Uri.fromFile是否返回null？

Question

由于某种原因，我的onActivityResult中的outputFileUri返回null：

Uri selectedImageUri;
if (isCamera) {
    selectedImageUri = outputFileUri;

我不明白为什么。请看一下我的代码，看看我哪里出了问题。我允许用户通过从图库中选择或使用相机拍摄4张图像。用户用相机拍摄的照片不会显示，可能是因为它们的uri为空。outputFileUri是一个类变量。

takePictureIntent()

private void dispatchTakePictureIntent() {
    for(int i = 0; i < 4; i++) {
        Intent takePictureIntent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
        if (takePictureIntent.resolveActivity(getPackageManager()) != null) {
            // Create the File where the photo should go
            File photoFile = null;
            try {
                photoFile = createImageFile();
                outputFileUri = Uri.fromFile(photoFile);
            } catch (IOException ex) {
                Log.w("error","IOException");
            }catch (NullPointerException nullEx) {
                Log.w("error","NullPointerException");
            }
            // Camera.
            final List<Intent> cameraIntents = new ArrayList<Intent>();
            final Intent captureIntent = new Intent(android.provider.MediaStore.ACTION_IMAGE_CAPTURE);
            final PackageManager packageManager = getPackageManager();
            final List<ResolveInfo> listCam = packageManager.queryIntentActivities(captureIntent, 0);
            for (ResolveInfo res : listCam) {
                final String packageName = res.activityInfo.packageName;
                final Intent intent = new Intent(captureIntent);
                intent.setComponent(new ComponentName(res.activityInfo.packageName, res.activityInfo.name));
                intent.setPackage(packageName);
                intent.putExtra(MediaStore.EXTRA_OUTPUT, Uri.fromFile(photoFile));
                cameraIntents.add(intent);
            }
            // Filesystem.
            final Intent galleryIntent = new Intent();
            galleryIntent.setType("image/*");
            galleryIntent.setAction(Intent.ACTION_OPEN_DOCUMENT);
            // Chooser of filesystem options.
            final Intent chooserIntent = Intent.createChooser(galleryIntent, "Select Source");
            // Add the camera options.
            chooserIntent.putExtra(Intent.EXTRA_INITIAL_INTENTS, cameraIntents.toArray(new Parcelable[cameraIntents.size()]));
            if(id.equals(HAPPY_ID))
                startActivityForResult(chooserIntent, REQUEST_HAPPY_PHOTO);
            if(id.equals(SURPRISED_ID))
                startActivityForResult(chooserIntent, REQUEST_SURPRISED_PHOTO);
            if(id.equals(AFRAID_ID))
                startActivityForResult(chooserIntent, REQUEST_AFRAID_PHOTO);
            if(id.equals(UPSET_ID))
                startActivityForResult(chooserIntent, REQUEST_UPSET_PHOTO);
            if(id.equals(SAD_ID))
                startActivityForResult(chooserIntent, REQUEST_SAD_PHOTO);
        }
    }
}

onActivityResult()

@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        if (resultCode == RESULT_OK) {
            if (requestCode == REQUEST_HAPPY_PHOTO || requestCode == REQUEST_SURPRISED_PHOTO || requestCode == REQUEST_AFRAID_PHOTO ||
                    requestCode == REQUEST_UPSET_PHOTO || requestCode == REQUEST_SAD_PHOTO) {
                final boolean isCamera;
                if (data == null) {
                    isCamera = true;
                } else {
                    final String action = data.getAction();
                    if (action == null) {
                        isCamera = false;
                    } else {
                        isCamera = action.equals(android.provider.MediaStore.ACTION_IMAGE_CAPTURE);
                    }
                }
                Uri selectedImageUri;
                if (isCamera) {
                    selectedImageUri = outputFileUri;
                } else {
                    selectedImageUri = data == null ? null : data.getData();
                }
                //Log.d("doing ids", "right before id");
                //Log.d("doing ids", "id is " + id);
                if(requestCode == REQUEST_HAPPY_PHOTO) {
                    //Log.d("doing ids", "in happy");
                    happyList.add(selectedImageUri);
                }
                if(requestCode == REQUEST_SURPRISED_PHOTO) {
                    //Log.d("doing ids", "in surprised");
                    surprisedList.add(selectedImageUri);
                }
                if(requestCode == REQUEST_AFRAID_PHOTO) {
                    //Log.d("doing ids", "in surprised");
                    afraidList.add(selectedImageUri);
                }
                if(requestCode == REQUEST_UPSET_PHOTO) {
                    //Log.d("doing ids", "in surprised");
                    upsetList.add(selectedImageUri);
                }
                if(requestCode == REQUEST_SAD_PHOTO) {
                    //Log.d("doing ids", "in surprised");
                    sadList.add(selectedImageUri);
                }
            }
        }
    }

My createImageFile()：

private File createImageFile() throws IOException {
    // Create an image file name
    String timeStamp = new SimpleDateFormat("yyyyMMdd_HHmmss").format(new Date());
    String imageFileName = "JPEG_" + timeStamp;
    File storageDir = getExternalFilesDir(Environment.DIRECTORY_PICTURES);
    File image = File.createTempFile(
            imageFileName,  /* prefix */
            ".jpg",         /* suffix */
            storageDir      /* directory */
    );

    // Save a file: path for use with ACTION_VIEW intents
    mCurrentPhotoPath = "file:" + image.getAbsolutePath();
    return image;
}

Answer 1

我遇到了类似的问题，我通过持有对传递给Intent的URI的引用来解决它。这允许我不依赖于返回URI的意图。

代码如下：

private Uri startCameraFileUri;

private void startCameraIntent() {
    final Intent intentCamera = new Intent(android.provider.MediaStore.ACTION_IMAGE_CAPTURE);
    try {
        startCameraFileUri = Uri.fromFile(Utils.getNewFile());
        intentCamera.putExtra(MediaStore.EXTRA_OUTPUT, startCameraFileUri);
        intentCamera.putExtra("return-data", true);
        startActivityForResult(intentCamera, IConstants.REQUEST_TAKE_PICTURE);
    } catch (Exception e) {
        e.printStackTrace();
    }
}

public void openGalleryIntent() {
    final boolean isKitKat = Build.VERSION.SDK_INT >= Build.VERSION_CODES.KITKAT;
    if (isKitKat) {
        final Intent openGalleryIntent = new Intent(Intent.ACTION_OPEN_DOCUMENT);
        openGalleryIntent.addCategory(Intent.CATEGORY_OPENABLE);
        openGalleryIntent.setType("image/*");
        openGalleryIntent.putExtra(Intent.EXTRA_LOCAL_ONLY, true);
        startActivityForResult(
                Intent.createChooser(openGalleryIntent, getString(R.string.PROFILE_PIC_LIBRARY)),
                IConstants.REQUEST_GALLERY);
    } else {
        final Intent openGalleryIntent = new Intent(Intent.ACTION_PICK,
                android.provider.MediaStore.Images.Media.EXTERNAL_CONTENT_URI);
        openGalleryIntent.putExtra(Intent.EXTRA_LOCAL_ONLY, true);
        startActivityForResult(Intent.createChooser(openGalleryIntent, getString(R.string.PROFILE_PIC_LIBRARY)), IConstants.REQUEST_GALLERY);
    }
}

@Override
public void onActivityResult(int requestCode, int resultCode, Intent data) {
    if (resultCode == Activity.RESULT_OK) {

        final Uri uri;
        if(data != null) {
            uri = data.getData();
        }
        else{
            uri = startCameraFileUri;
        }
        switch (requestCode) {
            case IConstants.REQUEST_GALLERY:
            case IConstants.REQUEST_TAKE_PICTURE:
                try {
                    if (!uri.toString().isEmpty()) {
                        loadUserPhoto(uri.toString());

                    }
                } catch (Exception e) {
                    e.printStackTrace();
                }
                break;
        }
    }
}