Question

最近将一个活动更改为一个片段之后我已经使用Layoutinflator来获取片段的用户界面但是我遇到了一个运行时错误，该错误显示在下面的LOGCAT中我该如何解决这个问题？

public class MainInstagramActivity extends Fragment {
private InstagramSession mInstagramSession;
private Instagram mInstagram;

private ProgressBar mLoadingPb;
private GridView mGridView;

private static final String CLIENT_ID = "83549f9eb76f4a5b90daf6e4e14da107";
private static final String CLIENT_SECRET = "6df26b0c8f664323a07126bfe8511651";
private static final String REDIRECT_URI = "http://www.yahoo.com";



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

    if (mInstagramSession.isActive()) {
        View view = LayoutInflater.from(getActivity()).inflate(
                R.layout.activity_user_instagram, null);
        return view;
    }
    else {
        View view = LayoutInflater.from(getActivity()).inflate(
                R.layout.activity_main_instagram, null);

        return view;
    }
}

@Override
public void onViewCreated(View container, Bundle savedInstanceState) {
    super.onViewCreated(container, savedInstanceState);

    mInstagram          = new Instagram(getActivity(), CLIENT_ID, CLIENT_SECRET, REDIRECT_URI);

    mInstagramSession   = mInstagram.getSession();

    if (mInstagramSession.isActive()) {
        View view = LayoutInflater.from(getActivity()).inflate(
                R.layout.activity_user_instagram, null);




        InstagramUser instagramUser = mInstagramSession.getUser();

        mLoadingPb = (ProgressBar)container.findViewById(R.id.pb_loading);
        mGridView   = (GridView)container.findViewById(R.id.gridView);

        ((TextView) container.findViewById(R.id.tv_name)).setText(instagramUser.fullName);
        ((TextView) container.findViewById(R.id.tv_username)).setText(instagramUser.username);

        ((Button) container.findViewById(R.id.btn_logout)).setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View arg0) {
                mInstagramSession.reset();

                startActivity(new Intent(getActivity(), MainInstagramActivity.class));

                getActivity().getFragmentManager().popBackStack();
            }
        });

        ImageView userIv = (ImageView) container.findViewById(R.id.iv_user);

        DisplayImageOptions displayOptions = new DisplayImageOptions.Builder()
                .showImageOnLoading(R.drawable.ic_user)
                .showImageForEmptyUri(R.drawable.ic_user)
                .showImageOnFail(R.drawable.ic_user)
                .cacheInMemory(true)
                .cacheOnDisc(false)
                .considerExifParams(true)
                .build();

        ImageLoaderConfiguration config = new ImageLoaderConfiguration.Builder(getActivity())
                .writeDebugLogs()
                .defaultDisplayImageOptions(displayOptions)
                .build();

        ImageLoader imageLoader = ImageLoader.getInstance();
        imageLoader.init(config);

        AnimateFirstDisplayListener animate  = new AnimateFirstDisplayListener();

        imageLoader.displayImage(instagramUser.profilPicture, userIv, animate);

        new DownloadTask().execute();



    } else {

        View view = LayoutInflater.from(getActivity()).inflate(
                R.layout.activity_main_instagram, null);

        ((Button) container.findViewById(R.id.btn_connect)).setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View arg0) {
                mInstagram.authorize(mAuthListener);
            }
        });

}
}

logcat的

09-22 10:41:31.065      986-986/com.virtualinsomniac.annaakana E/AndroidRuntime﹕ FATAL EXCEPTION: main
Process: com.virtualinsomniac.annaakana, PID: 986
java.lang.NullPointerException: Attempt to invoke virtual method 'boolean instagramlibrary.InstagramSession.isActive()' on a null object reference
        at com.virtualinsomniac.annaakana.Instagram.MainInstagramActivity.onCreateView(MainInstagramActivity.java:63)
        at android.app.Fragment.performCreateView(Fragment.java:1704)
        at android.app.FragmentManagerImpl.moveToState(FragmentManager.java:890)
        at android.app.FragmentManagerImpl.moveToState(FragmentManager.java:1063)
        at android.app.BackStackRecord.run(BackStackRecord.java:684)
        at android.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:1448)
        at android.app.FragmentManagerImpl$1.run(FragmentManager.java:443)
        at android.os.Handler.handleCallback(Handler.java:738)
        at android.os.Handler.dispatchMessage(Handler.java:95)
        at android.os.Looper.loop(Looper.java:135)
        at android.app.ActivityThread.main(ActivityThread.java:5070)
        at java.lang.reflect.Method.invoke(Native Method)
        at java.lang.reflect.Method.invoke(Method.java:372)
        at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:836)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:631)

Answer 1

这会返回一个视图，因此您可以返回该视图并在您的活动中对其进行充气，而不是让您的片段中的视图膨胀。

为什么我的这个片段中的充气器是一个空对象引用？

1 个答案: