in the world
v = LayoutInflater.from(parent.getContext())
.inflate(R.layout.recyclerview_picture, parent, false);
vh = new ViewHolder(v, viewType);
v.setOnClickListener(new View.OnClickListener(){
@Override
public void onClick(View v) {
Intent intent = new Intent(mContext, nextActivity.class);
intent.putExtra("ListNo",mRecyclerView.getChildPosition(v));
mContext.startActivity(intent);
}
});
return vh;
}
}
//Overridden so that I can display custom rows in the recyclerview
@Override
public int getItemViewType(int position) {
int viewType = 1; //Default is 1
if (position == 0) viewType = 0; //If zero, it will be a header view
return viewType;
}
@Override
public void onBindViewHolder(ViewHolder holder, int position) {
//position == 0 means it's the info header view on the Recycler
if (position == 0) {
holder.name.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
Toast.makeText(mContext,"name clicked", Toast.LENGTH_SHORT).show();
}
});
holder.description.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
Toast.makeText(mContext,"description clicked", Toast.LENGTH_SHORT).show();
}
});
//This means it is beyond the headerview now as it is no longer 0. For testing purposes, I'm alternating between two pics for now
} else if (position > 0) {
holder.place.setText(mDataset[position]);
if (position % 2 == 0) {
holder.pics.setImageDrawable(mContext.getResources().getDrawable(R.drawable.pic1));
}
if (position % 2 == 1) {
holder.pics.setImageDrawable(mContext.getResources().getDrawable(R.drawable.pic2));
}
}
}
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;
}
}
是的，这是可能的。
在您的适配器getItemViewType布局如下....
public class MultiViewTypeAdapter extends RecyclerView.Adapter {
private ArrayList<Model>dataSet;
Context mContext;
int total_types;
MediaPlayer mPlayer;
private boolean fabStateVolume = false;
public static class TextTypeViewHolder extends RecyclerView.ViewHolder {
TextView txtType;
CardView cardView;
public TextTypeViewHolder(View itemView) {
super(itemView);
this.txtType = (TextView) itemView.findViewById(R.id.type);
this.cardView = (CardView) itemView.findViewById(R.id.card_view);
}
}
public static class ImageTypeViewHolder extends RecyclerView.ViewHolder {
TextView txtType;
ImageView image;
public ImageTypeViewHolder(View itemView) {
super(itemView);
this.txtType = (TextView) itemView.findViewById(R.id.type);
this.image = (ImageView) itemView.findViewById(R.id.background);
}
}
public static class AudioTypeViewHolder extends RecyclerView.ViewHolder {
TextView txtType;
FloatingActionButton fab;
public AudioTypeViewHolder(View itemView) {
super(itemView);
this.txtType = (TextView) itemView.findViewById(R.id.type);
this.fab = (FloatingActionButton) itemView.findViewById(R.id.fab);
}
}
public MultiViewTypeAdapter(ArrayList<Model>data, Context context) {
this.dataSet = data;
this.mContext = context;
total_types = dataSet.size();
}
@Override
public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View view;
switch (viewType) {
case Model.TEXT_TYPE:
view = LayoutInflater.from(parent.getContext()).inflate(R.layout.text_type, parent, false);
return new TextTypeViewHolder(view);
case Model.IMAGE_TYPE:
view = LayoutInflater.from(parent.getContext()).inflate(R.layout.image_type, parent, false);
return new ImageTypeViewHolder(view);
case Model.AUDIO_TYPE:
view = LayoutInflater.from(parent.getContext()).inflate(R.layout.audio_type, parent, false);
return new AudioTypeViewHolder(view);
}
return null;
}
@Override
public int getItemViewType(int position) {
switch (dataSet.get(position).type) {
case 0:
return Model.TEXT_TYPE;
case 1:
return Model.IMAGE_TYPE;
case 2:
return Model.AUDIO_TYPE;
default:
return -1;
}
}
@Override
public void onBindViewHolder(final RecyclerView.ViewHolder holder, final int listPosition) {
Model object = dataSet.get(listPosition);
if (object != null) {
switch (object.type) {
case Model.TEXT_TYPE:
((TextTypeViewHolder) holder).txtType.setText(object.text);
break;
case Model.IMAGE_TYPE:
((ImageTypeViewHolder) holder).txtType.setText(object.text);
((ImageTypeViewHolder) holder).image.setImageResource(object.data);
break;
case Model.AUDIO_TYPE:
((AudioTypeViewHolder) holder).txtType.setText(object.text);
}
}
}
@Override
public int getItemCount() {
return dataSet.size();
}
}
Android RecyclerView示例-多个视图类型
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。
