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[英]How to access LayoutManager from RecyclerView.Adapter to get scrollToPosition?
[英]How to call scrollToPosition(position) inside recyclerView's adapter?
我的setOnClick
有一个setOnClick
侦听onBindViewHolder
@Override
public void onBindViewHolder(final RecyclerView.ViewHolder holder, final int position) {
((ViewHolder) holder).txtType.setText(object.text);
((ViewHolder) holder).checkBox.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
Toast.makeText(mContext, ""+position, Toast.LENGTH_SHORT).show();
//???.scrolltoPosition(position+1);
}
});
单击时,我会将视口滚动到下一个回收站视图项。 我已经通过recyclerView.scrollToPosition(position);
在我的 MainActivity java 中完成了这项工作recyclerView.scrollToPosition(position);
. 但是在 onBindViewHolder 上的适配器类中,我不知道如何在主 Java 类上调用我的 recyclerView。
我该怎么做?
编辑:为简化起见,我修改了之前的代码,因为我为我的回收器使用了多视图适配器。 这是多视图适配器:
public class MultiViewTypeAdapter extends RecyclerView.Adapter {
private ArrayList<InstructionModel>dataSet;
Context mContext;
int total_types;
private LinearLayoutManager manager;
public MultiViewTypeAdapter(LinearLayoutManager manager)
{
this.manager=manager;
}
public static class SimpleTextViewHolder extends RecyclerView.ViewHolder {
TextView txtType;
CardView cardView;
CheckBox checkBox;
public SimpleTextViewHolder(View itemView) {
super(itemView);
this.txtType = (TextView) itemView.findViewById(R.id.type);
this.cardView = (CardView) itemView.findViewById(R.id.card_view);
this.checkBox = (CheckBox) itemView.findViewById(R.id.checkBox);
}
}
public static class TimeTextViewHolder extends RecyclerView.ViewHolder {
TextView txtType;
CardView cardView;
CheckBox checkBox;
public TimeTextViewHolder(View itemView) {
super(itemView);
this.txtType = (TextView) itemView.findViewById(R.id.type);
this.cardView = (CardView) itemView.findViewById(R.id.card_view);
this.checkBox = (CheckBox) itemView.findViewById(R.id.checkBox);
}
}
public MultiViewTypeAdapter(ArrayList<InstructionModel> 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 InstructionModel.SIMPLE_TYPE:
view = LayoutInflater.from(parent.getContext()).inflate(R.layout.simple, parent, false);
return new SimpleTextViewHolder(view);
case InstructionModel.TIME_TYPE:
view = LayoutInflater.from(parent.getContext()).inflate(R.layout.time, parent, false);
return new TimeTextViewHolder(view);
}
return null;
}
@Override
public int getItemViewType(int position) {
switch (dataSet.get(position).type) {
case 0:
return InstructionModel.SIMPLE_TYPE;
case 1:
return InstructionModel.TIME_TYPE;
default: return -1;
}
}
@Override
public void onBindViewHolder(final RecyclerView.ViewHolder holder, final int listPosition) {
InstructionModel object = dataSet.get(listPosition);
if (object != null) {
switch (object.type) {
case InstructionModel.SIMPLE_TYPE:
((SimpleTextViewHolder) holder).txtType.setText(object.text);
break;
case InstructionModel.TIME_TYPE:
((TimeTextViewHolder) holder).txtType.setText(object.text);
break;
}
}
}
@Override
public int getItemCount() {
return dataSet.size();
}
PS如果你看到一些随机无用的东西,我正在尝试一些东西。
使用构造函数传递LayoutManger
class Adapter extends RecyclerView.Adapter<Adapter.ViewHolder> {
private LinearLayoutManager manager;
public Adapter(LinearLayoutManager manager)
{
this.manager=manager;
}
@Override
public void onBindViewHolder(final RecyclerView.ViewHolder holder, final int position) {
((ViewHolder) holder).txtType.setText(object.text);
((ViewHolder) holder).checkBox.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
Toast.makeText(mContext, ""+position, Toast.LENGTH_SHORT).show();
manager.scrollToPosition(position+1);
}
});
}
我觉得你应该定义一个接口来通知你的父RecyclerView做滚动操作,把RecyclerView放到ViewHodler里面操作,导致耦合
您可以在构造函数中传递一个侦听器对象,该对象由 Fragment OR Activity 实现。
/**
* item click interface of adapter
*/
public interface MultiViewTypeAdapterListener {
void onScroll(int position)
}
该接口由 Fragment OR Activity 实现
/**
* On Scroll Implement Method from adapter listener.
*
* @param position
*/
@Override
public void onScroll(int position) {
// Here you can call that method
recyclerview.scrolltoPosition(position)
}
然后在适配器的构造函数中传递这个监听器。
private void buildRecyclerView() {
multiViewTypeAdapter = new MultiViewTypeAdapter(this);
recyclerView.setAdapter(multiViewTypeAdapter);
}
在构造函数中,您可以像这样分配
private MultiViewTypeAdapterListener mMultiViewTypeAdapterListener;
public OfferAdapter(MultiViewTypeAdapterListener mMultiViewTypeAdapterListener) {
this.mMultiViewTypeAdapterListener = mMultiViewTypeAdapterListener
}
}
现在您可以通过在 anyViwe 上设置单击侦听器来使用此侦听器
((ViewHolder) holder).checkBox.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
Toast.makeText(mContext, ""+position, Toast.LENGTH_SHORT).show();
//???.scrolltoPosition(position+1);
mMultiViewTypeAdapterListener.onScroll(position+1);
}
});
它返回调用实现该方法的 onItemClick 方法。
private int getScrollRange() {
int scrollRange = 0;
if (parent.getChildCount() > 0) {
View child = parent.getChildAt(0);
scrollRange = Math.max(0,
child.getHeight() - (parent.getHeight()));
}
return scrollRange;
}
ScrollView parent=findViewById(R.id.scroll_Recipe_Detail);
parent.scrollTo(0,getScrollRange());
如果要滚动添加的新项目,则必须覆盖“onItemsAdded”。 这是我如何做到的:
recyclerView.apply {
setHasFixedSize(true)
layoutManager = MyLinearLayoutManager(this@MainActivity)
...
}
private class MyLinearLayoutManager(private val context: Context) :
LinearLayoutManager(context) {
// Force new items appear at the top
override fun onItemsAdded(recyclerView: RecyclerView, positionStart: Int, itemCount: Int) {
super.onItemsAdded(recyclerView, positionStart, itemCount)
scrollToPosition(findLastVisibleItemPosition())
}
}
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