如何实现RecyclerView?
显然调用的上下文菜单registerForContextMenu(recyclerView)
不起作用。我从一个片段中调用它。有没有人成功实施这个?
21 回答
感谢您的信息和评论。我能够ContextMenu
在Recyclerview
.
这是我所做的
在 Fragment 的onViewCreated
方法或 Activity 的onCreate
方法中:
registerForContextMenu(mRecyclerView);
然后在适配器中添加
private int position;
public int getPosition() {
return position;
}
public void setPosition(int position) {
this.position = position;
}
使ViewHolder
类实现OnCreateContextMenuListener
public static class ViewHolder extends RecyclerView.ViewHolder
implements View.OnCreateContextMenuListener {
public ImageView icon;
public TextView fileName;
public ImageButton menuButton;
public ViewHolder(View v) {
super(v);
icon = (ImageView)v.findViewById(R.id.file_icon);
fileName = (TextView)v.findViewById(R.id.file_name);
menuButton = (ImageButton)v.findViewById(R.id.menu_button);
v.setOnCreateContextMenuListener(this);
}
@Override
public void onCreateContextMenu(ContextMenu menu, View v,
ContextMenu.ContextMenuInfo menuInfo) {
//menuInfo is null
menu.add(Menu.NONE, R.id.ctx_menu_remove_backup,
Menu.NONE, R.string.remove_backup);
menu.add(Menu.NONE, R.id.ctx_menu_restore_backup,
Menu.NONE, R.string.restore_backup);
}
}
onBindViewHolder
在 holder.itemView 上添加方法OnLongClickListener
以在加载上下文菜单之前捕获位置:
holder.itemView.setOnLongClickListener(new View.OnLongClickListener() {
@Override
public boolean onLongClick(View v) {
setPosition(holder.getPosition());
return false;
}
});
然后onViewRecycled
删除侦听器,以免出现引用问题。(可能不需要)。
@Override
public void onViewRecycled(ViewHolder holder) {
holder.itemView.setOnLongClickListener(null);
super.onViewRecycled(holder);
}
最后在 Fragment/Activity 中覆盖onContextItemSelected
如下:
@Override
public boolean onContextItemSelected(MenuItem item) {
int position = -1;
try {
position = ((BackupRestoreListAdapter)getAdapter()).getPosition();
} catch (Exception e) {
Log.d(TAG, e.getLocalizedMessage(), e);
return super.onContextItemSelected(item);
}
switch (item.getItemId()) {
case R.id.ctx_menu_remove_backup:
// do your stuff
break;
case R.id.ctx_menu_restore_backup:
// do your stuff
break;
}
return super.onContextItemSelected(item);
}
您不能直接实现这些方法,如onClickListener、 OnContextMenuListener等,因为RecycleView扩展了android.view.ViewGroup。所以我们不能直接使用这些方法。我们可以在ViewHolder适配器类中实现这些方法。我们可以像这样在 RecycleView 中使用上下文菜单:
public static class ViewHolder extends RecyclerView.ViewHolder implements OnCreateContextMenuListener {
TextView tvTitle;
ImageView ivImage;
public ViewHolder(View v) {
super(v);
tvTitle =(TextView)v.findViewById(R.id.item_title);
v.setOnCreateContextMenuListener(this);
}
}
现在我们在实现上下文菜单时遵循相同的过程。
@Override
public void onCreateContextMenu(ContextMenu menu, View v, ContextMenuInfo menuInfo) {
menu.setHeaderTitle("Select The Action");
menu.add(0, v.getId(), 0, "Call");//groupId, itemId, order, title
menu.add(0, v.getId(), 0, "SMS");
}
如果您遇到任何困难,请在评论中提问。
目前的答案是不正确的。这是一个有效的实现:
public class ContextMenuRecyclerView extends RecyclerView {
private RecyclerViewContextMenuInfo mContextMenuInfo;
@Override
protected ContextMenu.ContextMenuInfo getContextMenuInfo() {
return mContextMenuInfo;
}
@Override
public boolean showContextMenuForChild(View originalView) {
final int longPressPosition = getChildPosition(originalView);
if (longPressPosition >= 0) {
final long longPressId = getAdapter().getItemId(longPressPosition);
mContextMenuInfo = new RecyclerViewContextMenuInfo(longPressPosition, longPressId);
return super.showContextMenuForChild(originalView);
}
return false;
}
public static class RecyclerViewContextMenuInfo implements ContextMenu.ContextMenuInfo {
public RecyclerViewContextMenuInfo(int position, long id) {
this.position = position;
this.id = id;
}
final public int position;
final public long id;
}
}
在您的片段(或活动)中:
@Override
public void onViewCreated(View view, @Nullable Bundle savedInstanceState) {
super.onViewCreated(view, savedInstanceState);
mRecyclerView = view.findViewById(R.id.recyclerview);
registerForContextMenu(mRecyclerView);
}
@Override
public void onCreateContextMenu(ContextMenu menu, View v, ContextMenu.ContextMenuInfo menuInfo) {
super.onCreateContextMenu(menu, v, menuInfo);
// inflate menu
MenuInflater inflater = getActivity().getMenuInflater();
inflater.inflate(R.menu.my_context_menu, menu);
}
@Override
public boolean onContextItemSelected(MenuItem item) {
return super.onContextItemSelected(item);
RecyclerViewContextMenuInfo info = (RecyclerViewContextMenuInfo) item.getMenuInfo();
// handle menu item here
}
最后,在您的 ViewHolder 中:
class MyViewHolder extends RecyclerView.View.ViewHolder {
...
private void onLongClick() {
itemView.showContextMenu();
}
}
试试这个View
recycleView中的一个项目
.setOnCreateContextMenuListener(new View.OnCreateContextMenuListener() {
@Override
public void onCreateContextMenu(ContextMenu menu, View v, ContextMenu.ContextMenuInfo menuInfo) {
menu.add("delete").setOnMenuItemClickListener(new MenuItem.OnMenuItemClickListener() {
@Override
public boolean onMenuItemClick(MenuItem item) {
//do what u want
return true;
}
});
}
});
您可以将它与将数据设置为ViewHolder
项目一起使用
Prabhakar的回答是正确的,但他没有解释如何在选择上下文菜单项时获取与按下的项目相关的数据。我们可以使用onContextItemSelected
回调,但在这种情况下ContextMenuInfo
不可用(null
)(如果getContextMenuInfo()
方法未被按下视图覆盖)。因此,最简单的解决方案是OnMenuItemClickListener
直接添加到MenuItem
.
private class ViewHolder extends RecyclerView.ViewHolder {
private final TextView mTitleTextView;
private MyItemData mData;
public ViewHolder(View view) {
super(view);
mTitleTextView = (TextView)view.findViewById(R.id.title);
view.setOnCreateContextMenuListener(mOnCreateContextMenuListener);
}
public void bind(@NonNull MyItemData data) {
mData = data;
String title = mData.getTitle();
mTitleTextView.setText(title);
}
private final View.OnCreateContextMenuListener mOnCreateContextMenuListener = new View.OnCreateContextMenuListener() {
@Override
public void onCreateContextMenu(ContextMenu menu, View v, ContextMenu.ContextMenuInfo menuInfo) {
if (mData!= null) {
MenuItem myActionItem = menu.add("My Context Action");
myActionItem.setOnMenuItemClickListener(mOnMyActionClickListener);
}
}
};
private final MenuItem.OnMenuItemClickListener mOnMyActionClickListener = new MenuItem.OnMenuItemClickListener() {
@Override
public boolean onMenuItemClick(MenuItem item) {
//todo: process item click, mData is available here!!!
return true;
}
};
}
这是在 RecyclerView 项目上使用菜单上下文的干净方法
首先,您需要一个项目位置
在适配器类中:
/**
* Custom on long click item listener.
*/
onLongItemClickListener mOnLongItemClickListener;
public void setOnLongItemClickListener(onLongItemClickListener onLongItemClickListener) {
mOnLongItemClickListener = onLongItemClickListener;
}
public interface onLongItemClickListener {
void ItemLongClicked(View v, int position);
}
在onBindViewHolder
挂钩自定义侦听器中:
// Hook our custom on long click item listener to the item view.
holder.itemView.setOnLongClickListener(new View.OnLongClickListener() {
@Override
public boolean onLongClick(View v) {
if (mOnLongItemClickListener != null) {
mOnLongItemClickListener.ItemLongClicked(v, position);
}
return true;
}
});
在 MainActivity (Activity/Fragment) 创建一个字段:
private int mCurrentItemPosition;
在您的 Adapter 对象中设置自定义侦听器:
mAdapter.setOnLongItemClickListener(new FileAdapter.onLongItemClickListener() {
@Override
public void ItemLongClicked(View v, int position) {
mCurrentItemPosition = position;
}
});
现在,您长时间单击的任何项目都有一个美味的位置
第二,创建你的菜单
在 res -> menu
创建一个包含您的菜单项的文件context_menu_main.xml
:
<?xml version="1.0" encoding="utf-8"?>
<menu xmlns:android="http://schemas.android.com/apk/res/android">
<item android:id="@+id/delete" android:title="Delete"/>
<item android:id="@+id/share" android:title="Share"/>
</menu>
在 MainActivity 中:
同时实现onCreateContextMenu
和onContextItemSelected
:
@Override
public void onCreateContextMenu(ContextMenu menu, View v, ContextMenu.ContextMenuInfo menuInfo) {
MenuInflater inflater = getMenuInflater();
inflater.inflate(R.menu.context_menu_main, menu);
}
@Override
public boolean onContextItemSelected(MenuItem item) {
int id = item.getItemId();
if (id == R.id.delete) {
}
if (id == R.id.share) {
}
return true;
}
三、回到你的 Adapter 对象
- 注册您的上下文菜单。
显示上下文菜单。
registerForContextMenu(mRecyclerView); mAdapter.setOnLongItemClickListener(new FileAdapter.onLongItemClickListener() { @Override public void ItemLongClicked(View v, int position) { mCurrentItemPosition = position; v.showContextMenu(); } });
希望我不会忘记任何事情
更多信息在菜单文档
@Renaud's answer worked for me but required several code fixes first. It's like he posted snippets from several different iterations of his code. The changes that need to be made are:
RecyclerContextMenuInfo
andRecyclerViewContextMenuInfo
are the same class. Pick a name and stick with it.- The
ViewHolder
must implementView.OnLongClickListener
, and remember to callsetOnLongClickListener()
on the item in the constructor. - In the
onLongClick()
listener,getView().showContextMenu()
is completely wrong. You must callshowContextMenuForChild()
in yourContextMenuRecyclerView
, otherwise theContextMenuInfo
you get inonCreateContextMenu()
andonContextItemSelected()
will be null.
My edited code below:
ContextMenuRecyclerView:
public class ContextMenuRecyclerView extends RecyclerView {
private RecyclerViewContextMenuInfo mContextMenuInfo;
@Override
protected ContextMenu.ContextMenuInfo getContextMenuInfo() {
return mContextMenuInfo;
}
@Override
public boolean showContextMenuForChild(View originalView) {
final int longPressPosition = getChildPosition(originalView);
if (longPressPosition >= 0) {
final long longPressId = getAdapter().getItemId(longPressPosition);
mContextMenuInfo = new RecyclerViewContextMenuInfo(longPressPosition, longPressId);
return super.showContextMenuForChild(originalView);
}
return false;
}
public static class RecyclerViewContextMenuInfo implements ContextMenu.ContextMenuInfo {
public RecyclerViewContextMenuInfo(int position, long id) {
this.position = position;
this.id = id;
}
final public int position;
final public long id;
}
}
In your fragment:
@Override
public void onViewCreated(View view, @Nullable Bundle savedInstanceState) {
super.onViewCreated(view, savedInstanceState);
mRecyclerView = view.findViewById(R.id.recyclerview);
registerForContextMenu(mRecyclerView);
}
@Override
public void onCreateContextMenu(ContextMenu menu, View v, ContextMenu.ContextMenuInfo menuInfo) {
super.onCreateContextMenu(menu, v, menuInfo);
// inflate menu here
// If you want the position of the item for which we're creating the context menu (perhaps to add a header or something):
int itemIndex = ((ContextMenuRecyclerView.RecyclerViewContextMenuInfo) menuInfo).position;
}
@Override
public boolean onContextItemSelected(MenuItem item) {
ContextMenuRecyclerView.RecyclerViewContextMenuInfo info = (ContextMenuRecyclerView.RecyclerViewContextMenuInfo) item.getMenuInfo();
// handle menu here - get item index or ID from info
return super.onContextItemSelected(item);
}
In your ViewHolder:
class MyViewHolder extends RecyclerView.ViewHolder implements View.OnLongClickListener {
public MyViewHolder( View itemView ) {
super( itemView );
itemView.setOnLongClickListener( this );
}
@Override public boolean onLongClick() {
recyclerView.showContextMenuForChild( v );
return true;
}
}
Also, make sure you replace RecyclerView
with ContextMenuRecyclerView
in your layout!
这是一种对我有用的使用 Kotlin 的更简单方法。主要的挑战是弄清楚被按下的项目的位置。在您的适配器中,您可以放置此代码片段,它将能够捕获为其显示上下文菜单的项目的位置;就这样。
override fun onBindViewHolder(holder: YourViewHolder, position: Int) {
...
holder.view.setOnCreateContextMenuListener { contextMenu, _, _ ->
contextMenu.add("Add").setOnMenuItemClickListener {
longToast("I'm pressed for the item at position => $position")
true
}
}
}
对于那些想要在调用时获取项目 IDContextMenu
的人的解决方案。
如果您有这样的RecyclerView
项目(包含 clickable ImageView
):
那么您应该收到来自onClickListener
.
适配器
class YourAdapter(private val contextMenuCallback: ContextMenuCallback) :
RecyclerView.Adapter<YourAdapter.ViewHolder>() {
private var items: MutableList<Item> = mutableListOf()
...
override fun onBindViewHolder(viewHolder: ViewHolder, position: Int) {
val item = items[position] as Item
updateItem(viewHolder, item)
setOnClickListener(viewHolder.itemView, items[position].id, items[position].title)
}
private fun setOnClickListener(view: View, id: Int, title: String) {
// view.setOnClickListener { v -> }
// A click listener for ImageView `more`.
view.more.setOnClickListener {
// Here we pass item id, title, etc. to Fragment.
contextMenuCallback.onContextMenuClick(view, id, title)
}
}
class ViewHolder(itemView: View) : RecyclerView.ViewHolder(itemView) {
val titleTextView: TextView = itemView.title
}
class Item(
val id: Int,
val title: String
)
interface ContextMenuCallback {
fun onContextMenuClick(view: View, id: Int, title: String)
}
}
分段
class YourFragment : Fragment(), YourAdapter.ContextMenuCallback {
private var adapter: YourAdapter? = null
private var linearLayoutManager: LinearLayoutManager? = null
private var selectedItemId: Int = -1
private lateinit var selectedItemTitle: String
override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
super.onViewCreated(view, savedInstanceState)
adapter = YourAdapter(this)
view.recycler_view.apply {
layoutManager = linearLayoutManager
adapter = this@YourFragment.adapter
setHasFixedSize(true)
}
registerForContextMenu(view.recycler_view)
}
override fun onCreateContextMenu(menu: ContextMenu?, v: View?,
menuInfo: ContextMenu.ContextMenuInfo?) {
activity?.menuInflater?.inflate(R.menu.menu_yours, menu)
}
override fun onContextItemSelected(item: MenuItem?): Boolean {
super.onContextItemSelected(item)
when (item?.itemId) {
R.id.action_your -> yourAction(selectedItemId, selectedItemTitle)
...
}
return true
}
override fun onContextMenuClick(view: View, id: Int, title: String) {
// Here we accept item id, title from adapter and show context menu.
selectedItemId = id
selectedItemTitle = title
view.showContextMenu()
}
}
警告!
如果您使用ViewPager
基于一个片段(所有页面都是相似列表),您将面临一个问题。当您覆盖onContextItemSelected
以了解选择了哪个菜单项时,您将从第一页获得一个列表项 id!要克服此问题,请参阅ViewPager 中的错误片段接收 onContextItemSelected 调用。
我可能迟到了,但我有一个可行的解决方案。我已经为它做了一个要点。
活动名称.java
//Import Statements
public class ActivityName extends AppCompatActivity {
private RecyclerView mRecyclerView;
private RecyclerView.Adapter mAdapter;
private RecyclerView.LayoutManager mLayoutManager;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_view_birthdays);
//Recycle View
mRecyclerView = (RecyclerView) findViewById(R.id.my_recycler_view);
mLayoutManager = new LinearLayoutManager(getApplicationContext());
mRecyclerView.setLayoutManager(mLayoutManager);
mAdapter = new BirthdaysListAdapter(data, this);
mRecyclerView.setAdapter(mAdapter);
}
RecyclerAdapter.java
//Import Statements
public class BirthdaysListAdapter extends RecyclerView.Adapter<BirthdaysListAdapter.ViewHolder> {
static Context ctx;
private List<typeOfData> Data;
public BirthdaysListAdapter(List<typeOfData> list, Context context) {
Data = list;
this.ctx = context;
}
BirthdaysListAdapter() {
}
public static class ViewHolder extends RecyclerView.ViewHolder implements View.OnCreateContextMenuListener {
public TextView name;
public TextView Birthday;
public ImageView colorAlphabet;
public TextView textInImg;
public ViewHolder(View v) {
super(v);
name = (TextView) v.findViewById(R.id.name);
Birthday = (TextView) v.findViewById(R.id.Birthday);
colorAlphabet = (ImageView) v.findViewById(R.id.colorAlphabet);
textInImg = (TextView) v.findViewById(R.id.textInImg);
v.setOnCreateContextMenuListener(this); //REGISTER ONCREATE MENU LISTENER
}
@Override
public void onCreateContextMenu(ContextMenu menu, View v //CREATE MENU BY THIS METHOD
ContextMenu.ContextMenuInfo menuInfo) {
new BirthdaysListAdapter().info = (AdapterView.AdapterContextMenuInfo) menuInfo;
MenuItem Edit = menu.add(Menu.NONE, 1, 1, "Edit");
MenuItem Delete = menu.add(Menu.NONE, 2, 2, "Delete");
Edit.setOnMenuItemClickListener(onEditMenu);
Delete.setOnMenuItemClickListener(onEditMenu);
}
//ADD AN ONMENUITEM LISTENER TO EXECUTE COMMANDS ONCLICK OF CONTEXT MENU TASK
private final MenuItem.OnMenuItemClickListener onEditMenu = new MenuItem.OnMenuItemClickListener() {
@Override
public boolean onMenuItemClick(MenuItem item) {
DBHandler dbHandler = new DBHandler(ctx);
List<WishMen> data = dbHandler.getWishmen();
switch (item.getItemId()) {
case 1:
//Do stuff
break;
case 2:
//Do stuff
break;
}
return true;
}
};
}
public List<ViewBirthdayModel> getData() {
return Data;
}
@Override
public long getItemId(int position) {
return super.getItemId(position);
}
@Override
public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.row_view_birthdays, parent, false);
ViewHolder vh = new ViewHolder(view);
return vh;
}
@Override
public void onBindViewHolder(final ViewHolder holder, int position) {
holder.name.setText(Data.get(position).getMan().getName());
holder.Birthday.setText(Data.get(position).getMan().getBday());
holder.colorAlphabet.setBackgroundColor(Color.parseColor(Data.get(position).getColor()));
holder.textInImg.setText(String.valueOf(Data.get(position).getMan().getName().toUpperCase().charAt(0)));
}
@Override
public int getItemCount() {
return Data.size();
}
private int position;
public int getPosition() {
return position;
}
public void setPosition(int position) {
this.position = position;
}
}
我将我的解决方案与@Hardik Shah 的解决方案相结合:
在活动中我有:
@Override
public void onCreateContextMenu(ContextMenu menu, View v, ContextMenu.ContextMenuInfo menuInfo) {
super.onCreateContextMenu(menu, v, menuInfo);
if (v.getId() == R.id.rvQuests) {
getMenuInflater().inflate(R.menu.list_menu, menu);
}
}
在适配器中我有:
private MainActivity context;
private int position;
public int getPosition() {
return position;
}
public void setPosition(int position) {
this.position = position;
}
public QuestsAdapter(MainActivity context, List<Quest> objects) {
this.context = context;
this.quests.addAll(objects);
}
public class QuestViewHolder extends RecyclerView.ViewHolder {
private QuestItemBinding questItemBinding;
public QuestViewHolder(View v) {
super(v);
questItemBinding = DataBindingUtil.bind(v);
v.setOnCreateContextMenuListener(context);
}
}
@Override
public void onBindViewHolder(final QuestViewHolder holder, int position) {
Quest quest = quests.get(position);
holder.questItemBinding.setQuest(quest);
holder.itemView.setOnLongClickListener(new View.OnLongClickListener() {
@Override
public boolean onLongClick(View v) {
setPosition(holder.getAdapterPosition());
return false;
}
});
}
@Override
public void onViewRecycled(QuestViewHolder holder) {
holder.itemView.setOnLongClickListener(null);
super.onViewRecycled(holder);
}
在片段中我有:
@Override
public boolean onContextItemSelected(MenuItem item) {
int position = ((QuestsAdapter) questsList.getAdapter()).getPosition();
switch (item.getItemId()) {
case R.id.menu_delete:
Quest quest = questsAdapter.getItem(position);
App.getQuestManager().deleteQuest(quest);
questsAdapter.remove(quest);
checkEmptyList();
return true;
default:
return super.onContextItemSelected(item);
}
}
以下是如何为 RecyclerView 实现上下文菜单,并获取已选择上下文菜单项的项目位置:
public class YourAdapter extends RecyclerView.Adapter<YourAdapter.ViewHolder> {
...
@Override
public void onBindViewHolder(@NonNull final ViewHolder viewHolder, int position) {
...
viewHolder.itemView.setOnCreateContextMenuListener(new View.OnCreateContextMenuListener() {
@Override
public void onCreateContextMenu(ContextMenu menu, View v, ContextMenu.ContextMenuInfo menuInfo) {
menu.add(0, R.id.mi_context_disable, 0, R.string.text_disable)
.setOnMenuItemClickListener(new MenuItem.OnMenuItemClickListener() {
@Override
public boolean onMenuItemClick(MenuItem item) {
// can do something with item at position given below,
// viewHolder is final
viewHolder.getAdapterPosition();
return true;
}
});
menu.add(0, R.id.mi_context_remove, 1, R.string.text_remove)
.setOnMenuItemClickListener(new MenuItem.OnMenuItemClickListener() {
@Override
public boolean onMenuItemClick(MenuItem item) {
// can do something with item at position given below,
// viewHolder is final
viewHolder.getAdapterPosition();
return true;
}
});
}
});
}
static class ViewHolder extends RecyclerView.ViewHolder {
private View itemView;
private ViewHolder(@NonNull View itemView) {
super(itemView);
this.itemView = itemView;
}
}
}
我已经使用这个解决方案一段时间了,对我来说效果很好。
public class CUSTOMVIEWNAME extends RecyclerView {
public CUSTOMVIEWNAME(Context context) {
super(context);
}
public CUSTOMVIEWNAME (Context context, AttributeSet attrs) {
super(context, attrs);
}
public CUSTOMVIEWNAME (Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
}
private RecyclerContextMenuInfo mContextMenuInfo;
@Override
protected ContextMenu.ContextMenuInfo getContextMenuInfo() {
return mContextMenuInfo;
}
@Override
public boolean showContextMenuForChild(View originalView) {
final int longPressPosition = getChildAdapterPosition(originalView);
if (longPressPosition >= 0) {
final long longPressId = getAdapter().getItemId(longPressPosition);
mContextMenuInfo = new RecyclerContextMenuInfo(longPressPosition, ` longPressId);
return super.showContextMenuForChild(originalView);
}
return false;
}
public class RecyclerContextMenuInfo implements ContextMenu.ContextMenuInfo {
public RecyclerContextMenuInfo(int position, long id) {
this.position = position;
this.id = id;
}
final public int position;
final public long id;
}
}
现在在您的片段或活动中实现以下方法。
@Override
public void onCreateContextMenu(ContextMenu menu, View v, ContextMenu.ContextMenuInfo menuInfo) {
super.onCreateContextMenu(menu, v, menuInfo);
// Inflate Menu from xml resource
MenuInflater menuInflater = getMenuInflater();
menuInflater.inflate(R.menu.context_menu, menu);
}
@Override
public boolean onContextItemSelected(MenuItem item) {
ContextMenuRecyclerView.RecyclerContextMenuInfo info = (ContextMenuRecyclerView.RecyclerContextMenuInfo) item.getMenuInfo();
Toast.makeText(InstanceOfContext , " User selected " + info.position, Toast.LENGTH_LONG).show();
return false;
}
最后在 recyclerview 上注册 contextMenu
//for showing a popup on LongClick of items in recycler.
registerForContextMenu(recyclerView);
那应该工作!
大家好,我提出了一种对我有用的替代方案。我只是用 registerContextMenu y ViewHolder 构造函数注册了我的 itemView,还将 onLongClikcListener 设置为同一个视图。在 onLongClick(View v) 实现中,我简单地使用 getLayoutPosition() 获取点击位置并保存在一个实例变量中(我创建了一个类来表示此数据,就像 ContextMenuInfo 预期工作一样),但更重要的是让确保在此方法中返回false 。您现在要做的就是在 onContextItemSelected(MenuItem item) 上,读取您存储在实例变量中的数据,如果它有效,则继续执行您的操作。这是一个片段。
public MyViewHolder(View itemView){
super(itemView);
registerForContextMenu(itemView);
itemView.setOnLongClickListener(this);
}
我让 ViewHolder 实现 OnLongClickListener,但你可以用任何你喜欢的方式来做。
@Override
public boolean onLongClick(View v){
mCurrentLongItem = new ListItemInfo(v.getId(), getLayoutPosition());
return false; // REMEMBER TO RETURN FALSE.
}
您也可以在适配器中设置它,或在 ViewHolder 中设置另一个视图(即 TextView)。重要的是 onLongClik() 实现。
@Override
public boolean onContextItemSelected(MenuItem item) {
switch (item.getItemId()){
case R.id.client_edit_context_menu:
if(mCurrentLongItem != null){
int position = mCurrentLongItem.position;
//TAKE SOME ACTIONS.
mCurrentLongItem = null;
}
return true;
}
return super.onContextItemSelected(item);
}
最好的部分是您仍然可以在您想要的情况下处理返回 true 的 LongClick 事件,并且 conextMenu 不会出现。
该方法之所以有效,是因为 registerForContextView 使 View LongClickable,并且在处理 ContextMenu 时,系统调用 performLongClick,它首先调用 onLongClick 实现,如果返回 false,则调用 showContextMenu。
我一直在努力解决这个问题,因为 Android 在 RecyclerView 中不能很好地为我处理这个问题,这对 ListView 来说效果很好。
最困难的部分是 ContextMenuInfo 部分嵌入在 View 中,除了覆盖 View 之外,您无法轻松附加它。
因此,您将需要一个包装器来帮助您将位置信息传递给 Activity。
public class RecyclerContextMenuInfoWrapperView extends FrameLayout {
private RecyclerView.ViewHolder mHolder;
private final View mView;
public RecyclerContextMenuInfoWrapperView(View view) {
super(view.getContext());
setLayoutParams(new ViewGroup.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.MATCH_PARENT));
mView = view;
addView(mView);
}
public void setHolder(RecyclerView.ViewHolder holder) {
mHolder = holder;
}
@Override
protected ContextMenu.ContextMenuInfo getContextMenuInfo() {
return new RecyclerContextMenuInfo(mHolder.getPosition(), mHolder.getItemId());
}
public static class RecyclerContextMenuInfo implements ContextMenu.ContextMenuInfo {
public RecyclerContextMenuInfo(int position, long id) {
this.position = position;
this.id = id;
}
final public int position;
final public long id;
}
}
然后在你的 RecyclerAdapter 中,当你创建 ViewHolders 时,你需要将 Wrapper 设置为根视图,并在每个视图上注册 contextMenu。
public static class AdapterViewHolder extends RecyclerView.ViewHolder {
public AdapterViewHolder( View originalView) {
super(new RecyclerContextMenuInfoWrapperView(originalView);
((RecyclerContextMenuInfoWrapperView)itemView).setHolder(this);
yourActivity.registerForContextMenu(itemView);
itemView.setOnCreateContextMenuListener(yourListener);
}
}
最后,在您的活动中,您将能够做您通常做的事情:
@Override
public boolean onContextItemSelected(MenuItem item) {
int position = ((RecyclerContextMenuInfoWrapperView.RecyclerContextMenuInfo)item.getMenuInfo()).position;
// do whatever you need as now you have access to position and id and everything
最好将上下文菜单与回收器视图一起使用,如果您制作自定义回收器视图并覆盖该getContextMenuInfo()
方法并返回您自己的上下文菜单信息对象实例,以便您可以在创建它时获取位置以及单击菜单时:
@Override
protected ContextMenu.ContextMenuInfo getContextMenuInfo() {
return mContextMenuInfo;
}
看看我创建的这个要点:
就我而言,我必须在方法中使用我的片段中的数据onContextItemSelected()
。我最终采用的解决方案是将片段实例传递到我的适配器并在视图持有者中注册视图项:
@Override
public void onBindViewHolder(final MyListAdapter.ViewHolder viewHolder, int position) {
final Object rowObject = myListItems.get(position);
// Do your data binding here
viewHolder.itemView.setTag(position);
fragment.registerForContextMenu(viewHolder.itemView);
}
然后,onCreateContextMenu()
您可以将索引保存到局部变量:
selectedViewIndex = (int)v.getTag();
并将其检索到onContextItemSelected()
当我第一次使用普通适配器遇到这个问题时,我最终创建了自己的自定义 View 子类并将我需要的东西存储在其中。我真的不喜欢那个解决方案,花了很多时间研究人们提出的好主意,并决定我不喜欢它们了。所以我把所有东西都放在一起,摇晃了一会儿,然后拿出了一些我喜欢的新东西。
我们从几个实用程序类开始。ContextMenuHandler 是用于处理上下文菜单的任何对象的接口。在实践中,这将是一个 ViewHolder 子类,但理论上它可以是任何东西
/**
* Interface for objects that wish to create and handle selections from a context
* menu associated with a view
*/
public interface ContextMenuHandler extends View.OnCreateContextMenuListener {
boolean onContextItemSelected(MenuItem item);
}
接下来是一个接口,它必须由将用作 RecyclerView 的直接子级的任何 View 实现。
public interface ViewWithContextMenu {
public void setContextMenuHandler(FragmentWithContextMenu fragment, ContextMenuHandler handler);
public ContextMenuHandler getContextMenuHandler();
}
接下来,任何要创建上下文菜单作为 RecylcerView 子级的视图都必须实现 ViewWIthContextMenu。在我的例子中,我只需要一个 LinearLayout 的子类。
public class LinearLayoutWithContextMenu extends LinearLayout implements ViewWithContextMenu {
public LinearLayoutWithContextMenu(Context context) {
super(context);
}
public LinearLayoutWithContextMenu(Context context, AttributeSet attrs) {
super(context, attrs);
}
private ContextMenuHandler handler;
@Override
public void setContextMenuHandler(FragmentWithContextMenu fragment, ContextMenuHandler handler) {
this.handler = handler;
setOnCreateContextMenuListener(fragment);
}
@Override
public ContextMenuHandler getContextMenuHandler() {
return handler;
}
}
最后,我们需要一个增强的 Fragment 类来拦截上下文菜单调用并将它们重定向到适当的处理程序。
public class FragmentWithContextMenu extends Fragment {
ContextMenuHandler handler = null;
@Override
public void onCreateContextMenu(ContextMenu menu, View view, ContextMenu.ContextMenuInfo menuInfo) {
super.onCreateContextMenu(menu, view, menuInfo);
handler = null;
if (view instanceof ViewWithContextMenu) {
handler = ((ViewWithContextMenu)view).getContextMenuHandler();
if (handler != null) handler.onCreateContextMenu(menu, view, menuInfo);
}
}
@Override
public boolean onContextItemSelected(MenuItem item) {
if (handler != null) {
if (handler.onContextItemSelected(item)) return true;
}
return super.onContextItemSelected(item);
}
}
有了所有这些,最终的实现就非常简单了。主片段必须是 FragmentWithContextMenu 的子类。它正常设置主 RecylerWindow 并将自身传递给 Adapter 子类。适配器子类看起来像
public class Adapter extends RecyclerView.Adapter<Adapter.ViewHolder> {
private final FragmentWithContextMenu fragment;
Adapter(FragmentWithContextMenu fragment) {
this.fragment = fragment;
}
@Override
public Adapter.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View view = LayoutInflater.from(context)
.inflate(R.layout.child_view, parent, false);
return new ViewHolder(view);
}
@Override
public void onBindViewHolder(final Adapter.ViewHolder holder, int position) {
// Logic needed to bind holder to specific position
// ......
}
@Override
public int getItemCount() {
// Logic to return current item count
// ....
}
public class ViewHolder extends RecyclerView.ViewHolder implements ContextMenuHandler {
ViewHolder(View view) {
super(view);
((ViewWithContextMenu)view).setContextMenuHandler(fragment, this);
view.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
// Do stuff to handle simple clicks on child views
// .......
}
});
}
@Override
public void onCreateContextMenu(ContextMenu menu, View v, ContextMenu.ContextMenuInfo menuInfo) {
// Logic to set up context menu goes here
// ....
}
@Override
public boolean onContextItemSelected(MenuItem item) {
// Logic to handle context menu item selections goes here
// ....
return true;
}
}
}
就是这样。这一切似乎都在起作用。它将所有实用程序类放在一个单独的 contextmenu 包中,因此我可以给出与子类匹配的类名称,但我认为会更令人困惑。
您可以在绑定时将 OnCreateContextMenuListener 传递给 ViewHolder。此侦听器可以为每个数据项创建自定义菜单。只需在 ViewHolder 中添加 setOnCreateContextMenuListener 并在绑定期间调用它。
public static class ItemViewHolder extends RecyclerView.ViewHolder
{
public ItemViewHolder(View itemView) {
super(itemView);
}
void setOnCreateContextMenuListener(View.OnCreateContextMenuListener listener) {
itemView.setOnCreateContextMenuListener(listener);
}
}
在适配器中:
@Override
public void onBindViewHolder(ItemViewHolder viewHolder,
int position) {
final MyObject myObject = mData.get(position);
viewHolder.setOnCreateContextMenuListener(new OnCreateContextMenuListener(){
@Override
public void onCreateContextMenu(ContextMenu menu,
View v, ContextMenuInfo menuInfo) {
switch (myObject.getMenuVariant() {
case MNU_VARIANT_1:
menu.add(Menu.NONE, CTX_MNU_1,
Menu.NONE,R.string.ctx_menu_item_1);
menu.add(Menu.NONE, CTX_MNU_2,Menu.NONE, R.string.ctx_menu_item_2);
break;
case MNU_VARIANT_2:
menu.add(Menu.NONE, CTX_MNU_3,Menu.NONE, R.string.ctx_menu_item_3);
break;
default:
menu.add(Menu.NONE, CTX_MNU_4,
Menu.NONE, R.string.ctx_menu_item_4);
}
}
});
}
扩展上面的一些答案,如果您想避免在 Adaptor/ViewHolder 的代码中手动定义菜单,那么您可以使用 PopupMenu 并从标准 menu.xml 资源文件中扩充菜单选项。
下面的示例显示了这一点,包括传入一个侦听器的能力,您可以在片段/活动中实现该侦听器以响应上下文菜单单击。
public class CustomAdapter extends RecyclerView.Adapter<CustomAdapter.ViewHolder> {
private List<CustomObject> objects;
private OnItemSelectedListener listener;
private final boolean withContextMenu;
class ViewHolder extends RecyclerView.ViewHolder
implements View.OnClickListener, View.OnCreateContextMenuListener, PopupMenu.OnMenuItemClickListener {
@BindView(R.id.custom_name)
TextView name;
@BindView(R.id.custom_value)
TextView value;
ViewHolder(View view) {
super(view);
ButterKnife.bind(this, view);
view.setOnClickListener(this);
if (withContextMenu) {
view.setOnCreateContextMenuListener(this);
}
}
@Override
public void onClick(View v) {
int position = getAdapterPosition();
if (listener != null) {
listener.onCustomerSelected(objects.get(position));
}
}
@Override
public void onCreateContextMenu(ContextMenu menu, View v, ContextMenu.ContextMenuInfo menuInfo) {
PopupMenu popup = new PopupMenu(v.getContext(), v);
popup.getMenuInflater().inflate(R.menu.custom_menu, popup.getMenu());
popup.setOnMenuItemClickListener(this);
popup.show();
}
@Override
public boolean onMenuItemClick(MenuItem item) {
if (listener != null) {
CustomObject object = objects.get(getAdapterPosition());
listener.onCustomerMenuAction(object, item);
}
return false;
}
}
public CustomerAdapter(List<CustomObject> objects, OnItemSelectedListener listener, boolean withContextMenu) {
this.listener = listener;
this.objects = objects;
this.withContextMenu = withContextMenu;
}
public interface OnItemSelectedListener {
void onSelected(CustomObject object);
void onMenuAction(CustomObject object, MenuItem item);
}
@Override
public CustomerAdapter.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View v = LayoutInflater.from(parent.getContext()).inflate(R.layout.snippet_custom_object_line, parent, false);
return new ViewHolder(v);
}
@Override
public void onBindViewHolder(CustomAdapter.ViewHolder holder, int position) {
CustomObject object = objects.get(position);
holder.name.setText(object.getName());
holder.value.setText(object.getValue());
}
@Override
public int getItemCount() {
return objects.size();
}
}
完整的要点在这里 https://gist.github.com/brettwold/45039b7f02ce752ae0d32522a8e2ad9c
好的,根据@Flexo 的回答,我将订购 mPosition ...
protected class ExampleViewHolder extends RecyclerView.ViewHolder implements View.OnCreateContextMenuListener {
int mPosition;
public KWViewHolder(View itemView) {
super(itemView);
itemView.setOnCreateContextMenuListener(this);
}
public void setPosition(int position) {
mPosition = position;
}
@Override
public void onCreateContextMenu(ContextMenu contextMenu, View view, ContextMenu.ContextMenuInfo contextMenuInfo) {
contextMenu.setHeaderTitle(R.string.menu_title_context);
contextMenu.add(0, R.id.menu_delete, mPosition, R.string.delete);
}
}
然后在onContextItemSelected我使用
item.getOrder()
一切正常我很容易得到数组的位置