getFragmentManager（）。findFragmentById返回null

Question

I just migrated an Android project to gradle. Everything worked before migrating. I have the same layout files. My repo is here:

https://github.com/jackygrahamez/MayDay/tree/gradle2

I am having trouble with certain activity setups. In my message setup activity setup I set the fragment:

Fragment fragment = getFragmentManager().findFragmentById(R.id.sms_message);

This returns a null which I am catching with if statements, but it means my activity is not getting properly configured.

package com.mayday.md.fragment;

import com.mayday.md.MainActivity;
import com.mayday.md.R;
import com.mayday.md.WizardActivity;
import com.mayday.md.adapter.PageItemAdapter;
import com.mayday.md.common.AppConstants;
import com.mayday.md.common.AppUtil;
import com.mayday.md.common.ApplicationSettings;
import com.mayday.md.common.MyTagHandler;
import com.mayday.md.data.PBDatabase;
import com.mayday.md.model.Page;
import com.mayday.md.model.PageItem;
import com.mayday.md.model.SMSSettings;

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.text.Html;
import android.util.DisplayMetrics;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.AdapterView;
import android.widget.Button;
import android.widget.EditText;
import android.widget.LinearLayout;
import android.widget.ListView;
import android.widget.TextView;
import android.widget.Toast;


/**
 * Created by aoe on 12/12/13.
 */
public class SetupMessageFragment extends Fragment {
    private EditText smsEditText;

    private static final String PAGE_ID = "page_id";
    private static final String PARENT_ACTIVITY = "parent_activity";
    private Activity activity;

    DisplayMetrics metrics;

    TextView tvTitle, tvContent, tvIntro, tvWarning;
    Button bAction;
    ListView lvItems;
    LinearLayout llWarning;

    Page currentPage;
    PageItemAdapter pageItemAdapter;

    public static SetupMessageFragment newInstance(String pageId, int parentActivity) {
        SetupMessageFragment f = new SetupMessageFragment();
        Bundle args = new Bundle();
        args.putString(PAGE_ID, pageId);
        args.putInt(PARENT_ACTIVITY, parentActivity);
        f.setArguments(args);
        return(f);
    }


    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {

        View view = inflater.inflate(R.layout.fragment_type_interactive_message, container, false);

        tvTitle = (TextView) view.findViewById(R.id.fragment_title);
        tvIntro = (TextView) view.findViewById(R.id.fragment_intro);
        tvContent = (TextView) view.findViewById(R.id.fragment_contents);

        bAction = (Button) view.findViewById(R.id.fragment_action);
        bAction.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Log.e(">>>>", "action button pressed");
                String msg =  getSMSSettingsFromView();

                SMSSettings.saveMessage(activity, msg);
                displaySettings(msg);

                if (currentPage != null) {
                    Log.e(">>>>", "onCreateView (currentPage != null)");
                    String pageId = currentPage.getAction().get(0).getLink();
                    int parentActivity = getArguments().getInt(PARENT_ACTIVITY);
                    Intent i;

                    if(parentActivity == AppConstants.FROM_WIZARD_ACTIVITY){
                        i = new Intent(activity, WizardActivity.class);
                    } else{
//                  AppUtil.showToast("Message saved.", 1000, activity);
                        String confirmation = (currentPage.getAction().get(0).getConfirmation() == null)
                                ? AppConstants.DEFAULT_CONFIRMATION_MESSAGE
                                : currentPage.getAction().get(0).getConfirmation();
                        Toast.makeText(activity, confirmation, Toast.LENGTH_SHORT).show();

                        i = new Intent(activity, MainActivity.class);
                    }
                    i.putExtra("page_id", pageId);
                    startActivity(i);

                    if(parentActivity == AppConstants.FROM_MAIN_ACTIVITY){
                        activity.finish();
                    }
                }

            }
        });


        lvItems = (ListView) view.findViewById(R.id.fragment_item_list);

        llWarning = (LinearLayout) view.findViewById(R.id.ll_fragment_warning);
        tvWarning  = (TextView) view.findViewById(R.id.fragment_warning);

        lvItems.setOnItemClickListener(new AdapterView.OnItemClickListener() {

            @Override
            public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
                PageItem selectedItem = (PageItem) parent.getItemAtPosition(position);

                String pageId = selectedItem.getLink();
                int parentActivity = getArguments().getInt(PARENT_ACTIVITY);
                Intent i;

                if(parentActivity == AppConstants.FROM_WIZARD_ACTIVITY){
                    i = new Intent(activity, WizardActivity.class);
                } else{
                    i = new Intent(activity, MainActivity.class);
                }
                i.putExtra("page_id", pageId);
                startActivity(i);

            }
        });

        return view;
    }


    @Override
    public void onActivityCreated(Bundle savedInstanceState) {
        super.onActivityCreated(savedInstanceState);

        activity = getActivity();
        if (activity != null) {
            metrics = new DisplayMetrics();
            activity.getWindowManager().getDefaultDisplay().getMetrics(metrics);

            Log.e(">>>>", "onActivityCreated setting fragment");
            Fragment fragment = getFragmentManager().findFragmentById(R.id.sms_message);
            if (fragment != null) {
                Log.e(">>>>", "onActivityCreated (fragment != null)");
                ((MessageTextFragment)fragment).setActionButtonStateListener(bAction);
                smsEditText = (EditText) fragment.getView().findViewById(R.id.message_edit_text);

                String currentMsg = SMSSettings.retrieveMessage(activity);
                if(currentMsg != null) {
                    displaySettings(currentMsg);
                }
                bAction.setEnabled(!smsEditText.getText().toString().trim().equals(""));

                String pageId = getArguments().getString(PAGE_ID);
                String selectedLang = ApplicationSettings.getSelectedLanguage(activity);

                PBDatabase dbInstance = new PBDatabase(activity);
                dbInstance.open();
                currentPage = dbInstance.retrievePage(pageId, selectedLang);
                dbInstance.close();

                tvTitle.setText(currentPage.getTitle());

                if(currentPage.getContent() == null)
                    tvContent.setVisibility(View.GONE);
                else
                    tvContent.setText(Html.fromHtml(currentPage.getContent(), null, new MyTagHandler()));

                if(currentPage.getIntroduction() == null)
                    tvIntro.setVisibility(View.GONE);
                else
                    tvIntro.setText(currentPage.getIntroduction());

                if(currentPage.getWarning() == null)
                    llWarning.setVisibility(View.GONE);
                else
                    tvWarning.setText(currentPage.getWarning());

                bAction.setText(currentPage.getAction().get(0).getTitle());

                pageItemAdapter = new PageItemAdapter(activity, null);
                lvItems.setAdapter(pageItemAdapter);
                pageItemAdapter.setData(currentPage.getItems());

                AppUtil.updateImages(true, currentPage.getContent(), activity, metrics, tvContent, AppConstants.IMAGE_INLINE);
            }
            else {
                Log.e(">>>>", "onActivityCreated (fragment == null)");
            }
        }
    }


    private void displaySettings(String msg) {

        if (smsEditText != null) {
            Log.e(">>>>", " smsEditText is not null");
            smsEditText.setText(msg);
        } else {
            Log.e(">>>>", "displaySettings smsEditText null");
        }
    }


    private String getSMSSettingsFromView() {
        if (smsEditText != null) {
            String message = smsEditText.getText().toString().trim();
            if (message != null) {
                Log.e(">>>>", "getSMSSettingsFromView set message " + message);
                return message;
            } else {
                Log.e(">>>>", "getSMSSettingsFromView message null");
                return "";
            }
        } else {
            Log.e(">>>>", "getSMSSettingsFromView smsEditText null");
            return "";
        }
    }
}

Here is the logcat

02-13 09:39:47.290  16841-16841/com.mayday.md E/SimpleFragment.onPause﹕ settings
02-13 09:39:47.290  16841-16841/com.mayday.md E/MainActivity.onPause﹕ .
02-13 09:39:47.290  16841-16841/com.mayday.md E/MainActivity.onPause﹕ flagRiseFromPause = true
02-13 09:39:47.310  16841-16841/com.mayday.md D/AbsListView﹕ unregisterIRListener() is called
02-13 09:39:47.310  16841-16841/com.mayday.md D/AbsListView﹕ unregisterIRListener() is called
02-13 09:39:47.320  16841-16841/com.mayday.md E/>>>>>﹕ Registering finish activity in oncreate -> BaseFragmentActivity
02-13 09:39:47.330  16841-16841/com.mayday.md E/MainActivity.onCreate﹕ pageId = settings-message
02-13 09:39:47.400  16841-16841/com.mayday.md D/AbsListView﹕ Get MotionRecognitionManager
02-13 09:39:47.400  16841-16841/com.mayday.md E/>>>>﹕ onActivityCreated setting fragment
02-13 09:39:47.400  16841-16841/com.mayday.md E/>>>>﹕ onActivityCreated (fragment == null)
02-13 09:39:47.400  16841-16841/com.mayday.md E/MainActivity.onStart﹕ .
02-13 09:39:47.400  16841-16841/com.mayday.md E/MainActivity.onResume﹕ pageId = settings-message and flagRiseFromPause = false
02-13 09:39:47.400  16841-16841/com.mayday.md D/AbsListView﹕ onVisibilityChanged() is called, visibility : 4
02-13 09:39:47.400  16841-16841/com.mayday.md D/AbsListView﹕ unregisterIRListener() is called
02-13 09:39:47.410  16841-16841/com.mayday.md D/AbsListView﹕ onVisibilityChanged() is called, visibility : 0
02-13 09:39:47.410  16841-16841/com.mayday.md D/AbsListView﹕ unregisterIRListener() is called
02-13 09:39:47.430  16841-16841/com.mayday.md D/AbsListView﹕ unregisterIRListener() is called
02-13 09:39:47.500  16841-16841/com.mayday.md D/AbsListView﹕ unregisterIRListener() is called
02-13 09:39:47.530  16841-16841/com.mayday.md D/AbsListView﹕ unregisterIRListener() is called
02-13 09:39:47.560  16841-16841/com.mayday.md D/AbsListView﹕ unregisterIRListener() is called
02-13 09:39:47.750  16841-16841/com.mayday.md D/AbsListView﹕ unregisterIRListener() is called
02-13 09:39:47.880  16841-16841/com.mayday.md E/SimpleFragment.onStop﹕ settings
02-13 09:39:47.880  16841-16841/com.mayday.md E/MainActivity.onStop﹕ .
02-13 09:39:47.890  16841-16841/com.mayday.md D/AbsListView﹕ onVisibilityChanged() is called, visibility : 4
02-13 09:39:47.890  16841-16841/com.mayday.md D/AbsListView﹕ unregisterIRListener() is called
02-13 09:39:47.890  16841-16841/com.mayday.md D/AbsListView﹕ onVisibilityChanged() is called, visibility : 4
02-13 09:39:47.890  16841-16841/com.mayday.md D/AbsListView﹕ unregisterIRListener() is called
02-13 09:39:51.220  16841-16841/com.mayday.md D/AbsListView﹕ unregisterIRListener() is called
02-13 09:39:53.260  16841-16841/com.mayday.md E/>>>>﹕ action button pressed
02-13 09:39:53.260  16841-16841/com.mayday.md E/>>>>﹕ getSMSSettingsFromView smsEditText null
02-13 09:39:53.260  16841-16841/com.mayday.md E/>>>>﹕ displaySettings smsEditText null

Answer 1

Since you are using the support library

import android.support.v4.app.Fragment;

You need to get the FragmentManager like this:

Fragment fragment = getSupportFragmentManager().findFragmentById(R.id.sms_message);

Answer 2

Thanks @Marcus for all the suggestions and they helped but the problem I had seemed to go away when I backed out of the dependencies from Maven central to local dependency versions for the following:

gson-2.2.4.jar
support-v4-r12.jar

It seems the versions of these are required or everything on THIS project breaks.