Android: transferring Context and activity from a fragment to a class

Question

I am trying to display an image into an image view. On the main activity it works. I would like to create a Navigation drawer, so I created a fragment. To display my image I use a class EdtTraitment and the method show(). This method tries to search a file in a directory. For this I need the Context of the main activity but, as you will see, I have errors when trying to get this context in the class EdtTraintement from the fragment.

The fragment code :

public class JourFragment extends Fragment {


public JourFragment() {
    // Required empty public constructor
}
Activity mActivity =  getActivity();
Context mContext = getActivity();
View view = null;
EdtTraitement edt = new EdtTraitement(mContext,mActivity);
TouchImageView img = null;
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
                         Bundle savedInstanceState) {

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

    new Thread(new Runnable() {
        public void run() {
            img = (TouchImageView) view.findViewById(R.id.image_emplois);


            edt.showEdt("URL","images.png","URL","text.txt",img); //diplay the img

        }
    }).start();
    try {
        Thread.sleep(1000);
    } catch (InterruptedException e) {
        e.printStackTrace();
    }

    return view;
}}

EdtTraitement :

public class EdtTraitement { //constructeur

protected Context mContext;
protected Activity activity;
protected TouchImageView image_edt = null;
protected Bitmap bitmap = null;
public  EdtTraitement(Context mContext,Activity _activity) {

    activity =  _activity;
    this.mContext = mContext;
}


public void showEdt(String url_image,String name_img ,String url_md5,String name_md5, TouchImageView img){
    image_edt = img;

    File img_file = new File(mContext.getFilesDir(), name_img);
    if(isOnline()) {
        if ((getMd5(url_md5).equals(readFile(name_md5))) && (img_file.exists())) {
            image_edt.setImageBitmap(BitmapFactory.decodeFile(img_file.getPath()));
        } else {
            try {
                InputStream inputStream = null;
                inputStream = (InputStream) new URL(url_image).getContent();
                bitmap = BitmapFactory.decodeStream(inputStream);
                image_edt.setImageBitmap(bitmap);
                //on le stoque:
                storeImage(bitmap);

            } catch (IOException e) {
                e.printStackTrace();
            }


        }
    }else{

        image_edt.setImageBitmap(BitmapFactory.decodeFile(img_file.getPath()));
    }
    image_edt.setZoom(image_edt.getMaxZoom());
    image_edt.setMaxZoom(image_edt.getMaxZoom());
    image_edt.setMinZoom(image_edt.getMinZoom());
}}

the log:

04-10 06:54:00.329 11605-11780/oytoch.iut_info E/AndroidRuntime: FATAL EXCEPTION: Thread-4
                                                             Process: oytoch.iut_info, PID: 11605
                                                             java.lang.NullPointerException: Attempt to invoke virtual method 'java.io.File android.content.Context.getFilesDir()' on a null object reference
                                                                 at oytoch.iut_info.EdtTraitement.showEdt(EdtTraitement.java:49)
                                                                 at oytoch.iut_info.JourFragment$1.run(JourFragment.java:38)
                                                                 at java.lang.Thread.run(Thread.java:761)

line 49:

 File img_file = new File(mContext.getFilesDir(), name_img);

It works with no fragment I need this context in other part of code in the class.

I have been unable to find a working solution; how can I change my code to receive my desired outcome?

score 0 · Accepted Answer · answered Apr 10 '17 at 11:09

0

When the Fragment is created, the getActivity() method returns null. You have to change the creation of your EdtTraitement to another method (when the activity is already createad) like this:

 @Override
        public void onActivityCreated(@Nullable Bundle savedInstanceState) {
            super.onActivityCreated(savedInstanceState);
        EdtTraitement edt = new EdtTraitement(mContext,mActivity);
        }

Also, remember, the Activity class is a Context, so is not necessary pass these 2 parameters, because it`s redundant.

answered Apr 10 '17 at 11:09

Luiz Fernando Salvaterra

4,192
2
24
42

Thanks you. it Works, I m always very impressed about the rapidity of answers. For other who trying to solve a problems like it , this post helped me http://stackoverflow.com/questions/28929637/difference-and-uses-of-oncreate-oncreateview-and-onactivitycreated-in-fra – Oytoch Apr 10 '17 at 13:37

Android: transferring Context and activity from a fragment to a class

1 Answers1