我在围绕安卓片段缠绕时遇到了一些困难。我有ActionBar
Spinner
,我在每次点击旋转项目时都会创建一个新的Fragment
。我有类似下面的代码:
public class MyActivity extends Activity
{
...
...
private void initActionBarSpinner()
{
getActionBar().setNavigationMode(ActionBar.NAVIGATION_MODE_LIST);
OnNavigationListener callback = new OnNavigationListener()
{
@Override
public boolean onNavigationItemSelected(int itemPosition, long itemId)
{
if (itemPosition >= 0 && itemPosition < dataSet.size())
{
openTagFragment(itemPosition);
return true;
}
return false;
}
};
spinnerAdapter = new ArrayAdapter<String>(this, R.layout.action_bar_spinner, R.id.spinnertAdapterItem, tags);
getActionBar().setListNavigationCallbacks(spinnerAdapter, callback);
}
@Override
public void onCreate(Bundle savedInstanceState)
{
Log.d(TAG, TAG + " oncreate");
super.onCreate(savedInstanceState);
initActionBarSpinnerAdapter();
}
protected void openTagFragment(int itemPosition)
{
Log.d(TAG, "Replacing fragment");
String fragmentTag = dataSet.get(itemPosition);
MyFragment myFragment = new MyFragment();
myFragment.setData(dataSet.get(itemPosition));
FragmentTransaction fragmentTransaction = getFragmentManager().beginTransaction();
fragmentTransaction.replace(R.id.fragmentContainer, myFragment, fragmentTag);
fragmentTransaction.addToBackStack(null);
fragmentTransaction.commit();
}
}
我面临的问题:在方向更改时,会创建一个新片段,这意味着它会再次从服务器获取相同的数据。我可以看到onSaveInstanceState()
在旋转时调用现有片段,但如果我要再次对Fragment
进行新操作,何时以及如何在片段onCreate()
上获得有效的savedInstance包?