自定义操作栏中的NPE，用于所有片段

Question

我在Activity和自定义ActionBar使用ActionBar ，并为每个Fragment使用单独的布局文件。 我在FrameLayout中总共添加了6个Fragment

MainActionBarActivity.java

public class MainActionBarActivity extends ActionBarActivity implements OnHeadlineSelectedListener,UserToProfileFragmentInterface {

// code here...

}

同样，片段之一是ProfileFragment.java

public class ProfileFragment extends Fragment   {

    Context context;
    public final String TAG = "ProfileFragment";
    FrameLayout fragmentContainer;
    private int mCurrentlyShowingFragment;
    public final String SAVED_STATE_KEY = ProfileFragment.class.getSimpleName();

    public static ProfileFragment newInstance(Fragment.SavedState savedState) {
        ProfileFragment frag = new ProfileFragment();
        frag.setInitialSavedState(savedState);
        return frag;
    }

    @Override
    public View onCreateView(LayoutInflater inflater, final ViewGroup container,
                             Bundle savedInstanceState) {
        View view = inflater.inflate(R.layout.temp_profile, container, false);
        context = getActivity();
        fragmentContainer = (FrameLayout)view.findViewById(R.id.flayout);
        return view;
    }

    @Override
    public void onViewCreated(View view, Bundle savedInstanceState) {
        super.onViewCreated(view, savedInstanceState);
        if (savedInstanceState == null) {
            getChildFragmentManager().beginTransaction().add(R.id.flayout,ProfileFragmentDetails.newInstance()).addToBackStack("").commit();
          //  setRetainInstance(true);
            mCurrentlyShowingFragment = 0;
        } else {
            mCurrentlyShowingFragment = savedInstanceState.getInt("currently_showing_fragment");
        }

    }

那只是替换新的Fragment - ProfileFragmentDetails 。

现在在此Fragment我尝试使用自定义ActionBar来在onResume()编写代码：

@Override
public void onResume(){

    Log.d(TAG, "onResume;");
    super.onResume();
    Log.d(TAG, "mSingleTon.profileUpdated:" + mSingleTon.profileUpdated);
    if(getActivity().getSupportFragmentManager().getBackStackEntryCount()>0){
        ActionBar actionBar =  ((MainActionBarActivity) getActivity()).getSupportActionBar();

        ((MainActionBarActivity) getActivity()).invalidateOptionsMenu();
        actionBar.setDisplayShowHomeEnabled(false);
        actionBar.setDisplayShowCustomEnabled(true);
        actionBar.setDisplayShowTitleEnabled(false);

        View mCustomView = LayoutInflater.from(context).inflate(R.layout.actionbar_profile_view, null);
        actionBar.setCustomView(R.layout.actionbar_profile_view);
        actionBar.setDisplayShowCustomEnabled(true);

        Toolbar parent =(Toolbar) mCustomView.getParent();//first get parent toolbar of current action bar
        if(parent != null)
        {
            parent.setContentInsetsAbsolute(0,0);// set padding programmatically to 0dp
        }
        View v1 = actionBar.getCustomView();
        imageViewBroadcastBack = (ImageView)v1.findViewById(R.id.imageViewBroadcastBack);
        imageViewProfileSetting = (ImageView)v1.findViewById(R.id.imageViewProfileSetting);
        textViewScreenTitle = (TextView)v1.findViewById(R.id.textViewScreenTitle);
        textViewScreenTitle.setTypeface(Typeface.createFromAsset(context.getAssets(), "HelveticaBold.ttf"));

        textViewScreenTitle.setText("Profile");
    }
    else
    {
        //getActivity().getSupportFragmentManager().popBackStack(null, FragmentManager.POP_BACK_STACK_INCLUSIVE);
        //userProfileResponse = null;
        /*
        // Clear all back stack.
        int backStackCount = getActivity().getSupportFragmentManager().getBackStackEntryCount();
        for (int i = 0; i < backStackCount; i++) {

            // Get the back stack fragment id.
            int backStackId = getActivity().getSupportFragmentManager().getBackStackEntryAt(i).getId();

            getActivity().getSupportFragmentManager().popBackStack(backStackId, FragmentManager.POP_BACK_STACK_INCLUSIVE);

        }
        // end of for
        */
        this.uid = mSingleTon.userResponse.getUser().getUid();


        ActionBar actionBar =  ((MainActionBarActivity) getActivity()).getSupportActionBar();
        ((MainActionBarActivity) getActivity()).invalidateOptionsMenu();
        actionBar.setDisplayShowHomeEnabled(false);
        actionBar.setDisplayShowCustomEnabled(true);
        actionBar.setDisplayShowTitleEnabled(false);

        View mCustomView = LayoutInflater.from(context).inflate(R.layout.actionbar_profile_view, null);
        ActionBar.LayoutParams layoutParams = new ActionBar.LayoutParams(ActionBar.LayoutParams.MATCH_PARENT,
                ActionBar.LayoutParams.MATCH_PARENT);
        actionBar.setCustomView(R.layout.actionbar_profile_view);
        actionBar.setDisplayShowCustomEnabled(true);
         Toolbar parent = (Toolbar) mCustomView.getParent();
        if(parent != null)
        {
            parent.setContentInsetsAbsolute(0, 0);
        }

        //actionBar.setCustomView(R.layout.actionbar_profile_view);

        View v1 = actionBar.getCustomView();
        imageViewBroadcastBack = (ImageView)v1.findViewById(R.id.imageViewBroadcastBack);
        textViewScreenTitle = (TextView)v1.findViewById(R.id.textViewScreenTitle);
        textViewScreenTitle.setTypeface(Typeface.createFromAsset(context.getAssets(), "HelveticaBold.ttf"));
        imageViewProfileSetting = (ImageView)v1.findViewById(R.id.imageViewProfileSetting);
    }

它给我null在这条线parent.setContentInsetsAbsolute如果我把里面的if条件检查，那么它不会崩溃的应用程序，但它不设置宽度fillparent 。

当我尝试从一个片段移动到另一个片段时，应用程序再次通过指示Null Pointer Exception在同一行parent.setContentInsetsAbsolute崩溃。

Answer 1

尝试使用

actionBar.setCustomView(mCustomView);

代替

actionBar.setCustomView(R.layout.actionbar_profile_view);

提供布局的ID，android将为您膨胀一个新视图，该视图不同于您膨胀并分配给mCustomView