Develop Reference

activity is blank in tab activity

I am creating ListView in my app in tab Activity.but when app runs emulator shows blank activity. I don't know what is the issue with this. Please help. I am not getting list in the tab. I am getting list in simple activity without tab but I can't see list in tab activity. Let me know if you want other information.
This my ArtistTab.java activity
public class ArtistsTab extends Fragment {
ListView listView1;
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View v = inflater.inflate(R.layout.artist, container, false);
listView1 =(ListView)v.findViewById(R.id.listView);
return v;
}
#Override
public void onViewCreated(View view, Bundle savedInstanceState) {
super.onViewCreated(view, savedInstanceState);
// add your code here which executes after the execution of onCreateView() method.
ArrayList<String>my=new ArrayList<>();
my.add("devesh");
my.add("devesh");
my.add("devesh");
my.add("devesh");
ArrayAdapter arrayAdapter=new ArrayAdapter(getActivity(), layout.simple_list_item_1,my);
listView1.setAdapter(arrayAdapter);
}
}
This is my main Activity
public class MainActivity extends AppCompatActivity {
public ViewPagerAdapter pagerAdapter;
private ViewPager mViewPager;
private Toolbar toolbar;
private TabLayout tabLayout;
public static View rootView;
public static int tabNo;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
pagerAdapter = new ViewPagerAdapter(getSupportFragmentManager());
mViewPager = (ViewPager) findViewById(R.id.container);
tabLayout = (TabLayout) findViewById(R.id.tabs);
tabLayout.setupWithViewPager(mViewPager);
mViewPager.setAdapter(pagerAdapter);
tabLayout.setOnTabSelectedListener(new TabLayout.OnTabSelectedListener() {
#Override
public void onTabSelected(TabLayout.Tab tab) {
mViewPager.setCurrentItem(tab.getPosition());//setting current selected item over viewpager
}
#Override
public void onTabUnselected(TabLayout.Tab tab) {
}
#Override
public void onTabReselected(TabLayout.Tab tab) {
}
});
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
getMenuInflater().inflate(R.menu.menu_main, menu);
return true;
}
#Override
public boolean onOptionsItemSelected(MenuItem item) {
int id = item.getItemId();
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
public static class PlaceholderFragment extends Fragment {
private static final String ARG_SECTION_NUMBER = "section_number";
public PlaceholderFragment() {
}
public static PlaceholderFragment newInstance(int sectionNumber) {
PlaceholderFragment fragment = new PlaceholderFragment();
Bundle args = new Bundle();
args.putInt(ARG_SECTION_NUMBER, sectionNumber);
fragment.setArguments(args);
return fragment;
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// View rootView;
switch (getArguments().getInt(ARG_SECTION_NUMBER))
{
case 1: {
rootView = inflater.inflate(R.layout.songs, container, false);
break;
}
case 2: {
rootView = inflater.inflate(R.layout.album, container, false);
break;
}
case 3: {
rootView = inflater.inflate(R.layout.genres, container, false);
break;
}
case 4: {
rootView = inflater.inflate(R.layout.artist, container, false);
break;
}
}
return rootView;
}
}
}
artistTab xml
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical" android:layout_width="match_parent"
android:layout_height="match_parent">
<ListView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:id="#+id/listView" />
</RelativeLayout>

Try like this to tabs with viewpager
public class MainActivity extends AppCompatActivity {
private Toolbar toolbar;
private TabLayout tabLayout;
private ViewPager viewPager;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
getSupportActionBar().setDisplayHomeAsUpEnabled(true);
viewPager = (ViewPager) findViewById(R.id.viewpager);
setupViewPager(viewPager);
tabLayout = (TabLayout) findViewById(R.id.tabs);
tabLayout.setupWithViewPager(viewPager);
}
private void setupViewPager(ViewPager viewPager) {
ViewPagerAdapter adapter = new ViewPagerAdapter(getSupportFragmentManager());
adapter.addFragment(new ArtistsTab(), "ArtistsTab");
adapter.addFragment(new SongsTab(), "Songs");
//Do your stuff here
viewPager.setAdapter(adapter);
}
class ViewPagerAdapter extends FragmentPagerAdapter {
private final List<Fragment> mFragmentList = new ArrayList<>();
private final List<String> mFragmentTitleList = new ArrayList<>();
public ViewPagerAdapter(FragmentManager manager) {
super(manager);
}
#Override
public Fragment getItem(int position) {
return mFragmentList.get(position);
}
#Override
public int getCount() {
return mFragmentList.size();
}
public void addFragment(Fragment fragment, String title) {
mFragmentList.add(fragment);
mFragmentTitleList.add(title);
}
#Override
public CharSequence getPageTitle(int position) {
return mFragmentTitleList.get(position);
}
}
}

Orientation with Fragments, text is not saved

When I change the orientation of my mobile phone, the text content is not saved and the default text is put in the textview, in my android manifest in my activity Cafeteria I have this
android:configChanges="keyboardHidden|orientation"
Cafeteria
public class Cafeteria extends BaseActivity {
private SectionsPagerAdapter mSectionsPagerAdapter;
private ViewPager mViewPager;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_cafeteria);
/*Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);*/
mSectionsPagerAdapter = new SectionsPagerAdapter(getSupportFragmentManager());
mViewPager = (ViewPager) findViewById(R.id.container);
mViewPager.setAdapter(mSectionsPagerAdapter);
TabLayout tabLayout = (TabLayout) findViewById(R.id.tabs);
tabLayout.setupWithViewPager(mViewPager);
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
getMenuInflater().inflate(R.menu.menu_cafeteria, menu);
return true;
}
#Override
public boolean onOptionsItemSelected(MenuItem item) {
int id = item.getItemId();
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
public class SectionsPagerAdapter extends FragmentPagerAdapter {
public SectionsPagerAdapter(FragmentManager fm) {
super(fm);
}
#Override
public Fragment getItem(int position) {
switch (position){
case 0:
Oferta oferta = new Oferta();
return oferta;
case 1:
MenuCafe men = new MenuCafe();
return men;
case 2:
Carta carta = new Carta();
return carta;
default:
return null;
}
}
#Override
public int getCount() {
// Show 3 total pages.
return 3;
}
#Override
public CharSequence getPageTitle(int position) {
switch (position) {
case 0:
return getString(R.string.ofertas);
case 1:
return getString(R.string.menu);
case 2:
return getString(R.string.carta);
}
return null;
}
}
MenuCafe
public class MenuCafe extends Fragment{
private RecyclerView recyclerView;
private LinearLayoutManager linearLayoutManager;
private AdaptadorMenu adapter;
private List<Menu> menu;
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment_menu, container, false);
recyclerView = (RecyclerView) rootView.findViewById(R.id.recycler_view_menu);
menu = new ArrayList<>();
load_data_from_server(0);
linearLayoutManager = new LinearLayoutManager(getContext());
recyclerView.setLayoutManager(linearLayoutManager);
adapter = new AdaptadorMenu(getContext(),menu);
recyclerView.setAdapter(adapter);
return rootView;
}
}
Thank you for the help

Try giving this in Android manifest file
android:screenOrientation="portrait"

You must save text content , because when rotation screen ,your activity will reset life cycle of android, same as first open.
See how to save the status here: Losing data when rotate screen

Transfer data between fragments with pagerAdapter

Current Replaced fragment.
public class SlidingTabsFragment extends Fragment {
private SlidingTabLayout mSlidingTabLayout;
private ViewPager mViewPager;
public SlidingTabsFragment(){}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
return inflater.inflate(R.layout.fragment_sample, container, false);
}
#Override
public void onViewCreated(View view, Bundle savedInstanceState) {
Context context= getActivity();
mViewPager = (ViewPager) view.findViewById(R.id.viewpager);
FragmentManager fm = getFragmentManager();
mViewPager.setAdapter(new Harkayin_PagerAdapter(fm,context));
mSlidingTabLayout = (SlidingTabLayout) view.findViewById(R.id.sliding_tabs);
mSlidingTabLayout.setViewPager(mViewPager);
}
...
Here is PagerAdapter, which holds three sliding pages with same fragment /Fragment_Hashvehamarner();/
public class Harkayin_PagerAdapter extends FragmentStatePagerAdapter {
private Context mContext;
public Harkayin_PagerAdapter(FragmentManager fm, Context context) {
super(fm);
mContext = context;
}
#Override
public int getCount() { return 3;}
#Override
public CharSequence getPageTitle(int position) {
String[] tabs= mContext.getResources().getStringArray(R.array.hashvehamar_tabs);
return tabs[position];
}
#Override
public Fragment getItem(int position) {
Fragment fragment = null;
switch (position){
case 0:
fragment = new Fragment_Hashvehamarner();
break;
case 1:
fragment = new Fragment_Hashvehamarner();
break;
case 2:
fragment = new Fragment_Hashvehamarner();
break;
default:
break;
}
if (fragment != null){
return fragment;
}else {
// error in creating fragment
Log.e("Harkayin_PagerAdapter", "Error in creating fragment");
return null;
}
}
}
And finally the page holder fragment
public class Fragment_Hashvehamarner extends Fragment {
ExpandableListAdapter listAdapter;
ExpandableListView expListView;
HashMap<String, List<String[]>> listDataChild;
ArrayList<String[]> listHeaderData;
View rootView;
public Fragment_Hashvehamarner() {}
...
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
rootView = inflater.inflate(R.layout.fragment_hashvayin_plan, container, false);
return rootView;
}
#Override
public void onActivityCreated(#Nullable Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
// get the listview
expListView = (ExpandableListView) rootView.findViewById(R.id.lvExp);
// preparing list data
prepareListData();
listAdapter = new ExpandableListAdapter(rootView.getContext(), listHeaderData,
listDataChild);
// setting list adapter
expListView.setAdapter(listAdapter);
// Inflate the layout for this fragment
private void prepareListData() {
DataAdapter mDbHelper = new DataAdapter(rootView.getContext());
mDbHelper.createDatabase();
mDbHelper.open();
listHeaderData = new ArrayList<String[]>(mDbHelper.getHashvehamarHeader(1));
listDataChild = new HashMap<String, List<String[]>>(mDbHelper.getHashvehamarChildData(1));
mDbHelper.close();
}
Now the question: how to get current page position from PageAdapter into current page holder fragment /Fragment_Hashvehamarner()/.

add below method to your Fragment_Hashvehamarner class.
public static final String EXTRA_PAGE_POSITION = "page.position";
public static Fragment_Hashvehamarner newInstance(int id) {
Bundle args = new Bundle();
args.putInt(EXTRA_PAGE_POSITION, id);
Fragment_Hashvehamarner fragment = new Fragment_Hashvehamarner();
fragment.setArguments(args);
return fragment;
}
and in onCreate method of Fragment_Hashvehamarner:
int mSelectedPosition= getArguments().getInt(EXTRA_PAGE_POSITION);
then in your adapter:
public Fragment getItem(int position) {
Fragment fragment = Fragment_Hashvehamarner.newInstance(position);
return fragment;
}

how to move to new fragment at on OnItemClickListener()

In my application I want to put a ListView in the first Fragment and I want to move to a new Fragment when I clicked on an item such that each item has its own details
in my code.
I implemented it to move to another Activity, but now my manager says it must go to another Fragment instead of other activity. I'm new to the Fragment world and I don't know how to do this. The manager says that I can use the list fragment but I have not found any useful code.
This my code:
public class MainActivity extends FragmentActivity {
SectionsPagerAdapter mSectionsPagerAdapter;
static ProgressDialog pd ;
ViewPager mViewPager;
List<Fragment> fragments ;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
// Create the adapter that will return a fragment for each of the three
// primary sections of the app.
fragments = new Vector<Fragment>();
fragments.add(Fragment.instantiate(this, FragmentOne.class.getName()));
fragments.add(Fragment.instantiate(this, FragmentTwo.class.getName()));
fragments.add(Fragment.instantiate(this, FragmentThree.class.getName()));
fragments.add(Fragment.instantiate(this, FragmentFour.class.getName()));
fragments.add(Fragment.instantiate(this, FragmentFive.class.getName()));
fragments.add(Fragment.instantiate(this, FragmentSix.class.getName()));
mSectionsPagerAdapter=new SectionsPagerAdapter(super.getSupportFragmentManager());
// Set up the ViewPager with the sections adapter.
mViewPager = (ViewPager) findViewById(R.id.pager);
pd = new ProgressDialog(this);
mViewPager.setAdapter(mSectionsPagerAdapter);
//
}
public class SectionsPagerAdapter extends FragmentPagerAdapter {
public SectionsPagerAdapter(FragmentManager fm) {
super(fm);
}
#Override
public Fragment getItem(int position) {
int _pos = position % 6;
return fragments.get(_pos);
}
#Override
public int getCount() {
// Show 3 total pages.
return 6;
}
#Override
public CharSequence getPageTitle(int position) {
final String title_section4="Section4";
final String title_section5="Section5";
final String title_section6="Section6";
final String title_section1="Section1";
final String title_section2="Section2";
final String title_section3="Section3";
Locale l = Locale.getDefault();
switch (position) {
case 0:
return title_section1.toUpperCase(l);
case 1:
return title_section2.toUpperCase(l);
case 2:
return title_section3.toUpperCase(l);
case 3:
return title_section4.toUpperCase(l);
case 4:
return title_section5.toUpperCase(l);
case 5:
return title_section6.toUpperCase(l);
}
return null;
}
}
public static class FragmentOne extends Fragment {
ArrayList< String > ar;
ArrayAdapter< String > ad ;
ListView lv ;
TextView tv;
public FragmentOne() {
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.one, container, false);
tv = (TextView) rootView.findViewById(R.id.mywidget);
tv.setSelected(true);
ar = new ArrayList<String>();
lv = (ListView) rootView.findViewById(R.id.listView1);
for (int i = 0 ; i< 10 ; i++){
ar.add("My Item " + String.valueOf(i));
}
ad = new ArrayAdapter<String>
(getActivity().getApplicationContext(), android.R.layout.simple_dropdown_item_1line,
ar);
lv.setAdapter(ad);
lv.setOnItemClickListener(new OnItemClickListener() {
public void onItemClick(AdapterView<?> parent, View view,
int position, long id) {
Toast t = Toast.makeText(getActivity(), "Message",
Toast.LENGTH_SHORT);
t.show();
Intent i = new Intent(getActivity(), tst.class);
startActivity(i);
}
});
return rootView;
}
}
public static class FragmentTwo extends Fragment {
public FragmentTwo() {
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.two, container, false);
return rootView;
}
}
public static class FragmentThree extends Fragment {
public FragmentThree() {
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.three, container, false);
return rootView;
}
}
public static class FragmentFour extends Fragment {
public FragmentFour() {
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.four, container, false);
return rootView;
}
}
public static class FragmentFive extends Fragment {
public FragmentFive() {
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.five, container, false);
return rootView;
}
}
public static class FragmentSix extends Fragment {
public FragmentSix() {
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.six, container, false);
return rootView;
}
}
}

You have to replace the fragment using Transaction
See here:
http://developer.android.com/guide/components/fragments.html#Example
Check the showDetails(int index) method of TitlesFragment class:
FragmentTransaction ft = getFragmentManager().beginTransaction();
if (index == 0) {
ft.replace(R.id.details, details);
} else {
ft.replace(R.id.a_item, details);
}
ft.setTransition(FragmentTransaction.TRANSIT_FRAGMENT_FADE);
ft.commit();

Use pager and give integer index to each fragment then use following code in itemclick
ViewPager pager;
pager.setCurrentItem(index, true);

How to edit a fragment and save its state?

I have to add TextViews and EditTexts in a Fragment ( Details() ) when i click in a button ( Button add ).
I was able to insert them, but when i swipe my 6 fragments and return in the first fragment this items disappear.
Can someone help me?
FragmentActivity class:
public class SubActivityTab extends FragmentActivity
{
SectionsPagerAdapter spa;
ViewPager vp;
#Override
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.scrolltab_layout);
spa = new SectionsPagerAdapter(getSupportFragmentManager(), this);
vp = (ViewPager) findViewById(R.id.pager);
vp.setAdapter(spa);
}
}
FragmentPagerAdapter class:
public class SectionsPagerAdapter extends FragmentPagerAdapter
{
Context c;
public SectionsPagerAdapter(FragmentManager fm, Context c) {
super(fm);
this.c = c;
}
#Override
public Fragment getItem(int position) {
switch(position)
{
case 0:
return Details.newInstance();
...
}
return null;
}
#Override
public int getCount() {
return 6;
}
#Override
public CharSequence getPageTitle(int position) {
Locale l = Locale.getDefault();
switch (position)
{
case 0:
return c.getString(R.string.tab1).toUpperCase(l);
...
}
return null;
}
}
Fragment class:
public final class Details extends Fragment {
public static View layout;
public static LinearLayout ll;
public static Details newInstance()
{
return new Details();
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState)
{
super.onCreateView(inflater, container, savedInstanceState);
layout = inflater.inflate(R.layout.details, container, false);
ll = (LinearLayout) layout.findViewById(R.id.linearlayout2);
Button add = (Button) layout.findViewById(R.id.button_add);
add.setOnClickListener(new OnClickListener(){
#Override
public void onClick(View v) {
insertLine();
insertClassEditText();
insertLevel();
}});
return layout;
}
private void insertLine()
{
View temp = (View) layout.findViewById(R.id.line);
View v = new View(temp.getContext());
v.setBackgroundColor(Color.rgb(209, 209, 209));
v.setId(0);
v.setLayoutParams(temp.getLayoutParams());
ll.addView(v);
}
private void insertClassEditText()
{
TextView label_classe = (TextView) layout.findViewById(R.id.textView10);
EditText edit_classe = (EditText) layout.findViewById(R.id.editText9);
TextView new_label_classe = new TextView(label_classe.getContext());
EditText new_edit_classe = new EditText(edit_classe.getContext());
new_label_classe.setId(1);
new_edit_classe.setId(2);
new_label_classe.setText("Label");
new_label_classe.setTextAppearance(new_label_classe.getContext(), android.R.style.TextAppearance_Medium);
ll.addView(new_label_classe);
new_edit_classe.setInputType(edit_classe.getInputType());
new_edit_classe.setLayoutParams(edit_classe.getLayoutParams());
ll.addView(new_edit_classe);
}
private void insertLevel()
{
TextView label_lv = (TextView) layout.findViewById(R.id.textView11);
EditText edit_lv = (EditText) layout.findViewById(R.id.editText10);
TextView new_label_lv = new TextView(label_lv.getContext());
EditText new_edit_lv = new EditText(edit_lv.getContext());
new_label_lv.setId(3);
new_edit_lv.setId(4);
new_label_lv.setText(label_lv.getText());
new_label_lv.setTextAppearance(new_label_lv.getContext(), android.R.style.TextAppearance_Medium);
ll.addView(new_label_lv);
new_edit_lv.setInputType(edit_lv.getInputType());
new_edit_lv.setLayoutParams(edit_lv.getLayoutParams());
ll.addView(new_edit_lv);
}
}

I believe ViewPager recycles the views as you swipe and therefore when you go back, it rebuilds from onCreateView.
I would suggest setting some tags and passing to onSaveInstanceState.
private void onSaveInstanceState(Bundle b) {
if (label_classe != null) {
b.putBoolean("label_classe", true);
}
}
Then in onCreateView you take savedInstanceState, check what elements were created and re-create them.
So in Fragment:
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState)
{
....
if (savedInstanceState.getBoolean("label_classe")) {
insertClassEditText();
}
....
}
And just to be sure, in Activity:
public class SubActivityTab extends FragmentActivity
{
SectionsPagerAdapter spa;
ViewPager vp;
#Override
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.scrolltab_layout);
spa = new SectionsPagerAdapter(getSupportFragmentManager(), this);
vp = (ViewPager) findViewById(R.id.pager);
vp.setSaveState(true);
vp.setSaveFromParentEnabled(true);
vp.setAdapter(spa);
}
}

Try to change your onCreateView method to:
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState){
if(layout ==null){
layout = inflater.inflate(R.layout.details, container, false); //Dont inflate every time.layout saved, data of layout,like EidtText also saved.
}
ViewParent parent = mLayout.getParent();
if(parent!=null){
((ViewGroup)parent).removeView(layout);//the view will be add to NoSaveStateFrameLayout after onCreateView,so remove self everytime
}
return layout;
}