Develop Reference

How to disable/enable the ActionBar.TabListener on some condition

I have implemented ActionBar.TabListener with viewpager. Now I want to disable tab click for some condition
I have stopped swipe using TouchListner but want to do same for Tab Click.
Here is my code.
MainActivity.java
public class MainActivity extends FragmentActivity implements ActionBar.TabListener {
ActionBar actionBar;
ViewPager viewPager;
String check ="";
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
viewPager = (ViewPager) findViewById(R.id.pager);
FragmentManager fragmentManager = getSupportFragmentManager();
viewPager.setAdapter(new MyAdpter(fragmentManager));
viewPager.setOnTouchListener(new View.OnTouchListener() {
#Override
public boolean onTouch(View arg0, MotionEvent arg1) {
// TODO Auto-generated method stub
if ("".equals(check)) {
return true;
}
return false;
}
});
viewPager.setOnPageChangeListener(new ViewPager.OnPageChangeListener() {
#Override
public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
}
#Override
public void onPageSelected(int position) {
actionBar.setSelectedNavigationItem(position);
}
#Override
public void onPageScrollStateChanged(int state) {
}
});
actionBar = getActionBar();
actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS);
ActionBar.Tab tab1 = actionBar.newTab();
tab1.setText("Tab 1");
tab1.setTabListener(this);
ActionBar.Tab tab2 = actionBar.newTab();
tab2.setText("Tab 2");
tab2.setTabListener(this);
ActionBar.Tab tab3 = actionBar.newTab();
tab3.setText("Tab 3");
tab3.setTabListener(this);
actionBar.addTab(tab1);
actionBar.addTab(tab2);
actionBar.addTab(tab3);
viewPager.setCurrentItem(2, false);
}
#Override
public void onTabSelected(ActionBar.Tab tab, FragmentTransaction ft) {
viewPager.setCurrentItem(tab.getPosition());
}
#Override
public void onTabUnselected(ActionBar.Tab tab, FragmentTransaction ft) {
}
#Override
public void onTabReselected(ActionBar.Tab tab, FragmentTransaction ft) {
}
}
MyAdpter.java
class MyAdpter extends FragmentPagerAdapter{
public MyAdpter(FragmentManager fm) {
super(fm);
}
#Override
public Fragment getItem(int position) {
Fragment fragment = null;
if(position==0){
fragment = new FragmentA();
}
if(position==1){
fragment = new FragmentB();
}
if(position==2){
fragment = new FragmentC();
}
return fragment;
}
#Override
public int getCount() {
return 3;
}
}
FragmentA.java
public class FragmentA extends Fragment {
#Nullable
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
return inflater.inflate(R.layout.fragment_a , container,false);
}
}
FragmentB/FragmentC are similar to FragmentA
activity_main.xml
<android.support.v4.view.ViewPager xmlns:android="http://schemas.android.com/apk/res/android"
android:id="#+id/pager"
android:layout_width="match_parent"
android:layout_height="match_parent" >
</android.support.v4.view.ViewPager>
ScreenShot

you can do something like this..
in OnCheckedChanged listener for checkbox, you can specify which tabs are enable..
just by doing
// to enable
tabLayout.getChildAt(position).setEnabled(true);
// or to disable
tabLayout.getChildAt(position).setClickable(false);.
use this property to enable or disable clicks on tab.

SherlockFragmentActivity tabs onBackPressed()

SherlockFragmentActivity with 3 tabs How can i add onBackPressed() in all tabs? It is possible? this code is default abs Viewpage totorial from http://www.androidbegin.com/tutorial/android-actionbarsherlock-viewpager-tabs-tutorial/. Any help?
MainActivity.jav
public class MainActivity extends SherlockFragmentActivity {
private FragmentTab2 F2;
ActionBar mActionBar;
ViewPager mPager;
Tab tab;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mActionBar = getSupportActionBar();
mActionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS);
mPager = (ViewPager) findViewById(R.id.pager);
FragmentManager fm = getSupportFragmentManager();
ViewPager.SimpleOnPageChangeListener ViewPagerListener = new ViewPager.SimpleOnPageChangeListener() {
#Override
public void onPageSelected(int position) {
super.onPageSelected(position);
mActionBar.setSelectedNavigationItem(position);
}
};
mPager.setOnPageChangeListener(ViewPagerListener);
ViewPagerAdapter viewpageradapter = new ViewPagerAdapter(fm);
mPager.setAdapter(viewpageradapter);
ActionBar.TabListener tabListener = new ActionBar.TabListener() {
#Override
public void onTabSelected(Tab tab, FragmentTransaction ft) {
mPager.setCurrentItem(tab.getPosition());
}
#Override
public void onTabUnselected(Tab tab, FragmentTransaction ft) {
}
#Override
public void onTabReselected(Tab tab, FragmentTransaction ft) {
}
};
tab = mActionBar.newTab().setText("Tab1").setTabListener(tabListener);
mActionBar.addTab(tab);
tab = mActionBar.newTab().setText("Tab2").setTabListener(tabListener);
mActionBar.addTab(tab);
tab = mActionBar.newTab().setText("Tab3").setTabListener(tabListener);
mActionBar.addTab(tab);
}
#Override
public void onBackPressed()
{
super.onBackPressed();
F2.onBackPressed();
}
}
ViewPagerAdapter.java
public class ViewPagerAdapter extends FragmentPagerAdapter {
final int PAGE_COUNT = 3;
public ViewPagerAdapter(FragmentManager fm) {
super(fm);
}
#Override
public Fragment getItem(int arg0) {
switch (arg0) {
case 0:
FragmentTab1 fragmenttab1 = new FragmentTab1();
return fragmenttab1;
case 1:
FragmentTab2 fragmenttab2 = new FragmentTab2();
return fragmenttab2;
case 2:
FragmentTab3 fragmenttab3 = new FragmentTab3();
return fragmenttab3;
}
return null;
}
#Override
public int getCount() {
return PAGE_COUNT;
}
}
FragmentTab2.java
public class FragmentTab2 extends SherlockFragment {
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.fragmenttab2, container, false);
return view;
}
#Override
public void onSaveInstanceState(Bundle outState) {
super.onSaveInstanceState(outState);
setUserVisibleHint(true);
}
public boolean onBackPressed() {
Toast.makeText(getActivity(), "this is my Toast message!!! =)",
Toast.LENGTH_LONG).show();
return false;
}
}
Error
Exception dispatching finished signal.
Exception in MessageQueue callback: handleReceiveCallback
java.lang.NullPointerException
at com.androidbegin.absviewpagertutorial.MainActivity.onBackPressed(MainActivity.java:87)
at android.app.Activity.onKeyUp(Activity.java:2193)
at android.view.KeyEvent.dispatch(KeyEvent.java:2664)
at android.app.Activity.dispatchKeyEvent(Activity.java:2423)
at com.actionbarsherlock.app.SherlockFragmentActivity.dispatchKeyEvent(SherlockFragmentActivity.java:121)

Use onPageSelected to check if user is on FragmentTab2 then initialize F2 as:
public void onPageSelected(int position) {
super.onPageSelected(position);
mActionBar.setSelectedNavigationItem(position);
if(position==1)
F2 = (FragmentTab2)viewpageradapter.getItem(position);
else
F2 =null;
}
and also put null check in onBackPressed of Activity :
#Override
public void onBackPressed()
{
super.onBackPressed();
if(F2 !=null)
F2.onBackPressed();
}

Access variable from within a fragment

I have a main activity consisting of three tabs with each its corresponding fragment. In each of the fragment, there is one textview. Also, I am using ViewPager to help me navigate through the tabs.
When I try to access a TextView from within a fragment, I get a NULL POINTER error. Here is my code:
Fragment 1 (tab1):
public class FragmentA extends Fragment{
TextView tv1;
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View parentView = inflater.inflate(R.layout.fragment_a, container, false);
//******* Error Here **********
tv1 = (TextView) getView().findViewById(R.id.fragAtv1);
return parentView;
}
}
Main Activity:
public class SwipeTabs extends FragmentActivity implements TabListener{
ViewPager viewPager;
ActionBar actionBar;
#Override
protected void onCreate(Bundle savedInstance) {
super.onCreate(savedInstance);
setContentView(R.layout.main_swipe);
viewPager = (ViewPager) findViewById(R.id.pager);
viewPager.setAdapter(new MySwipeAdapter(getSupportFragmentManager()));
viewPager.setOnPageChangeListener(new ViewPager.OnPageChangeListener() {
#Override
public void onPageSelected(int tab_pos) {
actionBar.setSelectedNavigationItem(tab_pos);
}
#Override
public void onPageScrolled(int arg0, float arg1, int arg2) {
}
#Override
public void onPageScrollStateChanged(int arg0) {
}
});
// Initialize action bar with tabs
actionBar = setupActionBar();
}
#Override
public void onTabReselected(Tab tab, FragmentTransaction arg1) {
}
#Override
public void onTabSelected(Tab tab, FragmentTransaction arg1) {
viewPager.setCurrentItem(tab.getPosition());
}
#Override
public void onTabUnselected(Tab tab, FragmentTransaction arg1) {
}
private ActionBar setupActionBar(){
ActionBar newAB = getActionBar();
newAB.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS);
ActionBar.Tab tab1 = newAB.newTab();
tab1.setText("Tab 1");
tab1.setTabListener(this);
newAB.addTab(tab1);
ActionBar.Tab tab2 = newAB.newTab();
tab2.setText("Tab 2");
tab2.setTabListener(this);
newAB.addTab(tab2);
ActionBar.Tab tab3 = newAB.newTab();
tab3.setText("Tab 3");
tab3.setTabListener(this);
newAB.addTab(tab3);
return newAB;
}
}
class MySwipeAdapter extends FragmentStatePagerAdapter{
//Construstor: retuns the
public MySwipeAdapter(FragmentManager fm) {
super(fm);
}
#Override
public Fragment getItem(int position) {
Fragment fragment = null;
switch(position){
case 0:
fragment = new FragmentA();
break;
case 1:
fragment = new FragmentB();
break;
case 2:
fragment = new FragmentC();
break;
}
return fragment;
}
#Override
public int getCount() {
return 3;
}
}

You can't access getView() and get a non-null value before onCreateView() returns. That doesn't make sense logically. Instead, do this:
tv1 = (TextView) parentView.findViewById(R.id.fragAtv1);
You could also override onViewCreated() but this is simpler.

Instead of using getView.findviewbyId try parentView.findViewById.
tv1 = (TextView) parentView.findViewById(R.id.fragAtv1);

how to renew the fragment when click at the tabs

I would like to create a new fragment every time when I click its tab.
I tried to get the tab and to create a fragment. But it doesn't seem to work.
Here is my code.
Main Activity
public class MainActivity extends FragmentActivity {
private static ViewPager viewPager;
private static TabsPagerAdapter mAdapter;
private static ActionBar actionBar;
// Tab titles
private String[] tabs = { "TopRated", "Hots", "NEW"};
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
// Initialization
viewPager = (ViewPager) findViewById(R.id.pager);
actionBar = getActionBar();
mAdapter = new TabsPagerAdapter(getSupportFragmentManager());
viewPager.setAdapter(mAdapter);
//actionBar.setHomeButtonEnabled(false);
actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS);
// Adding Tabs
for (String tab_name : tabs) {
actionBar.addTab(actionBar.newTab().setText(tab_name).setTabListener(tabListener));
}
/**
* on swiping the viewpager make respective tab selected
* */
viewPager.setOnPageChangeListener(new ViewPager.OnPageChangeListener() {
#Override
public void onPageSelected(int position) {
// on changing the page
// make respected tab selected
actionBar.setSelectedNavigationItem(position);
}
#Override
public void onPageScrolled(int arg0, float arg1, int arg2) {
}
#Override
public void onPageScrollStateChanged(int arg0) {
}
});
}
static ActionBar.TabListener tabListener = new ActionBar.TabListener() {
#Override
public void onTabReselected(Tab tab, FragmentTransaction ft) {
}
#Override
public void onTabSelected(Tab tab, FragmentTransaction ft) {
viewPager.setCurrentItem(tab.getPosition());
}
#Override
public void onTabUnselected(Tab tab, FragmentTransaction ft) {
}
};
TabsPagerAdapter
public class TabsPagerAdapter extends FragmentPagerAdapter {
public TabsPagerAdapter(FragmentManager fm) {
super(fm);
}
#Override
public int getItemPosition(Object object) {
return POSITION_NONE;
}
#Override
public Fragment getItem(int index) {
switch (index) {
case 0:
return new TopRatedFragment();
case 1:
return new HotStoryFragment();
case 2:
return new AllClassFragment();
}
return null;
}
#Override
public int getCount() {
// get item count - equal to number of tabs
return 3;
}
One of the fragments
public class HotStoryFragment extends Fragment {
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
Log.d("Refresh_F","(2) HotStory");
View rootView = inflater.inflate(R.layout.fragment_hotstory, container, false);
TextView tvStudy = (TextView)rootView.findViewById(R.id.text);
return rootView;
}

How to get which fragment has been selected

I am creating a tab application, using fragments.
I have successfully created tabs, but now I need to create an object when a specific fragment is selected. e.g. When I select SettingsTab I need to call a function that is defined in Test class. and similarly destroy
// SettingsTab
package com.example.sensorspositioningn;
import android.app.Fragment;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
public class SettingsTab extends Fragment {
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
// Inflate the layout for this fragment
return inflater.inflate(R.layout.settingstab, container, false);
}
}
Here is the code in mainActivity:
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
appContext = getApplicationContext();
//ActionBar
ActionBar actionbar = getActionBar();
actionbar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS);
ActionBar.Tab Tab1= actionbar.newTab().setText("Tab1");
ActionBar.Tab Tab2= actionbar.newTab().setText("Tab2");
ActionBar.Tab Tab3= actionbar.newTab().setText("Tab3");
ActionBar.Tab SettingsTab = actionbar.newTab().setText("Settings");
Fragment Tab1F= new Tab1();
Fragment Tab2F= new Tab2();
Fragment Tab3F= new Tab3();
Fragment mSettingsFragment = new SettingsTab();
Tab1.setTabListener(new MyTabsListener(Tab1F));
Tab1.setTabListener(new MyTabsListener(Tab2F));
Tab1.setTabListener(new MyTabsListener(Tab3F));
SettingsTab.setTabListener(new MyTabsListener(mSettingsFragment));
actionbar.addTab(Tab1);
actionbar.addTab(Tab2);
actionbar.addTab(Tab3);
actionbar.addTab(SettingsTab);
}
protected void onSaveInstanceState(Bundle outState) {
super.onSaveInstanceState(outState);
outState.putInt("tab", getActionBar().getSelectedNavigationIndex());
}
class MyTabsListener implements ActionBar.TabListener {
public Fragment fragment;
public MyTabsListener(Fragment fragment) {
this.fragment = fragment;
}
public void onTabReselected(Tab tab, FragmentTransaction ft) {
Toast.makeText(MainActivity.appContext, "Reselected!", Toast.LENGTH_LONG).show();
}
public void onTabSelected(Tab tab, FragmentTransaction ft) {
ft.replace(R.id.fragment_container, fragment);
}
public void onTabUnselected(Tab tab, FragmentTransaction ft) {
ft.remove(fragment);
}
}

In your ActionBar.TabListener you can do this - (I'm assuming that you need the object to be in the Activity)
class MyTabsListener implements ActionBar.TabListener {
public Fragment fragment;
public MyTabsListener(Fragment fragment) {
this.fragment = fragment;
}
public void onTabReselected(Tab tab, FragmentTransaction ft) {
Toast.makeText(MainActivity.appContext, "Reselected!", Toast.LENGTH_LONG).show();
}
public void onTabSelected(Tab tab, FragmentTransaction ft) {
ft.replace(R.id.fragment_container, fragment);
if(fragment instanceof SettingsTab) {
// Create your object, call your function
}
}
public void onTabUnselected(Tab tab, FragmentTransaction ft) {
ft.remove(fragment);
if(fragment instanceof SettingsTab) {
// Destroy your object
}
}
}

Try this
public void onTabSelected(Tab tab, FragmentTransaction ft) {
ft.replace(R.id.fragment_container, fragment);
if(fragment instanceof SettingsTab){
doSettingsMethod();
}
if(fragment instanceof Tab1){
doOtherMethod1();
}
if(fragment instanceof Tab2){
doOtherMethod2();
}
if(fragment instanceof Tab3){
doOtherMethod3();
}
}
Also you may change TabListener class in this way. As for me it's a better design.
class MyTabsListener implements ActionBar.TabListener {
public Fragment fragment;
private final Runnable onSelect;
public MyTabsListener(Fragment fragment) {
this.fragment = fragment;
this.onSelect = null;
}
public MyTabsListener(Fragment fragment, Runnable onSelect) {
this.fragment = fragment;
this.onSelect = onSelect;
}
public void onTabReselected(Tab tab, FragmentTransaction ft) {
Toast.makeText(MainActivity.appContext, "Reselected!", Toast.LENGTH_LONG).show();
}
public void onTabSelected(Tab tab, FragmentTransaction ft) {
ft.replace(R.id.fragment_container, fragment);
if(onSelect != null){
fragment.getActivity().runOnUiThread(onSelect);
}
}
public void onTabUnselected(Tab tab, FragmentTransaction ft) {
ft.remove(fragment);
}
}

The only official source I found to this was on the developer site:
http://developer.android.com/training/implementing-navigation/lateral.html
They simply put arguments for each created fragment, and read the arguments when the fragments get selected.

By default if you select a tab it will be highlighted. If you want to select Explicitly means use the given commented code under onTabSelected(TabLayout.Tab tab) with your specified tab index position. This code will explains about change fragment on tab selected position using viewpager.
public class GalleryFragment extends Fragment implements TabLayout.OnTabSelectedListener
{
private ViewPager viewPager;public ViewPagerAdapter adapter;private TabLayout tabLayout;
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment_gallery, container, false);
viewPager = (ViewPager) rootView.findViewById(R.id.viewpager);
adapter = new ViewPagerAdapter(getChildFragmentManager());
adapter.addFragment(new PaymentCardFragment(), "PAYMENT CARDS");
adapter.addFragment(new LoyaltyCardFragment(), "LOYALTY CARDS");
viewPager.setAdapter(adapter);
tabLayout = (TabLayout) rootView.findViewById(R.id.tabs);
tabLayout.setupWithViewPager(viewPager);
tabLayout.setOnTabSelectedListener(this);
}
#Override
public void onTabSelected(TabLayout.Tab tab) {
//This will be called 2nd when you select a tab or swipe using viewpager
final int position = tab.getPosition();
Log.i("card", "Tablayout pos: " + position);
//TabLayout.Tab tabdata=tabLayout.getTabAt(position);
//tabdata.select();
tabLayout.post(new Runnable() {
#Override
public void run() {
if (position == 0) {
PaymentCardFragment paymentCardFragment = getPaymentCardFragment();
if (paymentCardFragment != null) {
VerticalViewpager vp = paymentCardFragment.mypager;
if(vp!=null)
{
//vp.setCurrentItem(position,true);
vp.setCurrentItem(vp.getAdapter().getCount()-1,true);
}
}
}
if (position == 1) {
LoyaltyCardFragment loyaltyCardFragment = getLoyaltyCardFragment();
if (loyaltyCardFragment != null) {
VerticalViewpager vp = loyaltyCardFragment.mypager;
if(vp!=null)
{
vp.setCurrentItem(position);
}
}
}
}
});
}
#Override
public void onTabUnselected(TabLayout.Tab tab) {
//This will be called 1st when you select a tab or swipe using viewpager
}
#Override
public void onTabReselected(TabLayout.Tab tab) {
//This will be called only when you select the already selected tab(Ex: selecting 3rd tab again and again)
}
private PaymentCardFragment getLoyaltyCardFragment() {
Fragment f = adapter.mFragmentList.get(viewPager.getCurrentItem());
if(f instanceof PaymentCardFragment)
{
return (PaymentCardFragment) f;
}
return null;
}
private LoyaltyCardFragment getPaymentCardFragment() {
Fragment f = adapter.mFragmentList.get(viewPager.getCurrentItem());
if(f instanceof LoyaltyCardFragment)
{
return (LoyaltyCardFragment) f;
}
return null;
}
class ViewPagerAdapter extends FragmentPagerAdapter {
public List<Fragment> mFragmentList = new ArrayList<>();
private final List<String> mFragmentTitleList = new ArrayList<>();
public void addFragment(Fragment fragment, String title) {
mFragmentList.add(fragment);
mFragmentTitleList.add(title);
}
}
}