照片上传的设计实现

Question

我正在构建一个 Android 应用程序，其中有五个 Activity class，或者如果您熟悉 MVC 模式，它们通常是 Controller classes。

具体来说，User 将进入这 5 个 Activity class 之一（通过在整个应用程序中导航），有时他们可能会上传照片。现在上传照片的代码遵循非常相似的模式。请注意，所有这些代码在所有 5 classes (YUCK) 中重复了 5 次。

全局变量:

/*
Tracking
 */
private static final int TAKE_PHOTO_REQUEST = 1;
private static final int GET_FROM_GALLERY = 2;

private Uri mUri;
private String mCurrentPhotoPath;
private File mFile;
private TypedFile mTypedFile; // For Retrofit

用户点击照片上传按钮，弹出一个警告对话框：

private void showFileOptions() {
    new AlertDialog.Builder(this)
            .setItems(R.array.uploadOptions, new DialogInterface.OnClickListener() {
                @Override
                public void onClick(DialogInterface dialog, int which) {
                    switch (which) {
                        case 0:
                            dispatchTakePicture();
                            break;
                        case 1:
                            dispatchUploadFromGallery();
                            break;
                    }
                }
            })
            .setNegativeButton(android.R.string.cancel, new DialogInterface.OnClickListener() {
                @Override
                public void onClick(DialogInterface dialog, int which) {
                    dialog.cancel();
                }
            })
            .show();
}

dispatchTakePicture:

/*
Take picture from your camera
 */
private void dispatchTakePicture() {
    Intent intent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
    // Make sure that there is a camera activity to handle the intent
    if (intent.resolveActivity(getPackageManager()) != null) {

        // Create the File where the mTypedFile would go
        File picFile = null;

        try {
            picFile = createImageFile();
            mFile = picFile;
        } catch (IOException e) {
            e.printStackTrace();
            Toast.makeText(this, e.getMessage(), Toast.LENGTH_LONG).show();
        }

        // Continue only if the file was successfully created
        if (picFile != null) {
            intent.putExtra(MediaStore.EXTRA_OUTPUT, Uri.fromFile(picFile));
            startActivityForResult(intent, TAKE_PHOTO_REQUEST);
        }
    }
}

dispatchUploadFromGallery:

/*
Take a mTypedFile from your gallery
 */
private void dispatchUploadFromGallery() {
    // Launch gallery intent
    startActivityForResult(new Intent(Intent.ACTION_PICK, MediaStore
            .Images.Media.INTERNAL_CONTENT_URI), GET_FROM_GALLERY);
}

请注意，startActivityForResult 在这两种方法中都会被调用。接下来是 createImageFile() 方法，如果用户想从 Camera API:

中拍照

private File createImageFile() throws IOException {
    // Create the Image File name
    String timeStamp = new SimpleDateFormat("yyyyMMdd_HHmmss", Locale.getDefault()).format(new Date());
    String imageFileName = "JPEG_" + timeStamp + "_";

    File storageDir = Environment
            .getExternalStoragePublicDirectory(Environment.DIRECTORY_PICTURES);

    File image = File.createTempFile(
            imageFileName, // Prefix
            ".jpg", // Suffix
            storageDir // Directory
    );

    // Save the file, path for ACTION_VIEW intents
    mCurrentPhotoPath = "file:" + image.getAbsolutePath();
    mUri = Uri.fromFile(image);

    return image;
}

现在终于有了我们的 startActivityForResult(...) 方法：

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


    if (requestCode == TAKE_PHOTO_REQUEST && resultCode == RESULT_OK) {
        startUploadProgress();
        showContainer();

        mTypedFile = new TypedFile("image/*", mFile);
        RotatePictureHelper.rotatePicture(mFile, ExampleActivity.this, mAttachment); // Helper class to rotate pictures
        mBus.post(new LoadUploadFileEvent(mTypedFile));

    } else if (requestCode == GET_FROM_GALLERY && resultCode == RESULT_OK) {
        startUploadProgress();
        showContainer();

        mUri = data.getData();
        mTypedFile = UriHelper.handleUri(mUri, this); // Helper class to handle bitmap manipulation
        mFile = mTypedFile.file();
        mBus.post(new LoadUploadFileEvent(mTypedFile));
    } else if (resultCode != Activity.RESULT_CANCELED) {
        Toast.makeText(this, R.string.generalError, Toast.LENGTH_LONG).show();
    }
}

请注意，我已经创建了助手 classes 来处理位图操作和图片旋转问题。

仍然，这是非常丑陋的丑陋代码，并在 5 class 秒内重复此代码。

我现在有几个想法：

创建一个服务并将需要的变量传递给该服务来处理这个问题。
将 AlertDialog 选项移动到助手 class 并根据 instanceOf 调用不同的 AlertDialogs 无论 Activity 调用它什么。
我是否应该创建一个具有这些方法的父 Activity class，然后扩展 5 个 Activity 子 class 并调用这些方法？

Answer 1

创建一个扩展 DialogFragment 的片段（例如 UploadPhotoFragment），覆盖 onCreateDialog 和 onActivityResult 方法。并在需要时调用

(new UploadPhotoFragment()).show(getFragmentManager(), null);

Ps: 如果你正在使用支持库，请使用支持库的 DialogFragment 和 FragmentManager。

Answer 2

为了解决这个问题，我选择了第三个选项：

我创建了一个名为 CameraActivity 的 activity，然后在我的另外 5 个 Activity 类中扩展了这个 Activity。每个类的代码有 95% 的相似度，可能分别有 5% 的差异。

我的 CameraActivity 会有以下代码：

public class CameraActivity extends Activity {
    /*
      Tracking
     */
    private static final int TAKE_PHOTO_REQUEST = 1;
    private static final int GET_FROM_GALLERY = 2;

    private Uri mUri;
    private String mCurrentPhotoPath;
    private File mFile;
    private TypedFile mTypedFile; // For Retrofit

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

        startProgress();

        switch (requestCode) {
            case TAKE_PHOTO_REQUEST:
                if (resultCode == RESULT_OK) {
                    mTypedFile = new TypedFile("image/*", mFile);
                }
                break;
            case GET_FROM_GALLERY:
                if (resultCode == RESULT_OK) {
                    mUri = data.getData();
                    mTypedFile = UriHelper.handleUri(mUri, this);
                }
                break;
            default:
                stopProgress();
                Toast.makeText(this, R.string.generalError, Toast.LENGTH_LONG).show();
                break;
        }
    }

    protected void showFileOptions() {
        new AlertDialog.Builder(this)
                .setItems(R.array.uploadOptions, new DialogInterface.OnClickListener() {
                    @Override
                    public void onClick(DialogInterface dialog, int which) {
                        switch (which) {
                            case 0:
                                dispatchTakePicture();
                                break;
                            case 1:
                                dispatchUploadFromGallery();
                                break;
                            default:
                                dispatchUploadFromGallery();
                                break;
                        }
                    }
                })
                .setNegativeButton(android.R.string.cancel, new DialogInterface.OnClickListener() {
                    @Override
                    public void onClick(DialogInterface dialog, int which) {
                        dialog.cancel();
                    }
                })
                .show();
    }

    // Other code for handling Uri and File goes here....

}

现在我可以在我的另一个 Activity 类中扩展这个 Activity 并在那里实现其余 5% 的差异。请注意，showFileOptions() 已更改为 protected 状态，因此我可以从 child Activity 调用它。这里的一个例子是 activity.

public class PhotoUploadActivity extends CameraActivity {

    // Initialize methods
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        showFileOptions(); // Calling AlertDialog from Parent Activity
    }

    @Override
    public void onActivityResult(int requestCode, int resultCode, Intent data) {
        // Super call executes code in CameraActivity
        super.onActivityResult(requestCode, resultCode, data);
        switch (requestCode) {
            case TAKE_PHOTO_REQUEST:
                if (resultCode == RESULT_OK) {
                    // Implement logic if user take a photo, do something with mUri or mTypedFile
                }
                break;
            case GET_FROM_GALLERY:
                if (resultCode == RESULT_OK) {
                    // Implement logic if user gets something from gallery, do something with mUri or mTypedFile
                }
                break;
            default:
                break;
        }
    }

}

现在我可以简单地扩展我的 5 child Activity 类在那些类中调用 super.onActivityResult(...) 并考虑剩余的 5% 代码，同时 CameraActivity 处理其余部分。

照片上传的设计实现

Design implementation of photo upload

android

android-activity

android-camera

android-camera-intent