有人使用RecyclerView找到了一种方法来设置一个onClickListener的项目在RecyclerView? 我想设置一个监听器为每个项目的布局,但这似乎有点太麻烦了 我确信有一种方法让RecyclerView监听onClick事件,但我不能完全弄清楚。
当前回答
这是我的自定义适配器的完整代码,这段代码将用XML文件“list_item”中定义的列表项膨胀行,它还将在具有各自位置的所有列表项行上执行单击事件。
public class MyCustomAdapter extends RecyclerView.Adapter`<`AdapterMyCustomAdapter.ViewHolder> {
public static class ViewHolder extends RecyclerView.ViewHolder implements OnClickListener {
public onItemClickListener mListener;
public ViewHolder(View v, onItemClickListener listener) {
super(v);
mListener =listener;
v.setOnClickListener(this);
}
@Override
public void onClick(View v) {
mListener.onRecyclerItemClick(v, getPosition());
}
public static interface onItemClickListener {
public void onRecyclerItemClick(View view , int position);
}
}
@Override
public int getItemCount() {
return 5;
}
@Override
public void onBindViewHolder(ViewHolder holder, int pos) {
}
@Override
public ViewHolder onCreateViewHolder(ViewGroup parent, int position) {
View v = LayoutInflater.from(parent.getContext())
.inflate(R.layout.list_item, parent, false);
/* here list_item is an xml file we want to inflate ...it is same as we do in case of listview for customization.*/
MyCustomAdapter.ViewHolder vh = new ViewHolder(v, new MyCustomAdapter.ViewHolder.onItemClickListener() {
@Override
public void onRecyclerItemClick(View view, int position) {
System.out.println("clicked on list item at position " +position);
}
});
return vh;
}
}
其他回答
这里有一个更好的和不那么紧密耦合的方式来实现一个OnClickListener的RecyclerView。
用法片段:
RecyclerView recyclerView = findViewById(R.id.recycler);
recyclerView.addOnItemTouchListener(
new RecyclerItemClickListener(context, recyclerView ,new RecyclerItemClickListener.OnItemClickListener() {
@Override public void onItemClick(View view, int position) {
// do whatever
}
@Override public void onLongItemClick(View view, int position) {
// do whatever
}
})
);
RecyclerItemClickListener实现:
import android.content.Context;
import android.support.v7.widget.RecyclerView;
import android.view.GestureDetector;
import android.view.MotionEvent;
import android.view.View;
public class RecyclerItemClickListener implements RecyclerView.OnItemTouchListener {
private OnItemClickListener mListener;
public interface OnItemClickListener {
public void onItemClick(View view, int position);
public void onLongItemClick(View view, int position);
}
GestureDetector mGestureDetector;
public RecyclerItemClickListener(Context context, final RecyclerView recyclerView, OnItemClickListener listener) {
mListener = listener;
mGestureDetector = new GestureDetector(context, new GestureDetector.SimpleOnGestureListener() {
@Override
public boolean onSingleTapUp(MotionEvent e) {
return true;
}
@Override
public void onLongPress(MotionEvent e) {
View child = recyclerView.findChildViewUnder(e.getX(), e.getY());
if (child != null && mListener != null) {
mListener.onLongItemClick(child, recyclerView.getChildAdapterPosition(child));
}
}
});
}
@Override public boolean onInterceptTouchEvent(RecyclerView view, MotionEvent e) {
View childView = view.findChildViewUnder(e.getX(), e.getY());
if (childView != null && mListener != null && mGestureDetector.onTouchEvent(e)) {
mListener.onItemClick(childView, view.getChildAdapterPosition(childView));
return true;
}
return false;
}
@Override public void onTouchEvent(RecyclerView view, MotionEvent motionEvent) { }
@Override
public void onRequestDisallowInterceptTouchEvent (boolean disallowIntercept){}
}
让我们看看如何在Jetpack / AndroidX中实现这一点
你需要像这样在viewmodel类中创建一个观察对象
private MutableLiveData<Integer> adapterItem = new MutableLiveData<>();
public MutableLiveData<Integer> getAdapterItem() {
return adapterItem;
}
public void setAdapterItem(int adapterItem) {
this.getAdapterItem().setValue(adapterItem);
}
然后在适配器类中,确保将viewmodel引用作为构造函数的参数传递,然后在vieholder上实现clicklistener
public MyViewHolder(@NonNull View itemView) {
super(itemView);
if(itemView != null){
itemView.setOnClickListener(v -> {
int adapterPosition = getAdapterPosition();
viewModel.setAdapterItem(adapterPosition);
});
};
}
然后从活动课上观察变化
viewModel.getAdapterItem().observe(this, position -> {
Log.w(TAG, "clicked: " + ridesArray.get(position));
});
不幸的是,RecyclerView缺少ListView内置的几个功能。 例如,添加OnItemClickListener的能力,当一个项目被单击时触发。 RecyclerView允许你在适配器中设置一个OnClickListener,但是传递那个点击 从你的调用代码,到适配器,再到ViewHolder,监听器是复杂的 要捕捉一个简单的项目单击。
public class ItemClickSupport {
private final RecyclerView mRecyclerView;
private OnItemClickListener mOnItemClickListener;
private OnItemLongClickListener mOnItemLongClickListener;
private View.OnClickListener mOnClickListener = new View.OnClickListener() {
@Override
public void onClick(View v) {
if (mOnItemClickListener != null) {
RecyclerView.ViewHolder holder = mRecyclerView.getChildViewHolder(v);
mOnItemClickListener.onItemClicked(mRecyclerView, holder.getAdapterPosition(), v);
}
}
};
private View.OnLongClickListener mOnLongClickListener = new View.OnLongClickListener() {
@Override
public boolean onLongClick(View v) {
if (mOnItemLongClickListener != null) {
RecyclerView.ViewHolder holder = mRecyclerView.getChildViewHolder(v);
return mOnItemLongClickListener.onItemLongClicked(mRecyclerView, holder.getAdapterPosition(), v);
}
return false;
}
};
private RecyclerView.OnChildAttachStateChangeListener mAttachListener
= new RecyclerView.OnChildAttachStateChangeListener() {
@Override
public void onChildViewAttachedToWindow(View view) {
if (mOnItemClickListener != null) {
view.setOnClickListener(mOnClickListener);
}
if (mOnItemLongClickListener != null) {
view.setOnLongClickListener(mOnLongClickListener);
}
}
@Override
public void onChildViewDetachedFromWindow(View view) {
}
};
private ItemClickSupport(RecyclerView recyclerView) {
mRecyclerView = recyclerView;
mRecyclerView.setTag(R.id.item_click_support, this);
mRecyclerView.addOnChildAttachStateChangeListener(mAttachListener);
}
public static ItemClickSupport addTo(RecyclerView view) {
ItemClickSupport support = (ItemClickSupport) view.getTag(R.id.item_click_support);
if (support == null) {
support = new ItemClickSupport(view);
}
return support;
}
public static ItemClickSupport removeFrom(RecyclerView view) {
ItemClickSupport support = (ItemClickSupport) view.getTag(R.id.item_click_support);
if (support != null) {
support.detach(view);
}
return support;
}
public ItemClickSupport setOnItemClickListener(OnItemClickListener listener) {
mOnItemClickListener = listener;
return this;
}
public ItemClickSupport setOnItemLongClickListener(OnItemLongClickListener listener) {
mOnItemLongClickListener = listener;
return this;
}
private void detach(RecyclerView view) {
view.removeOnChildAttachStateChangeListener(mAttachListener);
view.setTag(R.id.item_click_support, null);
}
public interface OnItemClickListener {
void onItemClicked(RecyclerView recyclerView, int position, View v);
}
public interface OnItemLongClickListener {
boolean onItemLongClicked(RecyclerView recyclerView, int position, View v);
}
}
您还需要定义R.id。使用ids.xml:
<?xml version="1.0" encoding="utf-8"?>
<resources>
<item name="item_click_support" type="id" />
</resources>
结果代码点击侦听器现在看起来像这样:
ItemClickSupport.addTo(mRecyclerView).setOnItemClickListener(new ItemClickSupport.OnItemClickListener() {
@Override
public void onItemClicked(RecyclerView recyclerView, int position, View v) {
// do it
}
});
关于recyclerview点击的简要说明,请看看这个littlerobots_blog
很简单,添加这个类:
public class OnItemClickListener implements View.OnClickListener {
private int position;
private OnItemClickCallback onItemClickCallback;
public OnItemClickListener(int position, OnItemClickCallback onItemClickCallback) {
this.position = position;
this.onItemClickCallback = onItemClickCallback;
}
@Override
public void onClick(View view) {
onItemClickCallback.onItemClicked(view, position);
}
public interface OnItemClickCallback {
void onItemClicked(View view, int position);
}
}
获取一个'OnItemClickCallback'接口实例,并把它放在你的activity或fragment中:
private OnItemClickListener.OnItemClickCallback onItemClickCallback = new OnItemClickListener.OnItemClickCallback() {
@Override
public void onItemClicked(View view, int position) {
}
};
然后,将这个回调传递给你的recyclerView:
recyclerView.setAdapter(new SimpleStringRecyclerViewAdapter(Arrays.asList("1", "2", "3"), onItemClickCallback));
最后,这将是你的适配器:
public class SimpleStringRecyclerViewAdapter extends RecyclerView.Adapter<SimpleStringRecyclerViewAdapter.ViewHolder> {
private List<String> mValues;
private OnItemClickListener.OnItemClickCallback onItemClickCallback;
public SimpleStringRecyclerViewAdapter(List<String> items, OnItemClickListener.OnItemClickCallback onItemClickCallback) {
mValues = items;
this.onItemClickCallback = onItemClickCallback;
}
public static class ViewHolder extends RecyclerView.ViewHolder {
public final TextView mTextView;
public ViewHolder(View view) {
super(view);
mTextView = (TextView) view.findViewById(R.id.txt_title);
}
}
@Override
public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.list_item, parent, false);
return new ViewHolder(view);
}
@Override
public void onBindViewHolder(final ViewHolder holder, final int position) {
holder.mTextView.setText(mValues.get(position));
holder.mTextView.setOnClickListener(new OnItemClickListener(position, onItemClickCallback));
}
@Override
public int getItemCount() {
return mValues.size();
}
}
这就是重用View的方法。OnClickListener:
public class TestAdapter extends RecyclerView.Adapter<TestAdapter.MyviewHolder>
implements View.OnClickListener
在ViewHoder中获取项目布局的父视图:
public class MyviewHolder extends RecyclerView.ViewHolder {
LinearLayout linearLayout;
public MyviewHolder(View itemView) {
super(itemView);
linearLayout = itemView.findViewById(R.id.linear_layout_item);
}
}
在onBindViewHolder中设置标签为位置:
@Override
public void onBindViewHolder(MyviewHolder holder, int position) {
holder.linearLayout.setTag(position);
holder.linearLayout.setOnClickListener(this);
}
在你的onClick实现中:
@Override
public void onClick(View v) {
int position = (int) v.getTag();
switch (v.getId()) {
case R.id.linear_layout_item:
// do some thing with position
break;
}
}
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