android中非常困难的面向对象的“移植”

Question

在我的 android 应用程序中，至少有 4 个地方用户可以单击照片，然后出现一个对话框，上面写着“拍照或从图库中选择以更改您的照片” 在这些地方的每一个地方都有不同的活动，具有不同的变量和不同的 xml 元素名称，我有很多非常相似的代码，在我的应用程序中重复。

我想把它放在一个单独的班级里，但是被代码缠住了，感觉就像心脏移植一样。我的面向对象技能和 Java 技能不是很好（3 个月的经验），也许在 Android 中有一些我不知道的解决方法。

我将提供来自不同课程的两个示例，以便您了解有多少重复。如果有人能帮我制作一个单独的对象，我将不胜感激

设置类，图片转换器摘录：

iUserAvatarSettings.setOnClickListener(new OnClickListener() {

            @Override
            public void onClick(View v) {

                final Dialog dialog = new Dialog(Settings.this, R.style.no_title_dialog);
                if (!userHasProvidedOwnPhoto) {
                    dialog.setContentView(R.layout.signup_avatar_upload_dialog);
                } else {
                    dialog.setContentView(R.layout.signup_avatar_upload_dialog_2);
                    bDeleteAvatar = (Button) dialog.findViewById(R.id.bDeleteAvatar);
                    try {
                        bDeleteAvatar.setTypeface(font1);
                    } catch (Exception e) {
                    }
                    bDeleteAvatar.setOnClickListener(new OnClickListener() {

                        @Override
                        public void onClick(View v) {
                            setAvatarPath("default_avatar");
                            userHasProvidedOwnPhoto = false;
                            if (userSex.equals("Male") || userSex.equals("")) {
                                iUserAvatarSettings.setImageResource(R.drawable.avatar_default_male);

                            } else {
                                iUserAvatarSettings.setImageResource(R.drawable.avatar_default_female);
                            }
                            dialog.dismiss();
                        }
                    });
                }
                Button bTakeAPhoto = (Button) dialog.findViewById(R.id.bTakeAPhoto);
                Button bSelectPhotoFromFile = (Button) dialog.findViewById(R.id.bSelectPhotoFromFile);
                Button bCancelAvatarUpload = (Button) dialog.findViewById(R.id.bCancelAvatarUpload);
                try {
                    bTakeAPhoto.setTypeface(font1);
                    bSelectPhotoFromFile.setTypeface(font1);
                    bCancelAvatarUpload.setTypeface(font1);
                } catch (Exception e) {
                }

                bTakeAPhoto.setOnClickListener(new OnClickListener() {
                    @Override
                    public void onClick(View v) {

                        if (isIntentAvailable(Settings.this, MediaStore.ACTION_IMAGE_CAPTURE)) {
                            Intent takePictureIntent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
                            startActivityForResult(takePictureIntent, TAKE_IMAGE_WITH_CAMERA);

                            dialog.dismiss();

                        } else {
                            toastMaker.toast(net.asdqwe.activities.Settings.this, Configurationz.ErrorMessages.DEVICE_UNABLE_TO_TAKE_PHOTOS,  Toast.LENGTH_LONG);
                            dialog.dismiss();
                            userHasProvidedOwnPhoto = false;
                        }
                    }
                });

                bSelectPhotoFromFile.setOnClickListener(new OnClickListener() {
                    @Override
                    public void onClick(View v) {
                        Intent getImageFromGallery = new Intent(Intent.ACTION_PICK, android.provider.MediaStore.Images.Media.EXTERNAL_CONTENT_URI);
                        getImageFromGallery.setType("image/*");
                        startActivityForResult(getImageFromGallery, PICK_IMAGE);
                        //avatarPath = saveUserAvatar.getUserAvatar().toString();
                        //setAvatarPath(saveUserAvatar.getUserAvatar().toString()); // this remains under question
                        dialog.dismiss();
                    }
                });

                bCancelAvatarUpload.setOnClickListener(new OnClickListener() {
                    @Override
                    public void onClick(View v) {

                        dialog.dismiss();
                    }
                });
                dialog.show();
            }
        }); // end of image button on click handling

    public static boolean isIntentAvailable(Context context, String action) {
        final PackageManager packageManager = context.getPackageManager();
        final Intent intent = new Intent(action);
        List<ResolveInfo> list = packageManager.queryIntentActivities(intent, PackageManager.MATCH_DEFAULT_ONLY);
        return list.size() > 0;
    }

    private void handleSmallCameraPhoto(Intent intent) {

        try {
            Bundle extras = intent.getExtras();
            mImageBitmap = (Bitmap) extras.get("data");
            iUserAvatarSettings.setImageBitmap(mImageBitmap);
            saveUserAvatar.SaveImage(this, mImageBitmap);
            userHasProvidedOwnPhoto = true;
            setAvatarPath(saveUserAvatar.getUserAvatar().toString());
        } catch (Exception e) {
            toastMaker.toast(net.asdqwe.activities.Settings.this, Configurationz.ErrorMessages.TAKING_PHOTO_FAILED,  Toast.LENGTH_LONG);
            userHasProvidedOwnPhoto = false;
        }

    }

    private void handleGalleryPhoto(Intent intent) {
        try {
            Uri _uri = intent.getData();
            Cursor cursor = getContentResolver().query(_uri, new String[] { android.provider.MediaStore.Images.ImageColumns.DATA }, null, null, null);
            cursor.moveToFirst();
            final String imageFilePath = cursor.getString(0);
            cursor.close();
            mImageBitmap2 = BitmapFactory.decodeFile(imageFilePath);
            iUserAvatarSettings.setImageBitmap(mImageBitmap2);
            saveUserAvatar.SaveImage(this, mImageBitmap2);
            userHasProvidedOwnPhoto = true;
            setAvatarPath(saveUserAvatar.getUserAvatar().toString());
        } catch (Exception e) {
            toastMaker.toast(net.zxcasd.activities.Settings.this, Configurationz.ErrorMessages.PICKING_PHOTO_FROM_GALLERY_FAILED,  Toast.LENGTH_LONG);
            userHasProvidedOwnPhoto = false;
        }
    }

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

        if (requestCode == TAKE_IMAGE_WITH_CAMERA && resultCode == RESULT_OK && null != data) {
            handleSmallCameraPhoto(data);

        } else if (requestCode == PICK_IMAGE && resultCode == RESULT_OK && null != data) {
            handleGalleryPhoto(data);
        }
    }

注册类，图片摘录：

iUserAvatar.setOnClickListener(new OnClickListener() {

        @Override
        public void onClick(View v) {

            final Dialog dialog = new Dialog(Signup.this, R.style.no_title_dialog);
            if (!userHasProvidedOwnPhoto) {
                dialog.setContentView(R.layout.signup_avatar_upload_dialog);
            } else {
                dialog.setContentView(R.layout.signup_avatar_upload_dialog_2);
                bDeleteAvatar = (Button) dialog.findViewById(R.id.bDeleteAvatar);
                try {
                    bDeleteAvatar.setTypeface(font1);
                } catch (Exception e) {
                }
                bDeleteAvatar.setOnClickListener(new OnClickListener() {

                    @Override
                    public void onClick(View v) {
                        userHasProvidedOwnPhoto = false;
                        if (userSex.equals("Male") || userSex.equals("")) {
                            iUserAvatar.setImageResource(R.drawable.avatar_default_male);
                        } else {
                            iUserAvatar.setImageResource(R.drawable.avatar_default_female);
                        }
                        dialog.dismiss();
                    }
                });
            }
            Button bTakeAPhotoSignupPage = (Button) dialog.findViewById(R.id.bTakeAPhoto);
            Button bSelectPhotoFromFileSignupPage = (Button) dialog.findViewById(R.id.bSelectPhotoFromFile);
            Button bCancelAvatarUpload = (Button) dialog.findViewById(R.id.bCancelAvatarUpload);
            try {
                bTakeAPhotoSignupPage.setTypeface(font1);
                bSelectPhotoFromFileSignupPage.setTypeface(font1);
                bCancelAvatarUpload.setTypeface(font1);
            } catch (Exception e) {
            }
            bTakeAPhotoSignupPage.setOnClickListener(new OnClickListener() {
                @Override
                public void onClick(View v) {

                    if (isIntentAvailable(Signup.this, MediaStore.ACTION_IMAGE_CAPTURE)) {
                        Intent takePictureIntent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
                        startActivityForResult(takePictureIntent, TAKE_IMAGE_WITH_CAMERA);
                        dialog.dismiss();

                    } else {
                        toastMaker.toast(net.asdqwe.activities.Signup.this, Configurationz.ErrorMessages.DEVICE_UNABLE_TO_TAKE_PHOTOS,  Toast.LENGTH_LONG);
                        dialog.dismiss();
                        userHasProvidedOwnPhoto = false;
                    }
                }
            });

            bSelectPhotoFromFileSignupPage.setOnClickListener(new OnClickListener() {
                @Override
                public void onClick(View v) {
                    Intent getImageFromGallery = new Intent(Intent.ACTION_PICK, android.provider.MediaStore.Images.Media.EXTERNAL_CONTENT_URI);
                    getImageFromGallery.setType("image/*");
                    startActivityForResult(getImageFromGallery, PICK_IMAGE);
                    dialog.dismiss();
                }
            });

            bCancelAvatarUpload.setOnClickListener(new OnClickListener() {
                @Override
                public void onClick(View v) {
                    // and deal with photo
                    dialog.dismiss();
                }
            });
            dialog.show();
        }
    });

public static boolean isIntentAvailable(Context context, String action) {
    final PackageManager packageManager = context.getPackageManager();
    final Intent intent = new Intent(action);
    List<ResolveInfo> list = packageManager.queryIntentActivities(intent, PackageManager.MATCH_DEFAULT_ONLY);
    return list.size() > 0;
}
private void handleSmallCameraPhoto(Intent intent) {

    try {
        Bundle extras = intent.getExtras();
        mImageBitmap = (Bitmap) extras.get("data");
        iUserAvatar.setImageBitmap(mImageBitmap);
        saveUserAvatar.SaveImage(this, mImageBitmap);
        userHasProvidedOwnPhoto = true;
    } catch (Exception e) {
        toastMaker.toast(net.asdqwe.activities.Signup.this, Configurationz.ErrorMessages.TAKING_PHOTO_FAILED,  Toast.LENGTH_LONG);
        userHasProvidedOwnPhoto = false;
    }

}

private void handleGalleryPhoto(Intent intent) {
    try {
        Uri _uri = intent.getData();
        Cursor cursor = getContentResolver().query(_uri, new String[] { android.provider.MediaStore.Images.ImageColumns.DATA }, null, null, null);
        cursor.moveToFirst();
        final String imageFilePath = cursor.getString(0);
        cursor.close();
        mImageBitmap2 = BitmapFactory.decodeFile(imageFilePath);
        iUserAvatar.setImageBitmap(mImageBitmap2);
        saveUserAvatar.SaveImage(this, mImageBitmap2);
        userHasProvidedOwnPhoto = true;
    } catch (Exception e) {
        toastMaker.toast(net.asdqwe.activities.Signup.this, Configurationz.ErrorMessages.PICKING_PHOTO_FROM_GALLERY_FAILED,  Toast.LENGTH_LONG);
        userHasProvidedOwnPhoto = false;
    }
}

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

    if (requestCode == TAKE_IMAGE_WITH_CAMERA && resultCode == RESULT_OK && null != data) {
        handleSmallCameraPhoto(data);

    } else if (requestCode == PICK_IMAGE && resultCode == RESULT_OK && null != data) {
        handleGalleryPhoto(data);
    }
}

Answer 1

1. 将isIntentAvailable(Context, String) 移动到实用程序类中。这在其他一些用例中可能会有所帮助。
2. 创建一个包含所有常用活动方法的抽象类（称为MyAbstractActivity）：handleSmallCameraPhoto(Intent)、handleGalleryPhoto(Intent) 和onActivityResult(int, int, Intent)
   • iUserAvatarSettings / iUserAvatar 必须是 MyAbstractActivity 的一部分。如果您需要针对不同用例的不同实现，请创建一个抽象 getter，f.e. getUserAvatarButton()。
   • setAvatarPath(String) 仅用于两个类之一。在 MyAbstractActivity 中将其设为抽象方法并根据需要实现。
   • 让其他类继承自MyAbstractActivity。
3. 将 OnClickListener 转换为一个类。
   • 作为构造函数参数，您传递 MyAbstractActivity 的子类和 Button (iUserAvatarSettings / iUserAvatar)。
   • 使用构造函数参数来引用方法和变量，例如userHasProvidedOwnPhoto。
   • iUserAvatar.setOnClickListener(...) 部分将保留在 MyAbstractActivity 中。
4. 现在您已经删除了代码冗余，但还有更多工作要做。可能封装现在还不够好。
   • 考虑将方法和变量移动到 OnClickListener 类或远离它。
   • 考虑将方法和变量移至 MyAbstractActivity 或远离它。
   • 请一些更有经验的开发人员进行审核。 （不要让他重构它。）
   • 如果您有具体的重构问题，请回复她并询问社区。​​li>

Answer 2

你可以在 Github 上查看我的项目Android Image Helper

具有图像选择功能的 Activity 如下所示：

public class ImageUploaderActivity extends Activity implements ImageChooseCallback {
    ImageUploadEngine uploadEngine;
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        uploadEngine = new ImageUploadEngine.Builder(this, savedInstanceState).build();
        //...
        someButton.setOnClickListener(new OnClickListener() {
            @Override
            public void onClick(View v) {
                uploadEngine.performImageAsk(R.string.app_name, R.string.newphoto, R.string.oldphoto, R.string.choose, R.drawable.ic_launcher);
            }
        });
    }

    @Override
    public void onSaveInstanceState(Bundle outState) {
        uploadEngine.onSaveInstanceState(outState);
    }

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

    @Override
    public void onCanceled(ImageUploadEngine engine) {
        //notifying you that the user has canceled the request
    }

    @Override
    public void onChosen(ImageUploadEngine engine, String path, boolean newPicture) {
        //notifying you that the user has selected an image
    }

    @Override
    public void onError(ImageUploadEngine engine, Exception ex) {
        //notifying you that an error has occurred
    }
}

uploadEngine 还公开了 performImageTake 和 performImageChoose 函数，以防默认对话框（选择）不适合您的需要。

仅供参考：

本项目旨在为安卓开发者提供一个易于使用的工具，供安卓开发者在需要用户选择安卓手机上的图片并上传时使用。如果该过程在特定手机上出现任何错误，则应在库内进行处理，以在所有手机上提供相同的用户体验。

Answer 3

这是我重构代码的方法。我也试图为我的设计提供一些理由。

1) 您可以将对话框抽象为一个小部件。

您可以创建一个扩展Dialog 并提供所需功能的PhotoPickerDialog。然后你可以在不同的地方/活动中重复使用这个小部件。

public class PhotoPickerDialog extends Dialog {

    //private fields
    private Typeface buttonFont = Typeface.DEFAULT;
    private Button bTakeAPhoto;
    private Button bSelectPhotoFromFile;
    private Button bCancelAvatarUpload;
    private IMediaHelper mMediaHelper;

    public PhotoPickerDialog(Context context) {
        super(context);
        initView();
    }

    public PhotoPickerDialog(Context context, int theme) {
        super(context, theme);
        initView();
    }

    protected PhotoPickerDialog(Context context, boolean cancelable, OnCancelListener cancelListener) {
        super(context, cancelable, cancelListener);
        initView();
    }

    protected void setLayoutResource() {
        setContentView(R.layout.signup_avatar_upload_dialog);
    }

    protected void initView() {
        setLayoutResource();

        bTakeAPhoto = (Button) findViewById(R.id.bTakeAPhoto);
        bSelectPhotoFromFile = (Button) findViewById(R.id.bSelectPhotoFromFile);
        bCancelAvatarUpload = (Button) findViewById(R.id.bCancelAvatarUpload);

        bCancelAvatarUpload.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                dismiss();
            }
        });
    }

    /**
     * Set the type face of the button, in case you want to have different
     * font at different times.
     */
    public void setButtonFont(Typeface font) {
        buttonFont = font;
        bTakeAPhoto.setTypeface(buttonFont);
        bSelectPhotoFromFile.setTypeface(buttonFont);
        bCancelAvatarUpload.setTypeface(buttonFont);
    }

    /**
     * Set the media helper object which implements the functionality to
     * take and pick photo. So the task delegated to this media helper.
     */
    public void setMediaHelper(IMediaHelper mediaHelper) {
        mMediaHelper = mediaHelper;
        bTakeAPhoto.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                mMediaHelper.takePhoto();
                dismiss();
            }
        });

        bSelectPhotoFromFile.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                mMediaHelper.pickPhoto();
                dismiss();
            }
        });
    }
}

因为您需要两种不同类型的对话框，具体取决于用户是否已经拥有头像照片。让我们创建一个扩展PhotoPickerDialog 的PhotoPickerDialogWithDelete。然后我们只需要override几个方法并添加删除回调就可以制作我们的新型对话框，而无需重新编写大量代码。

public class PhotoPickerDialogWithDelete extends PhotoPickerDialog {
    private Button bDeleteAvatar;

    public PhotoPickerDialogWithDelete(Context context) {
        super(context);
    }

    public PhotoPickerDialogWithDelete(Context context, int theme) {
        super(context, theme);
    }

    protected PhotoPickerDialogWithDelete(Context context, boolean cancelable, OnCancelListener cancelListener) {
        super(context, cancelable, cancelListener);
    }

    @Override
    protected void setLayoutResource() {
        setContentView(R.layout.signup_avatar_upload_dialog_2);
    }

    @Override
    protected void initView() {
        super.initView();
        bDeleteAvatar = (Button) findViewById(R.id.bDeleteAvatar);
    }

    @Override
    public void setButtonFont(Typeface font) {
        super.setButtonFont(font);
        bDeleteAvatar.setTypeface(font);
    }

    public void setOnDeleteListener(final View.OnClickListener listener) {
        bDeleteAvatar.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                dismiss();
                listener.onClick(v);
            }
        });
    }
}

2) 将与照片意图相关的功能移至abstract 基类MediaSupportActivity。

所有需要支持拍照/挑选照片的活动只需要从这个类中extend并实现两个简单的方法handleSmallCameraPhoto(Bitmap)和handleGalleryPhoto(Bitmap)。他们不必明确关心如何拍摄/挑选照片，而只关心如何处理它们（对于不同的活动可能有所不同）。

public abstract class MediaSupportActivity extends Activity implements IMediaHelper {

    private static final int TAKE_IMAGE_WITH_CAMERA = 1;
    private static final int PICK_IMAGE = 2;

    protected abstract void handleSmallCameraPhoto(Bitmap image);
    protected abstract void handleGalleryPhoto(Bitmap image);

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

        if (requestCode == TAKE_IMAGE_WITH_CAMERA && resultCode == RESULT_OK && null != data) {
            Bundle extras = data.getExtras();
            Bitmap bitmap = (Bitmap) extras.get("data");
            handleSmallCameraPhoto(bitmap);
        }
        else if (requestCode == PICK_IMAGE && resultCode == RESULT_OK && null != data) {
            Uri _uri = data.getData();
            Cursor cursor = getContentResolver().query(_uri, new String[] { android.provider.MediaStore.Images.ImageColumns.DATA }, null, null, null);
            cursor.moveToFirst();
            final String imageFilePath = cursor.getString(0);
            cursor.close();
            Bitmap bitmap = BitmapFactory.decodeFile(imageFilePath);
            handleGalleryPhoto(bitmap);
        }
    }

    @Override
    public void takePhoto() {
        Intent takePictureIntent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
        startActivityForResult(takePictureIntent, MediaSupportActivity.TAKE_IMAGE_WITH_CAMERA);
    }

    @Override
    public void pickPhoto() {
        Intent getImageFromGallery = new Intent(Intent.ACTION_PICK, android.provider.MediaStore.Images.Media.EXTERNAL_CONTENT_URI);
        getImageFromGallery.setType("image/*");
        startActivityForResult(getImageFromGallery, MediaSupportActivity.PICK_IMAGE);
    }
}

3) 有一个接口IBBMediaHelper 定义了两个方法：takePhoto() 和pickPhoto()。我们将IBBMediaHelper 实例传递给对话框，以便该对话框无法完全访问MediaSupportActivity 的其他属性和方法

public interface IMediaHelper {

    public void takePhoto();

    public void pickPhoto();
}

4) 下面是如何一起使用上述类的示例：

public class MainActivity extends MediaSupportActivity {

    Button iUserAvatarSettings;
    private boolean userHasProvidedOwnPhoto = false;

    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        iUserAvatarSettings = (Button) findViewById(R.id.button);
        iUserAvatarSettings.setOnClickListener(new OnClickListener() {
            @Override
            public void onClick(View v) {
                final PhotoPickerDialog dialog;
                if (!userHasProvidedOwnPhoto) {
                    dialog = new PhotoPickerDialog(MainActivity.this);
                }
                else {
                    dialog = new PhotoPickerDialogWithDelete(MainActivity.this);
                    ((PhotoPickerDialogWithDelete)dialog).setOnDeleteListener(onAvatarDelete);
                }
                dialog.setButtonFont(Typeface.MONOSPACE);
                dialog.setMediaHelper(MainActivity.this);
                dialog.show();
            }
        });
    }

    @Override
    protected void handleSmallCameraPhoto(Bitmap image) {
        // sample code
        ImageView imageView = (ImageView) findViewById(R.id.imageView);
        imageView.setImageBitmap(image);
    }

    @Override
    protected void handleGalleryPhoto(Bitmap image) {
        // sample code
        ImageView imageView = (ImageView) findViewById(R.id.imageView);
        imageView.setImageBitmap(image);
    }

    private OnClickListener onAvatarDelete = new OnClickListener() {
        @Override
        public void onClick(View v) {
            // this is executed when delete is clicked
            // check for male/female and update the avatar
            // etc. etc.
        }
    };
}

更新：您还可以创建包含ImageView 和PhotoPickerDialog 的头像小部件AvatarWidget 类。该类封装了显示头像、点击显示菜单以及点击删除时设置默认头像的逻辑。然后在主活动中，只需通过代码或 XML 声明您的头像小部件，并在收到图像时调用其上的设置器。