Data Sharing between Fragments and Activity in Android

android, android-activity, android-fragments, data-sharing

Solution

Many ways :

1) Activity -> Fragment

- In your Activity : create a bundle and use fragment.setArguments(bundle)

- in your Fragment : use Bundle bundle = getArguments()

2) Activity -> Fragment

In your Fragment : create a public method

In your Activity : call an active fragment public method :

getSupportFragmentManager().findFragmentById(R.id.your_fragment).publicMethod(args)

3) Fragment -> Activity

- In your Fragment : create un interface with getter and setter methods (callback methods)

- In your Activity : implement the interface

4) Fragment -> Activity

- In your Activity : Create public getter and setter or other methods

In your Fragment : called public activity getter, setter or other methods using :

getActivity().getSomething(), getActivity().setSomething(args) or getActivity().someMethod(args)

Problem

Ive asked a similar question before and didn't get an answer and seems many other ppl are searching for an answer. So I am posting this question to hopefully get a clear answer that everyone can benefit from. I have an activity with 2 fragments in it. I want fragment2 to set a boolean variable in Activity when a checkbox is checked so that fragment1 can know if the checkbox was checked. This is my Code: Activity: ``` public class modestab extends Activity{ public static Context appContext; public boolean lf=false; public void onCreate(Bundle savedInstanceState){ appContext=this; super.onCreate(savedInstanceState); ActionBar tabbar= getActionBar(); tabbar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS); ActionBar.Tab ModesTab =tabbar.newTab().setText("Modes"); ActionBar.Tab CatTab =tabbar.newTab().setText("Categories"); Fragment ModesFragment =new modes(); Fragment CatFragment =new cats(); ModesTab.setTabListener(new MyTabsListener(ModesFragment)); CattTab.setTabListener(new MyTabsListener(CatFragment)); tabbar.addTab(ModesTab); tabbar.addTab(CatTab); } ``` Fragment 1:(Where I want to read the boolean lf set in Acitivity above: ``` @TargetApi(11) public class tabmodes extends Fragment{ @Override public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) { View V=inflater.inflate(R.layout.tab_modes, container, false); button1.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { // TODO Auto-generated method stub if(lf==false) //lf here is the lf in Activity which I want to get ``` Fragment 2: Where I want to set lf in Activity ``` ..... lifecheck.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener(){ @Override public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) { if(lifecheck.isChecked()) getActivity().lf=true;//Where I want to set the lf flag in Activity ; } }); ``` The code doesn't compile and I am not knowing how to set lf in the Activity nor how to read it. Someone suggested I do getActivity() but I am not able to see the variable. I tried to create a function setlf(boolean jk) but also I am not able to see it... Any help is welcome :)

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