ViewPager on DialogFragment - java.lang.IllegalStateException: No activity

问题

I am implementing a photo-zooming view appears on top of the thumbnail grid by using DialogFragment. It contains a ViewPager allowing user switch photos. Here is detail of DialogFragment:

    public class DialogContainer extends PhotoViewerDialogFragment{

    public DialogContainer () {
        super();
    }

    @Override
    public Dialog onCreateDialog(Bundle savedInstanceState) {
        Dialog dialog = super.onCreateDialog(savedInstanceState);
        // request a window without the title
        dialog.setContentView(R.layout.fragment_photo_viewer);
        dialog.getWindow().setLayout(AppDevice.getDeviceWidth(), AppDevice.getDeviceHeight());
        return dialog;
    }
    @Override
    public void onViewCreated(View view, Bundle savedInstanceState) {
        viewPager = (CustomViewPager) view.findViewById(R.id.photo_viewer_view_pager);
        photoAdapter = new PhotoViewerAdapter(getChildFragmentManager(), photoSupporter, null, null);
        viewPager.setAdapter(photoAdapter);
        super.onViewCreated(view, savedInstanceState);
    }

}

Here is dialog layout:

    <?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical" >

<android.support.v4.view.ViewPager
    android:id="@+id/photo_viewer_view_pager"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="@color/dark_background" >
</android.support.v4.view.ViewPager>

And here is how I implement the adapter:

public static class PhotoViewerAdapter extends FragmentStatePagerAdapter {

    private PhotoSupporter photoSupporter;


    public PhotoViewerAdapter(FragmentManager fm, PhotoSupporter photoSupporter) {
        super(fm);
        this.photoSupporter = photoSupporter;
    }

    @Override
    public Fragment getItem(int position) {
        String src = null;
        // get photo src
        return PhotoViewFragment.newInstance(src);
    }

    @Override
    public int getCount() {
        Log.w(TAG, "size in adapter: " + photoSupporter.getSize());
        return photoSupporter.getSize();
    }

}

Here is Fragment for each photo:

public static class PhotoViewFragment extends Fragment {

    private String imagePath;

    public PhotoViewFragment() {

    }

    public static PhotoViewFragment newInstance(String imagePath) {
        PhotoViewFragment previewFragment = new PhotoViewFragment();
        // put data
        Bundle bundle = new Bundle();
        bundle.putString("IMAGE_PATH",
                imagePath);
        previewFragment.setArguments(bundle);
        return previewFragment;

    }

    /**
     * When creating, retrieve this instance's number from its arguments.
     */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        imagePath = getArguments() != null ? getArguments().getString(
                "IMAGE_PATH") : "";
        Log.d("onCreate", imagePath);
    }

    /**
     * The Fragment's UI is just a simple text view showing its instance
     * number.
     */
    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
            Bundle savedInstanceState) {
        ImageView imageView = new ImageView(getActivity());
        LinearLayout.LayoutParams lp = new LinearLayout.LayoutParams
                (LinearLayout.LayoutParams.MATCH_PARENT, LinearLayout.LayoutParams.MATCH_PARENT);
        imageView.setLayoutParams(lp);
        // set image by Picasso
        Picasso picassoInstance = Picasso.with(getActivity());
        picassoInstance.setIndicatorsEnabled(true);
        picassoInstance.load(new File(imagePath))
                .error(R.drawable.ic_picture_placeholder_light2)
                .fit()
                .centerInside()
                .into(imageView);
        return imageView;
    }

}


}

When a thumbnail is clicked:

dialogContainer = new DialogContainer();
dialogContainer.show(((HomeActivity)parentActivity).getSupportFragmentManager(), "photo_viewer_dialog");

And I got this error:

01-16 15:46:28.916: E/AndroidRuntime(18338): FATAL EXCEPTION: main
01-16 15:46:28.916: E/AndroidRuntime(18338): java.lang.IllegalStateException: No activity
01-16 15:46:28.916: E/AndroidRuntime(18338):    at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1075)
01-16 15:46:28.916: E/AndroidRuntime(18338):    at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1070)
01-16 15:46:28.916: E/AndroidRuntime(18338):    at android.support.v4.app.FragmentManagerImpl.dispatchActivityCreated(FragmentManager.java:1861)
01-16 15:46:28.916: E/AndroidRuntime(18338):    at android.support.v4.app.Fragment.performActivityCreated(Fragment.java:1474)
01-16 15:46:28.916: E/AndroidRuntime(18338):    at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:931)
01-16 15:46:28.916: E/AndroidRuntime(18338):    at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1088)
01-16 15:46:28.916: E/AndroidRuntime(18338):    at android.support.v4.app.BackStackRecord.run(BackStackRecord.java:682)
01-16 15:46:28.916: E/AndroidRuntime(18338):    at android.support.v4.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:1444)
01-16 15:46:28.916: E/AndroidRuntime(18338):    at android.support.v4.app.FragmentManagerImpl$1.run(FragmentManager.java:429)
01-16 15:46:28.916: E/AndroidRuntime(18338):    at android.os.Handler.handleCallback(Handler.java:615)
01-16 15:46:28.916: E/AndroidRuntime(18338):    at android.os.Handler.dispatchMessage(Handler.java:92)
01-16 15:46:28.916: E/AndroidRuntime(18338):    at android.os.Looper.loop(Looper.java:137)
01-16 15:46:28.916: E/AndroidRuntime(18338):    at android.app.ActivityThread.main(ActivityThread.java:4745)
01-16 15:46:28.916: E/AndroidRuntime(18338):    at java.lang.reflect.Method.invokeNative(Native Method)
01-16 15:46:28.916: E/AndroidRuntime(18338):    at java.lang.reflect.Method.invoke(Method.java:511)
01-16 15:46:28.916: E/AndroidRuntime(18338):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:786)
01-16 15:46:28.916: E/AndroidRuntime(18338):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
01-16 15:46:28.916: E/AndroidRuntime(18338):    at dalvik.system.NativeStart.main(Native Method)

Thank you guys so much for any suggestion and please let me know anything not clear yet. ps: I did try this, this and getChildFragmentManager but nothing changed.

回答1:

Okay, finally I found the it. The reason is I call getChildFragmentManager on DialogFragment before it attached to activity:

dialogContainer = new DialogContainer();
dialogContainer.show(fm, "tag");
photoAdapter = new PhotoViewerAdapter(dialogContainer .getChildFragmentManager(), photoSupporter, null, null);

One more note: DialogFragment should be recreate its layout every single time you want to show it.

回答2:

Apparently,this exception occouring beacause it cannot find HomeActivity as you have Casted the parentActivity to HomeActivity here,

((HomeActivity)parentActivity).getSupportFragmentManager(), 

Use this, if you are calling DialogContainer in a fragment

((HomeActivity)getActivity()).getSupportFragmentManager(),

Or use this, if you are calling DialogContainer in a Activity

this.getSupportFragmentManager()

来源：https://stackoverflow.com/questions/27980543/viewpager-on-dialogfragment-java-lang-illegalstateexception-no-activity