如何從適配器訪問arrayList到活動？

Question

我在適配器中創建了一種方法。在這個方法中，我有一個數組列表。我想在一個活動中訪問這個arrayList。我怎樣才能做到這一點？

適配器：

public class InviteAdapter extends RecyclerView.Adapter<InviteAdapter.MyViewHolder> { 

    private ArrayList<Contact> contactArrayList; 
    private Context mContext; 

    public class MyViewHolder extends RecyclerView.ViewHolder { 
     public TextView name; 
     private CheckBox checkBox; 

     public MyViewHolder(View view) { 
      super(view); 
      name = (TextView) view.findViewById(R.id.textContactName); 
      checkBox = (CheckBox) view.findViewById(R.id.checkBox); 

     } 
    } 

    public InviteAdapter(Context context, ArrayList<Contact> contactArrayList) { 
     this.contactArrayList = contactArrayList; 
     this.mContext = context; 

    } 

    @Override 
    public MyViewHolder onCreateViewHolder(ViewGroup parent, int viewType) { 
     View itemView = LayoutInflater.from(parent.getContext()) 
       .inflate(R.layout.invite_contact_item, parent, false); 

     return new MyViewHolder(itemView); 
    } 

    @Override 
    public void onBindViewHolder(MyViewHolder holder, int position) { 
     Contact contact = contactArrayList.get(position); 
     holder.name.setText(contact.getmFullName()); 

     holder.checkBox.setChecked(contact.getSelected()); 
    } 

    @Override 
    public int getItemCount() { 
     return contactArrayList.size(); 
    } 



    public void toggleContactsSelection(boolean isSelected) { 
     for(Contact contact : contactArrayList) { 
      contact.setSelected(isSelected); 

      invite(contact); 
     } 
     notifyDataSetChanged(); // OR you can use notifyItemRangeChanged - which ever suits your needs 
    } 

    public void invite(Contact contact) 
    { 

     ArrayList<Invitation> invitationArrayList = new ArrayList<>(); 

     SharedPreferences sharedpreferences = mContext.getSharedPreferences("UserId", Context.MODE_PRIVATE); 

     String mUserId = sharedpreferences.getString("userId",""); 

     DateFormat df = new SimpleDateFormat("EEE, d MMM yyyy, HH:mm", Locale.ENGLISH); 
     String date = df.format(Calendar.getInstance().getTime()); 

     Invitation invitation = new Invitation(); 

     invitation.setSender_id(mUserId); 
     invitation.setDate(date); 
     invitation.setInvitee_no(contact.getmMobileNo()); 
     invitation.setStatus("0"); 
     invitation.setUser_name(contact.getmUserName()); 

     invitationArrayList.add(invitation); 
    } 
} 

我想邀請訪問數組列表，從邀請適配器的方法。

活動：

public class InviteContactsActivity extends AppCompatActivity { 

    private RecyclerView mRecyclerView; 
    private InviteAdapter mAdapter; 
    private ArrayList<Contact> mContactList; 
    private ContactTableHelper mContactDb; 
    private ArrayList<Invitation> invitationArrayList; 


    @Override 
    protected void onCreate(Bundle savedInstanceState) { 
     super.onCreate(savedInstanceState); 
     setContentView(R.layout.activity_invite_contacts); 


     final ImageView selectAll = (ImageView)findViewById(R.id.imageMenu); 

     selectAll.setOnClickListener(new View.OnClickListener() { 
      @Override 
      public void onClick(View view) { 

       PopupMenu popup = new PopupMenu(InviteContactsActivity.this,selectAll); 

       popup.getMenuInflater().inflate(R.menu.pop_up_menu, popup.getMenu()); 

       popup.setOnMenuItemClickListener(new PopupMenu.OnMenuItemClickListener() { 
        public boolean onMenuItemClick(MenuItem item) { 

         mAdapter.toggleContactsSelection(true); //Selects all contacts 
         return true; 
        } 
       }); 

       popup.show(); 
      } 
     }); 


     ImageView sendInvites = (ImageView)findViewById(R.id.imageSelect); 

     sendInvites.setOnClickListener(new View.OnClickListener() { 
      @Override 
      public void onClick(View view) { 

       Gson gson=new Gson(); 
       String toServer = gson.toJson(
         Collections.singletonMap("invitations", invitationArrayList) 
       ); 

       new SendMultipleInvitesAsyncTask(InviteContactsActivity.this).execute(toServer); 

      } 
     }); 

     mContactDb = new ContactTableHelper(InviteContactsActivity.this); 

     mContactList = mContactDb.getAllContacts(); 

     mRecyclerView = (RecyclerView) findViewById(R.id.recycler_view); 

     mRecyclerView.setHasFixedSize(true); 
     RecyclerView.LayoutManager mLayoutManager = new LinearLayoutManager(InviteContactsActivity.this); 
     mRecyclerView.setLayoutManager(mLayoutManager); 
     mRecyclerView.addItemDecoration(new DividerItemDecoration(this, LinearLayoutManager.VERTICAL)); 
     mRecyclerView.setItemAnimator(new DefaultItemAnimator()); 

     mAdapter = new InviteAdapter(InviteContactsActivity.this, mContactList); 
     mRecyclerView.setAdapter(mAdapter); 
    } 
} 

我想從一個適配器來sendInvite的onClickListener圖像視圖獲取邀請數組列表。

我該怎麼做？謝謝..

Answer 1

在適配器內寫入get方法，然後從您的活動中調用它。

public ArrayList<Object> getArrayList(){ 
    return yourArrayList; 
    } 

裏面的活動，你可以得到這個像，yourAdapterObject.getArrayList();

Answer 2

創建ivitearraylist如通過adpater在活動的公共和訪問。

ArrayList<Invitation> invitationArrayList = new ArrayList<>(); 

public void invite(Contact contact) 
    { 



     SharedPreferences sharedpreferences = mContext.getSharedPreferences("UserId", Context.MODE_PRIVATE); 

     String mUserId = sharedpreferences.getString("userId",""); 

     DateFormat df = new SimpleDateFormat("EEE, d MMM yyyy, HH:mm", Locale.ENGLISH); 
     String date = df.format(Calendar.getInstance().getTime()); 

     Invitation invitation = new Invitation(); 

     invitation.setSender_id(mUserId); 
     invitation.setDate(date); 
     invitation.setInvitee_no(contact.getmMobileNo()); 
     invitation.setStatus("0"); 
     invitation.setUser_name(contact.getmUserName()); 

     invitationArrayList.add(invitation); 
    } 

活動代碼： 訪問invitationArrayList爲adapter.invitationArrayList。

ImageView sendInvites = (ImageView)findViewById(R.id.imageSelect); 

     sendInvites.setOnClickListener(new View.OnClickListener() { 
      @Override 
      public void onClick(View view) { 

       Gson gson=new Gson(); 
       String toServer = gson.toJson(
         Collections.singletonMap("invitations", mAdpater.invitationArrayList) 
       ); 

       new SendMultipleInvitesAsyncTask(InviteContactsActivity.this).execute(toServer); 

      } 
     }); 

它可能對你有幫助:)

編碼快樂:)

Answer 3

您還可以使用接口從adpater類的數據發送到活動。 它在下面的鏈接中被精美地描述。

Pass Data from adapter to activity using interface