CODEWITHSUNDEEP
androidandroid-fragments
user866364
user866364

Reputation:

What's the correct way to use Fragments?

What is the correct way to use fragments? Should i use only one FragmentActivity per interface or use a unique FragmentActivity for all interfaces?

My app is quite simple: it has 4 distinct interfaces, a fixed options menu on top and i only show contextual menu in a interface called 'actions'.

I was thinking to use only one FragmentActivity with an area where i could switch between fragments. Is it a good practice or should i keep one FragmentActivity per interface?

By now, i'm using one FragmentActivity per interface but when i change ( start ) FragmentActivity, it looks like that is creating a new object and my app blinks before open the new activity.

Thank in advance.

edit:

Here is a drawing of my app: http://postimg.org/image/mvxyk2527/

Upvotes: 2

Views: 2321

Answers (3)

Yeray
Yeray

Reputation: 1265

I will try to explain it properly. In your case, you must use one FragmentActivity that includes fragments. You must create one fragment per interface and commit (exchange) when the user clicks on the menu. This may be an example of the structure of the project:

Java Classes:

  • MainActivity.class (extends FragmentActivity)
  • Interface1Fragment.class (extends Fragment)
  • Interface2Fragment.class (extends Fragment)
  • Interface3Fragment.class (extends Fragment)
  • Interface4Fragment.class (extends Fragment)

Layouts:

  • act_main.xml, frg_inter1, frg_inter2, frg_inter3 and frg_inter4.

In MainActivity and act_main.xml, you must create a tabhost o navigationDrawer for the menu and implement a method that allows to switch between fragments. Later, in each fragment you must implement the interface functionality.

Some code:

  • MainActivity:

    public class ActMain extends FragmentActivity {
@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.act_main);
}


private void createMenu() {
    //you can create a menu with tabhost or navigation drawer
}


// replace a fragment
public void replaceFragment(Fragment launchFragment) {
    FragmentTransaction ft = getSupportFragmentManager().beginTransaction();        
    ft.replace(android.R.id.tabcontent, launchFragment).commit();
}
}

  • A Fragment:

    public class Interface1Fragment extends Fragment {

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
    rootView = inflater.inflate(R.layout.frg_inicio, container, false);
    return rootView;
}
}

  • MainActivity.xml

    <android.support.v4.widget.DrawerLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:facebook="http://schemas.android.com/apk/res-auto"
android:id="@+id/drawer_layout"
android:layout_width="match_parent"
android:layout_height="match_parent" >

<!-- Main content -->

<FrameLayout
    android:id="@android:id/tabcontent"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:layout_weight="0" />

<!-- Left Navigation Drawer -->

<LinearLayout
    android:id="@+id/left_drawer"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:layout_gravity="start"
    android:background="@color/black_actionbar"
    android:choiceMode="singleChoice"
    android:onClick="emptyOnClick"
    android:orientation="vertical" >
  /LinearLayout>

   </android.support.v4.widget.DrawerLayout>

  • In fragments xml files you must design your interfaces.

Upvotes: 2

James Lockhart
James Lockhart

Reputation: 1040

It's a lot of personal preference and requirement really. I'm not a big believer of the "correct way" concept, if you achieve your goal then it's not wrong, but there may be a nicer way to do it.

For me it would depend on how many nested fragments each FragmentActivity handles. If you have a tree of nested fragments you can get into a mess with nested fragment stacks, etc.

http://developer.android.com/training/implementing-navigation/temporal.html

Personally, if I'm writing an application with lots of fragments I tend to have a single Activity which makes navigation a bit more manageable with a single Fragment stack as using multiple FragmentActivity instances will use multiple fragment stacks.

http://developer.android.com/training/implementing-navigation/index.html

You could consider the ViewPager approach which is great if you want to use a tabular and swiping navigation. Although if you have heavy scrollable content views I would be hesitant as for some individuals multi-directional gesture interfaces can be quite frustrating.

http://developer.android.com/training/implementing-navigation/lateral.html

If your code is clean, manageable and not leaking references then I would probably stick with what you have and wouldn't waste your time re-factoring it.

Upvotes: 4

Marija Milosevic
Marija Milosevic

Reputation: 516

Yeah, you should just change fragments, not restart the fragment activity if that part is gonna stay the same and work the same. You should just switch between fragments like this:

getFragmentManager().beginTransaction().replace(R.id.container, new MyFragment()).addToBackStack(null).commit();

or like this if you are supporting API < 14

getSupportFragmentManager().beginTransaction().replace(R.id.container, new MyFragment()).addToBackStack(null).commit();

Note : remove addToBackStack(null) if you dont want to go back to previously loaded fragment onBackPressed

Upvotes: 1

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