I know many applications using fragments in ViewPager. I need it in my application too. I have no found any guide how I can to do it exclude this. And here is my code:
public class MainActivity extends FragmentActivity {
Vector<Fragment> fragments;
ViewPager viewPager;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
viewPager = (ViewPager) findViewById(R.id.pager);
fragments = new Vector<Fragment>();
fragments.add(Fragment.instantiate(this, Fragment1.class.getName()));
fragments.add(Fragment.instantiate(this, Fragment2.class.getName()));
viewPager.setOffscreenPageLimit(fragments.size());
PagerAdapter pagerAdapter = new PagerAdapter(super.getSupportFragmentManager(), fragments);
viewPager.setAdapter(pagerAdapter);
viewPager.setCurrentItem(0);
}
class PagerAdapter extends FragmentPagerAdapter {
private List<Fragment> fragments;
public PagerAdapter(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();
}
}
}
But this code doesn't working well. Sometimes I get error in my Fragment1 about getActivity() return null. I read many posts from this site and other about this error and now I know that is bad way - use Vector for storing fragments. But I still don't know, how to do ViewPager with fragments properly. Please, help.
Even I had trouble understanding the concept at first and I won't say that I fully understood it. But,
Here's how I am using fragment in my sample application:
Step 1: Creating my Adapter:
public class AllPagesAdapter extends FragmentStatePagerAdapter {
public AllPagesAdapter(FragmentManager fm) {
super(fm);
}
#Override
public Fragment getItem(int index) {
switch (index) {
case 0:
return new Fragment1();
case 1:
return new Fragment2();
case 2:
return new Fragment3();
case 3:
return new Fragment4();
case 4:
return new Fragment5();
}
return null;
}
#Override
public int getCount() {
return 5;
}
}
Step 2: In the main activity, I am extending fragment activity and implementing an ActionBar.TabListener. Here's how I am doing it:
public class SomeActivity extends FragmentActivity implements ActionBar.TabListener {
public ViewPager viewPager;
private AllPagesAdapter mAdapter;
private ActionBar actionBar;
private String [] tabs = {"Fragment1","Fragment2","Fragment3","Fragment4","Fragment5"};
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
//Initializing all stuff
viewPager = (ViewPager)findViewById(R.id.pager);
actionBar = getActionBar();
mAdapter = new AllPagesAdapter(getSupportFragmentManager());
viewPager.setAdapter(mAdapter);
actionBar.setHomeButtonEnabled(true);
actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS);
//Add the tabs here
for(String tab_name:tabs){
actionBar.addTab(actionBar.newTab().setText(tab_name).setTabListener(this));
}
viewPager.setOnPageChangeListener(new ViewPager.SimpleOnPageChangeListener(){
#Override
public void onPageSelected(int position){
//on Page change, that particular page should be selected
actionBar.setSelectedNavigationItem(position);
}
#Override
public void onPageScrolled(int arg0,float arg1,int arg2){
}
#Override
public void onPageScrollStateChanged(int position){
}
});
}
#Override
public void onTabSelected(Tab tab, FragmentTransaction fragmentTransaction) {
viewPager.setCurrentItem(tab.getPosition());
}
#Override
public void onTabUnselected(Tab tab, FragmentTransaction fragmentTransaction) {
}
#Override
public void onTabReselected(Tab tab, FragmentTransaction fragmentTransaction) {
viewPager.setCurrentItem(tab.getPosition());
}
}
Step 3: I have just one fragment for this example:
Here's the code:
public class Fragment1 extends Fragment {
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
//Can be layout you want it to be.
View databaseview = inflater.inflate(R.layout.database, container, false);
return databaseview;
}
}
Step 4: Last part is the layout: This will be starting point.
<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>
Lastly, one important thing is that, number of fragments should be equal to the string array defined in the main activity. If not, the app crashes.
Hope I explained it well..:)
I know this is a very old post but this answer can be used for future viewers.
Related
but come across a problem. When i run the app i don't see that my screen is swipes, and also i can't see tabs. Can you help
Here is my code:
public class MainActivity extends AppCompatActivity {
Toolbar toolbar;
TabLayout tabLayout;
ViewPager viewPager;
ViewPagerAdapter viewPagerAdapter;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
toolbar= (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
tabLayout= (TabLayout) findViewById(R.id.tablayout);
viewPager= (ViewPager) findViewById(R.id.viewpager);
viewPagerAdapter=new ViewPagerAdapter(getSupportFragmentManager());
viewPagerAdapter.addFragments(new Home(),"Home");
// viewPagerAdapter.addFragments(new Top(),"Top");
// viewPagerAdapter.addFragments(new Buttom(),"Buttom");
viewPager.setAdapter(viewPagerAdapter);
tabLayout.setupWithViewPager(viewPager);
}
}
I'm getting an error on commented lines.
Here is my Pager Adapters code:
public class ViewPagerAdapter extends FragmentPagerAdapter {
ArrayList<Fragment> fragments= new ArrayList<>();
ArrayList<String> tabTitles = new ArrayList<>();
public void addFragments(Home fragments, String titles){
this.fragments.add(fragments);
this.tabTitles.add(titles);
}
public ViewPagerAdapter(FragmentManager fm) {
super(fm);
}
#Override
public Fragment getItem(int position) {
return fragments.get(position);
}
#Override
public int getCount() {
return fragments.size();
}
#Override
public CharSequence getPageTitle(int position) {
return tabTitles.get(position);
}
}
In my XML i've only Viewpager, Toolbarand TabLayout.
Please Help.
You need to change your type of parameter in addFragments
try this :
public void addFragments(Fragment fragments, String titles)
instead of
public void addFragments(Home fragments, String titles)
I hope this may help you
Probably is this:
Home fragments
Try change to this:
Fragment fragments
Method be like this:
public void addFragments(Fragment fragments, String titles){
this.fragments.add(fragments);
this.tabTitles.add(titles);
}
So you in the method you have Home fragments as paramter and when you call other fragments diferent than Home because parameter is Home you get error, to fix just do like I said change parameter to Fragment fragments. it's a small mistake.
Try this.
In your xml layout file.
<android.support.design.widget.TabLayout
android:id="#+id/tabLayout"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:background="#color/colorPrimary"
app:tabSelectedTextColor="#android:color/white"/>
<android.support.v4.view.ViewPager
android:id="#+id/viewPager"
android:layout_width="match_parent"
android:layout_height="match_parent"/>
In your mainactivity
tabLayout.addTab(tabLayout_ordering.newTab().setText("Tab 1"));
tabLayout.addTab(tabLayout_ordering.newTab().setText("Tab 2"));
viewPager.setAdapter(pagerAdapter);
viewPager.addOnPageChangeListener(new TabLayout.TabLayoutOnPageChangeListener(tabLayout_ordering));
tabLayout_ordering.setOnTabSelectedListener(new TabLayout.OnTabSelectedListener() {
#Override
public void onTabSelected(TabLayout.Tab tab) {
viewPager.setCurrentItem(tab.getPosition());
}
#Override
public void onTabUnselected(TabLayout.Tab tab) {
}
#Override
public void onTabReselected(TabLayout.Tab tab) {
}
});
Then create a class for your pager adapter.
public class TabPagerAdapter extends FragmentPagerAdapter {
public TabPagerAdapter(FragmentManager fm, int tabCount) {
super(fm);
}
#Override
public Fragment getItem(int position) {
switch (position) {
case 0:
FragmentA fragmentA = new FragmentA();
return fragmentFoods;
case 1:
FragmentDrinks fragmentA = new FragmentA();
return fragmentA;
default:
return null;
}
}
#Override
public int getCount() {
return 2;
}
}
Is it possible to change fragment defined i xml?
<fragment
android:id="#+id/fragment"
android:layout_width="wrap_content"
android:layout_height="wrap_content"/>
A have a lot of screens to show and switch. A tab-like menu on the right. Every tab have another tabs. I want to simply change this one by one. Maybe someone have better idea?
SOLVED
I used ViewPager and FragmentPagerAdapter
http://developer.android.com/reference/android/support/v4/app/FragmentPagerAdapter.html
private ViewPager pager;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main_content);
pager = (ViewPager) findViewById(R.id.pager);
ControllerFragment cf = new ControllerFragment(getSupportFragmentManager(), getFragment());
pager.setAdapter(cf);
}
private List<Fragment> getFragments() {
List<Fragment> list = new ArrayList<Fragment>();
FirstFragment fragment = new FirstFragment();
list.add(fragment);
return list;
}
public void onTabSelected(View v) {
switch (v.getId()) {
case R.id.ivProfile:
pager.setCurrentItem(0);
}
}
public class ControllerFragment extends FragmentPagerAdapter {
List<Fragment> fragments;
public ControllerFragment(FragmentManager fm, List<Fragment> fragments){
super(fm);
this.fragments = fragments;
}
#Override
public Fragment getItem(int arg0){
return this.fragments.get(arg0);
}
#Override
public int getCount(){
return this.fragments.size();
}
}
I used sherlock to have action bar in android 2.3, everythings is ok but the problem is:
I have 4 tabs, after doing some works on fisrt tab if I go to the second and third tab when I came back to first tab the contetnt is ok but when I go to the last tab and then came back to the first, the conent of first fragment was restarted and everything was gone, below is my codes, why is it like that?
MainActivity:
public class MainActivity extends SherlockFragmentActivity implements
TabListener {
private ViewPager viewPager;
private TabsPagerAdapter mAdapter;
private com.actionbarsherlock.app.ActionBar actionBar;
private String[] tabs = { "weblog", "news", "image", "web" };
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
viewPager = (ViewPager) findViewById(R.id.pager);
actionBar = getSupportActionBar();
actionBar.setDisplayShowTitleEnabled(false);
actionBar.setDisplayShowHomeEnabled(false);
mAdapter = new TabsPagerAdapter(getSupportFragmentManager());
actionBar.setHomeButtonEnabled(false);
viewPager.setAdapter(mAdapter);
actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS);
actionBar.addTab(actionBar.newTab().setText(tabs[0])
.setTabListener(this), false);
actionBar.addTab(actionBar.newTab().setText(tabs[1])
.setTabListener(this), false);
actionBar.addTab(actionBar.newTab().setText(tabs[2])
.setTabListener(this), false);
actionBar.addTab(actionBar.newTab().setText(tabs[3])
.setTabListener(this), true);
viewPager.setOnPageChangeListener(new ViewPager.OnPageChangeListener() {
#Override
public void onPageSelected(int position) {
actionBar.setSelectedNavigationItem(position);
}
#Override
public void onPageScrolled(int arg0, float arg1, int arg2) {
}
#Override
public void onPageScrollStateChanged(int arg0) {
}
});
}
#Override
public void onTabSelected(com.actionbarsherlock.app.ActionBar.Tab tab,
android.support.v4.app.FragmentTransaction ft) {
viewPager.setCurrentItem(tab.getPosition());
}
#Override
public void onTabUnselected(com.actionbarsherlock.app.ActionBar.Tab tab,
android.support.v4.app.FragmentTransaction ft) {
}
#Override
public void onTabReselected(com.actionbarsherlock.app.ActionBar.Tab tab,
android.support.v4.app.FragmentTransaction ft) {
}
}
TabsPagerAdapter:
public class TabsPagerAdapter extends FragmentPagerAdapter {
public TabsPagerAdapter(FragmentManager fm) {
super(fm);
}
#Override
public Fragment getItem(int index) {
switch (index) {
case 0:
return new Blog();
case 1:
return new News();
case 2:
return new Image();
case 3:
return new Search();
}
return null;
}
#Override
public int getCount() {
return 4;
}
}
The ViewPager typically only keeps a few fragments in an "idle" state and recreates the other fragments as a performance optimization. See this answer.
To override this behavior, you can call setOffscreenPageLimit
// keep 3 tabs in memory on either side of the current tab
viewPager.setOffscreenPageLimit(3);
I want to replace a Fragment by a new Fragment when an onClick method is called. I wanted to do it this way:
FragmentTransaction transaction = getFragmentManager().beginTransaction();
transaction.remove(this);
transaction.addToBackStack(null);
transaction.add(new ChooseCocktailFragment(), null);
transaction.commit();
The only thing that happens is the current Fragment is removed and the new one doesn't show. What am I doing wrong here?
Also, I use a ViewPager and this is the first time for me working with fragments. Usually I would have a Container with its ID but here the ViewPager contains the fragments, therefore I don't know how to use the transaction.replace(...) method.
You should use a FragmentPagerAdapter which is adequate to put Fragments inside ViewPagers.
A complete tutorial from android developer here
EDIT:
First of all, you need to override the getItemPosition of the adapter, and return the POSITION_NONE constant in order to be able to replace pager's fragments.
#Override
public int getItemPosition(Object object)
{
return POSITION_NONE;
}
Then create a listner for handling fragment switching:
public interface MyListener
{
public void onFragmentChange();
}
Your adapter should implements the listner and add some code inside onFragmentChange() method:
public class TabsPagerAdapter extends FragmentPagerAdapter {
private FragmentManager fm;
public TabsPagerAdapter(FragmentManager fm) {
super(fm);
this.fm = fm;
}
#Override
public Fragment getItem(int index) {
switch (index) {
case 0:
fragment1 = TopRatedFragment.newInstance(this);
return fragment1;
case 1:
// ...
return fragment2;
case 2:
// ...
return fragment3;
case 3:
// ...
return fragment4;
}
return null;
}
#Override
public int getCount() {
// get item count - equal to number of tabs
return 4;
}
public void onFragmentChange(){
fm.beginTransaction().remove(fragment1).commit();
fragment1 = NewFragment.newInstance();
notifyDataSetChanged(); // notify the viewpager adapter that content has changed
}
}
Pass an instance of the listner in the fragment you want to remove/replace later :
public class TopRatedFragment extends Fragment {
public static TopRatedFragment newInstance(MyListner listner) {
this.myListner = listner;
return new TopRatedFragment ();
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment_top_rated, container, false);
return rootView;
}
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
// some logical here ... and when you want to change fragment do this
myListner.onFragmentChange();
}
}
Here is some more explanation of this.
You should also read about FragmentStatePagerAdapter : here
Hope it helps !
You forget hide your fragment after another fragment is added up on your fragment.
Just add more a statement transaction.hide(Your_Fragment) before transaction.commit()
#mansoulx
Here is my code which my answer refers to. Since i implemented it using a tutorial it is very similiar, just Tab names and the content of the tabs changed. I also have 4 tabs, not three - but the problem would be the same:
TabsPagerAdapter.java
public class TabsPagerAdapter extends FragmentPagerAdapter {
public TabsPagerAdapter(FragmentManager fm) {
super(fm);
}
#Override
public Fragment getItem(int index) {
switch (index) {
case 0:
return new Fragment1();
case 1:
return new Fragment2();
case 2:
return new Fragment3();
}
return null;
}
#Override
public int getCount() {
// get item count - equal to number of tabs
return 3;
}
}
MainActivity.java
public class MainActivity extends FragmentActivity implements
ActionBar.TabListener {
private ViewPager viewPager;
private TabsPagerAdapter mAdapter;
private ActionBar actionBar;
// Tab titles
private String[] tabs = { "Tab1", "Tab2", "Tab3" };
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
// Initilization
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(this));
}
#Override
public void onTabReselected(Tab tab, FragmentTransaction ft) {
}
#Override
public void onTabSelected(Tab tab, FragmentTransaction ft) {
// on tab selected
// show respected fragment view
viewPager.setCurrentItem(tab.getPosition());
}
#Override
public void onTabUnselected(Tab tab, FragmentTransaction ft) {
}
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) {
}
});
let's say all Fragments would look like this:
Fragment1.java
public class TopRatedFragment extends Fragment {
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment_top_rated, container, false);
return rootView;
}
}
The thing which should be done now is:
Replace Fragment1 on Tab1 with FragmentNew which should appear in Tab1 too! The OnClick-Event takes place in the fragment1.java for example...
I've looked at quite a lot of code and can't figure this out. http://developer.android.com/reference/android/support/v4/app/FragmentPagerAdapter.html
It has to be something simple.
I'm showing most of the code. The error is in the next section.
public class MainActivity extends FragmentActivity implements
ActionBar.TabListener {
public static final int TAB_COUNT = 3;
public static InputMethodManager inputManager;
SectionsPagerAdapter mSectionsPagerAdapter;
ViewPager mViewPager;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mSectionsPagerAdapter = new SectionsPagerAdapter(
getSupportFragmentManager());
// Set up the action bar.
final ActionBar actionBar = getActionBar();
actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS);
mViewPager = (ViewPager) findViewById(R.id.pager);
mViewPager.setAdapter(mSectionsPagerAdapter);
// When swiping between different sections, select the corresponding
// tab.
mViewPager
.setOnPageChangeListener(new ViewPager.SimpleOnPageChangeListener() {
#Override
public void onPageSelected(int position) {
actionBar.setSelectedNavigationItem(position);
}
});
// For each of the sections in the app, add a tab to the action bar.
for (int i = 0; i < mSectionsPagerAdapter.getCount(); i++) {
actionBar.addTab(actionBar.newTab()
.setText(mSectionsPagerAdapter.getPageTitle(i))
.setTabListener(this));
}
// To control keyboard pop-up
inputManager = (InputMethodManager) getSystemService(Context.INPUT_METHOD_SERVICE);
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
getMenuInflater().inflate(R.menu.menu_main, menu);
return true;
}
#Override
public void onTabUnselected(ActionBar.Tab tab,
FragmentTransaction fragmentTransaction) {
}
#Override
public void onTabSelected(ActionBar.Tab tab,
FragmentTransaction fragmentTransaction) {
// When the given tab is selected, switch to the corresponding page in
// the ViewPager.
mViewPager.setCurrentItem(tab.getPosition());
}
#Override
public void onTabReselected(ActionBar.Tab tab,
FragmentTransaction fragmentTransaction) {
}
This is where my error is.
case 1 of getItem, Type mismatch: Cannot convert from MainActivity.HistoryFragment to Fragment. it is telling me to either change method return type to HistoryFragment or change return type of newInstance() to Fragment. Where I can't do either. Other examples I've seen look almost identical to my code. I have tried with and without passing an argument.
public class SectionsPagerAdapter extends FragmentPagerAdapter {
public SectionsPagerAdapter(FragmentManager fm) {
super(fm);
}
#Override
public Fragment getItem(int i) {
switch (i) {
case 0:
Fragment tipCalc = new TipCalcFragment();
return tipCalc;
case 1:
// Fragment history = new HistoryFragment();
return HistoryFragment.newInstance(i); //ERROR HERE
case 2:
Fragment stats = new StatsFragment();
return stats;
}
return null;
}
And my HistoryFragment that extends ListFragment. In the end it won't be pulling from the String[] values but from database resources. I just wanted to setup a structure first and see it/play with the layout.
public static class HistoryFragment extends ListFragment {
// public HistoryFragment() {
// }
String[] values = new String[] { ... };
static HistoryFragment newInstance(int num) {
HistoryFragment history = new HistoryFragment();
Bundle args = new Bundle();
args.putInt("num", num);
history.setArguments(args);
return history;
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.history, container, false);
return view;
}
#Override
public void onActivityCreated(Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
setListAdapter(new ArrayAdapter<String>(getActivity(),
android.R.layout.simple_list_item_1, android.R.id.text1,
values));
}
}
I figured it out after getting some sleep. I was importing android.app.ListFragment instead of android.support.v4.app.ListFragment
I think you will have to typecast to fragment before returning. So try this
Fragment history = HistoryFragment.newInstance(i);
return history;