Android 如何强制从FragmentStatePagerAdapter子级重新创建片段

有一点问题我似乎找不到解决的办法

我有一个FragmentStatePagerAdapter，它实现了一个自定义TabAdapter。这里一切正常，除了我遇到的情况，FragmentStatePagerAdapter中的一个片段可能会更改一些项目，这些项目需要所有片段重新创建它们自己的视图

例如，在片段D中，用户更改了一些内容->然后片段a、B、C中的值需要更改。这在片段A和B中立即发生，因为它们的视图尚未创建。然而，片段C已经被创建了，因为似乎在任何时候都会创建3个片段，至少在默认情况下是这样（上一个、当前、下一个）。因此，片段C不会得到更新

因此，最终我需要一种方法，当单个片段（a、B、C或D）中的某个发生更改时，强制适配器中的所有片段重新创建它们的视图

这是我的碎纸机

public class MyTabsAdapter extends FragmentStatePagerAdapter implements
    TabsAdapter {

private final ArrayList<TabInfo> mTabs = new ArrayList<TabInfo>();
private final ViewPager mPager;

private Activity mContext;

/*
 * TabInfo- Simple object to keep track of the tabs.
 */
private class TabInfo {
    private String fragName;
    private String title;

    TabInfo(String fragName, String title) {
        this.fragName = fragName;
        this.title = title;
    }

    String getFragName() {
        return this.fragName;
    }

    String getTitle() {
        return this.title;
    }
}

public MyTabsAdapter(FragmentActivity ctx, ViewPager pager) {
    super(ctx.getSupportFragmentManager());
    this.mContext = ctx;
    this.mPager = pager;

    this.mPager.setAdapter(this);
}

/*
 * getView - get Tab view
 */
@SuppressLint("DefaultLocale")
public View getView(int position) {
    Button tab;

    LayoutInflater inflater = mContext.getLayoutInflater();
    tab = (Button) inflater.inflate(R.layout.tab_scrolling, null);

    tab.setText(this.mTabs.get(position).getTitle().toUpperCase());

    return tab;
}

public void addTab(String fragName, String title) {
    TabInfo info = new TabInfo(fragName, title);
    mTabs.add(info);
}

@Override
public Fragment getItem(int position) {
    String fragName = mTabs.get(position).getFragName();
    if (fragName == "FragmentA") {
        return FragmentA.newInstance();
    } else if (fragName == "FragmentB") {
        return FragmentB.newInstance();
    } else if (fragName == "FragmentC") {
        return FragmentC.newInstance();
    } else if (fragName == "FragmentD") {
        return FragmentD.newInstance();
    }

    return null;
}

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

}

这一切都很好，我对选项卡adapters/views/等没有任何问题。我只是想知道如何在片段A/B/C/D中发生变化时“强制”适配器删除/重新创建其他项

---

谢谢，如果需要，我将提供更多信息

如果您需要更改适配器数据以删除或重新创建，我已在android Support4Demos中进行了简单更改，以演示如何更新适配器的片段页面

/**
 * Demonstrates combining a TabHost with a ViewPager to implement a tab UI
 * that switches between tabs and also allows the user to perform horizontal
 * flicks to move between the tabs.
 */
public class FragmentTabsPager extends FragmentActivity implements View.OnClickListener,FragmentCallBack{

    TabHost mTabHost;
    ViewPager  mViewPager;

    TabsAdapter mTabsAdapter;

    private Button mBtn_nextFragment;


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        setContentView(R.layout.fragment_tabs_pager);
        mTabHost = (TabHost)findViewById(android.R.id.tabhost);

        mBtn_nextFragment=(Button)findViewById(R.id.btn_next_fragment);

        mBtn_nextFragment.setOnClickListener(this);

        mTabHost.setup();

        mViewPager = (ViewPager)findViewById(R.id.pager);

        mTabsAdapter = new TabsAdapter(this, mTabHost, mViewPager);

        mTabsAdapter.addTab(mTabHost.newTabSpec("simple").setIndicator("Simple"),
                FragmentStackSupport.CountingFragment.class, null);
        mTabsAdapter.addTab(mTabHost.newTabSpec("contacts").setIndicator("Contacts"),
                LoaderCursorSupport.CursorLoaderListFragment.class, null);
        mTabsAdapter.addTab(mTabHost.newTabSpec("custom").setIndicator("Custom"),
                LoaderCustomSupport.AppListFragment.class, null);
        mTabsAdapter.addTab(mTabHost.newTabSpec("throttle").setIndicator("Throttle"),
                LoaderThrottleSupport.ThrottledLoaderListFragment.class, null);

        if (savedInstanceState != null) {
            mTabHost.setCurrentTabByTag(savedInstanceState.getString("tab"));
        }
    }

    @Override
    protected void onSaveInstanceState(Bundle outState) {
        super.onSaveInstanceState(outState);
        outState.putString("tab", mTabHost.getCurrentTabTag());
    }

    /**
     * This is a helper class that implements the management of tabs and all
     * details of connecting a ViewPager with associated TabHost.  It relies on a
     * trick.  Normally a tab host has a simple API for supplying a View or
     * Intent that each tab will show.  This is not sufficient for switching
     * between pages.  So instead we make the content part of the tab host
     * 0dp high (it is not shown) and the TabsAdapter supplies its own dummy
     * view to show as the tab content.  It listens to changes in tabs, and takes
     * care of switch to the correct paged in the ViewPager whenever the selected
     * tab changes.
     */
    public static class TabsAdapter extends FragmentStatePagerAdapter
            implements TabHost.OnTabChangeListener, ViewPager.OnPageChangeListener {
        private final Context mContext;
        private final TabHost mTabHost;
        private final ViewPager mViewPager;
        private final ArrayList<TabInfo> mTabs = new ArrayList<TabInfo>();

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

            TabInfo(String _tag, Class<?> _class, Bundle _args) {
                tag = _tag;
                clss = _class;
                args = _args;
            }
        }

        static class DummyTabFactory implements TabHost.TabContentFactory {
            private final Context mContext;

            public DummyTabFactory(Context context) {
                mContext = context;
            }

            @Override
            public View createTabContent(String tag) {
                View v = new View(mContext);
                v.setMinimumWidth(0);
                v.setMinimumHeight(0);
                return v;
            }
        }

        public TabsAdapter(FragmentActivity activity, TabHost tabHost, ViewPager pager) {
            super(activity.getSupportFragmentManager());
            mContext = activity;
            mTabHost = tabHost;
            mViewPager = pager;
            mTabHost.setOnTabChangedListener(this);
            mViewPager.setAdapter(this);
            mViewPager.setOnPageChangeListener(this);
        }

        public void clearData(){

            mTabs.clear();
            notifyDataSetChanged();

        }

        public void addTab(TabHost.TabSpec tabSpec, Class<?> clss, Bundle args) {
            tabSpec.setContent(new DummyTabFactory(mContext));
            String tag = tabSpec.getTag();

            TabInfo info = new TabInfo(tag, clss, args);
            mTabs.add(info);

            mTabHost.addTab(tabSpec);

            notifyDataSetChanged();
        }

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

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

        @Override
        public void onTabChanged(String tabId) {
            int position = mTabHost.getCurrentTab();
            mViewPager.setCurrentItem(position);
        }

        @Override
        public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {

        }

        @Override
        public void onPageSelected(int position) {
            // Unfortunately when TabHost changes the current tab, it kindly
            // also takes care of putting focus on it when not in touch mode.
            // The jerk.
            // This hack tries to prevent this from pulling focus out of our
            // ViewPager.
            TabWidget widget = mTabHost.getTabWidget();
            int oldFocusability = widget.getDescendantFocusability();
            widget.setDescendantFocusability(ViewGroup.FOCUS_BLOCK_DESCENDANTS);
            mTabHost.setCurrentTab(position);
            widget.setDescendantFocusability(oldFocusability);

        }

        @Override
        public void onPageScrollStateChanged(int state) {
        }
    }

    @Override
    public void onClick(View v) {


        mTabsAdapter.clearData();

        mTabHost.clearAllTabs();
        //mTabsAdapter.notifyDataSetChanged();

        Bundle mBundleSimple=new Bundle();
        mBundleSimple.putString("data", "SimpleData");

        mTabsAdapter.addTab(mTabHost.newTabSpec("simple").setIndicator("Simple"),
                FragmentStackSupport.CountingFragment.class, mBundleSimple);

        Bundle mBundleContacts=new Bundle();
        mBundleContacts.putString("data", "Contacts");

        mTabsAdapter.addTab(mTabHost.newTabSpec("contacts").setIndicator("Contacts"),
                LoaderCursorSupport.CursorLoaderListFragment.class, mBundleContacts);

        Bundle mBundleCustom=new Bundle();
        mBundleCustom.putString("data", "Custom");

        mTabsAdapter.addTab(mTabHost.newTabSpec("custom").setIndicator("Custom"),
                LoaderCustomSupport.AppListFragment.class, mBundleCustom);

        Bundle mBundleThrottle=new Bundle();
        mBundleThrottle.putString("data", "Throttle");

        mTabsAdapter.addTab(mTabHost.newTabSpec("throttle").setIndicator("Throttle"),
                LoaderThrottleSupport.ThrottledLoaderListFragment.class, mBundleThrottle);


        mViewPager.setAdapter(mTabsAdapter);

    }

    @Override
    public void ClickButton(String strToken) {

        if(strToken.equalsIgnoreCase("OneBtn")){


            mTabsAdapter.clearData();

            mTabHost.clearAllTabs();
            //mTabsAdapter.notifyDataSetChanged();

            Bundle mBundleSimple=new Bundle();
            mBundleSimple.putString("data", "SimpleData");

            mTabsAdapter.addTab(mTabHost.newTabSpec("simple").setIndicator("Simple"),
                    FragmentStackSupport.CountingFragment.class, mBundleSimple);

            Bundle mBundleContacts=new Bundle();
            mBundleContacts.putString("data", "SimpleData");

            mTabsAdapter.addTab(mTabHost.newTabSpec("contacts").setIndicator("Contacts"),
                    LoaderCursorSupport.CursorLoaderListFragment.class, mBundleContacts);

            Bundle mBundleCustom=new Bundle();
            mBundleCustom.putString("data", "Custom");

            mTabsAdapter.addTab(mTabHost.newTabSpec("custom").setIndicator("Custom"),
                    LoaderCustomSupport.AppListFragment.class, mBundleCustom);

            Bundle mBundleThrottle=new Bundle();
            mBundleThrottle.putString("data", "Throttle");

            mTabsAdapter.addTab(mTabHost.newTabSpec("throttle").setIndicator("Throttle"),
                    LoaderThrottleSupport.ThrottledLoaderListFragment.class, mBundleThrottle);


            mViewPager.setAdapter(mTabsAdapter);
        }

    }
}

现在，当任何片段中的某些内容发生更改时，您需要创建一个接口，该接口将回调发送到保存ViewPager的FragmentActivity，这样您就可以删除现有片段并重新创建它

这是我的接口类

public interface FragmentCallBack {


    public void ClickButton(String strToken);
} 

希望您能在代码中了解如何做到这一点

public class FragmentStackSupport extends FragmentActivity {
    int mStackLevel = 1;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.fragment_stack);

        // Watch for button clicks.
        Button button = (Button)findViewById(R.id.new_fragment);
        button.setOnClickListener(new OnClickListener() {
            public void onClick(View v) {
                addFragmentToStack();
            }
        });
        button = (Button)findViewById(R.id.home);
        button.setOnClickListener(new OnClickListener() {
            public void onClick(View v) {
                // If there is a back stack, pop it all.
                FragmentManager fm = getSupportFragmentManager();
                if (fm.getBackStackEntryCount() > 0) {
                    fm.popBackStack(fm.getBackStackEntryAt(0).getId(),
                            FragmentManager.POP_BACK_STACK_INCLUSIVE);
                }
            }
        });

        if (savedInstanceState == null) {
            // Do first time initialization -- add initial fragment.
            Fragment newFragment = CountingFragment.newInstance(mStackLevel);
            FragmentTransaction ft = getSupportFragmentManager().beginTransaction();
            ft.add(R.id.simple_fragment, newFragment).commit();
        } else {
            mStackLevel = savedInstanceState.getInt("level");
        }
    }

    @Override
    public void onSaveInstanceState(Bundle outState) {
        super.onSaveInstanceState(outState);
        outState.putInt("level", mStackLevel);
    }


    void addFragmentToStack() {
        mStackLevel++;

        // Instantiate a new fragment.
        Fragment newFragment = CountingFragment.newInstance(mStackLevel);

        // Add the fragment to the activity, pushing this transaction
        // on to the back stack.
        FragmentTransaction ft = getSupportFragmentManager().beginTransaction();
        ft.replace(R.id.simple_fragment, newFragment);
        ft.setTransition(FragmentTransaction.TRANSIT_FRAGMENT_OPEN);
        ft.addToBackStack(null);
        ft.commit();
    }



    public static class CountingFragment extends Fragment implements OnClickListener {
        int mNum;

        Button mBtnOne;

        FragmentCallBack mFragmentCallBack;

        /**
         * Create a new instance of CountingFragment, providing "num"
         * as an argument.
         */
        static CountingFragment newInstance(int num) {
            CountingFragment f = new CountingFragment();

            // Supply num input as an argument.
            Bundle args = new Bundle();
            args.putInt("num", num);
            f.setArguments(args);

            return f;
        }

        /**
         * When creating, retrieve this instance's number from its arguments.
         */
        @Override
        public void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            mNum = getArguments() != null ? getArguments().getInt("num") : 1;


            if(getArguments()!=null){

                if(getArguments().containsKey("data")){

                    String dataIs=getArguments().getString("data");

                    Log.v("LOG_TAG", "THis Tab data is  "+ dataIs );


                }
            }
        }

        /**
         * The Fragment's UI is just a simple text view showing its
         * instance number.
         */
        @Override
        public View onCreateView(LayoutInflater inflater, ViewGroup container,
                Bundle savedInstanceState) {

             if(getArguments()!=null){

                if(getArguments().containsKey("data")){

                    String dataIs=getArguments().getString("data");

                    Log.v("LOG_TAG", "THis Tab data is  onCreateView "+ dataIs );


                }
             }

            View v = inflater.inflate(R.layout.hello_world, container, false);

            TextView tv = (TextView) v.findViewById(R.id.text);

            mBtnOne=(Button)v.findViewById(R.id.btn_one);

            mBtnOne.setOnClickListener(this);

           tv.setText("Fragment #" + mNum);
            tv.setBackgroundDrawable(getResources().getDrawable(android.R.drawable.gallery_thumb));
            return v;
        }

        @Override
        public void onClick(View v) {

            try{
                mFragmentCallBack=(FragmentCallBack) this.getActivity();

                mFragmentCallBack.ClickButton("OneBtn");

            }catch(ClassCastException classExc){

                classExc.printStackTrace();
            }

        }
    }

}

public interface FragmentCallBack {


    public void ClickButton(String strToken);
}