Question

I’m starting using Fragments, and I’ve done like the API guide but … of course it’d be too easy 😉
When I launch the app, it crashes. After some research I’ve found this post Android fragment is not working
and the response of Stephen Wylie seems to correct the things for Ali, but .. I don’t get it !
Where should I put the FrameLayout ? The “where_i_want_my_fragment” id… it’s whatever I want, right ?
and finally where should I put the Java code ? in my activity (which is displaying 2 fragments by the way) .

Thanks !

Nico

EDIT : Let’s just say what I want for design you would understand better I think.
I want a list fragment on left side which display a list of strings, and to the right side I want a fragment displaying info regarding the selected string in the list. And I wanna be able to swip with fingers movements the right side of my app (I dont know if it s better to swipe fragment or whatever.. It’s the same layout but filled with differents datas)

Ok I just post my code because I really don’t see why it doesn’t do anything.
This is my activity_main.xml

<LinearLayout 
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:baselineAligned="false"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="horizontal" >

<FrameLayout  xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/list_frag"
    android:name="main.courante.c.DateListFragment"
    android:layout_width="fill_parent"
    android:layout_height="match_parent" >
</FrameLayout>

<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/fiche_frag"
    android:name="main.courante.c.fiche_frag"
    android:layout_weight="2"
    android:layout_width="0dp"
    android:layout_height="match_parent" >
</FrameLayout>

</LinearLayout>

Here is my main activity :
public class MainActivity extends Activity {

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    DateListFragment fragment = new DateListFragment();
    getFragmentManager().beginTransaction().add(R.id.list_frag, fragment).commit();
    fiche_freg frag2 = new fiche_frag();
    getFragmentManager().beginTransaction().add(R.id.fiche_frag,frag2).commit();

}

@Override
public boolean onCreateOptionsMenu(Menu menu) {
    getMenuInflater().inflate(R.menu.activity_main, menu);
    return true;
}

Here is DateListFragment (no onCreateView because it ‘s automatically generated)

public class DateListFragment extends ListFragment {
private int mposition = 1;
private String[] mListItem = new String[] {
        "Lundi 9 Juilllet",
        "Mardi 10 Juillet",
        "Mercredi maintenant"
};
@Override
public void onCreate(Bundle savedInstanceState) {
    // TODO Auto-generated method stub
    super.onCreate(savedInstanceState);

    this.setListAdapter(new ArrayAdapter<String>
                     (this.getActivity(),R.layout.frag_list_view ,mListItem));
    this.getListView().setChoiceMode(ListView.CHOICE_MODE_SINGLE);
}

and here is fiche_frag :
public class fiche_frag extends Fragment {

@Override
public void onCreate(Bundle savedInstanceState) {
    // TODO Auto-generated method stub
    super.onCreate(savedInstanceState);
}

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
        Bundle savedInstanceState) {
    // TODO Auto-generated method stub
    return inflater.inflate(R.layout.checks_matin,container,false);
}

R.layout.checks_matin works fine alone.

I thank you already and again for your help. I’m a beginner in android environnement and I find it difficult to englobe every notions for the UI at once… !!

Answer 1

You understand the basics. The FrameLayout goes wherever you want your fragment(s) to go. I’ve done it where my whole screen was one single FrameLayout before and I swapped up to five different fragments in and out of it.

If you have two Fragments that you want to display simultaneously, you could make your main layout with two FrameLayouts. However, this means you are locked into having both there all the time (or an empty space if you remove one.

If you want two fragments that don’t have to be on the screen at the same time you use a single FrameLayout and write code to swap the fragments as required.

Code to instantiate fragments should always be in the controlling activity (if they are dynamic).

Without code and a more specific problem, the above is the best answer I can give you.

EDIT

An example main layout to put two fragments side by side:

<?xml version="1.0" encoding="utf-8"?>
...
    <LinearLayout
        android:id="@+id/frames"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_above="@id/hline1"
        android:layout_below="@id/horizontalline"
        android:orientation="horizontal" >
        <FrameLayout
            android:id="@+id/leftpane"
            android:layout_width="0px"
            android:layout_height="match_parent"
            android:layout_weight=".4" />
        <FrameLayout
            android:id="@+id/rightpane"
            android:layout_width="0px"
            android:layout_height="match_parent"
            android:layout_weight="1" >
        </FrameLayout>
    </LinearLayout>
...

To add your fragment to one of the framelayouts:

FragmentClass fragment = new FragmentClass();
getFragmentManager().beginTransaction().add(R.id.leftpane, fragment).commit();

If you want to swap fragments in one of the framelayouts (say the left pane), you can do it like this:

FragmentClass fragment = new FragmentClass();
getFragmentManager().beginTransaction().replace(R.id.leftpane, fragment).commit();

I suggested instantiating from the XML because it sounded like you were going to have two fragments and not make any changes. If you are going to swap them in and out, then it would be appropriate to add a tag to each one so you can find them again if you want to display them again.