Android从非活动类问题调用cameraApp

Question

Though I found several similar answered questions, I couldn't solve my problem:

I use Fragment oFragment from where I want to call the Camera as a new Activity. Therefore I created a non-activity class Camera. When running I get the error:

java.lang.NullPointerException: Attempt to invoke virtual method 'android.content.pm.PackageManager android.app.Activity.getPackageManager()' on a null object reference

oFragment is placed in a FrameLayout in MainActivity . I also tried the constructor of Camera with Context context . Do you see any workarounds or mistakes? Thanks in advance!

Edit: The code works fine if implemented directly into oFragment .

Class Camera:

public class Camera {
    static final int REQUEST_IMAGE_CAPTURE = 1;
    Activity activity;

    public Camera(Activity activity) {
        this.activity = activity;
    }

    public void dispatchTakePictureIntent() {
        Intent takePictureIntent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
        if (takePictureIntent.resolveActivity(activity.getPackageManager()) != null) {
            activity.startActivityForResult(takePictureIntent, REQUEST_IMAGE_CAPTURE);
    }
}

Snipped from oFragment:

public class OFragment extends Fragment {

    Camera cam = new Camera(getActivity());
    ...
    @Override
    public void onClick(View v) {
    cam.dispatchTakePictureIntent();
    }

Answer 1

I just solved it. I had to add the line super(); to my constructer and it works fine!