I'm new to android programming and I can't find a way to switch between tab1 to tab2 in a TabLayout, when the user clicks a button located in the tab1.
It may be something very simple, but I am clueless in my first app.
I have tried the following at first:
TabLayout.Tab tab = tabLayout.getTabAt(1);
tab.select();
And it used to work, but I changed the code and, at some point, it just didn't work anymore.
I also triedtab.getCustomView().setSelected(true);, but I got NullPointerException. So I checked in a if statement if tab was null, and it wasn't.
And then I tried
tabLayout.setScrollPosition(1,0f,true);
ViewPager viewPager = new ViewPager(mainView.getContext());
viewPager.setCurrentItem(1);
But none of the solutions above worked for me.
Here is my code:
View view;
#Nullable
#Override
public View onCreateView(#NonNull LayoutInflater inflater, #Nullable ViewGroup container, #Nullable Bundle savedInstanceState) {
try {
view = inflater.inflate(R.layout.fragment_main, container, false);
Button GoB = view.findViewById(R.id.GoB);
final EditText USETV = view.findViewById(R.id.USETV);
final EditText commandEV = view.findViewById(R.id.CommandTV);
final SqlHelper db = new SqlHelper(getContext(), "myDatabase", null, 1);
GoB.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
try {
String a = "";
if (USETV.getText().toString().length() > 0) {
a += "USE " + USETV.getText().toString() + " ;";
}
a += commandEV.getText().toString();
String[][] c = db.SqlQuery(a);
LayoutInflater factory = getLayoutInflater();
View resultView = factory.inflate(R.layout.fragment_result, null);
TableLayout tableLayout = resultView.findViewById(R.id.ResultContainer);
tableLayout.removeAllViews();
View mainView = factory.inflate(R.layout.main_activity,null);
TabLayout tabLayout = mainView.findViewById(R.id.tabs);
if (c[0].length > 0 && c[1].length > 0) {
TabLayout.Tab tab = tabLayout.getTabAt(1);
//tab.select();
//tab.getCustomView().setSelected(true);
//tabLayout.setScrollPosition(1,0f,true);
//ViewPager viewPager = new ViewPager(mainView.getContext());
//viewPager.setCurrentItem(1);
//
// do some stuff
}
} catch (Exception e) {
showException(e);
}
}
});
} catch (Exception e) {
showException(e);
}
return view;
}
TabLayout and ViewPager belong to your Activity, so in your Fragment you have to call Activity function to switch tab
Here is an example:
public class MyActivity extends Activity {
private TabLayout mTabLayout;
private ViewPager mViewPager;
#Override
public onCreate(...) {
MyFrament myFragment = new MyFragment(this);
// Add fragment to Viewpager ...
// Attach ViewPager to TabLayout ...
}
public void switchTab(int index) {
// Check index ...
mViewPager.setCurrentItem(index);
}
}
then
public class MyFragment extends Fragment {
private Context mContext;
private Button mButton;
public MyFragment(Context context) {
mContext = context;
}
#Override
public View onCreateView(...) {
...
mButton.setOnClickListener(v->{
((MyActivity)mContext).switchTab(1);
});
...
}
}
Hope this help!
Try putting these two lines inside your button's handler :
ActionBar actionBar = (ActionBar)getActivity().getActionBar();
actionBar.setSelectedNavigationItem(1);
Right Click on your package name
new > activity > tabActivity click ok
Chose layout name whatever you want e.g (Example.java).
Select Navigation style is Action Bar Tabs(which is option 2) and click Finish
5.create two new Fragments
6.Go to the java file here Example.java
After open Example.java file paste the blow code in
SectionsPagerAdapter extends FragmentPagerAdapter
public SectionsPagerAdapter(FragmentManager fm) {
super(fm);
}
#Override
public Fragment getItem(int position) {
// getItem is called to instantiate the fragment for the given page.
// Return a PlaceholderFragment (defined as a static inner class below).
switch(position){
case 0:
return new Chats();
case 1:
return new Status();
case 2:
return new Call();
}
return PlaceholderFragment.newInstance(position + 1);
}
#Override
public int getCount() {
// Show 3 total pages.
return 3;
}
}
Related
I am trying to make a simple tabbed application with different ListViews and options.
I would like to manage the relationship between tabs and MainActivity and the problem right now is I cannot make an addItem() function in a menu button, to add a new item to my ListView (inside a Fragment) in a tabbed application.
I already searched a lot, and I found only about adding an item in a simple ListView (inside MainActivity) or add items not dynamically in a tabbed application.
So here it is the screen of my Tabbed Application and the ListView that I am trying to work with.
Custom List View Application Picture
And here is my code:
MainActivity.java
public class MainActivity extends AppCompatActivity {
private SectionsPagerAdapter mSectionsPagerAdapter;
/**
* The {#link ViewPager} that will host the section contents.
*/
private ViewPager mViewPager;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
// Create the adapter that will return a fragment for each of the three
// primary sections of the activity.
mSectionsPagerAdapter = new SectionsPagerAdapter(getSupportFragmentManager());
// Set up the ViewPager with the sections adapter.
mViewPager = (ViewPager) findViewById(R.id.container);
mViewPager.setAdapter(mSectionsPagerAdapter);
TabLayout tabLayout = (TabLayout) findViewById(R.id.tabs);
tabLayout.setupWithViewPager(mViewPager);
}
The Fragment with the CustomList, that I am trying to implement the menu button method action_add():
public class Catalogo extends Fragment {
ArrayList<CustomList> custom = null;
ListView lv = null;
ArrayAdapter adapter = null;
ArrayList<CustomList> elementos = new ArrayList<CustomList>();
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.catalogo, container, false);
ListView lv = rootView.findViewById(R.id.catalogoListView);
custom = addItems();
adapter = new CustomAdapter(this.getContext(), custom);
lv.setAdapter(adapter);
return rootView;
}
private ArrayList<CustomList> addItems(){
CustomList custom = new CustomList("Banana", "4.0");
elementos.add(custom);
custom = new CustomList("Morango", "5.0");
elementos.add(custom);
return elementos;
}
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
if (id == R.id.action_add){
AlertDialog.Builder builder = new AlertDialog.Builder(this.getActivity());
//builder.setTitle("Adicionar novo item"); //THESE ARE NOT WORKING
//final EditText input = new EditText(this); //THIS SHOULD BE 2 Text Fields
//builder.setView(input);
builder.setPositiveButton("OK", new DialogInterface.OnClickListener() {
#Override
public void onClick(DialogInterface dialog, int which) {
//NEED TO IMPLEMENT HERE
}
});
builder.setNegativeButton("Cancelar", new DialogInterface.OnClickListener() {
#Override
public void onClick(DialogInterface dialog, int which) {
dialog.cancel();
}
});
builder.show();
return true;
}
return super.onOptionsItemSelected(item);
}
public static String preferredCase(String original, String price)
{
if (original.isEmpty())
return original;
return original.substring(0, 1).toUpperCase() + original.substring(1).toLowerCase();
}
}
My CustomItem Structure:
public class CustomList {
String name;
String price;
public CustomList(String name, String price) {
this.name = name;
this.price = price;
}
public String getName() {
return name;
}
public String getPrice() {
return price;
}
}
And at the end, my CustomAdapter:
public class CustomAdapter extends ArrayAdapter<CustomList> {
private final Context context;
private final ArrayList<CustomList> elementos;
public CustomAdapter(Context context, ArrayList<CustomList> elementos){
super(context, R.layout.modelolista, elementos);
this.context = context;
this.elementos = elementos;
}
public View getView(int position, View convertView, ViewGroup parent){
LayoutInflater inflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
View rowView = inflater.inflate(R.layout.modelolista, parent, false);
TextView nameItem = rowView.findViewById(R.id.tvName);
TextView priceItem = rowView.findViewById(R.id.tvPrice);
nameItem.setText(elementos.get(position).getName());
priceItem.setText(elementos.get(position).getPrice());
return rowView;
}
}
First of all a suggestion: instead of calling your item CustomList, consider calling it CustomListItem. This way you will remember easily in the future that it is an item, not a list.
That said, you should implement an add page\dialog.
There are many ways for doing this.. the "best approach" (i think) will be creating a custom add dialog. So you will have to create a custom layout and give it as the view of your layout with something like this:
AlertDialog.Builder builder = new AlertDialog.Builder(activity);
LayoutInflater inflater = activity.getLayoutInflater();
View dialogView = inflater.inflate(R.layout.my_custom_view, null);
builder.setView(dialogView);
Now you can simply implement all listners and stuffs here by getting items as Button byButton = (Button)dialogView.getItemById(R.id.mybutton);
For any info check this answer that might help you (there are many others).
Now what we miss is refreshing the listview, this I think is the simplest way:
You can save a reference of your custom Fragment in your Activity. Then add in your Fragment a method like AddItemToList(). Now when user clicks the "Add" button, you can call this method from your fragment reference and implement the method as below(+-):
CallBack (MainActivity)
//add this param
private MyFragment myFragment;
//when you show the fragment add this:
myFragment = myFragmentIstance;
//on the save of the dialog, add this:
//do all checks and create item
CustomListItem cli = new CustomListItem(editTextName.getText().toString(), editTextPrice.getText().toString());
myFragment.AddItemToList(cli);
AddItemToList (Fragment):
public void AddItemToList(CustomListItem cli){
myCustomListItemList.Add(cli);
myAdapterView.notifyDataSetChanged();
}
Something like this should work.. For any question or explaination I'm here. Good luck
The best way to use activity's data in fragment is to create a interface in fragment and implement in activity class
public class Catalogo extends Fragment {
private CatalogFragmentInteface catalogInterface;
//rest of your code
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.catalogo, container, false);
catalogIntreface.catalogInterfaceFunction(rootView);
}
#Override
public void onAttach(Context context) {
super.onAttach(context);
if (context instanceof CatalogFragmentInterface) {
catalogInterface = (CatalogFragmentInterface) context;
} else {
throw new RuntimeException(context.toString()
+ " must implement CatalogFragmentInterface");
}
}
interface CatalogFragmentInterface {
void catalogInterfaceFunction(View view);
}
}
And in your Activity class implement this interface
public class MainActivity extends AppCompatActivity implement Catalog.CatalogFragmentInterface{
#Overide
void catalogInterfaceFunction(View view) {
//access your listview in fragment using view variable
}
}
In this way all your data and listview is present in same class.
I hope this will help you now.
This question already has answers here:
What is a NullPointerException, and how do I fix it?
(12 answers)
Closed 6 years ago.
My app works with a TabLayout (and so a ViewPager).
I have a Fragment A and a Fragment B. My goal is to recover data from my EditTexts of Fragment A to, obviously, print and works with them in my Fragment B.
For this, I use an interface named ButtonCliked, but seems not to work well. Did I forgot something ?
TabFragment.java (use to manage my fragments)
public class TabFragment extends Fragment implements EquationsCalculFragment.ButtonClicked {
public static TabLayout tabLayout;
public static ViewPager viewPager;
public static int int_items = 3 ;
#Override
public void sendResultats(float a, float b) {
EquationsResultatFragment fragRes = (EquationsResultatFragment) getFragmentManager().findFragmentById(R.id.Equa_2nd_ResLayout);
fragRes.getResultat(a, b);
}
#Nullable
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
/**
*Inflate tab_layout and setup Views.
*/
View x = inflater.inflate(R.layout.tab_layout,null);
tabLayout = (TabLayout) x.findViewById(R.id.tabs);
viewPager = (ViewPager) x.findViewById(R.id.viewpager);
/**
*Set an Apater for the View Pager
*/
viewPager.setAdapter(new MyAdapter(getChildFragmentManager()));
tabLayout.post(new Runnable() {
#Override
public void run() {
tabLayout.setupWithViewPager(viewPager);
}
});
return x;
}
class MyAdapter extends FragmentPagerAdapter{
public MyAdapter(FragmentManager fm) {
super(fm);
}
/**
* Return fragment with respect to Position .
*/
#Override
public Fragment getItem(int position)
{
switch (position){
case 0 : return new EquationsCalculFragment();
case 1 : return new EquationsResultatFragment();
case 2 : return new EquationsInfosFragment();
}
return null;
}
#Override
public int getCount() {
return int_items;
}
/**
* This method returns the title of the tab according to the position.
*/
#Override
public CharSequence getPageTitle(int position) {
switch (position){
case 0 :
return "Calcul";
case 1 :
return "Résultats";
case 2 :
return "Infos";
}
return null;
}
}
}
Fragment A : EquationsCalculFragment.java
public class EquationsCalculFragment extends Fragment {
private String aS;
private String bS;
private EquationsCalculFragment.ButtonClicked callEqua2ndRes;
public interface ButtonClicked {
void sendResultats(float a, float b);
}
private ViewPager viewPager;
#Nullable
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.fragment_equations_calcul, container, false);
viewPager = (ViewPager) getActivity().findViewById(R.id.viewpager);
final EditText champ_a = (EditText) view.findViewById(R.id.equa_2nd_a);
final EditText champ_b = (EditText) view.findViewById(R.id.equa_2nd_b);
Button button = (Button) view.findViewById(R.id.btn_equations_resultats);
button.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
bS = champ_b.getText().toString();
aS = champ_a.getText().toString();
callEqua2ndRes.sendResultats(Float.parseFloat(aS), Float.parseFloat(bS));
viewPager.setCurrentItem(1, true);
}
});
return view;
}
#Override
public void onAttach(Context context) {
super.onAttach(context);
// This makes sure that the container activity has implemented
// the callback interface. If not, it throws an exception
try {
if (context instanceof EquationsCalculFragment.ButtonClicked) {
callEqua2ndRes = (EquationsCalculFragment.ButtonClicked) context;
}
} catch (ClassCastException e) {
throw new ClassCastException(context.toString()
+ " must implement ButtonClicked");
}
}
#Override
public void onDetach() {
callEqua2ndRes = null;
super.onDetach();
}
}
Fragment B : EquationsResultatFragment.java
public class EquationsResultatFragment extends Fragment {
private TextView results;
#Nullable
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.fragment_equations_resultat, container, false);
return view;
}
#Override
public void onActivityCreated(#Nullable Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
results = (TextView) getView().findViewById(R.id.equa_2nd_resultat);
}
public void getResultat(float a, float b) {
results.setText(String.valueOf((a*a)+(2*a*b)+(b*b)));
}
}
Is there anything I'm doing wrong ?
I thinkthe NPE is because you try to find the fragment with it's id, but you supply I guess the id of the ViewPager? Try finding it by tag, it should look something like this:
int position;
getSupportFragmentManager().findFragmentByTag("android:switcher:" + R.id.yourViewPagerIdGoesHere + ":" + position);
Where the position is the pos of your targeted fragment just like in the adapter's public Fragment getItem(int position) method
Issue is you have declared an interface in EquationsCalculFragment but never initialied it :)
So here is what you can do :)
In EquationsCalculFragment, change
private EquationsCalculFragment.ButtonClicked callEqua2ndRes;
to
public EquationsCalculFragment.ButtonClicked callEqua2ndRes;
and in TabFragment, getItem methods case 0, make this change :)
case 0 : EquationsCalculFragment calculationFragment = new EquationsCalculFragment();
calculationFragment.callEqua2ndRes = TabFragment.this;
return calculationFragment;
Should solve your issue :) Hope my answer helped :)
P.S : Code provided above is to explain the concept and not for copy paste, might contain syntactic error :) If contains please modify and use it :D
Is it possible to pass a data from fragment to fragment by swipe?
There are many articles teaching us how to pass the data from fragment to fragment, but most of the article or questions had implemented OnClickListener in their first fragment, which used to pass value to another fragment.
But my case is pass the data from two fragments without any button click and finally save them in different tables by clicking button in the last fragment. What can I do to achieve this??
The flow is Information >> WorkForce >>WorkDetailsTable and save them to different table by one button click.
I have tried to work it out but I get NULL value in SQLite. I think I have miss out a lot but have no idea. PLEASE help me...I've been stuck at here for more than two days...Thanks
Tab.java
public class Tab extends ActionBarActivity implements ActionBar.TabListener {
ViewPager Tab;
TabPagerAdapter TabAdapter;
ActionBar actionBar;
public static String name = null;
public static String subContractors = null;
// will be used for data communication
public static Force force_bean;;
public static Info info_bean;
public static Force getForce(){
return force_bean;
}
public static void setForce(Force force){
force_bean=force;
}
public static Info getInfo(){
return info_bean;
}
public static void setInfo(Info info){
info_bean=info;
}
final Activity mActivity = (Activity) this;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.tab1);
info_bean = new Info();
force_bean = new Force();
TabAdapter = new TabPagerAdapter(getSupportFragmentManager());
Tab = (ViewPager) findViewById(R.id.pager);
Tab.setOnPageChangeListener(
new ViewPager.SimpleOnPageChangeListener() {
#Override
public void onPageSelected(int position) {
actionBar = ((AppCompatActivity) mActivity).getSupportActionBar();
actionBar.setSelectedNavigationItem(position);
}
});
Tab.setAdapter(TabAdapter);
actionBar = ((AppCompatActivity) mActivity).getSupportActionBar();
//Enable Tabs on Action Bar
actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS);
//Add New Tabs
actionBar.addTab(actionBar.newTab().setText("Information").setTabListener(this));
actionBar.addTab(actionBar.newTab().setText("Work Force").setTabListener(this));
actionBar.addTab(actionBar.newTab().setText("Work Details").setTabListener(this));
}
#Override
public void onTabSelected(ActionBar.Tab tab, android.support.v4.app.FragmentTransaction ft) {
}
#Override
public void onTabUnselected(ActionBar.Tab tab, android.support.v4.app.FragmentTransaction ft) {
}
#Override
public void onTabReselected(ActionBar.Tab tab, android.support.v4.app.FragmentTransaction ft) {
}
}
TabPagerAdapter.java
public class TabPagerAdapter extends FragmentStatePagerAdapter {
public TabPagerAdapter(FragmentManager fm) {
super(fm);
}
#Override
public Fragment getItem(int i) {
switch (i) {
case 0:
return Information.newInstance("name");
case 1:
return WorkForce.newInstance("SubCon");
case 2:
return WorkDetailsTable.newInstance();
}
return null ;
}
#Override
public int getCount() {
return 3; //No of Tabs you can give your number of tabs
}
Informmation.java
public class Information extends Fragment implements View.OnClickListener {
private Spinner spinner, spinner2, spinner3;
private static String a;
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
View info = inflater.inflate(R.layout.information, container, false);
dialog = new DateDialog();
spinner = (Spinner)info.findViewById(R.id.spinner);
addItemsOnSpinner();
a= spinner.getSelectedItem().toString();
return info;
}
public static Information newInstance(String a)
{
Information fragment=new Information();
Bundle bundle=new Bundle();
bundle.putString("a",a);
fragment.setArguments(bundle);
return fragment;
}
public void addItemsOnSpinner() {
List<String> list = new ArrayList<String>();
list.add("1 ");
list.add("2");
ArrayAdapter<String> adapter = new ArrayAdapter<String>(getActivity(), android.R.layout.simple_spinner_dropdown_item, list);
adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
spinner.setAdapter(adapter);
}
WorkForce.java
public class WorkForce extends Fragment {
private static EditText txt1;
private static String subCon;
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
View work = inflater.inflate(R.layout.workforce, container, false);
txt1 = (EditText) work.findViewById(R.id.editText);
subCon = txt1.getText().toString();
return work;
}
public static WorkForce newInstance(String subCon) {
WorkForce f = new WorkForce();
Bundle bundle = new Bundle();
bundle.putString("subCon", subCon);
f.setArguments(bundle);
return f;
}
}
WorkDetails.java
private com.example.project.project.API.InfoAPI ts;
private com.example.project.project.API.WorkDetailsAPI WD;
private com.example.project.project.API.WorkForceAPI WF;
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
View workDetails = inflater.inflate(R.layout.tableworkdetails, container, false);
getActivity().setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_LANDSCAPE);
spinnerTra = (Spinner) workDetails.findViewById(R.id.spinner6);
addItemsOnSpinner();
Button btn1 = (Button)workDetails.findViewById(R.id.button2);
WD = new com.example.project.project.API.WorkDetailsAPI(getActivity());
ts = new com.example.project.project.API.InfoAPI(getActivity());
WF = new com.example.project.project.API.WorkForceAPI(getActivity());
a1 = spinnerTra.getSelectedItem().toString();
Bundle bundle = new Bundle();
final String name = bundle.getString("a");
final String subContractors = bundle.getString("subCon");
btn1.setOnClickListener(new View.OnClickListener() {
public void onClick(View arg0) {
add(name, subContractors);
}
});
return workDetails;
}
public void add(String name,String subContractors)
{
Toast.makeText(getActivity(),+name+subContractors, Toast.LENGTH_SHORT).show();
ts.insertTimeSheet(name);
WF.insertWorkForce(subContractors);
}
Note: My case is pass the data from two fragments without any button click and finally save them in different tables by clicking button in the last fragment.
If I understand your problem correctly, you are essentially implementing something a little bit like a "Wizard" where each step passes information to the next step as you swipe between the tabs or select them.
So in reality your problem is how to get the information out of a fragment when it is deselected and into a fragment when selected.
At the simplest level I would suggest your activity holds the "master" copy of all of the information and passes it into/takes it from each fragment in your tab pager adapter.
You would need some kind of "Domain" object to hold all the information you need to collect. Each tab would only update the bits of information it cares about..
public class WorkData {
string information;
string subCon;
... etc..
}
You add an instance of this to hold the master copy to your "tab" activity:
public class Tab extends ActionBarActivity implements ActionBar.TabListener {
...
WorkData workData = new WorkData();
...
I would then suggest a simple interface that each of your "tab" fragments implement; something like:
public interface DataUpdate {
void setData(WorkData data);
WorkData getData();
}
Each of your tab fragments would implement this interface, updating the WorkData as required..
public class WorkForce extends Fragment implements DataUpdate {
...
private WorkData workData; // this fragment's "copy" of the data
...
#Override
public WorkData getData() {
this.workData.subCon = this.subCon; // Assuming subcon has been updated.. else use txt1.getText();
return this.workData;
}
#Override
public void setData(WorkData workData) {
this.workData = workData;
// Update this page's views with the workData...
// This assumes the fragment has already been created and txt1 is set to a view
txt1.setText(workData.subCon);
this.subCon = workData.subCon; // Actually could just use subCon in workData, but be aware that workData actually points to the Activity's copy (kinda makes getdata redundant.. but I like symmetry and couldn't be bothered making lots of copies of the object).
}
Then you just need to add the code to pass the data backwards and forwards.. in your "Tab" activity which looks like...
#Override
public void onTabSelected(ActionBar.Tab tab, android.support.v4.app.FragmentTransaction ft) {
int position = tab.getPosition();
DataUpdate dataUpdate = (DataUpdate) TabAdapter.getItem(position);
// Pass the master workdata to the selected fragment
dataUpdate.setData(this.workData);
}
#Override
public void onTabUnselected(ActionBar.Tab tab, android.support.v4.app.FragmentTransaction ft) {
int position = tab.getPosition();
DataUpdate dataUpdate = (DataUpdate) TabAdapter.getItem(position);
// Update the master workdata from the unselected fragment
this.workData = dataUpdate.getData();
}
#Override
public void onTabReselected(ActionBar.Tab tab, android.support.v4.app.FragmentTransaction ft) {
// This might be pointless, but we'll do it anyway..
int position = tab.getPosition();
DataUpdate dataUpdate = (DataUpdate) TabAdapter.getItem(position);
// Pass the master workdata to the selected fragment
dataUpdate.setData(this.workData);
}
An important thing to notice here is that your TabPagerAdapter will create a new fragment every time you call getItem().. that will mean that we will never get any updates because each time we try to get the fragment it returns a new, empty fragment. We need to change this so that the fragments are still created when first asked for, but only created once so that we don't keep throwing away our work.
public class TabPagerAdapter extends FragmentStatePagerAdapter {
private static final int NUMBER_OF_TABS = 3;
private Fragment[] tabList = new Fragment[NUMBER_OF_TABS];
public TabPagerAdapter(FragmentManager fm) {
super(fm);
}
#Override
public Fragment getItem(int i) {
if (tabList[i] != null) {
// Return a tab we created earlier..
return tabList[i];
} else {
switch (i) {
case 0:
tabList[0] = Information.newInstance("name");
return tabList[0];
case 1:
tabList[1] = WorkForce.newInstance("SubCon");
return tabList[1];
case 2:
tabList[2] = WorkDetailsTable.newInstance();
return tabList[2];
}
}
return null ;
}
#Override
public int getCount() {
return NUMBER_OF_TABS;
}
Hope this helps. Good luck :-)
Although C James provides good tips to solve your problems, I would like to introduce another way without using implementing of interfaces. Please check below link out. If you use an event bus library such a http://square.github.io/otto/, you can easily pass data you want to share among fragments and even activities. Additionally, you can reduce a lot of code line since it only requires Sender(PUBLISHING), Receiver(Subscriber) while implementation of interfaces requires additional lines of code.
Here is a tutorial of Otto libarary.
http://www.vogella.com/tutorials/JavaLibrary-EventBusOtto/article.html
Hope it helps :)
I would more go the Observer Pattern way.
Each Fragments changes an POJO with is rendered in your Fragments in some way. You simply have to Observe the pojo in your Fragments. Changing Fragments will notify interested observers without knowing them.
I believe that's a much cleaner way to implement this.
Fragment A -> PojoInstance.setXY("foo");
Fragment A -> informs the Observers which e.b Informs Fragment B:
Fragment B will see the change tru the Observer.
Because ViewPagers or other Components will cache Fragments thats a way to get information in already created Fragments, even when their are not seen.
You could also try to use an EventBus where you pass the POJO around.
To transfer data from one fragment to another fragment when swipe is performed ,firstly you should get the view of the each fragment.here is the sample code that can help you out a bit.
write this code in Activity:
mviewpager.addOnPageChangeListener(new TabLayout.TabLayoutOnPageChangeListener(tabLayout));
mviewpager.addOnPageChangeListener(new ViewPager.OnPageChangeListener() {
#Override
public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
adapter = ((SOFragmentPagerAdapter) mviewpager.getAdapter());
//getting the view of fragments at positions
if(position==0)
{
View v = null;
Fragment1=(Fragment1)adapter.getFragment(position);
v=fragment1.getMyView();//this is how you get the view
ListView lv=(ListView)v.findViewById(R.id.lv_services);
ArrayAdapter<String> arrayAdapter=new ArrayAdapter<String>(SOListItemSelectedActivity.this,android.R.layout.simple_list_item_1,soRequestFragment.al_list_of_services);
lv.setAdapter(arrayAdapter);
}
if(position==1)
{
}
}
#Override
public void onPageSelected(int position) {
if(position==0)
{
View v = null;
soRequestFragment=(SORequestFragment)adapter.getFragment(position);
v=soRequestFragment.getMyView();
}
if(position==1)
{
}
}
#Override
public void onPageScrollStateChanged(int state) {
}
});
tabLayout.setOnTabSelectedListener(new TabLayout.OnTabSelectedListener() {
#Override
public void onTabSelected(TabLayout.Tab tab) {
mviewpager.setCurrentItem(tab.getPosition());
}
#Override
public void onTabUnselected(TabLayout.Tab tab) {
}
#Override
public void onTabReselected(TabLayout.Tab tab) {
}
});
and create a FragmentPagerAdapter as:
public class SOFragmentPagerAdapter extends FragmentPagerAdapter {
HashMap<Integer,Fragment> mPageReferenceMap;
int mNumOfTabs;
public SOFragmentPagerAdapter(FragmentManager fm,int mNumOfTabs) {
super(fm);
this.mNumOfTabs=mNumOfTabs;
mPageReferenceMap=new HashMap<Integer,Fragment>();
}
#Override
public Fragment getItem(int position) {
switch (position)
{
case 0:
Fragment1 fragment1=new tFragment1();
mPageReferenceMap.put(position,fragment1);
return fragment1;
case 1:
Fragment2 fragment2=new Fragment2();
mPageReferenceMap.put(position,fragment2);
return fragment2;
default:
return null;
}
}
public Fragment getFragment(int key) {
return mPageReferenceMap.get(key);
}
#Override
public int getCount() {
return 2;
}}
In Fragments add the getmyview() which will return the view of that fragment as:
public void getmyview()
{
return myview;//myview is fragment view which you will return in oncreateview method
}
Note: Viewpager execute onpagescroll first and get the position 0,1 and when you scroll ,views at position 1,2 will execute and page selected 0 will execute.
For tabselections: Tabunselected,Tabselected Tab reselected is the sequence of execution.
so write accordingly in the respective positions of fragments.
Hope this helps you.
I have an activity that hosts 2 tabs fragments. I fetch some data from database and based on that I want to update textviews inside my 2 tab fragments after AsyncTask finishes. However I get java.lang.NullPointerException at computing.gmit.ie.scorerapp.Team1Fragment.update(Team1Fragment.java:36) when I try to update the view inside the fragment. This is the code:
public class Tabs extends FragmentActivity implements ActionBar.TabListener {
private static final String SERVER_ROOT_URI_CYPHER = "xxxxxx";
private Map<String, List<String>> map = new HashMap<>();
ActionBar actionBar;
ActionBar.Tab tab1;
ActionBar.Tab tab2;
ViewPager viewPager;
private List<String> teamList;
// list of players team 1
private List<String> team1Players = new ArrayList<>();
// list of players team 2
private List<String> team2Players = new ArrayList<>();
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_tabs);
viewPager = (ViewPager) findViewById(R.id.pager);
viewPager.setAdapter(new MyAdapter(getSupportFragmentManager()));
viewPager.setOnPageChangeListener(new ViewPager.OnPageChangeListener() {
#Override
public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
}
#Override
public void onPageSelected(int position) {
getActionBar().setSelectedNavigationItem(position);
}
#Override
public void onPageScrollStateChanged(int state) {
}
});
actionBar = getActionBar();
actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS);
tab1 = actionBar.newTab();
tab1.setText("Tab 1 ");
tab1.setTabListener(this);
tab2 = actionBar.newTab();
tab2.setText("Tab 2");
tab2.setTabListener(this);
actionBar.addTab(tab1);
actionBar.addTab(tab2);
//execute async task here
TeamPlayer teamPlayer = new TeamPlayer();
teamPlayer.execute();
}
My adapter
class MyAdapter extends FragmentPagerAdapter {
MyAdapter(FragmentManager fm) {
super(fm);
}
#Override
public Fragment getItem(int position) {
Fragment fragement = null;
if (position == 0) {
fragement = new Team1Fragment();
} else {
fragement = new Team2Fragment();
}
return fragement;
}
#Override
public int getCount() {
return 2;
}
}
My async task -->> null here
private class TeamPlayer extends AsyncTask<Void, Void, Void> {
Team1Fragment frg = new Team1Fragment();
#Override
protected Void doInBackground(Void... params) {
try {
getPlayersAndTeams(SERVER_ROOT_URI_CYPHER);
} catch (Exception e) {
e.printStackTrace();
}
return null;
}
#Override
protected void onPostExecute(Void aVoid) {
// title of the tabs
tab1.setText(teamList.get(0));
tab2.setText(teamList.get(1));
frg.update(); ------> null
}
}
My fragment
public class Team1Fragment extends Fragment {
TextView textView;
public Team1Fragment() {
// Required empty public constructor
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
View view = inflater.inflate(R.layout.fragment_team1, container, false);
textView = (TextView) view.findViewById(R.id.tvTeam1Fragment);
return view;
}
public void update(){
textView.setText("HELLOOOO");
}
}
Team1Fragment frg = new Team1Fragment();
That's your problem. The only time you instantiate a new fragment when using it with a pager adapter is inside the getItem() method, never anywhere else. Please refer to the Android samples regarding fragments inside a pager with an actionbar. If you did that, make sure you implement everything correctly and then you can do async stuff.
Regarding your main problem:
If you want to update your fragment from an async task, attach your fragment to the task by reference and then update it, if its still attached to the activity.
Regarding the implementation:
If your task resides inside your activity, you notify your activity from within your fragments (use getActivity() inside onAttach() or onViewReady()), then the activity can start the task and attach the fragments to the tasks.
It's better to abstract the whole mechanism with interfaces, so the task doesn't really know about fragments, but about subscribers, which implement the interface TeamDataSubscriber (or something like that) and get the data. A setSubscribers(TeamDataSubscribers... subs) is needed, etc .you hopefully know that stuff.
I am trying to open a fragment, when a dialog is clicked inside another fragment. I am using ActionBarSherlock with Tab. My fragment is attached in the view pager. I have almost done the job. But I can't replace a new fragment inside a view pager. I got an error. I read the thread here. The solution isn't clear.
Error:
10-18 21:34:40.379: E/AndroidRuntime(19618): FATAL EXCEPTION: main
10-18 21:34:40.379: E/AndroidRuntime(19618):
java.lang.IllegalArgumentException: No view found for id 0x7f040032
(com.example.actionbartestwithsherlock:id/pager) for fragment
AllContactsFragment{41fd4ba0 #0 id=0x7f040032} 10-18 21:34:40.379:
E/AndroidRuntime(19618): at
android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:903)
I have three fragment associates with pager named FragmentTab1,FragmentTab2 & FragmentTab3.
My MainActivity & FragmentAdapter looks like below:
public class MainActivity extends SherlockFragmentActivity {
ActionBar.Tab Tab1, Tab2, Tab3, Tab4;
private Context context = this;
// view pager
// Declare Variables
ActionBar actionBar;
ViewPager mPager;
Tab tab;
FragmentAdapter mAdapter;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
// set application in portrait mode
ActivityHelper.initialize(this);
actionBar = getSupportActionBar();
actionBar.setDisplayShowHomeEnabled(true);
actionBar.setDisplayShowTitleEnabled(true);
actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS);
// Locate ViewPager in activity_main.xml
mPager = (ViewPager) findViewById(R.id.pager);
// add an adapter to pager
mPager.setAdapter(new FragmentAdapter(getSupportFragmentManager(),
mPager, actionBar));
addActionBarTabs();
}
private void addActionBarTabs() {
String[] tabs = { "Tab 1", "Tab 2", "Tab 3" };
for (String tabTitle : tabs) {
ActionBar.Tab tab = actionBar.newTab().setText(tabTitle)
.setTabListener(tabListener);
actionBar.addTab(tab);
}
actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS);
}
private ActionBar.TabListener tabListener = new ActionBar.TabListener() {
#Override
public void onTabSelected(ActionBar.Tab tab, FragmentTransaction ft) {
mPager.setCurrentItem(tab.getPosition());
}
#Override
public void onTabUnselected(ActionBar.Tab tab, FragmentTransaction ft) {
}
#Override
public void onTabReselected(ActionBar.Tab tab, FragmentTransaction ft) {
}
};
class FragmentAdapter extends FragmentPagerAdapter implements
ViewPager.OnPageChangeListener {
private ViewPager mViewPager;
final int TOTAL_PAGES = 3;
public FragmentAdapter(FragmentManager fm, ViewPager pager,
ActionBar actionBar) {
super(fm);
this.mViewPager = pager;
this.mViewPager.setOnPageChangeListener(this);
}
#Override
public Fragment getItem(int position) {
switch (position) {
case 0:
return FragmentTab1.newInstance();
case 1:
return FragmentTab2.newInstance();
case 2:
return FragmentTab3.newInstance();
default:
throw new IllegalArgumentException(
"The item position should be less or equal to:"
+ TOTAL_PAGES);
}
}
#Override
public int getCount() {
return TOTAL_PAGES;
}
#Override
public void onPageScrollStateChanged(int arg0) {
}
#Override
public void onPageScrolled(int arg0, float arg1, int arg2) {
}
#Override
public void onPageSelected(int position) {
actionBar.setSelectedNavigationItem(position);
}
}
}
Now, Inside my first tab FragmentTab1, I open a customized dialog when a button clicks. I want to replace new fragment AllContactsFragment in FragmentTab1 when the dialog options are selected.
FragmentTab1 fragment class:
public class FragmentTab1 extends SherlockFragment implements OnClickListener {
Button btnTest;
ViewPager pager;
LinearLayout layoutBlockNumbers;
LinearLayout layoutContact, layoutCallLog, layoutSMSLog, layoutManually;
Context context;
CustomizedDialog dialog;
private static final int CONTACT_PICKER_RESULT = 1001;
private static final String DEBUG_TAG = "Contact List";
private static final double RESULT_OK = -1;
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragmenttab1, container,
false);
layoutBlockNumbers = (LinearLayout) rootView
.findViewById(R.id.layoutAddBlockNumbers);
layoutBlockNumbers.setOnClickListener(this);
return rootView;
}
#Override
public void onClick(View v) {
if (v == layoutCallLog) {
dialog.dismiss();
// want to replace new fragment at position 0 in pager
// problem is here ??? how to open new fragmnet
Fragment allContactsFragment = AllContactsFragment.newInstance();
FragmentTransaction transaction = getChildFragmentManager()
.beginTransaction();
transaction.addToBackStack(null);
transaction.replace(R.id.pager, allContactsFragment).commit();
}
if (v == layoutBlockNumbers) {
// open a dialog
showDialog();
} else if (v == layoutContact) {
openContactList();
dialog.dismiss();
} else if (v == layoutSMSLog) {
}
}
#Override
public void onSaveInstanceState(Bundle outState) {
super.onSaveInstanceState(outState);
setUserVisibleHint(true);
}
// open a dialog
private void showDialog() {
dialog = new CustomizedDialog(getActivity());
dialog.setContentView(R.layout.dialog_add_number_type);
dialog.setTitle("Add Black List Number");
//initialize all linear layouts in dialog
layoutCallLog = (LinearLayout) dialog.findViewById(R.id.layoutCallLog);
layoutContact = (LinearLayout) dialog.findViewById(R.id.layoutContact);
layoutSMSLog = (LinearLayout) dialog.findViewById(R.id.layoutSMSLog);
layoutManually = (LinearLayout) dialog
.findViewById(R.id.layoutManually);
// add listener to several linear layout
layoutContact.setOnClickListener(this);
layoutCallLog.setOnClickListener(this);
layoutSMSLog.setOnClickListener(this);
layoutManually.setOnClickListener(this);
dialog.show();
}
public static Fragment newInstance() {
Fragment f = new FragmentTab1();
return f;
}
}
activity_main.xml looks like below :
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent" >
<android.support.v4.view.ViewPager
android:id="#+id/pager"
android:layout_width="fill_parent"
android:layout_height="wrap_content" >
</android.support.v4.view.ViewPager>
</RelativeLayout>
Can anybody can help me to solve this issue? Sorry for the massive code.
I'm not sure you can do things the way you want to. A ViewPager is not set up the same way a normal container/fragment set up would be. In a ViewPager you're not using fragment transactions to add fragments but rather an adapter that loads instances of fragments from a backing list.
Replacing the fragment would then work as follows:
(1) Create an instance of the fragment you want to add
(2) Add that fragment to the list that is backing your PagerAdapter
(3) Display the new fragment
(4) Remove the old one
The problem with implementing this in your current project is the set up of your adapter. Currently you are using a switch statment that can only return a fixed number of fragments. Your adapter should be set up something like this.
class MyPageAdapter extends FragmentPagerAdapter{
private List<Fragment> fragments
public MyPageAdapter(FragmentManager fm, List<Fragment> fragments) {
super(fm);
this.fragments = fragments;
}
#Override
public Fragment getItem(int position) {
return this.fragments.get(position);
}
#Override
public int getCount() {
return this.fragments.size();
}
}
Then you can just add a method to your adapter class to add or remove new fragments. If you know the index of the fragment you want to replace accomplishing this should be pretty easy. All you have to do is create a new instance of the contacts fragment, add it to your array or list. This Post explains how a ViewPager handles the adding/removing of new content and how to ensure your new fragment is displayed.
After I read this post I solved the answer.
I just add an ID android:id="#+id/fragmentTabLayout1 to top layout of my fragmenttab1.xml . Then call
new fragment as usual:
Fragment allContactsFragment = AllContactsFragment.newInstance();
FragmentTransaction transaction = getChildFragmentManager()
.beginTransaction();
transaction.addToBackStack(null);
// use this id to replace new fragment
transaction.replace(R.id.fragmentTabLayout1, allContactsFragment).commit();