Android camera capture activity returns null Uri

问题

This code worked on samsung before but now that i'm using Nexus One with Android 2.3.6, it's crashing as soon as I take a picture and click ok or choose a photo from gallery. Stacktrace shows a null pointer exception on the Uri.
My code for the activating the camera is as follows:

public void activateCamera(View view){      
    Intent i = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
    // start the image capture Intent
    startActivityForResult(i, CAPTURE_IMAGE_ACTIVITY_REQUEST_CODE);
}

protected void onActivityResult(int requestCode, int resultCode, Intent data) {

    super.onActivityResult(requestCode, resultCode, data);

    if ((requestCode == CHOOSE_IMAGE_ACTIVITY_REQUEST_CODE  || requestCode == CAPTURE_IMAGE_ACTIVITY_REQUEST_CODE) 
        && resultCode == RESULT_OK && null != data) {

        selectedImage = data.getData();

        String[] filePathColumn = { MediaStore.Images.Media.DATA };

        Cursor cursor = getContentResolver().query(selectedImage,
                filePathColumn, null, null, null);

        cursor.moveToFirst();

        int columnIndex = cursor.getColumnIndex(filePathColumn[0]);

        String picturePath = cursor.getString(columnIndex);

        cursor.close();

        Bitmap bits = null;

        BitmapFactory.Options options = new BitmapFactory.Options();

        options.inSampleSize = inSampleSize;

        try {
            bits = BitmapFactory.decodeStream(new FileInputStream(picturePath),null,options);
        } catch (FileNotFoundException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
        }

Any idea what could be the problem? Thanks!

回答1:

You have to tell the camera, where to save the picture and remeber the uri yourself:

private Uri mMakePhotoUri;

private File createImageFile() {
    // return a File object for your image.
}

private void makePhoto() {
    try {
        File f = createImageFile();
        Intent i = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
        mMakePhotoUri = Uri.fromFile(f);
        i.putExtra(MediaStore.EXTRA_OUTPUT, mMakePhotoUri);
        startActivityForResult(i, REQUEST_MAKE_PHOTO);
    } catch (IOException e) {
        Log.e(TAG, "IO error", e);
        Toast.makeText(getActivity(), R.string.error_writing_image, Toast.LENGTH_LONG).show();
    }
}

@Override
public void onActivityResult(final int requestCode, final int resultCode, final Intent data) {
    switch (requestCode) {
        case REQUEST_MAKE_PHOTO:
            if (resultCode == Activity.RESULT_OK) {
                // do something with mMakePhotoUri
            }
            return;
        default: // do nothing
            super.onActivityResult(requestCode, resultCode, data);
    }
}

You should save the value of mMakePhotoUri over instance states withing onCreate() and onSaveInstanceState().

回答2:

Inject this extra into the Intent that called onActivityResult and the system will do all the heavy lifting for you.

File f = createImageFile();
takePictureIntent.putExtra(MediaStore.EXTRA_OUTPUT, Uri.fromFile(f));

Doing this makes it as easy as this to retrieve the photo as a bitmap.

private void handleSmallCameraPhoto(Intent intent) {
    Bundle extras = intent.getExtras();
    mImageBitmap = (Bitmap) extras.get("data");
    mImageView.setImageBitmap(mImageBitmap);
}

回答3:

dont pass any extras, just define the path where you have placed or saved the file directly in onActivityResult

 public void openCamera() {

    Intent cameraIntent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
    file = createImageFile();
    boolean isDirectoryCreated = file.getParentFile().mkdirs();
    Log.d("", "openCamera: isDirectoryCreated: " + isDirectoryCreated);
    if (Build.VERSION.SDK_INT >= 23) {
        tempFileUri = FileProvider.getUriForFile(getActivity().getApplicationContext(),
                "com.scanlibrary.provider", // As defined in Manifest
                file);
    } else {
        tempFileUri = Uri.fromFile(file);
    }

    try
    {
        cameraIntent.putExtra("return-data", true);
        startActivityForResult(cameraIntent, ScanConstants.START_CAMERA_REQUEST_CODE);
    }
    catch (Exception e)
    {
    }
}

private File createImageFile() {
    clearTempImages();
    String timeStamp = new SimpleDateFormat("yyyyMMdd_HHmmss").format(new
            Date());
    File file = new File(ScanConstants.IMAGE_PATH, "IMG_" + timeStamp +
            ".jpg");
    fileUri = Uri.fromFile(file);
    return file;
}

@Override
public void onActivityResult(int requestCode, int resultCode, Intent data) {
    super.onActivityResult(requestCode, resultCode, data);

    Bitmap bitmap = null ;
    if (resultCode == Activity.RESULT_OK ) {
        try {
            if (Build.VERSION.SDK_INT >= 23) {
                    tempFileUri = FileProvider.getUriForFile(getActivity().getApplicationContext(),
                            "com.scanlibrary.provider", // As defined in Manifest
                            file);
                } else {
                    tempFileUri = Uri.fromFile(file);
                }

                    bitmap = getBitmap(tempFileUri);



                    bitmap = getBitmap(data.getData());

        } catch (Exception e) {
            e.printStackTrace();
        }
    } else {
        getActivity().finish();
    }
    if (bitmap != null) {
        postImagePick(bitmap);
    }
}

来源：https://stackoverflow.com/questions/18501439/android-camera-capture-activity-returns-null-uri