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?
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
为不同的布局创建不同的ViewHolder
RecyclerView可以有任意数量的viewholders，但为了更好的可读性，让我们看看如何创建一个有两个viewholders的viewholders。
这可以通过三个简单的步骤来完成
覆盖公共int getItemViewType(int position)
在onCreateViewHolder()方法中根据ViewType返回不同的ViewHolders
根据onBindViewHolder()方法中的itemViewType填充视图
下面是一小段代码片段:
public class YourListAdapter extends RecyclerView.Adapter<RecyclerView.ViewHolder> {
private static final int LAYOUT_ONE = 0;
private static final int LAYOUT_TWO = 1;
@Override
public int getItemViewType(int position)
{
if(position==0)
return LAYOUT_ONE;
else
return LAYOUT_TWO;
}
@Override
public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View view = null;
RecyclerView.ViewHolder viewHolder = null;
if(viewType==LAYOUT_ONE)
{
view = LayoutInflater.from(parent.getContext()).inflate(R.layout.one,parent,false);
viewHolder = new ViewHolderOne(view);
}
else
{
view = LayoutInflater.from(parent.getContext()).inflate(R.layout.two,parent,false);
viewHolder= new ViewHolderTwo(view);
}
return viewHolder;
}
@Override
public void onBindViewHolder(RecyclerView.ViewHolder holder, final int position) {
if(holder.getItemViewType() == LAYOUT_ONE)
{
// Typecast Viewholder
// Set Viewholder properties
// Add any click listener if any
}
else {
ViewHolderOne vaultItemHolder = (ViewHolderOne) holder;
vaultItemHolder.name.setText(displayText);
vaultItemHolder.name.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
.......
}
});
}
}
//**************** VIEW HOLDER 1 ******************//
public class ViewHolderOne extends RecyclerView.ViewHolder {
public TextView name;
public ViewHolderOne(View itemView) {
super(itemView);
name = (TextView)itemView.findViewById(R.id.displayName);
}
}
//**************** VIEW HOLDER 2 ******************//
public class ViewHolderTwo extends RecyclerView.ViewHolder {
public ViewHolderTwo(View itemView) {
super(itemView);
..... Do something
}
}
}
getItemViewType(int position)是键。
在我看来，创建这种recyclerView的起点是这个方法的知识。因为这个方法是可选的，所以默认情况下它在RecylerView类中是不可见的，这使得许多开发人员(包括我)不知道从哪里开始。
一旦您知道了这个方法的存在，创建这样的RecyclerView将是小菜一菜。
让我们看一个例子来证明我的观点。如果你想显示两个布局
在交替的位置上这样做
@Override
public int getItemViewType(int position)
{
if(position%2==0) // Even position
return LAYOUT_ONE;
else // Odd position
return LAYOUT_TWO;
}
相关链接:
看看我已经实现了这个项目。
