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Java Android remove name of Application

I have a fragment and an activity. I want to display name of tags(fragments) but I don't want to show name of application in actionBar.
This is my activity: when I remove an ActionBarActivity I can not use a FragmentManager
public class ObjectListActivity extends ActionBarActivity implements android.support.v7.app.ActionBar.TabListener {
private ViewPager viewPager;
private android.support.v7.app.ActionBar actionBar;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_object_list2);
// View pager for showing many fragments over a single activity
viewPager = (ViewPager) findViewById(R.id.pager);
// Getting fragment manager to control fragments
FragmentManager fragmnetManager = getSupportFragmentManager();
// Setting adapter over view pager
viewPager.setAdapter(new MyAdapter(fragmnetManager));
// Implementing view pager pagechangelistener to navigate between tabs
viewPager.setOnPageChangeListener(new ViewPager.OnPageChangeListener() {
#Override
public void onPageSelected(int pos) {
// Setting navigation of tabs to actionbar
actionBar.setSelectedNavigationItem(pos);
}
#Override
public void onPageScrolled(int arg0, float arg1, int arg2) {
}
#Override
public void onPageScrollStateChanged(int arg0) {
}
});
// Getting actionbar
actionBar = getSupportActionBar();
// Setting navigation mode to actionbar
actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS);
// Now adding a new tab to action bar and setting title, icon and
// implementing listener
android.support.v7.app.ActionBar.Tab tab1 = actionBar.newTab();
tab1.setText("Wszytskie");
// tab1.setIcon(R.drawable.ic_launcher);
tab1.setTabListener(this);
android.support.v7.app.ActionBar.Tab tab2 = actionBar.newTab();
tab2.setText("Grupy");
tab2.setTabListener(this);
// Now finally adding all tabs to actionbar
actionBar.addTab(tab1);
actionBar.addTab(tab2);
}
#Override
public void onTabReselected(android.support.v7.app.ActionBar.Tab arg0,
FragmentTransaction arg1) {
}
#Override
public void onTabSelected(android.support.v7.app.ActionBar.Tab tab,
FragmentTransaction arg1) {
// Setting current position of tab to view pager
viewPager.setCurrentItem(tab.getPosition());
}
#Override
public void onTabUnselected(android.support.v7.app.ActionBar.Tab arg0,
FragmentTransaction arg1) {
}
}
class MyAdapter extends FragmentPagerAdapter {
public MyAdapter(FragmentManager fm) {
super(fm);
}
#Override
public Fragment getItem(int i) {
// Getting fragments according to selected position
Fragment fragment = null;
if (i == 0) {
fragment = new FragmentAllObjectActivity();
}
if (i == 1) {
fragment = new FragmentGroupObjectsActivity();
}
// and finally returning fragments
return fragment;
}
#Override
public int getCount() {
// Returning no. of counts of fragments
return 2;
}
}

Inside onTabSelected add the line:
#Override
public void onTabSelected(android.support.v7.app.ActionBar.Tab tab,
FragmentTransaction arg1) {
// Setting current position of tab to view pager
viewPager.setCurrentItem(tab.getPosition());
setTitle(getText(tab.getPosition()));
}
You have to implement a getText() method which return the right text based on the current fragment like:
public String getText(android.support.v7.app.ActionBar.Tab tab){
// if tab == tabType 1 return "Title 1"
// else return "Title 2"
}

Use bellow code in your onCreate method
setTitle("");//it will remove your app name

Can't use Spinner in Android

I'm a beginner. I am having a problem with Spinner. I'm using tabbed activity with fragments. When I add spinner in fragment main and add listener to it and when I run the app, it crashes, saying
( java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.Spinner.setOnItemSelectedListener(android.widget.AdapterView$OnItemSelectedListener)' on a null object reference)
I've checked everything and seems fine. I don't know what is the matter, please guys help me out. I really need to fix this bug, my Android Studio version is 2.1.2
MainActivity.java
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
spinner = (Spinner)findViewById(R.id.spin);
spinner.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
#Override
public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
Toast.makeText(MainActivity.this, parent.getItemAtPosition(position).toString(), Toast.LENGTH_SHORT).show();
}
#Override
public void onNothingSelected(AdapterView<?> parent) {
}
});
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);
FloatingActionButton fab = (FloatingActionButton) findViewById(R.id.fab);
fab.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
Snackbar.make(view, "Replace with your own action", Snackbar.LENGTH_LONG)
.setAction("Action", null).show();
}
});
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.menu_main, menu);
return true;
}
#Override
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();
//noinspection SimplifiableIfStatement
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
/**
* A placeholder fragment containing a simple view.
*/
public static class PlaceholderFragment extends Fragment {
/**
* The fragment argument representing the section number for this
* 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 = inflater.inflate(R.layout.fragment_main, container, false);
TextView textView = (TextView) rootView.findViewById(R.id.section_label);
textView.setText(getString(R.string.section_format, getArguments().getInt(ARG_SECTION_NUMBER)));
return rootView;
}
}
/**
* A {#link FragmentPagerAdapter} that returns a fragment corresponding to
* one of the sections/tabs/pages.
*/
public class 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).
return PlaceholderFragment.newInstance(position + 1);
}
#Override
public int getCount() {
// Show 3 total pages.
return 3;
}
#Override
public CharSequence getPageTitle(int position) {
switch (position) {
case 0:
return "SECTION 1";
case 1:
return "SECTION 2";
case 2:
return "SECTION 3";
}
return null;
}
}
}

Passing a string between fragments in a viewpager doesnt work properly

My main activity has 3 tabs, each one loads a different fragment.
i am trying to pass data from fragment 1 to fragment 3, but it doesnt work
all 3 fragment can be loaded, but the problem is that only 1&2 are loaded when i start the application. so when i run the application and i want to pass a string from fragment 1 to 3 it doesnt work because it doesnt exist yet. how can i change this?
I am using Eventbus (https://github.com/greenrobot/EventBus) for the communication between fragments.
public class MainActivity extends AppCompatActivity {
private Toolbar mToolbar;
private TabLayout mTabLayout;
private ViewPager mPager;
private MyPagerAdapter mAdapter;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mAdapter = new MyPagerAdapter(getSupportFragmentManager());
mToolbar = (Toolbar) findViewById(R.id.app_bar);
setSupportActionBar(mToolbar);
mTabLayout = (TabLayout) findViewById(R.id.tab_layout);
mPager = (ViewPager) findViewById(R.id.pager);
mPager.setAdapter(mAdapter);
mTabLayout.setTabsFromPagerAdapter(mAdapter);
mTabLayout.setupWithViewPager(mPager);
mPager.addOnPageChangeListener(new TabLayout.TabLayoutOnPageChangeListener(mTabLayout));
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.menu_main, menu);
return true;
}
#Override
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();
//noinspection SimplifiableIfStatement
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
public static class MyFragment extends Fragment {
public static final java.lang.String ARG_PAGE = "arg_page";
public MyFragment() {
}
public static MyFragment newInstance(int pageNumber) {
MyFragment myFragment = new MyFragment();
Bundle arguments = new Bundle();
arguments.putInt(ARG_PAGE, pageNumber + 1);
myFragment.setArguments(arguments);
return myFragment;
}
}
class MyPagerAdapter extends FragmentStatePagerAdapter {
public MyPagerAdapter(FragmentManager fm) {
super(fm);
}
#Override
public Fragment getItem(int position) {
Fragment fragment = MainActivity.MyFragment.newInstance(position); //FRAGMENT fragment;
switch (position) {
case 0:
fragment = new Fragment1();
break;
case 1:
fragment = new Fragment2();
break;
case 2:
fragment = new Fragment3();
break;
default:
break;
}
return fragment;
}
#Override
public int getCount() {
return 3;
}
#Override
public CharSequence getPageTitle(int position) { //set tab names
switch (position) {
case 0:
return "Thread";
case 1:
return "AsyncTask";
case 2:
return "TODO";
}
return null;
}}}

Minimum number of pages you want your adapter to load is set this way
Viewpager.setOffscreenPageLimit(3);

Detecting what sliding tab user is on

This is one of my first apps. I want to know how I can detect what sliding tab the user is currently on. I know it in ViewPagerAdapter but I can't do anything because it's a fragment. How can I access this information?
MainActivity.java
public class MainActivity extends AppCompatActivity {
Toolbar mToolbar;
ViewPager pager;
ViewPagerAdapter adapter;
SlidingTabLayout tabs;
CharSequence Titles[] = {"Factorial", "Permutation", "Random"};
int Numboftabs = 3;
FloatingActionButton fab;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mToolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(mToolbar);
// Creating The ViewPagerAdapter and Passing Fragment Manager, Titles fot the Tabs and Number Of Tabs.
adapter = new ViewPagerAdapter(getSupportFragmentManager(),Titles,Numboftabs);
// Assigning ViewPager View and setting the adapter
pager = (ViewPager) findViewById(R.id.pager);
pager.setAdapter(adapter);
// Assiging the Sliding Tab Layout View
tabs = (SlidingTabLayout) findViewById(R.id.tabs);
tabs.setDistributeEvenly(true); // To make the Tabs Fixed set this true, This makes the tabs Space Evenly in Available width
// Setting Custom Color for the Scroll bar indicator of the Tab View
tabs.setCustomTabColorizer(new SlidingTabLayout.TabColorizer() {
#Override
public int getIndicatorColor(int position) {
return getResources().getColor(R.color.fab_pressed);
}
});
// Setting the ViewPager For the SlidingTabsLayout
tabs.setViewPager(pager);
fab = (FloatingActionButton) findViewById(R.id.fab);
fab.show(false);
//Animation FAB
Animation animation = AnimationUtils.loadAnimation(this, R.anim.simple_grow);
fab.startAnimation(animation);
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.menu_main, menu);
return true;
}
#Override
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();
//noinspection SimplifiableIfStatement
if (id == R.id.action_settings) {
Toast.makeText(this, "Text", Toast.LENGTH_SHORT).show();
Animation animation = AnimationUtils.loadAnimation(this, R.anim.simple_grow);
fab = (FloatingActionButton) findViewById(R.id.fab);
fab.startAnimation(animation);
return true;
}
return super.onOptionsItemSelected(item);
}
}
ViewPagerAdapter.java
public class ViewPagerAdapter extends FragmentStatePagerAdapter {
CharSequence Titles[]; // This will Store the Titles of the Tabs which are Going to be passed when ViewPagerAdapter is created
int NumbOfTabs; // Store the number of tabs, this will also be passed when the ViewPagerAdapter is created
// Build a Constructor and assign the passed Values to appropriate values in the class
public ViewPagerAdapter(FragmentManager fm,CharSequence mTitles[], int mNumbOfTabsumb) {
super(fm);
this.Titles = mTitles;
this.NumbOfTabs = mNumbOfTabsumb;
}
//This method return the fragment for the every position in the View Pager
#Override
public Fragment getItem(int position) {
if(position == 0) // if the position is 0 we are returning the First tab
{
FactorialTab factorialTab = new FactorialTab();
return factorialTab;
} else if(position == 1) // As we are having 2 tabs if the position is now 0 it must be 1 so we are returning second tab
{
PermutationTab permutationTab = new PermutationTab();
return permutationTab;
}
else {
RandomTab randomTab = new RandomTab();
return randomTab;
}
}
// This method return the titles for the Tabs in the Tab Strip
#Override
public CharSequence getPageTitle(int position) {
return Titles[position];
}
// This method return the Number of tabs for the tabs Strip
#Override
public int getCount() {
return NumbOfTabs;
}
}
RandomTab.java (one of the sliding tabs)
public class RandomTab extends Fragment {
#Override
public View onCreateView(LayoutInflater inflater, #Nullable ViewGroup container, #Nullable Bundle savedInstanceState) {
View v = inflater.inflate(R.layout.tab_random, container, false);
return v;
}
}

Set an OnPageChangeListener to your ViewPager
pager.addOnPageChangeListener(new ViewPager.OnPageChangeListener() {
#Override
public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
}
#Override
public void onPageSelected(int position) {
if (position == WHATEVER) {
//do what you want
}
}
#Override
public void onPageScrollStateChanged(int state) {
}
});

How can I use a PreferenceFragment with a ViewPager?

I cannot figure out how to get PreferenceFragment to work correctly. I have a ViewPager hooked up to a FragmentPagerAdapter, with two Fragments that the user can swipe between. I am trying to get the "Settings" menu working, using a PreferenceFragment, but I am unsure what I'm doing wrong. When I tap Settings the view is changed to a blank white screen.
My SettingsFragment class:
public class SettingsFragment extends PreferenceFragment{
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
addPreferencesFromResource(R.xml.preferences);
}
}
My PagerAdapter class:
public class PagerAdapter extends FragmentPagerAdapter {
SparseArray<Fragment> registeredFragments = new SparseArray<Fragment>();
public PagerAdapter(FragmentManager fm) {
super(fm);
}
#Override
public Object instantiateItem(ViewGroup container, int position){
Fragment fragment = (Fragment) super.instantiateItem(container, position);
registeredFragments.put(position, fragment);
return fragment;
}
#Override
public void destroyItem(ViewGroup container, int position, Object object) {
registeredFragments.remove(position);
super.destroyItem(container, position, object);
}
#Override
public Fragment getItem(int i) {
switch (i) {
// default case is also case 0 to avoid redundant code
default: return new CalculatorFragment();
case 1: return new TapeFragment();
}
}
#Override
public int getCount() {
return 2;
}
#Override
public CharSequence getPageTitle(int position) {
switch (position) {
case 1: return "Review";
default: return "Calculator";
}
}
public Fragment getRegisteredFragment(int position){
return registeredFragments.get(position);
}
}
My main class which should create the PreferenceFragment when user taps "Settings"
public class MangoCalc extends FragmentActivity implements CalculatorFragment.CalcTapeInterface{
PagerAdapter pagerAdapter;
ViewPager myViewPager;
#Override
protected void onCreate(Bundle savedInstanceState) {
final ActionBar actionBar = getActionBar();
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_mango_calc);
pagerAdapter = new PagerAdapter(getFragmentManager());
myViewPager = (ViewPager) findViewById(R.id.main);
myViewPager.setAdapter(pagerAdapter);
actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_STANDARD);
ActionBar.TabListener tabListener = new ActionBar.TabListener() {
#Override
public void onTabSelected(ActionBar.Tab tab, FragmentTransaction fragmentTransaction) {
myViewPager.setCurrentItem(tab.getPosition());
}
#Override
public void onTabUnselected(ActionBar.Tab tab, FragmentTransaction fragmentTransaction) {}
#Override
public void onTabReselected(ActionBar.Tab tab, FragmentTransaction fragmentTransaction) {}
};
for (int i=0; i< pagerAdapter.getCount(); i++) {
actionBar.addTab(actionBar.newTab()
.setText(pagerAdapter.getPageTitle(i))
.setTabListener(tabListener));
}
myViewPager.setOnPageChangeListener(new ViewPager.SimpleOnPageChangeListener());
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.mango_calc, menu);
return true;
}
#Override
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_settings) {
FragmentManager fm = getFragmentManager();
SettingsFragment settingsFragment = new SettingsFragment();
fm.beginTransaction().replace(R.id.main, settingsFragment).commit();
return true;
}
return super.onOptionsItemSelected(item);
}
#Override
public void onTapePass(ArrayList<String> data) {
if (data!=null) Log.d("Tape", "Last element got: "+data.get(data.size()-1));
TapeFragment tapeFragment = (TapeFragment) pagerAdapter.getRegisteredFragment(1);
tapeFragment.updateTape(data);
}
}
My preferences.XML
<?xml version="1.0" encoding="utf-8"?>
<PreferenceScreen xmlns:android="http://schemas.android.com/apk/res/android">
<PreferenceCategory android:title="#string/lookandfeel">
<ListPreference
android:key="theme_preference"
android:title="#string/theme"
android:summary="#string/summary_theme_preference"
android:entries="#array/entries_theme_preference"
android:entryValues="#array/entryvalues_theme_preference"
android:defaultValue="mango"/>
<SwitchPreference
android:key="keypress_vibration_preference"
android:title="#string/keypress_vibration"
android:summaryOn="#string/summaryon_keypress_vibration_preference"
android:summaryOff="#string/summaryoff_keypress_vibration_preference"
android:switchTextOn="#string/text_keypress_vibration_on"
android:switchTextOff="#string/text_keypress_vibration_off"
android:defaultValue="true" />
</PreferenceCategory>
</PreferenceScreen>
and the XML for the activity:
<android.support.v4.view.ViewPager xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:id="#+id/main"
/>

In your getitem case 1 needs to be listed before the default