如何从片段类到适配器类访问方法

Question

I want to use reloadTransList() method in the onClick function in the adapter class. This is the method in a fragment class.

translistTab.java

public void reloadTransList() {
    productTransList.clear();
    transRecyclerView.getAdapter().notifyDataSetChanged();
    loadTransList();
}

And this is how I called it in the adapter class.

prodAdapter.java

translistTab translistTab = new translistTab();
translistTab.reloadTransList();

EDIT:

The method now is being called. But the loadproducts(); is not working without errors. The loadproducts() method is the loading of products in recyclerview. The method is running, but the recyclerview is not reloading.

Answer 1

Maybe you forgot to add setOnCLickListner(this) in your ViewHolder inner class in the adapter. If you add this, you would be able to call reloadTransList() from onClick() method.

Answer 2

A short answer is to pass the fragment into your adapter via constructor or setter.

A longer, better answer is to define a custom interface that gets implemented by your fragment and passed into your adapter. The implemented interface will contain your reloadTransList() method

EDIT

I don't know exactly how your classes are setup, but the long solution would look something like the following.

First, define a interface.

public interface MyCustomInterface {
    void onCustomAction();
}

The exact implementation can vary depending on your needs.

Next, in your fragment class, implement the interface. Place the reloadTransList() method inside.

public class MyFragment extends Fragment implements MyCustomInterface {
    // All your other, unrelated Fragment code

    @Override
    public void onCustomAction() {
        reloadTransList();
    }
}

Now, in your adapter class. Pass the Interface (not the Fragment) into the adapter and assign it to an instance variable. I personally prefer to do that via constructor:

public class prodAdapter extends Adapter { // I'm only assuming the adapter you are using. It has no relevance to this

    private MyCustomInterface customInterface;

    public prodAdapter(MyCustomInterface customInterface) {
        this.customInterface = customInterface;
    }
}

From there, simply call customInterface.onCustomAction() wherever you need the reloadTransList() method fired.

The short solution is just like the above code, except with just the fragment and no interface. Strongly recommend you go the long way. Especially for testing purposes.

EDIT #2

Another advantage to the long solution is you can re-use the adapter in another class without changing it. For your other fragments using the adapter, implement the MyCustomInterface .

public class AnotherFragment extends Fragment implements MyCustomInterface {
    @Override
    public void onCustomAction() {
        // Put whatever you need here. Or nothing.
    }
}

This allows the adapter to be re-used across multiple fragments.