Since TabActivity is deprecated I need to find a way to do it with Fragments. I have worked with Fragments before I know how it works but I need a guide to create my tab host with FragmentActivities. I have found a couple of examples on the internet, and they are all about putting fragments into a container for the tabs.
What I want is to put FragmentActivities for each tab. Because in my application I will be using 4 tabs and each of the tabs have really complex content in it. As a result, I need to have a FragmentActivity for each tab to manage the Fragments that I will put under each tab within a separated container.
SOLUTION:
After answers and searching on internet I ended up with a Solution. According to the solution I have found, I keep track of Fragments in separated stack for each tab under tab host. Here is my GitHub repository, I created a small sample app for this problem.
A Fragment must always be embedded in an Activity . Fragments are not part of the API prior to HoneyComb (3.0). If you want to use Fragments in an app targeting a platform version prior to HoneyComb, you need to add the Support Package to your project and use the FragmentActivity to hold your Fragments .
use getActivity() method. Which will return the enclosing activity for the fragment.
FragmentActivity is part of the support library, while Activity is the framework's default class. They are functionally equivalent. You should always use FragmentActivity and android.
You can use multiple instances of the same fragment class within the same activity, in multiple activities, or even as a child of another fragment. With this in mind, you should only provide a fragment with the logic necessary to manage its own UI.
Since TabActivity is deprecated I need to find a way to do it with Fragments.
If you don't want to use TabActivity
- forget about putting FragmentActivities
into tab's content.
I remind that you can use TabWidget
without TabActivity
. So you can try this solution:
FragmentActivity
.TabWidget
into FragmentActivity
's layout. Make TabWidget
's content's height = 0. TabWidget
in XML declare container for you Fragment
s (FrameLayout
for example).FragmentActivity
just handle which tab is selected (TabHost.OnTabChangeListener
) and put needed Fragment
into container. Or you can create FragmentActivity
with TabWidget
, and instead of switching Fragment
s you can directly put Fragment
s into each tab's content.
For example if you have 3 tabs and 3 fragments try what i do. Call showFragmentX
when you need to change one fragment to another.
public class Test extends FragmentActivity {
private Fragment1 fragment1=new Fragment1();
private Fragment2 fragment2=new Fragment2();
private Fragment3 fragment3=new Fragment3();
private void showFragment1(){
FragmentTransaction ft = getSupportFragmentManager().beginTransaction();
ft.replace(R.id.fragments_container, fragment1);
ft.setTransition(FragmentTransaction.TRANSIT_FRAGMENT_OPEN);
ft.commit();
}
private void showFragment2(){
FragmentTransaction ft = getSupportFragmentManager().beginTransaction();
ft.replace(R.id.fragments_container, fragment2);
ft.setTransition(FragmentTransaction.TRANSIT_FRAGMENT_OPEN);
ft.commit();
}
private void showFragment3(){
FragmentTransaction ft = getSupportFragmentManager().beginTransaction();
ft.replace(R.id.fragments_container, fragment3);
ft.setTransition(FragmentTransaction.TRANSIT_FRAGMENT_OPEN);
ft.commit();
}
@Override
protected void onCreate(Bundle arg0) {
// TODO Auto-generated method stub
super.onCreate(arg0);
setContentView(R.layout.fragmentactivity_layout);
}
}
If you do so your fragmentX
variables will not be deleted each time you put them in fragment_container
. They will live while your FragmentActivity
live. Take look at fragments lifecycle.
Only OnCreateView
and onDestroyView
methods of fragments will call again and again while you replace
one fragment to another.
Also Fragments has their onSaveInstanceState
method where you can save the state of your fragment. For example: user typed his name in fragment1's editText. If you want to keep this data(name string) while user discover other fragments you should
1.save name string in fragment1's onSaveInstanceState
method
2. into fragment1's onCreateView
method check savedInstanceState bundle, if it's not null - fill edittext with string that you get from bundle.
public class Fragment1 extends Fragment {
EditText nameEditText;
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
super.onCreateView(inflater, container, savedInstanceState);
View fragment1View=inflater.inflate(R.layout.fragment1_layout, container, false);
nameEditText=(EditText) fragment1View.findViewById(R.id.edittext_name);
//check for saved data. if it is not null - fill your edittext with saved string
if(savedInstanceState!=null){
String nameString=(String) savedInstanceState.get("nameString");
nameEditText.setText(nameString);
}
return fragment1View;
}
@Override
public void onSaveInstanceState(Bundle outState) {
super.onSaveInstanceState(outState);
//save data that user have entered
outState.putString("nameString", nameEditText.getText().toString());
}
}
You can check data before saving. I hope my point is clear now.
Also if you call setRetainInstance(true)
in onCreateView()
method of your fragment
- system will try to save the state of fragment (with all input data). link to description
The approach of putting tab contents into separate Activities is deprecated, since now we have the Fragment framework. You should put the complex content of the tabs into Fragments, and swap those Fragments when the user selects tabs.
The recommended solution for this is to use the ActionBar with Tab navigation instead of using the TabHost widget.
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