16

几个月来，我一直在我的一个应用程序中使用 FragmentStatePagerAdapter，它运行良好。我最近切换到 IntelliJ IDEA 并更新到 ADT 22，现在当应用程序尝试破坏选项卡并创建新选项卡时，适配器会导致应用程序强制关闭。

正常工作时，Activity 将加载一系列选项卡。用户可以在它们之间滑动。所有这些仍然可以正常工作。

当用户在菜单中选择一个按钮时，应用程序应该销毁这些选项卡并创建新的选项卡。通常，这工作得很好，但现在它突然停止工作。这是代码：

/** TabsAdapter - Make Tabs Swipe-Able, Handle Fragments */
public static class TabsAdapter extends FragmentStatePagerAdapter implements ActionBar.TabListener, ViewPager.OnPageChangeListener {
    private final Context mContext;
    private final ActionBar mActionBar;
    private final ViewPager mViewPager;
    private final ArrayList<TabInfo> mTabs = new ArrayList<TabInfo>();

    static final class TabInfo {
        private final Class<?> clss;
        private final Bundle args;

        TabInfo(Class<?> _class, Bundle _args) {
            clss = _class;
            args = _args;
        }
    } // end TabInfo

    public TabsAdapter(SherlockFragmentActivity activity, ViewPager pager) {
        super(activity.getSupportFragmentManager());
        mContext = activity;
        mActionBar = activity.getSupportActionBar();
        mViewPager = pager;
        mViewPager.setAdapter(this);
        mViewPager.setOnPageChangeListener(this);
    } // end TabsAdapter

    public void addTab(ActionBar.Tab tab, Class<?> clss, Bundle args) {
        TabInfo info = new TabInfo(clss, args);
        tab.setTag(info);
        tab.setTabListener(this);
        mTabs.add(info);
        mActionBar.addTab(tab);
        notifyDataSetChanged();
    } // end addTab

    public void removeTab(ActionBar.Tab tab) {
        mTabs.remove(tab.getTag());
        mActionBar.removeTab(tab);
        notifyDataSetChanged();
    }

    @Override
    public int getItemPosition(Object object) {
        return TabsAdapter.POSITION_NONE;
    }

    @Override
    public int getCount() {
        return mTabs.size();
    } // end getCount()

    @Override
    public Fragment getItem(int position) {
        TabInfo info = mTabs.get(position);
        return Fragment.instantiate(mContext, info.clss.getName(), info.args);
    } // end getItem()

    @Override
    public void onPageScrolled(int position, float positionOffest, int postionOffsetPixels){

    } // end onPageScrolled

    @Override
    public void onPageSelected(int position) {
        mActionBar.setSelectedNavigationItem(position);
    } // end onPageSelected

    @Override
    public void onTabSelected(Tab tab, FragmentTransaction ft) {
        Object tag = tab.getTag();
        for (int i = 0; i < mTabs.size(); i++) {
            if (mTabs.get(i) == tag) {
                mViewPager.setCurrentItem(i);
            }
        }
    } // end onTabSelected

    @Override
    public void onTabUnselected(Tab tab, FragmentTransaction ft){} // end onTabUnselected

    @Override
    public void onTabReselected(Tab tab, FragmentTransaction ft){} // end onTabReselected

    @Override
    public void onPageScrollStateChanged(int arg0) {}

} // end TabsAdapter

在 onCreate() 期间，我调用了一个方法，我们称之为 CreateTabs1()，它成功构建了选项卡，用户可以滑动。只有当寻呼机试图破坏标签并创建新标签时，它才会突然失败，即使我再次调用 CreateTabs1() 也是如此。同样，这在以前总是完美无缺。

这是日志：

05-25 23:41:24.857: ERROR/AndroidRuntime(27290): FATAL EXCEPTION: main
    java.lang.IllegalStateException: The application's PagerAdapter changed the adapter's contents without calling PagerAdapter#notifyDataSetChanged! Expected adapter item count: 11, found: 10 Pager id: com.######:id/pager Pager class: class android.support.v4.view.ViewPager Problematic adapter: class com.#####.######.#####$TabsAdapter
    at android.support.v4.view.ViewPager.populate(ViewPager.java:959)
    at android.support.v4.view.ViewPager.setCurrentItemInternal(ViewPager.java:548)
    at android.support.v4.view.ViewPager.setCurrentItemInternal(ViewPager.java:507)
    at android.support.v4.view.ViewPager.setCurrentItem(ViewPager.java:488)
    at com.#####.#####.#####$TabsAdapter.onTabSelected(#####.java:215)
    at com.actionbarsherlock.internal.app.ActionBarWrapper$TabWrapper.onTabSelected(ActionBarWrapper.java:356)
    at com.android.internal.app.ActionBarImpl.selectTab(ActionBarImpl.java:570)
    at com.android.internal.app.ActionBarImpl.removeTabAt(ActionBarImpl.java:544)
    at com.android.internal.app.ActionBarImpl.removeTab(ActionBarImpl.java:520)
    at com.actionbarsherlock.internal.app.ActionBarWrapper.removeTab(ActionBarWrapper.java:409)
    at com.#####.#####.#####$TabsAdapter.removeTab(#####.java:181)
    at com.#####.#####.#####.tabDrop(#####.java:381)
    at com.#####.#####.#####.onOptionsItemSelected(#####.java:459)
    at android.support.v4.app.Watson.onMenuItemSelected(Watson.java:118)
    at com.actionbarsherlock.ActionBarSherlock.callbackOptionsItemSelected(ActionBarSherlock.java:603)
    at com.actionbarsherlock.internal.ActionBarSherlockNative.dispatchOptionsItemSelected(ActionBarSherlockNative.java:93)
    at com.actionbarsherlock.app.SherlockFragmentActivity.onMenuItemSelected(SherlockFragmentActivity.java:205)
    at com.android.internal.policy.impl.PhoneWindow.onMenuItemSelected(PhoneWindow.java:980)
    at com.android.internal.view.menu.MenuBuilder.dispatchMenuItemSelected(MenuBuilder.java:735)
    at com.android.internal.view.menu.SubMenuBuilder.dispatchMenuItemSelected(SubMenuBuilder.java:81)
    at com.android.internal.view.menu.MenuItemImpl.invoke(MenuItemImpl.java:149)
    at com.android.internal.view.menu.MenuBuilder.performItemAction(MenuBuilder.java:874)
    at com.android.internal.view.menu.MenuPopupHelper.onItemClick(MenuPopupHelper.java:156)
    at android.widget.AdapterView.performItemClick(AdapterView.java:298)
    at android.widget.AbsListView.performItemClick(AbsListView.java:1100)
    at android.widget.AbsListView$PerformClick.run(AbsListView.java:2749)
    at android.widget.AbsListView$1.run(AbsListView.java:3423)
    at android.os.Handler.handleCallback(Handler.java:725)
    at android.os.Handler.dispatchMessage(Handler.java:92)
    at android.os.Looper.loop(Looper.java:137)
    at android.app.ActivityThread.main(ActivityThread.java:5041)
    at java.lang.reflect.Method.invokeNative(Native Method)
    at java.lang.reflect.Method.invoke(Method.java:511)
    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793)
    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560)
    at dalvik.system.NativeStart.main(Native Method)
4

4 回答 4

21

在 ADT 22 之后，PagerAdapter 在调用 getCount() 之前调用 notifyDataSetChanged() 变得非常严格。它显然会跟踪它认为计数应该是什么，如果这与 getCount() 返回的不同，它就会抛出这个异常。所以解决方法就是每次数据大小发生变化时，在适配器上调用 notifyDataSetChanged() 即可。

就我而言，我有一个创建数据数组的后台任务。填充数组后，我在 onPostExecute() 中调用 notifyDataSetChanged()。当我在 onPostExecute() 中有一条没有调用 notifyDataSetChanged() 的路径时，我遇到了异常。

于 2013-05-27T17:53:47.673 回答
1

将notifyDataSetChanged();方法直接放置在向寻呼机添加/删除页面的方法下方确实有效。谢谢 @Ninjalan

于 2015-01-20T15:09:07.263 回答
0

您可以ViewPager.setAdapter(null)在所有添加/删除选项卡逻辑之前调用，最后使用更新的适配器重新分配。解决了我的烦恼。

mPager.setAdapter(null);
mTabHost.clearAllTabs();
mTabHost.addTab(...);
mTabHost.addTab(...);
mTabHost.addTab(...);
mPager.setAdapter(YOUR_UPDATED_ADAPTER_HERE);
于 2013-08-27T11:36:42.197 回答
0

Youtry set Codeing myViewPagerAdapter.notifyDataSetChanged();

@Override
public void onActivityCreated(@Nullable Bundle savedInstanceState) {
    super.onActivityCreated(savedInstanceState);

    feedItemComics = (FeedItemComics) getArguments().getSerializable( DESCRIBABLE_KEY);
    feedItemComics.getTitle();
    feedItemComics.getLast_modified();

    sceneNo.setText(feedItemComics.getScene_no());
    title.setText(feedItemComics.getTitle());
  //  Logger.Log("feedItemComics.getThumbnail", feedItemComics.getLast_modified());
    Logger.Log("feedItemComics.getTitle", feedItemComics.getTitle());

    itemComicses = (ArrayList<FeedItemComics>) getArguments().getSerializable("images");
   // feedItemList = (ArrayList<FeedItemComics>) getArguments().getSerializable("images");
    selectedPosition = getArguments().getInt("position");

   Logger.Log("itemComicses size", String.valueOf(itemComicses.size()));
    Logger.Log("selectedPosition", String.valueOf(selectedPosition));

    myViewPagerAdapter.notifyDataSetChanged();

    clickPrevious.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            if(viewPager.getCurrentItem()-1 < itemComicses.size()+1 ){
                viewPager.setCurrentItem(viewPager.getCurrentItem()-1);
                Logger.Log("position " , String.valueOf(viewPager.getCurrentItem()-1));
            }
        }
    });


    clickNext.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {

            if(viewPager.getCurrentItem()+1 < itemComicses.size() ){
                viewPager.setCurrentItem(viewPager.getCurrentItem()+1);
                Logger.Log("position " , String.valueOf(viewPager.getCurrentItem()+1));
            }

        }
    });

}
于 2016-05-19T10:34:33.250 回答