getArguments() returns null (Value from Adapter passed to Fragment)

Question

I know there are duplicate questions for this. But their problem is between Activity and Fragment . My problem is about passing a value from Adapter to Fragment.

I Toast the value from adapter and it shows the correct value. I used the putString and setArguments methods but it returns null.

Here is what I did in my Adapter:

 Bundle cart_bundle = new Bundle();
        cart_bundle.putString("total", String.valueOf(total_amount));
        Cart_Fragment fragment = new Cart_Fragment();
        fragment.setArguments(cart_bundle);
        ((User_Activity)context).getSupportFragmentManager().beginTransaction()
                .commit();

Here is how I receive the argument in Fragment :

Bundle cart_bundle = this.getArguments();
tv_total_amount.setText("Total Amount: "+ cart_bundle.getString("total"));

Maybe there is something wrong in ((User_Activity)context).getSupportFragmentManager().beginTransaction() .commit();

There is an error if I try to replace the User_Activity to Fragment.

P.S. I don't need to use replace() method because the adapter is an adapter for the list view in the fragment.

you create the new fragment, and don't use it. Why you do that? — Vladyslav Matviienko, Jul 11 '17 at 06:30
If you don't replace the current fragment, how will you use the new instance of `Cart_Fragment` that you created with the new arguments? — Kamran Ahmed, Jul 11 '17 at 06:31
@KamranAhmed can you tell me what should be my parameters inside the replace method? I tried adding replace(R.id.user_cart_fragment_container, fragment) but it made my fragment blank. — Trying to be Nerd, Jul 11 '17 at 06:43
@KamranAhmed I entirely changed my method. I didn't solve for the total in the fragment and solved it in the adapter. thanks for your help! — Trying to be Nerd, Jul 13 '17 at 06:51

Praveen Rawat · Answer 1 · 2017-07-11T09:42:44.017

The best and good way to pass the adapter is first you have pass the object of the class from where you create the adapter . suppose :-

Adapter adapter=new Adapter(activityname or fragmentname.class);

here on click of item In adapter class;-

adapter.updateData(xyz,abz)

will create the method in that Fragment.

IN Fragment , you have to make interface that will update the data or you can directly call fragment , here you get the how to pass data How to pass values between Fragments

or you can

Fragment fragment = new Fragment();
Bundle bundle = new Bundle();
bundle.putInt("total", String.valueOf(total_amount));
fragment.setArguments(bundle);

score 0 · Answer 2 · answered Jul 11 '17 at 06:23

0

The way you are getting the argument is wrong. Fragment has setArgument method which you need to override in your code and one your load your fragment you can call fragment instance and setargument.

So your fragment class will look like

public class Cart_Fragment extends Fragment{
    public void setArguments(Bundle args) {
         super.setArguments(args);
         //Get the argument here.
    }
}

Modify your adapter code as

Cart_Fragment fragment = new Cart_Fragment();
((User_Activity)context).getSupportFragmentManager().beginTransaction().commit();

Bundle cart_bundle = new Bundle();
cart_bundle.putString("total", String.valueOf(total_amount));
fragment.setArguments(cart_bundle);

answered Jul 11 '17 at 06:23

Rajen Raiyarela

5,526
4
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I will be receiving the value in Cart_Fragment. isn't it supposed to be getArguments instead of setArguments in public void setArguments()? sorry I'm confused. – Trying to be Nerd Jul 11 '17 at 06:28
oh i see. so it's an override. sorry will try this one. – Trying to be Nerd Jul 11 '17 at 06:29
it returns an error sir. "null object reference" when i tried to do total = Double.parseDouble(args.getString("total")); inside the setArguments() method. – Trying to be Nerd Jul 11 '17 at 06:36

Kamran Ahmed · Answer 3 · 2017-07-11T09:41:26.247

0

You are creating a new instance of Cart_Fragment, setting the new arguments to it but never using it. The instance being used (the one that was actually transacted to replace or add) and this new instance of the Fragment are not the same. Hence, you will not get the arguments in the existing Fragment magically.

What you can do instead is keep a reference of the Fragment you first transacted and pass the values to it using a custom method of your own like:

public class Cart_Fragment extends Fragment {
    public void setNewTotal(String total) {
         tv_total_amount.setText("Total Amount: " + total);
    }
}

And in your adapter:

fragment.setNewTotal(String.valueOf(total_amount));

If you have used the Fragment right in the XML like:

<fragment
    android:id="@+id/cart_fragment"
    android:name="com.example.Cart_Fragment"
    ...

you can get the instance of the fragment with:

Cart_Fragment fragment = ((Cart_Fragment) getSupportFragmentManager().findFragmentById(R.id.cart_fragment));

edited Jul 11 '17 at 09:41

answered Jul 11 '17 at 06:41

Kamran Ahmed

7,661
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sorry sir but the logcat says "Attempt to invoke virtual method on a null object reference" in the TextView – Trying to be Nerd Jul 11 '17 at 06:51
Did you do it on the fragment being used? Or did you create a new instance of it? – Kamran Ahmed Jul 11 '17 at 06:53
Cart_Fragment fragment = new Cart_Fragment(); fragment.setNewTotal(String.valueOf(total_amount)); – Trying to be Nerd Jul 11 '17 at 06:54
that's what I did sir. am I missing something? or is it wrong? – Trying to be Nerd Jul 11 '17 at 06:55
Yes. You are not supposed to do `new Cart_Fragment()` again, call that method on the instance that is already transacted. – Kamran Ahmed Jul 11 '17 at 07:48
How do you transact the fragment for the first time? Are you transacting it with Java code or have you declared it in the XML with `` tag? – Kamran Ahmed Jul 11 '17 at 07:50

getArguments() returns null (Value from Adapter passed to Fragment)

3 Answers3