Adding fragments to activity

Question

First of all, I read everything here. https://developer.android.com/guide/components/fragments.html

I have one activity and I want to divide the screen horizontally and add 2 fragments. I know how to add fragments on XML but I don't want that. I want to add them on Java.

So the problem is FragmentManager doesnt work unless my activity extends Fragment. Should I do that on the activity or should I add fragment transaction methods on one of the fragments?

If I extend my activity to Fragment, does it also become a fragment?

If I put the fragmentmanager and fragmenttransaction on one of the fragments how can I make the connection with activity?

this is the activity which I want my fragments displayed on

import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentTransaction;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;

public class ConversionActivity extends AppCompatActivity {

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

        NumpadFragment fragment = new NumpadFragment();
        FragmentManager fragmentManager = getFragmentManager();
        FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
        fragmentTransaction.add(R.id.numpad_layout,fragment);
        fragmentTransaction.commit();

    }
}

and this is one of the fragments

import android.os.Bundle;
import android.support.annotation.Nullable;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;

public class NumpadFragment extends Fragment {
    @Nullable
    @Override
    public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
        return inflater.inflate(R.layout.fragment_numpad,container,false);
    }
}

What do you mean by `So the problem is FragmentManager doesnt work unless my activity extends Fragment` ? — ρяσѕρєя K, Jun 07 '17 at 07:54
For adding to Fragment using Code just create two container layouts in `activity_conversion.xml` and add both Fragments using `fragmentTransaction.add(R.id.,fragment);` and `fragmentTransaction.add(R.id.,fragment);` — ρяσѕρєя K, Jun 07 '17 at 07:55
You want to use `getSupportFragmentManager()` instead of `getFragmentManager()`. — Mike M., Jun 07 '17 at 07:57
When I hover the mouse on FragmentManager. I get imcompatible types error. It says I need to import android.support.v4.app.FragmentManager not android.app.FragmentManager. But I have the first one. If I extend to Fragment that error disappears. — gunesevitan, Jun 07 '17 at 08:03
That would be a different problem. If it compiles, then you've got the types right. Look at the logcat for the stack trace from the crash. http://stackoverflow.com/questions/23353173 — Mike M., Jun 07 '17 at 08:14
@MikeM. I get no view found error for my fragment on logcat but I have it? — gunesevitan, Jun 07 '17 at 08:31
The ID you pass a `FragmentTransaction` is for the `ViewGroup` that the `Fragment` will go into, not one in the `Fragment`'s layout. Apparently `numpad_layout` is not in the `activity_conversion` layout. — Mike M., Jun 07 '17 at 08:32

score 1 · Accepted Answer · answered Jun 07 '17 at 08:39

Some suggestions:

Use fragmentTransaction.replace (unless you need your fragments to be added to stack)
As containter for your fragment, use FrameLayout
Don't create new fragment by "new" operator. Add newInstance() method instead and create new fragment instance by calling that methrod. Also, implement interaction between your fragment and activity. Tip: use Android Studio wizard to add fragment to your project. Android Studio will generate skeleton with all needed methods already included
You definitely need to use getSupportFragmentManager (because your fragment is android.support.v4.app.Fragment)
DEBUG! - if you say "my app is crashing", it's useless. Post your logcat/exception/whatever to show crash reason.

Using getSupportFragmentManager answered my question thank you. Is it because getFragmentManager is not compatible with android.support.v4.app.Fragment? — gunesevitan, Jun 09 '17 at 07:34

Adding fragments to activity

1 Answers1