虽然这似乎很容易出问题，但我已经被困了好几个小时。如果有人能帮助我提供一些代码，那就太好了。这就是我的问题。
有一个MainActivity，它有一个带有两个按钮的ActionBar。每个按钮在单击时启动ListFragment。然后每个ListFragment的每个项目都会启动另一个片段（这是我无法实现的）。以下是MainActivity的代码：
public class MainActivity extends Activity implements
DataListFragment.DataListSelectionListener {
private final String TAG = "MainActivity";
// Reference the buttons in the ActionBar
private Button actionBarData;
private Button actionBarElu;
private Button actionBarOptions;
// Reference the ListFragments
DataListFragment dataListFragment;
EluListFragment eluListFragment;
// Reference the fragments related to the listItems
SectionTypeFragment sectionTypeFragment;
SectionDimensionsFragment sectionDimensionsFragment;
MaterialsFragment materialsFragment;
ReinforcementFragment reinforcementFragment;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
// Inflate the custom layout for the ActionBar
final ViewGroup actionBarLayout = (ViewGroup) getLayoutInflater().inflate(
R.layout.action_bar,
null);
// Set the custom ActionBar
final ActionBar actionBar = getActionBar();
actionBar.setDisplayShowHomeEnabled(true);
actionBar.setDisplayShowTitleEnabled(true);
actionBar.setDisplayShowCustomEnabled(true);
actionBar.setCustomView(actionBarLayout);
// ActionBar Customization with buttons
final int actionBarColor = getResources().getColor(R.color.blue_2);
actionBar.setBackgroundDrawable(new ColorDrawable(actionBarColor));
actionBarData = (Button) findViewById(R.id.action_bar_data);
actionBarData.setOnClickListener(new Button.OnClickListener(){
@Override
public void onClick(View v) {
Log.i(TAG, "DATA button clicked.");
clickActionBarButton(v);
}
});
actionBarElu = (Button) findViewById(R.id.action_bar_elu);
actionBarElu.setOnClickListener(new Button.OnClickListener() {
@Override
public void onClick(View v) {
Log.i(TAG, "ELU button clicked.");
clickActionBarButton(v);
}
});
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.menu_main, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
//noinspection SimplifiableIfStatement
if (id == R.id.action_bar_data) {
return true;
}
return super.onOptionsItemSelected(item);
}
public void clickActionBarButton(View v){
// Get a reference to the FragmentManager
FragmentManager fragmentManager = getFragmentManager();
// Begin a new FragmentTransaction
FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
// Create the fragment depending on the button pressed
if(v == actionBarData){
// If there is no FeedFragment instance, then create one
if(sectionTypeFragment == null)
dataListFragment = new DataListFragment();
// Replace the main_frame_layout with the sectionTypeFragment
fragmentTransaction.replace(R.id.main_frame_layoout, dataListFragment);
}else if(v == actionBarElu){
// If there is no FeedFragment instance, then create one
if(sectionTypeFragment == null)
eluListFragment = new EluListFragment();
// Replace the main_frame_layout with the sectionTypeFragment
fragmentTransaction.replace(R.id.main_frame_layout, eluListFragment);
}
// Commit the FragmentTransaction
fragmentTransaction.commit();
}
// Called when the user selects an item in the DataListFragment
public void onDataListSelection(int index){
// Get a reference to the FragmentManager
FragmentManager fragmentManager = getFragmentManager();
// Begin a new FragmentTransaction
FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
// Add the fragment related to the selected item in the List
switch (index){
case 0:
// If there is no SectionTypeFragment instance, then create one
if(sectionTypeFragment == null)
sectionTypeFragment = new SectionTypeFragment();
// Replace the main_frame_layout with the sectionTypeFragment
fragmentTransaction.replace(R.id.main_frame_layout, sectionTypeFragment);
// Add this FragmentTransaction to the backstack
fragmentTransaction.addToBackStack(null);
break;
case 1:
...
}
// Commit the FragmentTransaction
fragmentTransaction.commit();
}
}
以下是其中一个ListFragments（DataListFragment）的代码：
public class DataListFragment extends ListFragment {
private static final String TAG = "DataFragment";
// List items
private String[] listItems;
private DataListSelectionListener mListener = null;
// Callback interface that allows this Fragment to notify the MainActivity when
// user clicks on a DataList Item
public interface DataListSelectionListener {
public void onDataListSelection(int index);
}
// Called when the user selects an item from the DataList
@Override
public void onListItemClick(ListView l, View v, int position, long id) {
// Indicates the selected item has been checked
getListView().setItemChecked(position, true);
// Inform the MainActivity that an item has been selected
mListener.onDataListSelection(position);
}
public void onActivityCreated(Bundle savedInstanceState){
super.onActivityCreated(savedInstanceState);
// Get the the items to show in the List from the strings.xml
listItems = getResources().getStringArray(R.array.data_list_array);
ArrayAdapter<String> adapter = new ArrayAdapter<String>(getActivity(), android.R.layout.simple_list_item_1, listItems);
setListAdapter(adapter);
}
}
以下是例外：
03-12 14:39:38.681 29515-29515/com.tari.rcsec E/AndroidRuntime﹕ FATAL EXCEPTION: main
java.lang.IllegalStateException: The specified child already has a parent. You must call removeView() on the child's parent first.
at android.view.ViewGroup.addViewInner(ViewGroup.java:3459)
at android.view.ViewGroup.addView(ViewGroup.java:3330)
at android.view.ViewGroup.addView(ViewGroup.java:3275)
at android.view.ViewGroup.addView(ViewGroup.java:3251)
at android.app.FragmentManagerImpl.moveToState(FragmentManager.java:840)
at android.app.FragmentManagerImpl.moveToState(FragmentManager.java:1035)
at android.app.BackStackRecord.run(BackStackRecord.java:635)
at android.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:1397)
at android.app.FragmentManagerImpl$1.run(FragmentManager.java:426)
at android.os.Handler.handleCallback(Handler.java:615)
at android.os.Handler.dispatchMessage(Handler.java:92)
at android.os.Looper.loop(Looper.java:153)
at android.app.ActivityThread.main(ActivityThread.java:5022)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:511)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1032)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:790)
at dalvik.system.NativeStart.main(Native Method)