Calling a method from Activity in Adapter

Question

I am using Retrofit to load data from my server in a RecyclerView. I have successfully implement the Get, and Post Retrofit methods but I am facing some problems for the Put and Delete ones. Since ReclyclerView requires an Adapter to load the data, and I need to get the position of the row that I am clicking, I had to implement the onKeyPressed (because I am using and EditText) inside my Adapter.

The problem is that the method that calls my Interceptor, the Retrofit call and Everything is in my Activity. So i decided to call the method from this Activity inside my Adapter to do the Put and Delete of a singular item. But I am getting a

java.lang.ClassCastException saying that the method cannot be casted to the Adapter.

This is the onKeyPressed method, ViewCategoryActivity si my Activity and SendNetworkRequest is my method:

holder.nameCategory.setOnKeyListener(new View.OnKeyListener() {
            public boolean onKey(View v, int keyCode, KeyEvent event) {
                // If the event is a key-down event on the "enter" button
                if ((event.getAction() == KeyEvent.ACTION_DOWN) &&
                        (keyCode == KeyEvent.KEYCODE_ENTER)) {

                    System.out.println("Entrou no adapter!!");
                    Category2 category = new Category2();
                    category.setName(holder.nameCategory.getText().toString());
                    ((ViewCategoriesActivity)mContext).SendNetworkRequest(categoryList.get(position).getProjectId(), 2, categoryList.get(position).get_id(), new SendCategory(holder.nameCategory.getText().toString()));

                    //Variable to check if the category inserted is equal to a previous one
                    int bool = 0;
                    //The for goes through the list and tries to find a category with the name equal to the one inserted
                    for (int i = 0; i < categoryList.size(); i++){

                        //if it finds equal names bool = 1
                        if (categoryList.get(i).getName().equals(holder.nameCategory.getText().toString())){
                            bool = 1;
                            Toast.makeText(mContext, mContext.getResources().getString(R.string.category_different_name),
                                    Toast.LENGTH_LONG).show();
                        }
                    }

                    //There's no category with the same name so it' OK so insert a new one
                    if (bool == 0){

                        if(mContext instanceof ViewCategoriesActivity){
                            ((ViewCategoriesActivity)mContext).SendNetworkRequest(categoryList.get(position).getProjectId(), 2, categoryList.get(position).get_id(), new SendCategory(holder.nameCategory.getText().toString()));
                        }
                        //categoryList.add(category);

                    } else {

                    }


                    // hide virtual keyboard
                    InputMethodManager imm =
                            (InputMethodManager)mContext.getSystemService(Context.INPUT_METHOD_SERVICE);
                    imm.hideSoftInputFromWindow(holder.nameCategory.getWindowToken(), 0);
                    return true;
                }
                return false;
            }
        });

How can I do that using callback? Would you mind explain it to me? — Marcos Guimaraes, Sep 01 '17 at 16:01
SendNetworkRequest is the method that I was not able to cast. — Marcos Guimaraes, Sep 01 '17 at 16:02

score 1 · Accepted Answer · answered Sep 01 '17 at 14:53

1

You should be passing a listener from your activity to the adapter. You should be then using that listener to call the function in your activity. i.e, if you are calling your adapter like the following,

adapter = new DataAdapter(data);

where data can be an arraylist(suppose), then pass the context like this

adapter = new DataAdapter(data,ViewCategoriesActivity.this);

Accept this listener using a constructor in your adapter and then call your activity function like listener.yourFunction()

answered Sep 01 '17 at 14:53

Navneet Krishna

5,009
5
25
44

I didn't understand your answer, could you explain it to me a little bit more? – Marcos Guimaraes Sep 01 '17 at 16:01
in your activity : adapter = new DataAdapter(data,ViewCategoriesActivity.this); in your adapter class : public DataAdapter(String data, Activity activity){ } – CharlesAE Sep 01 '17 at 16:05
and then wherever needed call activity.SendNetworkRequest() – Navneet Krishna Sep 01 '17 at 16:09
I am calling my adapter like this: adapter = new CategoryAdapter(getApplicationContext(), listCategories); – Marcos Guimaraes Sep 01 '17 at 16:32
It worked by calling it like this: adapter = new CategoryAdapter(ViewCategoriesActivity.this, listCategories); Could you explain the difference for me? – Marcos Guimaraes Sep 01 '17 at 16:37
instead of getApplicationContext() use ViewCategoriesActivity.this , please post your complete adapter class – Navneet Krishna Sep 01 '17 at 16:38
by passing ViewCategoriesActivity.this, you can now have access to this activity's context in your adapter and hence you can use the funtions in your adapter – Navneet Krishna Sep 01 '17 at 16:41
:) glad that it helped – Navneet Krishna Sep 01 '17 at 16:54

score 0 · Answer 2 · answered Sep 01 '17 at 15:26

0

You can do it using the listener easily, try not to make your code that complex. As per i know your problem has good answer here, hope it will work.

answered Sep 01 '17 at 15:26

TankRaj

89
7

Calling a method from Activity in Adapter

2 Answers2