I have a Fragment. This fragment contains a view pager where the view page has multiple fragments. I can scroll the pages but seeing nothing even though getItem did call when scroll and initialised the fragment.
I have changed the code with support.v4.app.Fragment and support.v4.app.FragmentManager and change the main activity to FragmentActivity. In addition, I use getChildFragmentManager to the adapter but still can't showing anything.
I also change the line below to return true always but it can show the first fragment. Subsequent fragment aren't showing and behave badly when start paging it.
#Override
public boolean isViewFromObject(View view, Object object) {
return true;
}
Below is the code I implement the ViewPager.
public class AppsPagerAdapter extends FragmentPagerAdapter {
private int appsSize;
private int appsPerPage = 12;
private Activity activity;
public AppsPagerAdapter (Activity activity1, FragmentManager manager, int size)
{
super(manager);
appsSize = size;
activity = activity1;
}
#Override
public int getCount() {
int offset = appsSize % appsPerPage;
int pageExtra = (offset > 0)? 1: 0;
return appsSize / appsPerPage + pageExtra;
}
#Override
public boolean isViewFromObject(View view, Object object) {
return view == object;
}
public Fragment getItem(int position) {
Bundle bundle = new Bundle();
bundle.putInt (AppPageFragment.PAGE_NUMBER_PARAMS, position);
return Fragment.instantiate(activity, AppPageFragment.class.getName(), bundle);
}
}
Outer Fragment:
#Override
public View onCreateView (LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState)
{
View view = inflater.inflate (R.layout.fragment_all_app, container, false);
ViewPager appsPager = (ViewPager) view.findViewById(R.id.grid_allapps);
//adapter = new AppsPagerAdapter(((AppCompatActivity)getActivity()).getSupportFragmentManager(), GlobalData.getInstance().getApps().getAll().size());
adapter = new AppsPagerAdapter(getActivity(), getChildFragmentManager(), GlobalData.getInstance().getApps().getAll().size());
appsPager.setAdapter(adapter);
appsPager.addOnPageChangeListener(pageChangeListener);
return view;
Related
I am currently using Material Design in an Android app that I am making. In this app, I am using the Material Design tab layout to display some information that I am receiving. However when I tap the tabs, the animation is not smooth, and it is very abrupt. Sliding to go to the other tab, however is very smooth.
mTabLayout = (TabLayout) findViewById(R.id.chem_tab_layout);
mGenericAdapter = new GenericPagerAdapter(getSupportFragmentManager());
mPager = (ViewPager) findViewById(R.id.view_pager);
mPager.setAdapter(mGenericAdapter);
//Notice how the Tab Layout links with the Pager Adapter
mTabLayout.setTabsFromPagerAdapter(mGenericAdapter);
//Notice how The Tab Layout and View Pager object are linked
mTabLayout.setupWithViewPager(mPager);
mPager.addOnPageChangeListener(new TabLayout.TabLayoutOnPageChangeListener(mTabLayout){
#Override
public void onPageSelected(int position) {
mGenericAdapter.notifyDataSetChanged();
}
});
That is my code for setting the adapter, etc.
This is my custom adapter code for the tabs:
class GenericPagerAdapter extends FragmentStatePagerAdapter {
public GenericPagerAdapter(FragmentManager fm) {
super(fm);
}
#Override
public Fragment getItem(int position) {
ChemGridActivity.MyFragment myFragment = new ChemGridActivity.MyFragment();
return myFragment;
}
#Override
public int getCount() {
return 3; //returns number of tabs that need to be created
}
#Override
public CharSequence getPageTitle(int position) {
if (position == 0) return "Chemistry";
if (position == 1) return "Mathematics";
if (position == 2) return "Physics";
else return null;
}
#Override
public int getItemPosition(Object object) {
return POSITION_NONE;
}
I feel that the choppy transition between tabs is caused by the overriden method onPageSelected method when I add onPageChangeListener. What do I add to this method to make tapping on tabs a smoother animation?
Without knowing much about the internals of your classes, I imagine the problem is not that you have a listener, but what you are doing inside that listener.
In the case of most adapters notifyDataSetChanged() will cause it to re-render the entire view again (including all pages).
Seeing as you haven't specified what the intent here with the notification is, it's hard to tell you how you can do this in an alternative way, but you do need to do something less intensive if you want the animation to remain smooth.
I suspect you just want to change which fragment is shown, in which case just use the FragmentManager where necessary, remembering to reuse fragments which have already been seen once.
EDIT Based on additional info in comments
#Override
public Fragment getItem(int position) {
//POSITION_SOMETHINHG would be one of a set of constants to indicate hwa to display
return ChemGridActivity.MyFragment.newInstance(ChemGridActivity.MyFragment.POSITION_SOMETHINHG);
}
public class ChemGridActivity.MyFragment ... {
private static final String KEY_DISPLAY_TYPE = "KEY_DISPLAY_TYPE";
public static final int POSITION_SOMETHINHG = 11111;
public static MyFragment newInstance(int display) {
MyFragment f = new MyFragment();
Bundle bund = new Bundle();
bund.putInt(KEY_DISPLAY_TYPE, display);
f.setArguments(bund);
return f;
}
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
Bundle args = getArguments();
if (args != null) {
mDisplay = args.getInt(KEY_DISPLAY_TYPE, 0);
}
}
#Override
public View onCreateView(final LayoutInflater inflater, final ViewGroup container, final Bundle savedInstanceState) {
final View view = inflater.inflate(R.layout.my_layout, container, false);
//TODO: change something based on mDisplay
return view;
}
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;
I have a fragment A, containing a listview. To this listview I add a listheader containing a ViewPager that pages through childfragments.
When the user clicks an item in the list, the listfragment A gets replaced by a detail-view-fragment of that listitem.
I want the user to be able to go back to the list by clicking the back button.
So far everything works, except when the user presses the back button to pop the detail fragment from the stack to get back to the listview fragment A, the app crashes with an
java.lang.IllegalArgumentException: No view found for id 0x7f06002e (com.makamedia.hockeyweb:id/news_header_pager) for fragment NewsHeaderFragment{41f7b6f8 #0 id=0x7f06002e android:switcher:2131099694:0}
My suspicion is, that maybe the nested fragments for the viewpager in the listheader get recreated before the viewpager gets recreated, thus crashing the app, but I am not sure.
Any help is appreciated!
My ViewPagerAdapter for the listheader-viewpager (removed some unrelated code):
public class NewsHeaderAdapter extends FragmentPagerAdapter {
private int mCount;
public final NewsListAdapter mListAdapter;
public NewsHeaderAdapter(FragmentManager fm, int count, long autoSwipeInterval, NewsListAdapter adapter) {
super(fm);
this.mCount = count;
this.mListAdapter = adapter;
}
#Override
public Fragment getItem(int pos) {
return NewsHeaderFragment.getNew(this.mListAdapter.getItem(pos));
}
public void setCount(int newCount){
if(newCount < 1){
this.mCount = 1;
} else if(newCount >= this.mListAdapter.getCount()){
this.mCount = this.mListAdapter.getCount();
} else {
this.mCount = newCount;
}
}
#Override
public int getCount() {
return mCount;
}
#Override
public CharSequence getPageTitle(int position) {
return this.mListAdapter.getItem(position).getTitle();
}
}
My news detail fragment (pretty straight forward):
public class NewsHeaderFragment extends Fragment {
private NewsItem mNewsItem;
private TextView mHeaderNewsBigTitle;
private ImageView mHeaderNewsBigImage;
// Convenience method for creating a new fragment with parameters
public static NewsHeaderFragment getNew(NewsItem item){
NewsHeaderFragment fragment = new NewsHeaderFragment();
Bundle args = new Bundle();
args.putSerializable(Constants.SIG_NEWS_ITEM, item);
fragment.setArguments(args);
return fragment;
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.row_big_news, container, false);
Bundle newsHeaderArgs = getArguments();
mNewsItem = (NewsItem)newsHeaderArgs.getSerializable(Constants.SIG_NEWS_ITEM);
setupUI(rootView);
fillUI();
return rootView;
}
private void fillUI() {
mHeaderNewsBigTitle.setText(mNewsItem.getTitle());
Picasso.with(getActivity()).load(mNewsItem.getImageBig2x()).into(mHeaderNewsBigImage);
}
private void setupUI(View rootView) {
mHeaderNewsBigTitle = (TextView) rootView.findViewById(R.id.news_big_title);
mHeaderNewsBigImage = (ImageView) rootView.findViewById(R.id.news_big_img);
}
}
My viewpager is declared in xml in a row-layout and added like so:
private void addHeaderPager(int count) {
if(mNewsListAdapter != null && mNewsListAdapter.getCount()>0) {
if (count >= mNewsListAdapter.getCount()) {
count = mNewsListAdapter.getCount() - 1;
}
LayoutInflater inflater = (LayoutInflater) getActivity().getSystemService(Context.LAYOUT_INFLATER_SERVICE);
mHeader = (RelativeLayout) inflater.inflate(R.layout.row_big_news_pager, null);
mHeaderPager = (ViewPager) mHeader.findViewById(R.id.news_header_pager);
mHeaderPagerAdapter = new NewsHeaderAdapter(getChildFragmentManager(), count, 6000, mNewsListAdapter);
mHeaderPager.setOffscreenPageLimit(count);
mHeaderPager.setAdapter(mHeaderPagerAdapter);
// Bind the title indicator to the adapter
CirclePageIndicator circleIndicator = (CirclePageIndicator) mHeader.findViewById(R.id.news_header_pager_indicator);
circleIndicator.setViewPager(mHeaderPager);
mNewsListView.addHeaderView(mHeader);
}
}
Are you sure tha you use the right FragmentManager in addHeaderPager()?
I normally use getFragmentManager() and if there is a parent fragment I have to use getParentFragment().getFragmentManager() - if I don't I get the same error ("No view found for id") when trying to replace the current visible fragment.
I seem to be having an issue updating the fragments that I am using in my ViewPager, regardless of whether I try in onCreate(), onCreateView(), or onResume(). Here is how I'm setting up my ViewPager in my MainFragment:
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment_main_screen, container, false);
mPager = (ViewPager)rootView.findViewById(R.id.pager);
mPager.setOffscreenPageLimit(2); // So all 3 pages are loaded at once.
mAdapter = new JournalPagerAdapter(getActivity().getSupportFragmentManager(), this);
mPager.setAdapter(mAdapter);
// Add bar graph to view
mGraphLayout = (LinearLayout) rootView.findViewById(R.id.journalGraph);
updateGraph();
mGraphLayout.addView(mGraphView);
mPainFrag = (PainFragment)mAdapter.getRegisteredFragment(0);
// Null pointer here, but if I put the action in a button listener, it works.
mPainFrag.setScale(mEntry.getPain());
...
I'm accessing the fragments through some overridden methods in my FragmentPagerAdapter:
public class JournalPagerAdapter extends FragmentPagerAdapter {
SparseArray<Fragment> registeredFragments = new SparseArray<Fragment>();
private View.OnClickListener mOnClickListener;
public JournalPagerAdapter(FragmentManager mgr, View.OnClickListener onClickListener) {
super(mgr);
mOnClickListener = onClickListener;
}
#Override
public Fragment getItem(int pos) {
switch(pos) {
case 0: return PainFragment.newInstance("PainFragment", mOnClickListener);
case 1: return StressFragment.newInstance("StressFragment", mOnClickListener);
case 2: return SleepFragment.newInstance("SleepFragment", mOnClickListener);
default: return PainFragment.newInstance("PainFragment", mOnClickListener);
}
}
#Override
public int getCount() {
return 3;
}
/* Thanks to Streets of Boston (http://stackoverflow.com/questions/8785221/retrieve-a-fragment-from-a-viewpager)
*/
#Override
public Object instantiateItem(ViewGroup container, int position) {
Log.v("rx", "itemInstantiated");
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);
}
public Fragment getRegisteredFragment(int position) {
return registeredFragments.get(position);
}
I can't seem to figure out why the fragment is null right after I set the adapter, but if I put the fragment update code in a click event, I have no issues.
I would try adding a layout listener to your ViewPager to get notified when the laying out of views has occurred.
When you create your ViewPager call mPager.getViewTreeObserver().addOnGlobalLayoutListener() and pass something implementing OnGlobalLayoutListener.
In the callback method, do your fragment updating. Make sure to call mPager.getViewTreeObserver().removeGlobalOnLayoutListener(this) in the callback, otherwise the callback will be called multiple times.
You could instantiate your fragments in the PagerAdapter's constructor and just have getItem return them instead of instantiating them.
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);
}
}