我知道人们已经提出了这个问题，但我遵循了所有的答案，我仍然遇到同样的问题。我有两个脚本一个是片段管理器（IngredientsActivity），另一个是片段（OtherList）。代码如下
IngredientsActivity
import java.util.ArrayList;
import android.app.ActionBar;
import android.app.FragmentTransaction;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentActivity;
import android.view.Gravity;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;
public class IngredientsActivity extends FragmentActivity implements ActionBar.TabListener {
private static final String STATE_SELECTED_NAVIGATION_ITEM = "selected_navigation_item";
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.check_list);
// Set up the action bar.
final ActionBar actionBar = getActionBar();
actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS);
// For each of the sections in the app, add a tab to the action bar.
actionBar.addTab(actionBar.newTab().setText("Alcahol").setTabListener(this));
actionBar.addTab(actionBar.newTab().setText("Juice").setTabListener(this));
actionBar.addTab(actionBar.newTab().setText("Other").setTabListener(this));
}
@Override
public void onRestoreInstanceState(Bundle savedInstanceState) {
if (savedInstanceState.containsKey(STATE_SELECTED_NAVIGATION_ITEM)) {
getActionBar().setSelectedNavigationItem(savedInstanceState.getInt(STATE_SELECTED_NAVIGATION_ITEM));
}
}
@Override
public void onSaveInstanceState(Bundle outState) {
super.onSaveInstanceState(outState); //OVERRIDE SAVE ON MAINCLASS
outState.putInt(STATE_SELECTED_NAVIGATION_ITEM, getActionBar().getSelectedNavigationIndex());
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
return true;
}
@Override
public void onTabUnselected(ActionBar.Tab tab, FragmentTransaction fragmentTransaction) {
}
@Override
public void onTabSelected(ActionBar.Tab tab, FragmentTransaction fragmentTransaction) {
if (tab.getPosition() == 0) {
AlcoholList simpleListFragment = new AlcoholList();
getSupportFragmentManager().beginTransaction().replace(R.id.containert, simpleListFragment).commit();
}
else if (tab.getPosition() == 1) {
JuiceList androidlidt = new JuiceList();
getSupportFragmentManager().beginTransaction().replace(R.id.containert, androidlidt).commit();
}
else {
OtherList androidversionlist = new OtherList();
getSupportFragmentManager().beginTransaction().replace(R.id.containert, androidversionlist).commit();
}
}
@Override
public void onTabReselected(ActionBar.Tab tab, FragmentTransaction fragmentTransaction) {
}
public static class DummySectionFragment extends Fragment {
public DummySectionFragment() {
}
public static final String ARG_SECTION_NUMBER = "section_number";
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
TextView textView = new TextView(getActivity());
textView.setGravity(Gravity.CENTER);
Bundle args = getArguments();
textView.setText(Integer.toString(args.getInt(ARG_SECTION_NUMBER)));
return textView;
}
}
}
OtherList
import java.util.ArrayList;
import android.content.Context;
import android.os.Bundle;
import android.support.v4.app.ListFragment;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.widget.CheckBox;
import android.widget.ListView;
public class OtherList extends ListFragment{
MyCustomAdapter dataAdapter = null;
private ArrayList<String> recipesList;
private ArrayList<Items> stateList ;
public OtherList() {
setRetainInstance(true);
stateList = new ArrayList<Items>();
Items _states1 = new Items ("Gin",false);
stateList.add(_states1);
Items _states2 = new Items ("Ginger Liqueur",false);
stateList.add(_states2);
Items _states3 = new Items ("Citrus Vodka",false);
stateList.add(_states3);
Items _states4 = new Items ("Champagne",false);
stateList.add(_states4);
Items _states5 = new Items ("Coconut Rum",false);
stateList.add(_states5);
Items _states6 = new Items ("Pear Vodka",false);
stateList.add(_states6);
Items _states7 = new Items ("Rum",false);
stateList.add(_states7);
Items _states8 = new Items ("Tequila",false);
stateList.add(_states8);
Items _states9 = new Items ("Triple Sec",false);
stateList.add(_states9);
Items _states10 = new Items ("Kahlua",false);
stateList.add(_states10);
}
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
dataAdapter = new MyCustomAdapter(this.getActivity(),R.layout.da_item, stateList);
setListAdapter(dataAdapter);
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
return inflater.inflate(R.layout.list_fragment, container, false);
}
@Override
public void onListItemClick(ListView list, View v, int position, long id) {
}
private class MyCustomAdapter extends ArrayAdapter<Items>
{
private ArrayList<Items> stateList;
public MyCustomAdapter(Context context, int textViewResourceId,
ArrayList<Items> stateList)
{
super(context, textViewResourceId, stateList);
this.stateList = new ArrayList<Items>();
this.stateList.addAll(stateList);
}
private class ViewHolder
{
CheckBox name;
}
@Override
public View getView(int position, View convertView, ViewGroup parent)
{
ViewHolder holder = null;
Log.v("ConvertView", String.valueOf(position));
if (convertView == null)
{
LayoutInflater vi = (LayoutInflater) getContext().getSystemService(Context.LAYOUT_INFLATER_SERVICE);
convertView = vi.inflate(R.layout.da_item, null);
holder = new ViewHolder();
holder.name = (CheckBox) convertView.findViewById(R.id.ingredientbox);
convertView.setTag(holder);
holder.name.setOnClickListener( new View.OnClickListener()
{
public void onClick(View v)
{
CheckBox cb = (CheckBox) v;
Items _state = (Items) cb.getTag();
_state.setSelected(cb.isChecked());
}
});
}
else
{
holder = (ViewHolder) convertView.getTag();
}
Items state = stateList.get(position);
holder.name.setText(state.getName());
holder.name.setChecked(state.isSelected());
holder.name.setTag(state);
return convertView;
}
}
@Override
public void onActivityCreated(Bundle savedInstanceState){
super.onActivityCreated(savedInstanceState);
}
@Override
public void onSaveInstanceState(Bundle outState) {
Log.d("hey","SAVING"); //NOT SAVING
super.onSaveInstanceState(outState);
save();
outState.putStringArrayList("index", recipesList);
}
}
}
}
}
我找到了多个建议来覆盖onSaveInstanceState，我做了，我发现更多告诉我使用setRetainInstance。我不知道为什么setRetainInstance状态会有用，如果我想保存列表的值。 我的问题 - 为什么不在OtherList类中调用save，或者如果我想在列表视图中保存值（在这种情况下我使用的是复选框），有什么更好的实现方法
答案 0 :(得分：6)
我有一个类似的问题，我试图让Fragment保存它的状态，但是没有在FragmentTransaction.replace（）上调用onSaveInstanceState（）。我试图找到一个解决方案，并想，如果Fragment本身无法保存自己的状态，那么无法做任何替换保存它。所以我做了这样的事情：
在Fragment中有一个名为getState（）的方法或任何你想要的方法：
public Bundle getState()
{
// save whatever you would have in onSaveInstanceState() and return a bundle with the saved data
}
然后在托管对象中，在更换Fragment之前将该bundle保存到其实例变量，并在切换回时将参数设置为该保存的bundle。
FragmentManager fm = getFragmentManager();
FragmentTransaction ft = fm.beginTransaction();
// assume Fragment a exists and you're trying to save the state and "state" is an instance variable
state = a.getState();
ft.replace(android.R.id.content, b);
然后当交换回Fragment a时，你会将包作为参数传递。
a.setArguments(state);
ft.replace(android.R.id.content, a);
我没有深入研究你的代码，但这听起来与我在描述中遇到的问题类似。
答案 1 :(得分：1)
onSaveInstanceState()仅在Android系统可能需要重新创建Fragment的特定实例时调用。有许多实例可以远离Fragment导航，甚至可以在不会被调用的地方摧毁Fragment。有关详细信息，请参阅文档，请阅读Activity.onSaveInstanceState()文档，因为此处也适用：http://developer.android.com/reference/android/app/Fragment.html#onSaveInstanceState(android.os.Bundle)
http://developer.android.com/reference/android/app/Activity.html#onSaveInstanceState(android.os.Bundle)
编辑：在您的情况下，每次用户导航回片段时都不得重新创建片段。我建议考虑使用ViewPager和FragmentPagerAdapter来自动管理片段。另请看这篇文章：ViewPager and fragments — what's the right way to store fragment's state?