在Xamarin android中使用RecyclerView的Contextual Action Bar？

Question

任何人都可以告訴如何實施RecyclerView上下文操作欄上的龍舌蘭ListAtem選擇上xamarin android？

Answer 1

任何人都可以告訴如何實現RecyclerView上下文動作欄上的ListItem選擇上的長龍的android xamarin？

以Xamarin Official RecyclerViewer例如，你可以按照下面的步驟來實現對recyclerview上下文操作欄：

1. 爲你的動作條創建一個簡單的菜單資源（Resource/menu/ContextualMenu）：

   <?xml version="1.0" encoding="utf-8" ?> 
   <menu xmlns:android="http://schemas.android.com/apk/res/android"> 
       <item android:id="@+id/itemOneId" 
       android:title="Item One"/> 
       <item android:id="@+id/itemTwoId" 
       android:title="Item Two" /> 
   </menu> 
   

2. 創建班級（MyActionMode）器具ActionMode.ICallBack：

   public class MyActionMode : Java.Lang.Object, ActionMode.ICallback 
   { 
       private Context mContext; 
       public MyActionMode(Context context) 
       { 
        mContext = context; 
       } 
   
       public bool OnActionItemClicked(ActionMode mode, IMenuItem item) 
       { 
        switch (item.ItemId) 
        { 
         case Resource.Id.itemOneId: 
          // do whatever you want 
          return true; 
         case Resource.Id.itemTwoId: 
          // do whatever you want 
          return true; 
         default: 
          return false; 
        } 
       } 
   
       public bool OnCreateActionMode(ActionMode mode, IMenu menu) 
       { 
        mode.MenuInflater.Inflate(Resource.Menu.ContextualMenu, menu); 
        return true; 
       } 
   
       public void OnDestroyActionMode(ActionMode mode) 
       { 
        mode.Dispose(); 
       } 
   
       public bool OnPrepareActionMode(ActionMode mode, IMenu menu) 
       { 
        return false; 
       } 
   } 
   

3. 在PhotoViewHolder修改構造函數接受長按操作：

   public PhotoViewHolder (View itemView, Action<int> listener,Action<object,View.LongClickEventArgs> longClickListener) 
       : base (itemView) 
   { 
       // Locate and cache view references: 
       Image = itemView.FindViewById<ImageView> (Resource.Id.imageView); 
       Caption = itemView.FindViewById<TextView> (Resource.Id.textView); 
   
       // Detect user clicks on the item view and report which item 
       // was clicked (by position) to the listener: 
       itemView.Click += (sender, e) => listener (base.Position); 
       ItemView.LongClick +=(sender,e)=> longClickListener(sender,e); 
   } 
   

4. 修改PhotoAlbumAdapter這樣的：

   public class PhotoAlbumAdapter : RecyclerView.Adapter 
   { 
       ... 
       // add this variable 
       private Activity mActivity; 
   
       // 
       private MyActionMode mActionMode; 
   
       ... 
       // add this constructor 
       public PhotoAlbumAdapter(PhotoAlbum photoAlbum, Activity activity) 
       { 
        mPhotoAlbum = photoAlbum; 
        mActivity = activity; 
       } 
   
   
       //add this function 
       void OnLongClick(object sender, View.LongClickEventArgs args) 
       { 
        mActionMode = new MyActionMode(mActivity); 
        mActivity.StartActionMode(mActionMode); 
        ((View)sender).Selected = true; 
        return; 
       } 
       ... 
   } 
   

5. 在MainActivity變化PhotoAlbumAdapter創建以使用新創建構造函數：

   mAdapter = new PhotoAlbumAdapter (mPhotoAlbum,this); 
   

這裏是complete modified demo。