即使onCreateView再次运行，视图也不会在BACK按下后正确重新组装

Question

我的应用程序几乎完成了。在下面的第二段代码中，您将看到一个临时的while循环。这个循环的目的是将十个表行添加到我的questionContainer中（很快，我将用从SQL数据库获取类似元素的AsyncTask来替换它）。我在while循环中放了一个Log.v，看看它什么时候运行。事实证明，在初始启动时，while循环和onCreateView运行得很好。但在按下后退键，然后通过应用程序切换器重新打开应用程序后，当onCreateView重新运行时，whileloop显然不会执行。有人能提供任何见解吗？

public class Polling extends SherlockFragmentActivity {
    private ViewPager mViewPager;
    private TabsAdapter mTabsAdapter;
    private final static String TAG = "21st Polling:";
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        Log.v(TAG, "onCreate");
        mViewPager = new ViewPager(this);
        mViewPager.setId(R.id.pager);
        setContentView(mViewPager);
        ActionBar bar = getSupportActionBar();
        bar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS);
        bar.setDisplayShowTitleEnabled(false);
        bar.setDisplayShowHomeEnabled(false);
        mTabsAdapter = new TabsAdapter(this, mViewPager);
        mTabsAdapter.addTab(bar.newTab().setText(R.string.login),
                LoginFragment.class, null);
        mTabsAdapter.addTab(bar.newTab().setText(R.string.economics),
                EconFragment.class, null);
        mTabsAdapter.addTab(bar.newTab().setText(R.string.elections),
                ElectionsFragment.class, null);
        mTabsAdapter.addTab(bar.newTab().setText(R.string.politics),
                PoliticsFragment.class, null);
        mTabsAdapter.addTab(bar.newTab().setText(R.string.science),
                ScienceFragment.class, null);
        mTabsAdapter.addTab(bar.newTab().setText(R.string.finance),
                FinanceFragment.class, null);
        mTabsAdapter.addTab(bar.newTab().setText(R.string.religion),
                ReligionFragment.class, null);
        mTabsAdapter.addTab(bar.newTab().setText(R.string.military),
                MilitaryFragment.class, null);
        mTabsAdapter.addTab(bar.newTab().setText(R.string.international),
                InternationalFragment.class, null); 
        Log.v(TAG, (String)bar.getTabAt(0).getText());
    }
public static class TabsAdapter extends FragmentPagerAdapter
    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;
            }
        }
        public TabsAdapter(SherlockFragmentActivity activity, ViewPager pager) {
            super(activity.getSupportFragmentManager());
            mContext = activity;
            mActionBar = activity.getSupportActionBar();
            mViewPager = pager;
            mViewPager.setAdapter(this);
            mViewPager.setOnPageChangeListener(this);
        }
        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();
        }

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

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

        public void onPageSelected(int position) {
            mActionBar.setSelectedNavigationItem(position);
        }

        public void onPageScrollStateChanged(int state) {
        }

        public void onTabSelected(Tab tab, FragmentTransaction ft) {
            mViewPager.setCurrentItem(tab.getPosition());
            //Log.v(TAG, "clicked");
            Object tag = tab.getTag();
            for (int i=0; i<mTabs.size(); i++) {
                if (mTabs.get(i) == tag) {
                    mViewPager.setCurrentItem(i);
                }
            }
        }
        public void onTabUnselected(Tab tab, FragmentTransaction ft) {}
        public void onTabReselected(Tab tab, FragmentTransaction ft) {}
        public void onTabReselected(Tab tab, android.app.FragmentTransaction ft) {}
        public void onTabUnselected(Tab tab, android.app.FragmentTransaction ft) {}
    }
}

按下退出应用程序后没有重新填充的片段，然后任务切换程序返回：

import com.actionbarsherlock.R;
import com.actionbarsherlock.app.SherlockFragment;
import android.app.Activity;
import android.app.AlertDialog;
import android.content.Context;
import android.content.Intent;
import android.os.Bundle;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.view.View.OnClickListener;
import android.view.ViewGroup.LayoutParams;
import android.view.inputmethod.InputMethodManager;
import android.widget.Button;
import android.widget.LinearLayout;
import android.widget.RelativeLayout;
import android.widget.ScrollView;
import android.widget.TableLayout;
import android.widget.TableRow;
import android.widget.TextView;
import android.support.v4.app.Fragment;
public class EconFragment extends SherlockFragment {
    private TableLayout questionContainer;
    static int pos = 0;
    private String[] titles = {"The first title ", "hallo1","hallo2", "hallo3",
            "hallo4", "hallo5","hallo6", "hallo7","hallo8", "hallo9"};
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        Log.v("Econ", "onCreateView");
        View v = inflater.inflate(R.layout.econfragment, container, false);
        questionContainer = (TableLayout) v.findViewById(R.id.questionContainer);
        int leftMargin=5;
        int topMargin=5;
        int rightMargin=5;
        int bottomMargin=5;
        while (pos < 10) {
        View question = inflater.inflate(R.layout.question, null);
        question.setId(pos);
        TextView title = (TextView) question.findViewById(R.id.questionTextView);
        title.setText(titles[pos]);
        Button charts = (Button) question.findViewById(R.id.chartsButton);
        charts.setId(pos);
        charts.setOnClickListener(chartsListener);
        TableRow tr = (TableRow) question;
        TableLayout.LayoutParams trParams = new TableLayout.LayoutParams(
                TableLayout.LayoutParams.MATCH_PARENT,
                TableLayout.LayoutParams.WRAP_CONTENT);
        trParams.setMargins(leftMargin, topMargin, rightMargin, bottomMargin);
        tr.setLayoutParams(trParams);
        Log.v("econ", "while loop");
        questionContainer.addView(tr);
        pos++;
        }
        return v;
    }

这里有一个Logcat示例，流程如下：启动应用程序，滚动到"除经济外"选项卡，按BACK，重新打开应用程序，滚到"经济"选项卡（其中十个表行不重建：

03-31 21:55:13.163: V/21st Polling:(1918): onCreate
03-31 21:55:13.943: D/dalvikvm(1918): GC_FOR_ALLOC freed 122K, 3% free 9149K/9347K, paused 365ms
03-31 21:55:14.044: I/dalvikvm-heap(1918): Grow heap (frag case) to 10.002MB for 1048592-byte allocation
03-31 21:55:14.173: D/dalvikvm(1918): GC_CONCURRENT freed <1K, 3% free 10172K/10439K, paused 4ms+6ms
03-31 21:55:14.283: D/dalvikvm(1918): GC_FOR_ALLOC freed 0K, 3% free 10172K/10439K, paused 35ms
03-31 21:55:14.323: I/dalvikvm-heap(1918): Grow heap (frag case) to 12.252MB for 2359312-byte allocation
03-31 21:55:14.424: D/dalvikvm(1918): GC_CONCURRENT freed 0K, 3% free 12476K/12807K, paused 4ms+3ms
03-31 21:55:14.594: V/21st Polling:(1918): Login
03-31 21:55:14.594: V/21st Polling:(1918): onResume
03-31 21:55:14.703: D/dalvikvm(1918): GC_FOR_ALLOC freed 1053K, 10% free 11826K/13127K, paused 37ms
03-31 21:55:14.813: D/Econ(1918): onstart
03-31 21:55:14.813: D/Econ(1918): onresume
03-31 21:55:14.813: D/Econ(1918): onAttach
03-31 21:55:14.813: D/Econ(1918): onCreate
03-31 21:55:14.813: V/Econ(1918): onCreateView
03-31 21:55:14.853: V/econ(1918): while loop
03-31 21:55:14.883: V/econ(1918): while loop
03-31 21:55:15.003: V/econ(1918): while loop
03-31 21:55:15.113: V/econ(1918): while loop
03-31 21:55:15.113: D/dalvikvm(1918): GC_CONCURRENT freed 291K, 6% free 12387K/13127K, paused 4ms+5ms
03-31 21:55:15.154: V/econ(1918): while loop
03-31 21:55:15.173: V/econ(1918): while loop
03-31 21:55:15.204: V/econ(1918): while loop
03-31 21:55:15.223: V/econ(1918): while loop
03-31 21:55:15.253: V/econ(1918): while loop
03-31 21:55:15.273: V/econ(1918): while loop
03-31 21:55:15.413: D/Econ(1918): onActivityCreated
03-31 21:55:15.413: D/Econ(1918): OnStart
03-31 21:55:15.413: V/Econ(1918): onResume
03-31 21:55:16.063: D/gralloc_goldfish(1918): Emulator without GPU emulation detected.
03-31 21:55:23.496: D/Econ(1918): onpause
03-31 21:55:23.514: D/Econ(1918): onstop
03-31 21:55:23.523: D/Econ(1918): ondestroyview
03-31 21:55:24.023: D/Econ(1918): onpause
03-31 21:55:24.033: D/Econ(1918): onpause
03-31 21:55:24.093: W/IInputConnectionWrapper(1918): showStatusIcon on inactive InputConnection
03-31 21:55:24.683: D/Econ(1918): onstop
03-31 21:55:24.683: D/Econ(1918): ondestroy
03-31 21:55:24.683: D/Econ(1918): ondetach
03-31 21:55:24.683: D/Econ(1918): ondestroyview
03-31 21:55:24.763: D/Econ(1918): ondestroy
03-31 21:55:24.763: D/Econ(1918): ondetach
03-31 21:55:27.913: V/21st Polling:(1918): onCreate
03-31 21:55:28.833: V/21st Polling:(1918): Login
03-31 21:55:28.833: V/21st Polling:(1918): onResume
03-31 21:55:28.993: D/Econ(1918): onstart
03-31 21:55:28.993: D/Econ(1918): onresume
03-31 21:55:28.993: D/Econ(1918): onAttach
03-31 21:55:28.993: D/Econ(1918): onCreate
03-31 21:55:29.013: V/Econ(1918): onCreateView
03-31 21:55:29.013: D/Econ(1918): onActivityCreated
03-31 21:55:29.013: D/Econ(1918): OnStart
03-31 21:55:29.013: V/Econ(1918): onResume

Answer 1

您的变量pos被声明为静态。因此，即使创建了一个新的Fragment实例，静态变量也会保持其值（在您的情况下为10），因此第二次出现的while循环会被跳过。