Develop Reference

moving from one fragment to another using viewpager

So currently my code can move between objects from the same fragment, but I want to move between different fragments that have different layouts.What code do I need to add to viewpager to make it work? Do I need to make use of a FragentManager? Can anyone guide me on how to go about it? Thanks.
Below if my code:
ScreenSlidePagerActivity.java
public class ScreenSlidePagerActivity extends FragmentActivity {
private static final int NUM_PAGES = 5;
private ViewPager mPager;
private PagerAdapter pagerAdapter;
/**
* The pager adapter, which provides the pages to the view pager widget.
*/
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.slide_screen_viewpager);
//declare viewpager and pageradapter
mPager = findViewById(R.id.ViewPageSlide);
pagerAdapter = new ScreenSlidePagerAdapter(getSupportFragmentManager());
mPager.setAdapter(pagerAdapter);
}
#Override
public void onBackPressed() {
if (mPager.getCurrentItem() == 0){
// If the user is currently looking at the first step, allow the system to handle the
// Back button. This calls finish() on this activity and pops the back stack.
super.onBackPressed();
}
else {
mPager.setCurrentItem(mPager.getCurrentItem() -1 );
}
}
private class ScreenSlidePagerAdapter extends FragmentStatePagerAdapter {
public ScreenSlidePagerAdapter(FragmentManager fm)
{
super(fm);
}
#Override
public Fragment getItem(int position) {
return new ScreenSlidePageFragment();
}
#Override
public int getCount() {
return NUM_PAGES;
}
}
}
ScreenSlidePageFragment.java
public class ScreenSlidePageFragment extends Fragment {
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState)
{
ViewGroup rootView = (ViewGroup) inflater.inflate(
R.layout.slide_content_page, container, false
);
return rootView;
}
}

You have only one class i.e.,ScreenSlidePageFragment that extends fragments. If you want different layouts for that, its better if you create different classes that inflates different layouts. eg: if you want two layouts, create two classes and both classes should inflate different layouts. The changes need to be done are :
//inside ScreenSlidePagerAdapter
#Override
public Fragment getItem(int position) {
switch (position) {
case 0:
return new ScreenSlidePageFragment();
case 1:
return new NewClass();
//and so on
}
}
You have to create the new Class similar to ScreenSlidePageFragment. The only change is inflate a different layout.
public class NewClass extends Fragment {
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState)
{
ViewGroup rootView = (ViewGroup) inflater.inflate(
R.layout.new_layout, container, false
);
return rootView;
}
}
You can create a new_layout similar to slide_content_page and customize it as you want. You can also increase the no of fragment objects and layout as you wish.
But a new way of doing this things has come. Its better if you extend FragmentStateAdapter instead of FragmentStatePagerAdapter. This is more easy and efficient. You have to override createFragment in this case instead of getItem. Ignore of you are okay with it.
Hope this is the question you have asked and this helps. Thankyou.

Android ViewPager onClickListener reacts even if other fragment is show

I have a ViewPager which holds two fragments. one fragment contains nothing and the other fragment contains a gridview with ImageViews.
The ImageViews have a onClickListener set.
Everything works fine so far... but when i am on the fragment which contains nothing and tap somewhere the onClickListener of the other fragments gridviews imagview reacts to my click even if its elements aren't visible.
I could change my onClickListener so that it checks which fragment is shown but is that really the way i should do it ??? it feels a bit dirty
This is my FragmentStatePageAdapter
public class OwnPagerAdapter extends FragmentStatePagerAdapter{
private BackgroundImage backgroundImage = new BackgroundImage();
private Apps apps = new Apps();
private Home_Screen ac;
public OwnPagerAdapter(FragmentManager fm, Home_Screen activity) {
super(fm);
this.ac = activity;
}
#Override
public Fragment getItem(int position) {
if(position == 0) {
return backgroundImage;
}else if(position == 1) {
return this.apps;
}
return null;
}
#Override
public int getCount() {
return 2;
}
}
This is my BaseAdapter
public class AppAdapter extends BaseAdapter {
private AppLauncher launcherListener = new AppLauncher();
private ArrayList<ApplicationInfo> appList;
private Context ctx;
public AppAdapter(ArrayList<ApplicationInfo> listOfApps, Context ctx){
this.appList = listOfApps;
this.ctx = ctx;
}
#Override
public int getCount() {
return this.appList.size();
}
#Override
public Object getItem(int i) {
ImageView v = new ImageView(this.ctx);
v.setImageDrawable(this.appList.get(i).loadIcon(this.ctx.getPackageManager()));
return v;
}
#Override
public long getItemId(int i) {
return 0;
}
#Override
public View getView(final int i, View view, ViewGroup viewGroup) {
if(view != null){
((ImageView) view).setImageDrawable(this.appList.get(i).loadIcon(this.ctx.getPackageManager()));
view.setTag(i);
return view;
}
ImageView v = new ImageView(this.ctx);
v.setImageDrawable(this.appList.get(i).loadIcon(this.ctx.getPackageManager()));
v.setScaleType(ImageView.ScaleType.CENTER);
v.setOnClickListener(launcherListener);
v.setTag(i);
return v;
}
private class AppLauncher implements View.OnClickListener {
#Override
public void onClick(View view) {
ctx.startActivity(ctx.getPackageManager().getLaunchIntentForPackage(appList.get((int) view.getTag()).packageName));
}
}
}
Thats my fragment class
public class Apps extends Fragment implements LoaderManager.LoaderCallbacks<ArrayList<ApplicationInfo>>{
private GridView gridview;
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
getLoaderManager().initLoader(1, null, this).forceLoad();
View rootView = inflater.inflate(R.layout.fragment_apps, container, false);
this.gridview = (GridView)rootView.findViewById(R.id.apptable);
return rootView;
}
#Override
public Loader<ArrayList<ApplicationInfo>> onCreateLoader(int id, Bundle args) {
return new AppLoader(getActivity());
}
#Override
public void onLoadFinished(Loader<ArrayList<ApplicationInfo>> loader, ArrayList<ApplicationInfo> data) {
Toast.makeText(getActivity(), "Done with loading Apps", Toast.LENGTH_LONG).show();
this.gridview.setAdapter(new AppAdapter(data,getActivity()));
}
#Override
public void onLoaderReset(Loader<ArrayList<ApplicationInfo>> loader) {
}
}

While i cant find any specific cause to your problem i have to suggest a cleaner way of achieving the same result you're seeking, using an inner class just to capture click events is dirty and just unnecessary. it is quite possible that using this method will solve your problem as well.
Instead of using AppLauncher class which implements an OnClickListener and then set it manualy for each item, why not using an OnItemClickListener on the whole gridview ? it will take care of click events for each item and is specific only to items inside your gridview so you dont have to worry about any leaks like you would using inner classes.
In your fragment implement OnItemClickListener :
public class Apps extends Fragment implements LoaderManager.LoaderCallbacks<ArrayList<ApplicationInfo>>, OnItemClickListener
Then in your fragment's onCreate simply set the adapter to the gridview:
gridview.setOnItemClickListener(this);
and implement the necessary method:
#Override
public void onItemClick(AdapterView<?> parent, View v, int position, long id) {
getActivity().startActivity(getActivity().getPackageManager().getLaunchIntentForPackage(appList.get(position).packageName));
}
Now you can remove the OnClickListener logic from your gridview's adapter and it should work fine, my guess is it will also solve your problem, and even if not, hey at least you end up with a cleaner code.
Another thing i find odd about your code is that you override getItemId() yet always return 0, make sure this is the normal behaviour you're looking for since im not sure it is.
Good luck.

Random Out Of Bounds after removing item from static list used by multiple fragments

I have a fragment with a viewpager with adapter extending FragmentStatePagerAdapter with three slidable fragments inside. the main fragment has a static list of data, and three sub-fragments references and show the same list (don't ask why). The list item can be removed by a button inside the row layout or by clicking clear-all button after the list in each of those three fragments.
My problem is that after removing one or all the items with the buttons, sometimes i get an instant index out of bounds exception (no application code in stack trace, to find where the exception is coming from) or randomly sometimes removal work, but fragments nearby display old data with the extra item, and clicking to remove it ofcourse throws out of bounds exception, because after some debugging I can see that size of list passed to adapter to recreate the nearby fragment is lower by one (removal is successful) so I believe the list is not notified/invalidated correctly. Any help, since stacktrace can't help?
Btw I'm using FragmentStatePagerAdapter.POSITION_NONE to recreate the fragments with new data on each swipe, notifyDataSetChanged to notify the adapter of changed data, and invalidate() the listview in onViewCreated(), but they don't help.
relevant code:
Main Fragment
public class MainFragment extends BaseFragment<CategoryTreeItem> {
public static List<Map.Entry<EventTreeItem, String>> betList = new ArrayList<>();
...
#Override
public void onViewCreated(View view, Bundle savedInstanceState) {
super.onViewCreated(view, savedInstanceState);
ViewPager mViewPager = (ViewPager) view.findViewById(R.id.viewpager);
mViewPager.setAdapter(new MyPagerAdapter(getChildFragmentManager()));
SlidingTabLayout mSlidingTabLayout = (SlidingTabLayout) view.findViewById(R.id.sliding_tabs);
mSlidingTabLayout.setViewPager(mViewPager);
}
}
class MyPagerAdapter extends FragmentStatePagerAdapter {
private List<String> items;
public MyPagerAdapter(FragmentManager fm) {
super(fm);
items = getResources().getStringArray(R.array.three_categories);
}
#Override
public Fragment getItem(int i) {
Fragment fragment;
switch (i) {
case 0:
fragment = new FirstFragment();
return fragment;
case 1:
fragment = new SecondFragment();
return fragment;
case 2:
fragment = new ThirdFragment();
return fragment;
default:
return null;
}
}
...
#Override
public int getItemPosition(Object object) {
return FragmentStatePagerAdapter.POSITION_NONE;
}
}
Three fragments (they are needed since the layout and functionality is a bit different)
public class First/Second/ThirdFragment extends BaseListFragment<ArrayList<EventTreeItem>> {
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
return inflater.inflate(R.layout.fragment_main, container, false);
}
#Override
public void onViewCreated(View view, Bundle savedInstanceState) {
super.onViewCreated(view, savedInstanceState);
MyListAdapter adapter = new MyListdapter(getActivity(), R.layout.item_first/second/thirdfragment, MainFragment.betList);
getListView().setItemsCanFocus(true);
View footerView = getLayoutInflater(savedInstanceState).inflate(R.layout.include_first/second/third_footer, getListView(), false);
getListView().addFooterView(footerView);
adapter.notifyDataSetChanged();
setListAdapter(adapter);
getListView().invalidate();
//handles REMOVE ALL button for all fragments footer button
Helper.setUpClearOption(footerView, adapter);
}
}
MyListAdapter
#CompileStatic
public class MyListAdapter extends ArrayAdapter<Map.Entry<EventTreeItem,String>> {
private int mResourceId;
private List<Map.Entry<EventTreeItem,String>> mObjects;
public MyListAdapter(Context context, int resource, List<Map.Entry<EventTreeItem,String>> objects) {
super(context, resource, objects);
mResourceId = resource;
mObjects = objects;
}
#Override
public View getView(final int position, View convertView, ViewGroup parent) {
View view = convertView;
if (view == null) {
view = LayoutInflater.from(getContext()).inflate(mResourceId, parent, false);
}
//------setting a lot of text for textViews
// .....
//------
ImageView ivRemove = (ImageView) view.findViewById(R.id.ivRemove);
ivRemove.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
//Tried removing directly from adapter, not helping
// MyListAdapter.this.remove(mObjects.get(position));
MainFragment.betList.remove(position);
MyListAdapter.this.notifyDataSetChanged();
}
});
return view;
}
}
Remove All helper method (also returning instant OOB or not notifying neighbor fragments)
public static void setUpClearOption(View view, final ArrayAdapter adapter) {
ImageView ivRemoveAll = (ImageView) view.findViewById(R.id.ivRemoveAll);
ivRemoveAll.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
adapter.clear();
adapter.notifyDataSetChanged();
}
});
}
So any help is much appreciated!

I managed to fix My problem by creating three listadapters for each of my fragments (static adapters instantiaiting with null value ) and in onClick I check each of those three adapters if they are not null (since adapters are null until after onViewCreated, and it is called only when the current fragment is a neighbor). All three adapters use the same data.

Using ViewPager with Custom ViewGroups

I'm creating an Android app and I have several custom ViewGroups I've created and wanted to add a ViewPager to my MainActivity so that I can swipe the screen to go back and forth between the Views. However it looks like items added to a ViewPager have to be a Fragment. Do I need to create a separate Fragment for each custom ViewGroup or is there someway to directly add them instead?

No, you dont need it.
In your FragmenAdapter set a desired id layout for each Fragment, based on the current Position.
//FragmentStatePagerAdapter
public class DynamicViewsFragmentAdapter extends FragmentStatePagerAdapter {
public DynamicViewsFragmentAdapter(FragmentActivity activity) {
super(activity.getSupportFragmentManager());
}
#Override
public Fragment getItem(int position) {
DynamicViewsFragment fragment = new DynamicViewsFragment();
int idLayout = getIdLayoutBasedOnPosition(position);
fragment.setIdLayout(idLayout);
return fragment;
}
#Override
public int getCount() {
return 3;
}
private int getIdLayoutBasedOnPosition(int position) {
if(position == 0) return R.layout.one;
else if (position == 1) return R.layout.one;
else return R.layout.three;
}
}
//Fragment
public class DynamicViewsFragment extends Fragment {
private int _idLayout;
public void setIdLayout(int idLayout) {
_idLayout = idLayout;
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
super.onCreateView(inflater, container, savedInstanceState);
View rootView = inflater.inflate(_idLayout, container, false);
return rootView;
}
}

Thank you both for your help. I started out using valbertos solution but my app crashed because I tried to access _idLayout before it was set. I ended up finding this solution
http://architects.dzone.com/articles/android-tutorial-using
and modified it to fit my needs and it worked great! Thank you both for your suggestions;

Circular ViewPager which uses FragmentPagerAdapter

I would like to implement a ViewPager which uses Fragments and can be swiped in a curcular motion e.g. Page (A<-->B<-->C<-->A).
I have read a couple of posts on how this is done, e.g. returning a fake count of how many elements there are and setting the position at the start in the middle.
how to create circular viewpager?
These all seem to be based of a PagerAdapter. When I try to do a similar thing while extending FragmentPagerAdapter, as soon as I return a fakeCount of pages I get an exception when I Swipe through my Fragments, I only have 2 Fragments.
Exception: java.lang.IllegalStateException: Can't change tag of fragment.
I think this is caused as the FragmentManager thinks I am in position 2 but position 2 points to the fragment at position 0. Does anyone know how I can avoid this? I am thinking I should experiment with extending Fragmentmanager. Any examples or help with this would be greatly appreciated.

I know it is a bit late but this is how it worked for me:
I needed a circular swipe between 3 fragments, so I made those 3 and two more virtual to help me implement the page looping:
public static class FirstViewFragment extends Fragment {
// Empty Constructor
public FirstViewFragment() {
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
return inflater.inflate(R.layout.fragment_landing_1, container, false);
}
}
public static class SecondViewFragment extends Fragment {
// Empty Constructor
public SecondViewFragment() {
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
return inflater.inflate(R.layout.fragment_landing_2, container, false);
}
}
public static class ThirdViewFragment extends Fragment {
// Empty Constructor
public ThirdViewFragment() {
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
return inflater.inflate(R.layout.fragment_landing_3, container, false);
}
}
And two more virtual fragments that enabled me to swipe left from the first and right from the last. The first virtual inflates the same layout as the last actual and the last virtual the same layout as the first actual:
public static class StartVirtualFragment extends Fragment {
public StartVirtualFragment() {}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
return inflater.inflate(R.layout.fragment_landing_3, container, false);
}
}
public static class EndVirtualFragment extends Fragment {
public EndVirtualFragment() {}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
return inflater.inflate(R.layout.fragment_landing_1, container, false);
}
}
My Adapter:
private class ViewPagerAdapter extends FragmentPagerAdapter {
public ViewPagerAdapter(FragmentManager fm) {
super(fm);
}
#Override
public Fragment getItem(int i) {
switch (i) {
case 0:
return new StartVirtualFragment();
case 1:
if (firstViewFragment == null) {
firstViewFragment = new FirstViewFragment();
}
return firstViewFragment;
case 2:
if (secondViewFragment == null) {
secondViewFragment = new SecondViewFragment();
}
return secondViewFragment;
case 3:
if (thirdViewFragment == null) {
thirdViewFragment = new ThirdViewFragment();
}
return thirdViewFragment;
case 4:
return new EndVirtualFragment();
}
return null;
}
#Override
public int getCount() {
return 5;
}
}
And my page listener I used the onPageScrollStateChanged to set the correct page and implement the loop:
viewPager.setOnPageChangeListener(new ViewPager.OnPageChangeListener() {
#Override
public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
}
#Override
public void onPageSelected(int position) {
}
#Override
public void onPageScrollStateChanged(int state) {
if (state == ViewPager.SCROLL_STATE_DRAGGING) {
int pageCount = viewPager.getChildCount();
int currentItem = viewPager.getCurrentItem();
if (currentItem == 0) {
viewPager.setCurrentItem(pageCount - 2, false);
} else if (currentItem == pageCount - 1) {
viewPager.setCurrentItem(1, false);
}
}
}
});
And in the end:
viewPager.setCurrentItem(1);
Hope I helped

I have a project in the GitHub with some widgets I've created. Here it its:
https://github.com/CyberEagle/AndroidWidgets
In the following package, there are the adapters to be used with the CircularViewPager:
https://github.com/CyberEagle/AndroidWidgets/tree/master/src/main/java/br/com/cybereagle/androidwidgets/adapter
First, you will use CircularViewPager instead of ViewPager in your layout. The CircularViewPager is here: https://github.com/CyberEagle/AndroidWidgets/blob/master/src/main/java/br/com/cybereagle/androidwidgets/view/CircularViewPager.java
This ViewPager expects a WrapperCircularPagerAdapter, instead of a PagerAdapter. This wrapper is used to trick the ViewPager, making it to think there are a lot of items in the ViewPager, but it actually repeat your items to make the circular effect. So, instead of implementing either PagerAdapter, FragmentPagerAdapter or FragmentStatePagerAdapter, you will implement either CircularFragmentPagerAdapter, CircularFragmentStatePagerAdapter or CircularPagerAdapter. Then, you will wrap your adapter with the WrapperCircularPagerAdapter and set the wrapper in the CircularViewPager, instead of your adapter. Also, when it's time to notify dataset changed, you will call the notifyDatasetChanged() in the wrapper.
When implementing one of the circular adapter, you will notice that instead of implementing instantiateItem, you will have to implement instantiateVirtualItem. For the fragment's pager adapter, you will implement getVirtualItem instead of getItem. That is because I've created the concept of virtual items.
To make it clear, imagine a view pager with 4 items, giving that each item represents a music. When you go all the way to left, you will see the 4th item in the left of the first. Actually, it's a whole new item, but it's linked to the virtual item that represents the 4th music.
Another example: imagine there's only one music now. You will see the same music on the left and on the right. There're 3 items at a time, but only one virtual item.
So, as explained, the Wrapper is tricking the ViewPager, making it think that there are a lot of items. To make it more difficult for the user to reach one of the ends of the ViewPager (it'd take a long time anyway), everytime a change happens to the dataset, the ViewPager goes to the same virtual item, but to one of the real items near the middle.
One more important thing is that the CircularViewPager has the method setCurrentVirtualItem. This method calculates which real item is the nearest desired virtual item and then it uses the setCurrentItem to set it. You have also the option to use the getCurrentVirtualItem, that will return the index of the current virtual item. Notice that if you use getCurrentItem, you'll get a large index.
Well, this is it. I'm sorry for the lack of documentation of the project. I'm planning document it soon. I'm also planning to remove the need for the wrapper. Feel free to copy the code (respecting the Apache 2.0 license), to fork or even contribute to it.

**If you want to make 3 views visible at same time and make it circular**
public abstract class CircularPagerAdapter extends PagerAdapter{
private int count;
int[] pagePositionArray;
public static final int EXTRA_ITEM_EACH_SIDE = 2;
private ViewPager.OnPageChangeListener pageChangeListener;
private ViewPager viewPager;
public CircularPagerAdapter(final ViewPager pager, int originalCount ) {
super();
this.viewPager = pager;
count = originalCount + 2*EXTRA_ITEM_EACH_SIDE;
pager.setOffscreenPageLimit(count-2);
pagePositionArray = new int[count];
for (int i = 0; i < originalCount; i++) {
pagePositionArray[i + EXTRA_ITEM_EACH_SIDE] = i;
}
pagePositionArray[0] = originalCount - 2;
pagePositionArray[1] = originalCount -1;
pagePositionArray[count - 2] = 0;
pagePositionArray[count - 1] = 1;
pager.setOnPageChangeListener(new ViewPager.OnPageChangeListener() {
public void onPageSelected(final int position) {
if(pageChangeListener != null)
{
pageChangeListener.onPageSelected(pagePositionArray[position]);
}
pager.post(new Runnable() {
#Override
public void run() {
if (position == 1){
pager.setCurrentItem(count-3,false);
} else if (position == count-2){
pager.setCurrentItem(2,false);
}
}
});
}
public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
if(pageChangeListener != null)
{
pageChangeListener.onPageScrolled(pagePositionArray[position],positionOffset,positionOffsetPixels);
}
}
public void onPageScrollStateChanged(int state) {
if(pageChangeListener != null)
{
pageChangeListener.onPageScrollStateChanged(state);
}
}
});
}
#Override
public int getCount() {
return count;
}
#Override
public boolean isViewFromObject(View view, Object object) {
return false;
}
public abstract Object customInstantiateItem(ViewGroup container, int position);
public void setPageChangeListener(ViewPager.OnPageChangeListener pageChangeListener)
{
this.pageChangeListener = pageChangeListener;
}
#Override
public Object instantiateItem(ViewGroup container, int position) {
int pageId = pagePositionArray[position];
return customInstantiateItem(container,pageId);
}
#Override
public void destroyItem(View container, int position, Object object) {
((ViewPager) container).removeView((View) object);
}
public void setFirstItem()
{
viewPager.setCurrentItem(EXTRA_ITEM_EACH_SIDE - 1);
}
}