Android FragmentPagerAdapter未正确删除项目(片段)
我已经实现了Android FragmentPagerAdapter未正确删除项目(片段),android,android-fragments,android-viewpager,Android,Android Fragments,Android Viewpager,我已经实现了FragmentPagerAdapter,并使用列表保存所有片段,以便我的查看页面显示。在addItem()上,我只需添加一个实例化的片段,然后调用notifyDataSetChanged()。我不确定这是否必要 我的问题只是。。。 从片段1开始 [Fragment 1] 添加新片段2 [Fragment 1] [Fragment 2] 删除片段2 [Fragment 1] 添加新片段3 [Fragment 1] [Fragment 2] 当添加新片段时,一切看起来都很棒。
FragmentPagerAdapter
,并使用列表
保存所有片段,以便我的查看页面
显示。在addItem()
上,我只需添加一个实例化的片段
,然后调用notifyDataSetChanged()
。我不确定这是否必要
我的问题只是。。。
从片段1开始
[Fragment 1]
添加新片段2
[Fragment 1] [Fragment 2]
删除片段2
[Fragment 1]
添加新片段3
[Fragment 1] [Fragment 2]
当添加新片段时,一切看起来都很棒。一旦我删除一个片段,然后添加一个新实例化的片段,旧片段仍然显示出来。当我转到.getClass.getName()
时,它给了我片段3的名称,但我仍然看到片段2
我相信这可能是instantiateItem()
之类的问题,但我认为适配器可以为我们解决这个问题。任何建议都很好
适配器代码
public class MyPagerAdapter extends FragmentPagerAdapter {
public final ArrayList<Fragment> screens2 = new ArrayList<Fragment>();
private Context context;
public MyPagerAdapter(FragmentManager fm, Context context) {
super(fm);
this.context = context;
}
public void removeType(String name){
for(Fragment f: screens2){
if(f.getClass().getName().contains(name)){ screens2.remove(f); return; }
}
this.notifyDataSetChanged();
}
public boolean addSt(String tag, Class<?> clss, Bundle args){
if(clss==null) return false;
if(!clss.getName().contains("St")) return false;
if(!args.containsKey("cId")) return false;
boolean has = false;
boolean hasAlready = false;
for(Fragment tab: screens2){
if(tab.getClass().getName().contains("St")){
has = true;
if(tab.getArguments().containsKey("cId"))
if(tab.getArguments().getLong("cId") == args.getLong("cId")){
hasAlready = true;
}
if(!hasAlready){
// exists but is different so replace
screens2.remove(tab);
this.addScreen(tag, clss, args, C.PAGE_ST);
// if returned true then it notifies dataset
return true;
}
}
hasAlready = false;
}
if(!has){
// no st yet exist in adapter
this.addScreen(tag, clss, args, C.PAGE_ST);
return true;
}
return false;
}
public boolean removeCCreate(){
this.removeType("Create");
return false;
}
@Override
public int getItemPosition(Object object) {
return POSITION_NONE; //To make notifyDataSetChanged() do something
}
public void addCCreate(){
this.removeCCreate();
Log.w("addding c", " ");
this.addScreen("Create C", CreateCFragment.class, null, C.PAGE_CREATE_C);
}
public void addScreen(String tag, Class<?> clss, Bundle args, int type){
if(clss!=null){
screens2.add(Fragment.instantiate(context, clss.getName(), args));
}
}
@Override
public int getCount() {
return screens2.size();
}
@Override
public Fragment getItem(int position) {
return screens2.get(position);
}
}
公共类MyPagerAdapter扩展了FragmentPagerAdapter{
公共最终ArrayList屏幕2=新ArrayList();
私人语境;
公共MyPagerAdapter(FragmentManager格式,上下文){
超级(fm);
this.context=上下文;
}
public void removeType(字符串名称){
对于(片段f:screens2){
如果(f.getClass().getName().contains(name)){screens2.remove(f);return;}
}
this.notifyDataSetChanged();
}
公共布尔addSt(字符串标记、类clss、包参数){
if(clss==null)返回false;
如果(!clss.getName().contains(“St”))返回false;
如果(!args.containsKey(“cId”))返回false;
布尔has=false;
布尔值=false;
对于(片段选项卡:屏幕2){
如果(tab.getClass().getName()包含(“St”)){
has=真;
if(tab.getArguments().containsKey(“cId”))
if(tab.getArguments().getLong(“cId”)==args.getLong(“cId”)){
haseready=true;
}
如果(!haseready){
//存在但不同,所以请替换
屏幕2.移除(选项卡);
此.addScreen(标记、clss、参数、C.PAGE_ST);
//如果返回true,则通知dataset
返回true;
}
}
haseready=false;
}
如果(!has){
//适配器中尚不存在st
此.addScreen(标记、clss、参数、C.PAGE_ST);
返回true;
}
返回false;
}
公共布尔值removecreate(){
此.removeType(“创建”);
返回false;
}
@凌驾
public int getItemPosition(对象){
返回位置\u NONE;//使notifyDataSetChanged()执行某些操作
}
public void addCCreate(){
这个.removecreate();
Log.w(“添加c”和“);
this.addScreen(“Create C”,CreateCFragment.class,null,C.PAGE\u Create\u C);
}
公共void addScreen(字符串标记、类cls、捆绑参数、int类型){
如果(clss!=null){
screens2.add(Fragment.instantiate(context,clss.getName(),args));
}
}
@凌驾
public int getCount(){
返回screens2.size();
}
@凌驾
公共片段getItem(int位置){
返回屏幕2.get(位置);
}
}
我意识到代码使用了一些“隔离区”的方法来确定片段类型,但是我编写这段代码完全是为了测试功能。任何帮助或想法都会很好,因为似乎没有多少人冒险进入
FragmentPagerAdapter
s的世界。更新了这篇文章并包含了我的解决方案(如果有人可以改进,请告诉我)
好的,我现在已经用一种黑客的方式解决了我的问题,但是是的,它正在工作;)。如果有人能改进我的解决方案,请让我知道。对于我的新解决方案,我现在使用CustomFragmentStatePagerAdapter,但它并没有像应该的那样保存状态,而是将所有片段存储在一个列表中。如果用户有超过50个片段,这可能会导致内存问题,就像正常的FragmentPagerAdapter一样。如果有人能够在不删除我的修复程序的情况下将状态添加回我的解决方案,那就太好了。谢谢
下面是我的CustomFragmentStatePagerAdapter.java
package com.tundem.webLab.Adapter;
import java.util.ArrayList;
import android.os.Bundle;
import android.os.Parcelable;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentTransaction;
import android.support.v4.view.PagerAdapter;
import android.util.Log;
import android.view.View;
import android.view.ViewGroup;
public abstract class CustomFragmentStatePagerAdapter extends PagerAdapter {
private static final String TAG = "FragmentStatePagerAdapter";
private static final boolean DEBUG = false;
private final FragmentManager mFragmentManager;
private FragmentTransaction mCurTransaction = null;
public ArrayList<Fragment.SavedState> mSavedState = new ArrayList<Fragment.SavedState>();
public ArrayList<Fragment> mFragments = new ArrayList<Fragment>();
private Fragment mCurrentPrimaryItem = null;
public CustomFragmentStatePagerAdapter(FragmentManager fm) {
mFragmentManager = fm;
}
/**
* Return the Fragment associated with a specified position.
*/
public abstract Fragment getItem(int position);
@Override
public void startUpdate(ViewGroup container) {}
@Override
public Object instantiateItem(ViewGroup container, int position) {
// If we already have this item instantiated, there is nothing
// to do. This can happen when we are restoring the entire pager
// from its saved state, where the fragment manager has already
// taken care of restoring the fragments we previously had instantiated.
// DONE Remove of the add process of the old stuff
/* if (mFragments.size() > position) { Fragment f = mFragments.get(position); if (f != null) { return f; } } */
if (mCurTransaction == null) {
mCurTransaction = mFragmentManager.beginTransaction();
}
Fragment fragment = getItem(position);
if (DEBUG)
Log.v(TAG, "Adding item #" + position + ": f=" + fragment);
if (mSavedState.size() > position) {
Fragment.SavedState fss = mSavedState.get(position);
if (fss != null) {
try // DONE: Try Catch
{
fragment.setInitialSavedState(fss);
} catch (Exception ex) {
// Schon aktiv (kA was das heißt xD)
}
}
}
while (mFragments.size() <= position) {
mFragments.add(null);
}
fragment.setMenuVisibility(false);
mFragments.set(position, fragment);
mCurTransaction.add(container.getId(), fragment);
return fragment;
}
@Override
public void destroyItem(ViewGroup container, int position, Object object) {
Fragment fragment = (Fragment) object;
if (mCurTransaction == null) {
mCurTransaction = mFragmentManager.beginTransaction();
}
mCurTransaction.remove(fragment);
/*if (mCurTransaction == null) { mCurTransaction = mFragmentManager.beginTransaction(); } if (DEBUG) Log.v(TAG, "Removing item #" + position + ": f=" + object + " v=" + ((Fragment)
* object).getView()); while (mSavedState.size() <= position) { mSavedState.add(null); } mSavedState.set(position, mFragmentManager.saveFragmentInstanceState(fragment));
* mFragments.set(position, null); mCurTransaction.remove(fragment); */
}
@Override
public void setPrimaryItem(ViewGroup container, int position, Object object) {
Fragment fragment = (Fragment) object;
if (fragment != mCurrentPrimaryItem) {
if (mCurrentPrimaryItem != null) {
mCurrentPrimaryItem.setMenuVisibility(false);
}
if (fragment != null) {
fragment.setMenuVisibility(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() {
Bundle state = null;
if (mSavedState.size() > 0) {
state = new Bundle();
Fragment.SavedState[] fss = new Fragment.SavedState[mSavedState.size()];
mSavedState.toArray(fss);
state.putParcelableArray("states", fss);
}
for (int i = 0; i < mFragments.size(); i++) {
Fragment f = mFragments.get(i);
if (f != null) {
if (state == null) {
state = new Bundle();
}
String key = "f" + i;
mFragmentManager.putFragment(state, key, f);
}
}
return state;
}
@Override
public void restoreState(Parcelable state, ClassLoader loader) {
if (state != null) {
Bundle bundle = (Bundle) state;
bundle.setClassLoader(loader);
Parcelable[] fss = bundle.getParcelableArray("states");
mSavedState.clear();
mFragments.clear();
if (fss != null) {
for (int i = 0; i < fss.length; i++) {
mSavedState.add((Fragment.SavedState) fss[i]);
}
}
Iterable<String> keys = bundle.keySet();
for (String key : keys) {
if (key.startsWith("f")) {
int index = Integer.parseInt(key.substring(1));
Fragment f = mFragmentManager.getFragment(bundle, key);
if (f != null) {
while (mFragments.size() <= index) {
mFragments.add(null);
}
f.setMenuVisibility(false);
mFragments.set(index, f);
} else {
Log.w(TAG, "Bad fragment at key " + key);
}
}
}
}
}
}
package com.tundem.webLab.Adapter;
import java.util.LinkedList;
import java.util.List;
import android.support.v4.app.FragmentManager;
import com.tundem.webLab.fragments.BaseFragment;
import com.viewpagerindicator.TitleProvider;
public class FragmentAdapter extends CustomFragmentStatePagerAdapter implements TitleProvider {
public List<BaseFragment> fragments = new LinkedList<BaseFragment>();
private int actPage;
public FragmentAdapter(FragmentManager fm) {
super(fm);
}
public void setActPage(int actPage) {
this.actPage = actPage;
}
public void addItem(BaseFragment fragment) {
// TODO if exists don't open / change to that tab
fragments.add(fragment);
}
public BaseFragment getActFragment() {
return getItem(getActPage());
}
public int getActPage() {
return actPage;
}
@Override
public BaseFragment getItem(int position) {
if (position < getCount()) {
return fragments.get(position);
} else
return null;
}
@Override
public int getCount() {
return fragments.size();
}
@Override
public String getTitle(int position) {
return fragments.get(position).getTitle();
}
@Override
public int getItemPosition(Object object) {
return POSITION_NONE;
}
}
Cfg的描述。事情我将对这些对象的引用保存在一个cfg类中,这样我就可以始终使用它们,而无需特殊的Factory.java
嗯。我希望我能帮上忙。请随意改进,但请让我知道,这样我也可以改进我的代码
谢谢
如果我遗漏了任何代码,请告诉我
我以前的答案也适用,但前提是你有不同的片段。FileFragment,WebFragment。。。如果您两次使用其中一种碎片类型,则不会 我现在的工作是假的。这是一个非常肮脏的解决方案,我仍在寻找更好的解决方案。请帮忙 我更改了代码,将其中的一个选项卡删除为:
public static void deleteActTab()
{
//We set this on the indicator, NOT the pager
int act = Cfg.mPager.getCurrentItem();
Cfg.mAdapter.removeItem(act);
List<BaseFragment> frags = new LinkedList<BaseFragment>();
frags = Cfg.mAdapter.fragments;
Cfg.mPager = (ViewPager)Cfg.act.findViewById(R.id.pager);
Cfg.mPager.setAdapter(Cfg.mAdapter);
Cfg.mIndicator.setViewPager(Cfg.mPager);
Cfg.mAdapter.fragments = frags;
if(act > 0)
{
Cfg.mPager.setCurrentItem(act-1);
Cfg.mIndicator.setCurrentItem(act-1);
}
Cfg.mIndicator.notifyDataSetChanged();
}
公共静态void deleteActTab()
{
//我们是在指示灯上设置的,不是在传呼机上
int act=Cfg.mPager.getCurrentItem();
Cfg.mAdapter.removietem(法案);
List frags=newlinkedlist();
frags=Cfg.mAdapter.fragments;
Cfg.mPager=(ViewPager)Cfg.act.findViewById(R.id.pager);
Cfg.mPager.setAdapter(Cfg.mAdapter);
Cfg.mIndicator.setViewPager(Cfg.mPager);
Cfg.mAdapter.fragments=碎片;
如果(动作>0)
{
Cfg.mPager.setCurrentItem(act-1);
Cfg.mIndicator.setCurrentItem(act-1);
}
Cfg.mIndicator.notifyDataSetChanged();
}
如果有人可以改进此代码,请告诉我。如果有人能告诉我们这个问题的真正答案。请加在这里。很多人都经历过这个问题。我为解决这个问题的人增加了50的声望。我也可以为解决问题的人捐款
谢谢我也遇到了同样的问题,我的解决方案超越了“destroyItem”方法,如下所示
@Override
public void destroyItem(ViewGroup container, int position, Object object) {
FragmentManager manager = ((Fragment)object).getFragmentManager();
FragmentTransaction trans = manager.beginTransaction();
trans.remove((Fragment)object);
trans.commit();
}
这对我来说很有用,有人有其他解决办法吗?@Override
public void destroyItem(ViewGroup container, int position, Object object) {
FragmentManager manager = ((Fragment)object).getFragmentManager();
FragmentTransaction trans = manager.beginTransaction();
trans.remove((Fragment)object);
trans.commit();
}
@Override
public void destroyItem(ViewGroup container, int position, Object object) {
if (position >= getCount()) {
FragmentManager manager = ((Fragment) object).getFragmentManager();
FragmentTransaction trans = manager.beginTransaction();
trans.remove((Fragment) object);
trans.commit();
}
}
// mFragments.set(position, null);
if (position < mFragments.size())mFragments.remove(position);
public class MyPagerAdapter extends FragmentPagerAdapter {
public ArrayList<Fragment> fragments = new ArrayList<Fragment>();
...
@Override
public void destroyItem(ViewGroup container, int position, Object object) {
super.destroyItem(container, position, object);
if (position >= getCount()) fm.beginTransaction().remove((Fragment) object).commit();
}
@Override
public int getItemPosition(Object object) {
if (fragments.contains(object)) return fragments.indexOf(object);
else return POSITION_NONE;
}
}
public class SectionsPagerAdapter extends FragmentPagerAdapter
{
...
@Override
public long getItemId(int position)
{
// Mode 1 uses Fragments 0, 1 and 2. Mode 2 uses Fragments 0 and 3
if ( mode == 2 && position == 1 )
return 3;
return position;
}
@Override
public Fragment getItem(int position)
{
if ( mode == 1 )
{
switch (position)
{
case 0:
return <<fragment 0>>;
case 1:
return <<fragment 1>>;
case 2:
return <<fragment 2>>;
}
}
else // Mode 2
{
switch (position)
{
case 0:
return <<fragment 0>>;
case 1:
return <<fragment 3>>;
}
}
return null;
}
}
private void modeChanged(int newMode)
{
if ( newMode == mode )
return;
mode = newMode;
// Calling mSectionsPagerAdapter.notifyDataSetChanged() is not enough here
mViewPager.setAdapter(mSectionsPagerAdapter);
}
Object fragments[] = new Object[3];
int mItems = 2;
MyAdapter mAdapter;
ViewPager mPager;
public void addFragment(boolean bool) {
mAdapter.startUpdate(mPager);
if (!bool) {
mAdapter.destroyItem(mPager, 2, fragments[2]);
mItems = 2;
fNach = false;
}
else if (bool && !fNach){
mItems = 3;
mAdapter.instantiateItem(mPager,2);
fNach = true;
}
mAdapter.finishUpdate(mPager);
mAdapter.notifyDataSetChanged();
}
public class MyAdapter extends FragmentPagerAdapter {
MyAdapter(FragmentManager fm) {
super(fm);
}
@Override
public int getCount() {
return mItems;
}
@Override
public CharSequence getPageTitle(int position) {
... (code for the PagerTitleStrip)
}
@Override
public Fragment getItem(int position) {
Fragment f = null;
switch (position) {
case 0:
f = new Fragment1();
break;
case 1:
f = new Fragment2();
break;
case 2:
f = new Fragment3();
break;
}
return f;
}
@Override
public Object instantiateItem(ViewGroup container, int position) {
Object o = super.instantiateItem(container,position);
fragments[position] = o;
return o;
}
@Override
public void destroyItem(ViewGroup container, int position, Object object) {
super.destroyItem(container, position, object);
System.out.println("Destroy item " + position);
if (position >= getCount()) {
FragmentManager manager = ((Fragment) object).getFragmentManager();
FragmentTransaction ft = manager.beginTransaction();
ft.remove((Fragment) object);
ft.commit();
}
}
}
@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;
}
private static String makeFragmentName(int viewId, long id) {
return "android:switcher:" + viewId + ":" + id;
}
* Return a unique identifier for the item at the given position.
* <p>
* <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;
}