无法从ViewPager删除片段，为什么呢？ [英] Cannot remove fragment from ViewPager, why?
问题描述
我必须失去了一些东西，但我无法从我的 ViewPager 删除片段。我保存的页面标题在的ArrayList ：
I must be missing something but I cannot remove a fragment from my ViewPager. I store the page titles in an ArrayList:
ViewPagerActivity.java 的一部分（这是一个 FragmentActivity ，主要活动）：
Part of ViewPagerActivity.java (which is a FragmentActivity, the main activity):
public static ArrayList<String> mEntries = new ArrayList<String>();
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate( savedInstanceState );
setContentView( R.layout.main );
context=this;
mEntries.add(" 111");
mEntries.add(" 222");
mEntries.add(" 333");
mEntries.add(" 444");
mEntries.add(" 555");
mEntries.add(" 666");
List<String> fragments = new Vector<String>();
fragments.add(111.class.getName());
fragments.add(222.class.getName());
fragments.add(333.class.getName());
fragments.add(444.class.getName());
fragments.add(555.class.getName());
fragments.add(666.class.getName());
this.mPagerAdapter = new PagerAdapter1(super.getSupportFragmentManager(), fragments);
pager = (ViewPager)super.findViewById(R.id.viewpager);
pager.setAdapter(this.mPagerAdapter);
// ...
我有一个片段（ 111 ），我想通过点击一个按钮来删除 555 片段 111 。 （因为它与 0 ， 555 开始是第四片段）。
I have a fragment (111) where I would like to remove the 555 fragment by clicking a button in 111. (Since it starts with 0, 555 is the 4th fragment).
fragment111.java 的一部分（这是一个片段）
Part of fragment111.java (which is a Fragment):
button.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
ViewPagerActivity.mEntries.remove(5);
ViewPagerActivity.mPagerAdapter.removeX(5);
ViewPagerActivity.mPagerAdapter.removeX2(5);
ViewPagerActivity.pager.setAdapter( ViewPagerActivity.mPagerAdapter);
ViewPagerActivity.pager.getAdapter().notifyDataSetChanged();
}
});
我有 POSITION_NONE 的事情，有些人通过覆盖错过 getItemPosition（）方法。
I have the POSITION_NONE thing that some people miss by overriding the getItemPosition() method.
我的适配器类：
public class PagerAdapter1 extends FragmentStatePagerAdapter {
private List<String> fragments;
private static final String TAG = "FragmentPagerAdapter";
private static final boolean DEBUG = true;
private Fragment mCurrentPrimaryItem = null;
private final FragmentManager mFragmentManager;
private FragmentTransaction mCurTransaction = null;
/**
* @param fm
* @param fragments2
*/
public PagerAdapter1(FragmentManager fm, List<String> fragments2) {
super(fm);
mFragmentManager=fm;
this.fragments = fragments2;
}
/* (non-Javadoc)
* @see android.support.v4.app.FragmentPagerAdapter#getItem(int)
*/
@Override
public Fragment getItem(int position) {
//return this.fragments.get(position);
return Fragment.instantiate(ViewPagerActivity.context, fragments.get(position));
}
/* (non-Javadoc)
* @see android.support.v4.view.PagerAdapter#getCount()
*/
@Override
public int getCount() {
return this.fragments.size();
}
/**
* Return the Fragment associated with a specified position.
*/
@Override
public void startUpdate(ViewGroup container) {
}
@Override
public Object instantiateItem(ViewGroup container, int position) {
if (mCurTransaction == null) {
mCurTransaction = mFragmentManager.beginTransaction();
}
final long itemId = getItemId(position);
// Do we already have this fragment?
String name = makeFragmentName(container.getId(), itemId);
Fragment fragment = mFragmentManager.findFragmentByTag(name);
if (fragment != null) {
if (DEBUG) Log.v(TAG, "Attaching item #" + itemId + ": f=" + fragment);
mCurTransaction.attach(fragment);
} else {
fragment = getItem(position);
if (DEBUG) Log.v(TAG, "Adding item #" + itemId + ": f=" + fragment);
mCurTransaction.add(container.getId(), fragment,
makeFragmentName(container.getId(), itemId));
}
if (fragment != mCurrentPrimaryItem) {
fragment.setMenuVisibility(false);
fragment.setUserVisibleHint(false);
}
return fragment;
}
@Override
public void destroyItem(ViewGroup container, int position, Object object) {
if (mCurTransaction == null) {
mCurTransaction = mFragmentManager.beginTransaction();
}
if (DEBUG) Log.v(TAG, "Detaching item #" + getItemId(position) + ": f=" + object
+ " v=" + ((Fragment)object).getView());
mCurTransaction.detach((Fragment)object);
}
@Override
public void setPrimaryItem(ViewGroup container, int position, Object object) {
Fragment fragment = (Fragment)object;
if (fragment != mCurrentPrimaryItem) {
if (mCurrentPrimaryItem != null) {
mCurrentPrimaryItem.setMenuVisibility(false);
mCurrentPrimaryItem.setUserVisibleHint(false);
}
if (fragment != null) {
fragment.setMenuVisibility(true);
fragment.setUserVisibleHint(true);
}
mCurrentPrimaryItem = fragment;
}
}
@Override
public void finishUpdate(ViewGroup container) {
if (mCurTransaction != null) {
mCurTransaction.commitAllowingStateLoss();
mCurTransaction = null;
mFragmentManager.executePendingTransactions();
}
}
@Override
public boolean isViewFromObject(View view, Object object) {
return ((Fragment)object).getView() == view;
}
@Override
public Parcelable saveState() {
return null;
}
@Override
public void restoreState(Parcelable state, ClassLoader loader) {
}
/**
* Return a unique identifier for the item at the given position.
*
* <p>The default implementation returns the given position.
* Subclasses should override this method if the positions of items can change.</p>
*
* @param position Position within this adapter
* @return Unique identifier for the item at position
*/
public long getItemId(int position) {
return position;
}
private static String makeFragmentName(int viewId, long id) {
return "android:switcher:" + viewId + ":" + id;
}
@Override
public int getItemPosition(Object object) {
return POSITION_NONE;
}
public void removeX(int position){
fragments.remove(5);
}
public void removeX2(int position){
Fragment ff = getItem(position);
mFragmentManager.beginTransaction().remove(ff).commit();
notifyDataSetChanged();
}
}
我使用 FragmentStatePagerAdapter 和 notifyDataSetChanged（）效果很好（我更新<$ C $状态C>复选框，我看到它的工作原理）。我怎样才能把这个片段 ViewPager
I am using FragmentStatePagerAdapter and the notifyDataSetChanged() works well (I update state of a CheckBox and I see it works). How can I remove this fragment from the ViewPager?
在此先感谢！
推荐答案
我有同样的问题，我发现的唯一的解决办法是删除片段这样后再设置适配器：
I had the same problem, the only solution I found was to set the adapter again after removing the fragment like this :
@Override
public void onClick(View v) {
ViewPagerActivity.mEntries.remove(4);
pager.setAdapter(mPagerAdapter);
}
更新：您不需要重新设置适配器。下面的一些方法我的 PagerAdapter ，你可能需要做一些修改，把它作为FragmentPagerAdapter
UPDATE : YOU DON'T NEED TO SET THE ADAPTER AGAIN. Here some methods of my PagerAdapter, you need probably to do some modifications to use it as FragmentPagerAdapter
要删除的看法：
public static void deleteChildren(int pStart) {
List<ViewInfo> viewToRemove = new ArrayList<ViewInfo>();
for (int iView = pStart+1; iView < _views.size(); iView++) {
viewToRemove.add(_views.get(iView));
}
if (viewToRemove.size() != 0) {
_views.removeAll(viewToRemove);
}
}
@Override
public void destroyItem(View pView, int pIndex, Object pObject) {
((ViewPager) pView).removeView((View)pObject);
}
覆盖getItemPosition（对象pObject）：
Override getItemPosition(Object pObject) :
@Override
public int getItemPosition(Object pObject) {
int pos = 0;
for (ViewInfo iView : _views) {
if (iView.mView == (View)pObject) {
break;
}
pos++;
}
return pos;
}
刷新所有视图：
public static void refreshAdapterViewPager() {
_pagerAdapter.notifyDataSetChanged();
}
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