如何将启动活动结果封装在 Java 类中，并获取调用该方法的活动上的 onActivity结果

Question

我在几个活动中使用下一个相机代码，我想做一个类来封装在Android中使用相机的方法。我试图得到的是活动类是这样的：Public class Myfragment extends Fragment{@Nullable@Overridepublic View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {    View v = inflater.inflate(R.layout.profile_fragment, container, false);        mButtonProfilePhoto = v.findViewById(R.id.buttonProfilePhoto);        mButtonProfilePhoto.setOnClickListener(new View.OnClickListener() {        @Override        public void onClick(View v) {        //Here I call the camera intent.            Camera.dispatchTakePictureIntent(getActivity(), mPhotoFile);            }            });    return v;    }        @Override        public void onActivityResult(int requestCode, int resultCode, Intent data) {              //handle the camera result}相机类如下所示：public class Camera{public static void dispatchTakePictureIntent(Activity activity, File file) {    Intent takePictureIntent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);    // Ensure that there's a camera activity to handle the intent    if (takePictureIntent.resolveActivity(activity.getPackageManager()) != null) {        // Create the File where the photo should go        file = null;        try {            file = Camera.createImageFile(activity);        } catch (IOException ex) {            // Error occurred while creating the File        }        // Continue only if the File was successfully created        if (file  != null) {            Uri photoURI = FileProvider.getUriForFile(activity,                    "com.itcom202.weroom.fileprovider",                    file );            takePictureIntent.putExtra(MediaStore.EXTRA_OUTPUT, photoURI);            startActivityForResult( takePictureIntent, REQUEST_IMAGE_CAPTURE);        }    }}}我现在遇到的问题是，我从来没有从片段中接到回电。onActivityResult

Answer 1

操作系统不支持发送到 的 。但是，支持库具有执行此操作的机制，该机制将调用注册到 中的特殊表。这里的诀窍是，你必须使用 自己的启动活动结果（），而不是 的一个。onActivityResult()FragmentAppCompatActivityFragmentActivity

因此，您的类代码应如下所示：Camera

public class Camera{

    public static void dispatchTakePictureIntent(Activity activity, Fragment fragment, File file) {

        Intent takePictureIntent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);

        // Ensure that there's a camera activity to handle the intent

        if (takePictureIntent.resolveActivity(activity.getPackageManager()) != null) {

            // Create the File where the photo should go

            file = null;

            try {

                file = Camera.createImageFile(activity);

            } catch (IOException ex) {

                // Error occurred while creating the File

            }

            // Continue only if the File was successfully created

            if (file  != null) {

                Uri photoURI = FileProvider.getUriForFile(activity,

                        "com.itcom202.weroom.fileprovider",

                        file );

                takePictureIntent.putExtra(MediaStore.EXTRA_OUTPUT, photoURI);

                fragment.startActivityForResult(takePictureIntent, REQUEST_IMAGE_CAPTURE);

            }

        }

    }

}

请注意，最后一行使用 的FragmentstartActivityForResult()