I using view pager for swipe view for android app. I build view pager Dynamically. Like add and remove item. Now i want to know how to get exactly position of view pager items.For example, I have 3 items, i want to get 3rd number position when i am in 2nd or 1st item. i used viewPager.getCurrentItem() but it return where i am.
Please suggest me how to give personal ids of every viewpager items and used it in when item is background or on screen.Thanks please help me about this, i left 2 weeks already for this. Thanks in advance
public TabsPageAdapter(FragmentManager fm) {
super(fm);
}
#Override
public Fragment getItem(int i) {
return new MyWebBrowser();
}
#Override
public int getItemPosition(Object object) {
return PagerAdapter.POSITION_NONE;
}
#Override
public int getCount() {
return COUNT_TAB;
}
}
Now this code Under my fragment class, from WebView chrom class i want to set up title as website title.
#Override
public void onReceivedTitle(WebView view, String title) {
TAB_TITLE=title;
Toast.makeText(HomeActivity.this,title,Toast.LENGTH_LONG).show();
super.onReceivedTitle(view, title);
}
take a look at this Adapter:
class MyAdapter extends FragmentStatePagerAdapter
{
private final SparseArray<WeakReference<YourFragment>> mPageReferences;
public MyAdapter(FragmentManager fm) {
super(fm);
mPageReferences = new SparseArray<WeakReference<YourFragment>>();
}
#Override
public Fragment getItem(int i) {
WeakReference<YourFragment> fragment =
new WeakReference<YourFragment>(YourFragment.newInstance());
mPageReferences.put(i, fragment);
return fragment.get();
}
#Override
public void destroyItem(ViewGroup container, int position, Object object) {
super.destroyItem(container, position, object);
mPageReferences.remove(position);
}
#Override
public int getCount() {
return number of fragment;
}
public YourFragment getFragment(int key) {
return mPageReferences.get(key).get();
}
#Override
public Object instantiateItem(ViewGroup container, int position) {
WeakReference<YourFragment> fragment = new WeakReference<YourFragment>((YourFragment) super.instantiateItem(container,
position));
mPageReferences.put(position, fragment);
return fragment.get();
}
}
you can easily get the reference of any pages from mPageReferences BUT be careful because it may be null because it is possible that it has not created when you call it. you can use (getFragment(int key) to get the item at the position of key)
you can know the current position from the PagerAdapter.
by calling pageAdapter.getItemPosition(itemNumber)
link to the documentation
Related
I use FragmentStatePagerAdapter to manage my ViewPager. I have overwritten "getItemPosition" function. Here is my code:
mViewPager.setAdapter(new FragmentStatePagerAdapter(fm) {
#Override
public Fragment getItem(int position) {
Crime c = mCrimes.get(position);
return CrimeFragment.newInstance(c.getmId());
}
#Override
public int getCount() {
return mCrimes.size();
}
#Override
public int getItemPosition(Object object) {
return POSITION_NONE;
}
});
But the problem is that when I delete the first fragment, the last fragment will be deleted, but others work well. I don't know why.
I want to update container fragment base on data inside the page fragment in ViewPager. I used this solution Retrieve a Fragment from a ViewPager and it works fine when I swipe the view.
But I cannot figure out how to get hint (callback) if first page is loaded. At the beginning? Of course onPageSelected is called but when I try to get fragment I got null.
Data data = null;
mViewPager.addOnPageChangeListener(new ViewPager.SimpleOnPageChangeListener(){
#Override
public void onPageSelected(int position) {
PageFragment page = MyPagerAdapter.getPageFragment(position);
if(page != null)
data = page.getData();
else
Log.w(TAG,"page is null"); //i get it at first time. :(
}
});
Below MyPageAdapter which I use (accordint to Retrieve a Fragment from a ViewPager)
public class MyPagerAdapter extends FragmentStatePagerAdapter {
SparseArray<PageFragment> registeredFragments = new SparseArray<PageFragment>();
public MyPagerAdapter(FragmentManager fm) {
super(fm);
}
#Override
public int getCount() {
return ...;
}
#Override
public Fragment getItem(int position) {
return PageFragment.newInstance(...);
}
#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);
}
public PageFragment getPageFragment(int position) {
return registeredFragments.get(position);
}
}
I use a PageViewer to scroll through two types of fragments.
One of them has an EditText the other multiple buttons.
Upon entering the EditText Fragment I automatically open the softkeyboard. Upon entering the Button Fragment i close it.
This works fine.
The problem is that I have multiple EditText Fragments as direct neighbours to each other.
-> I dont want the keyboard to be closed when transitioning from one EditText Fragment to the next.
For this I somehow need to predict the class to which I am transitioning next.
Is there a way to achieve this?
Note: I close the keyboard in the pageTransform method as soon as a swipe movement occurs.
EDIT
because of an request in the comments here my PagerAdapter:
public class ButtonCollectionPagerAdapter extends FragmentStatePagerAdapter {
public ButtonCollectionPagerAdapter(FragmentManager fm) {
super(fm);
}
private Fragment currentFragment;
#Override
public Fragment getItem(int i) {
Bundle args = new Bundle();
List<MultipleChoiceQuestion> multipleChoiceQuestions = QuestionTexts.getMCQuestionTexts();
List<String> questionTexts = QuestionTexts.getQuestionTexts();
if(i < multipleChoiceQuestions.size()){
String question = multipleChoiceQuestions.get(i).getText();
ArrayList<String> choices = (ArrayList<String>) multipleChoiceQuestions.get(i).getChoices();
currentFragment = ButtonFragment.newInstance(question, choices, i);
} else if(i < (multipleChoiceQuestions.size() + questionTexts.size())){
currentFragment = TextViewFragment.newInstance(questionTexts.get(i - multipleChoiceQuestions.size()), i);
} else {
currentFragment = SendFragment.newInstance(i);
}
return currentFragment;
}
#Override
public int getCount() {
return 23;
}
#Override
public CharSequence getPageTitle(int position) {
return "OBJECT " + (position + 1);
}
#Override
public void setPrimaryItem(ViewGroup container, int position, Object object){
super.setPrimaryItem(container, position, object);
currentFragment = (Fragment) object;
((PagerAdapterUpdateProgress) object).onGettingPrimary(position);
}
public Fragment getCurrentFragment() {
return currentFragment;
}
}
I think the more simple way to do that is to open/close keyboard directly from your fragments. You can determine when your fragment becomes visible by overriding setUserVisibleHint method of your fragment. The code in this method for your EditText Fragment should just show keyboard, and the code for other fragment should hide keyboard.
This is an interesting question.
I believe that you can achieve what you are doing by using ViewPager.OnPageChangeListener listener especially onPageSelected(int position) method in which we could get the position of the currently selected fragment after the swipe animation has finished.
mViewPager.setOnPageChangeListener(new ViewPager.OnPageChangeListener() {
#Override
public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
}
#Override
public void onPageSelected(int position) {
Log.d("ViewPager", "Page selected " + position);
onPageSelectedLogic(position);
}
#Override
public void onPageScrollStateChanged(int state) {
}
});
// This is because the first fragment doesn't fire the OnPageChangeListener.
onPageSelectedLogic(0);
an this is the implementation of onPageSelectedLogic method
private void onPageSelectedLogic(int position) {
// Check the type of the fragment editable vs button
if(!mPagerAdpater.isFragmentEdiatable(position)) {
// Close the Keyboard
}
}
And this is how you should implement your PagerAdapter
class CustomPagerAdapter extends FragmentStatePagerAdapter {
private SparseBooleanArray fragmentsEditable = new SparseBooleanArray();
public ScreenSlidePagerAdapter(FragmentManager fm) {
super(fm);
}
#Override
public Fragment getItem(int position) {
Fragment fargment;
// get the fragment
if(some condition) {
// Get an editable fragment
fragmentsEditable.put(position, true);
} else {
fragmentsEditable.put(position, false);
}
return fragment;
}
#Override
public int getCount() {
return NUM_PAGES;
}
public boolean isFragmentEditable(int postion) {
return fragmentsEditable.get(postion);
}
}
I am showing 100 images in viewpager, and my application crash ( out of memory error ) when i navigate between these images . I want to use destroyItem to free up memory but it is not worked. Can you help me ?
public class ViewPagerAdapter extends FragmentPagerAdapter {
public ViewPagerAdapter(FragmentManager fm) {
super(fm);
}
#Override
public Fragment getItem(int pos) {
return JpgFragment.newInstance(pos);
}
#Override
public int getCount() {
return ViewPagerActivity.slidesSize;
}
public String getPageTitle(int pos) {
return null;
}
#Override
public void destroyItem(View collection, int position, Object o) {
Log.d("DESTROY", "destroying view at position " + position);
View view = (View) o;
((ViewPager) collection).removeView(view);
view = null;
}
}
I set the ImageView in my fragment( in onCreateView )
Well FragmentPagerAdapter will load all the fragments in memory at once. Consider using a FragmentStatePagerAdapter, as this is efficient when you have to show a large number of fragments on screen at once.
I tried to do what the other answers suggested, but when I look at the logs, after getItemPosition is returned with POSITION_NONE, position 0 does not get called for getItem, any idea? I also tried to override destoryItem when getItemPosition is returned, it DOES get called but nothing happens.
public class ProvidersActivityPagerAdapter extends FragmentPagerAdapter {
private ArrayList<String> fragments;
public ProvidersActivityPagerAdapter(FragmentManager fm) {
super(fm);
fragments=new ArrayList<String>();
if(provider.isInitialized()){
fragments.add(BaseDetailsFragment.class.getName());
}else{
fragments.add(BaseAuthFragment.class.getName());
}
this.fm=fm;
}
#Override
public int getCount(){
return fragments.size();
}
#Override
public int getItemPosition(Object object) {
AppUtils.logI("Get Item Position: "+POSITION_NONE+" "+object.getClass().getName());
return POSITION_NONE;
}
#Override
public Fragment getItem(int position) {
AppUtils.logI("Get Fragment for: "+position);
String f=fragments.get(position);
if(f.equals(BaseDetailsFragment.class.getName())){
return provider.getDetailFragment();
}
if(f.equals(BaseAuthFragment.class.getName())){
return provider.getAuthFragment();
}
if(f.equals(BaseSelectorFragment.class.getName())){
return provider.getCurrentSelector();
}
return new Fragment();
}
private void addItem(int loc,String fa,String tag){
this.fragments.add(loc,fa);
AppUtils.logI(fragments.toString());
notifyDataSetChanged(); //only creates the new fragment but not updating the old ones.
mViewPager.setCurrentItem(loc);
}
It appears that the support library version of the FragmentPagerAdapter does NOTHING in destroy item. So the solution is to save the fragment manager when constructing the page adapter and override the destoryItem() function. Note that this may not be compatible to future editions of the support library.
#Override
public void destroyItem(ViewGroup container,int position,Object object){
super.destroyItem(container, position, object);
FragmentTransaction bt = fm.beginTransaction();
bt.remove((Fragment)object);
bt.commit();
}