拍照，图册选取，截图的心路历程

背景

考研过程中使用了Anki，不能不感叹这款神器的牛皮，尽管自己尚未开发出这款App的全部功能，但它已经将我的英语词汇和写作往前面推了一些。感叹和由衷地感激这款遍布全球的项目的伟大，我也想为这个项目做些什么。首先就是想完成考研中咒骂了无数次的坑，怎么不自带一个截图功能。后哦来！我总算懂的这个坑因何无人来填。TMD，适配太难受了。尤其是小米和华为这两个行业巨头（中指），系统定制化太过严重，为了提升用户体验，篡改了很多原生Intent设置，不得不写出很多冗余代码只为适配这些独特机型，呵呵，MMP， 在墙内，原生的无法使用必须定制化这可以理解，定制化的系统更加方便国内用户的使用，这毫无疑问，在全球怕是再没有那个国家像中国的Android这样友好的用户体验，一切以用户为核心，从利益出发。这也导致在国内碎片话严重的令人发指，以及各种千奇百怪的保活策略和有意思的白名单。哎呀，现在强盗收保护费都收的那么理直气壮吗？ 我记得一次在面试招XX银行时的时候我遇到这么一个问题，请问你怎么实现保活？emmmm，哈哈哈哈。

顺利完成裁剪任务

历时两天我完成了裁剪功能的添加。想想也还是有点小激动的，马上成为34个国家app的贡献者之一啦！代码如下：

public class BasicImageFieldController extends FieldControllerBase implements IFieldController {

    private static final int ACTIVITY_SELECT_IMAGE = 1;
    private static final int ACTIVITY_TAKE_PICTURE = 2;
    private static final int ACTIVITY_CROP_PICTURE = 3;
    private static final int IMAGE_SAVE_MAX_WIDTH = 1920;

    private ImageView mImagePreview;
 
    private int showCropButton = 0;

   
    @Override
    public void createUI(Context context, LinearLayout layout) {
        mImagePreview = new ImageView(mActivity);
        mLinearLayout = layout;
        DisplayMetrics metrics = getDisplayMetrics();

        int height = metrics.heightPixels;
        int width = metrics.widthPixels;

        LinearLayout.LayoutParams p = new LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT,
                android.view.ViewGroup.LayoutParams.WRAP_CONTENT);
        setPreviewImage(mField.getImagePath(), getMaxImageSize());
        mImagePreview.setScaleType(ImageView.ScaleType.CENTER_INSIDE);
        mImagePreview.setAdjustViewBounds(true);

        mImagePreview.setMaxHeight((int) Math.round(height * 0.4));
        mImagePreview.setMaxWidth((int) Math.round(width * 0.6));

        Button mBtnGallery = new Button(mActivity);
        mBtnGallery.setText(gtxt(R.string.multimedia_editor_image_field_editing_galery));
        mBtnGallery.setOnClickListener(v -> {
            Intent i = new Intent(Intent.ACTION_PICK, MediaStore.Images.Media.EXTERNAL_CONTENT_URI);
            mActivity.startActivityForResultWithoutAnimation(i, ACTIVITY_SELECT_IMAGE);
        });

        Button mBtnCamera = new Button(mActivity);
        mBtnCamera.setText(gtxt(R.string.multimedia_editor_image_field_editing_photo));
        mBtnCamera.setOnClickListener(v -> {
            Intent cameraIntent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
            File image;
            File storageDir;
            String timeStamp = new SimpleDateFormat("yyyyMMddHHmmss", Locale.US).format(new Date());
            try {
                storageDir = mActivity.getCacheDir();
                image = File.createTempFile("img_" + timeStamp, ".jpg", storageDir);
                mTempImagePath = image.getPath();
                Uri uriSavedImage = FileProvider.getUriForFile(mActivity,
                        mActivity.getApplicationContext().getPackageName() + ".apkgfileprovider",
                        image);

                cameraIntent.putExtra(MediaStore.EXTRA_OUTPUT, uriSavedImage);
                if (cameraIntent.resolveActivity(context.getPackageManager()) != null) {
                    mActivity.startActivityForResultWithoutAnimation(cameraIntent, ACTIVITY_TAKE_PICTURE);
                }
                else {
                    Timber.w("Device has a camera, but no app to handle ACTION_IMAGE_CAPTURE Intent");
                }
            } catch (IOException e) {
                e.printStackTrace();
            }
        });

        if (ContextCompat.checkSelfPermission(context, Manifest.permission.CAMERA) != PackageManager.PERMISSION_GRANTED) {
            mBtnCamera.setVisibility(View.INVISIBLE);
        }

        // Some hardware has no camera or reports yes but has zero (e.g., cheap devices, and Chromebook emulator)
        if ((!context.getPackageManager().hasSystemFeature(PackageManager.FEATURE_CAMERA) &&
                !context.getPackageManager().hasSystemFeature(PackageManager.FEATURE_CAMERA_FRONT)) ||
                (CompatHelper.getCompat().getCameraCount() < 1)) {
            mBtnCamera.setVisibility(View.INVISIBLE);
        }

        layout.addView(mImagePreview, ViewGroup.LayoutParams.MATCH_PARENT, p);
        layout.addView(mBtnGallery, ViewGroup.LayoutParams.MATCH_PARENT);
        layout.addView(mBtnCamera, ViewGroup.LayoutParams.MATCH_PARENT);
    }


    private String gtxt(int id) {
        return mActivity.getText(id).toString();
    }


    private DisplayMetrics getDisplayMetrics() {
        if (mMetrics == null) {
            mMetrics = new DisplayMetrics();
            mActivity.getWindowManager().getDefaultDisplay().getMetrics(mMetrics);
        }
        return mMetrics;
    }


    @Override
    public void onActivityResult(int requestCode, int resultCode, Intent data) {
        // ignore RESULT_CANCELED but handle image select and take
        if (resultCode == Activity.RESULT_CANCELED) {
            return;
        }
        if (requestCode == ACTIVITY_SELECT_IMAGE) {
            handleSelectImageResult(data);
        } else if (requestCode == ACTIVITY_TAKE_PICTURE) {
            handleTakePictureResult();
        }else if (requestCode == ACTIVITY_CROP_PICTURE) {
            handleCropResult(data);
        }

        showCropButton++;

        if (showCropButton == 1) {
            Button cropBtn = new Button(mActivity);
            cropBtn.setText(gtxt(R.string.crop_button));
            cropBtn.setOnClickListener(v -> {
                File file = new File(mTempImagePath);
                Uri uri = FileProvider.getUriForFile(mActivity, mActivity.getApplicationContext().getPackageName() + ".apkgfileprovider", file);
                photoCrop(uri);
            });
            mLinearLayout.addView(cropBtn);
        }
    }


    private String rotateAndCompress(String inPath) {
        // Set the rotation of the camera image and save as png
        File f = new File(inPath);
        // use same filename but with png extension for output file
        String outPath = inPath.substring(0, inPath.lastIndexOf(".")) + ".png";
        // Load into a bitmap with max size of 1920 pixels and rotate if necessary
        Bitmap b = BitmapUtil.decodeFile(f, IMAGE_SAVE_MAX_WIDTH);
        FileOutputStream out = null;
        try {
            out = new FileOutputStream(outPath);
            b = ExifUtil.rotateFromCamera(f, b);
            b.compress(Bitmap.CompressFormat.PNG, 90, out);
            f.delete();
            return outPath;
        } catch (FileNotFoundException e) {
            Timber.e(e, "Error in BasicImageFieldController.rotateAndCompress()");
            return inPath;
        } finally {
            try {
                if (out != null) {
                    out.close();
                }
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }


    private void setPreviewImage(String imagePath, int maxsize) {
        if (imagePath != null && !imagePath.equals("")) {
            File f = new File(imagePath);
            Bitmap b = BitmapUtil.decodeFile(f, maxsize);
            b = ExifUtil.rotateFromCamera(f, b);
            mImagePreview.setImageBitmap(b);
        }
    }


    @Override
    public void onDestroy() {
        ImageView imageView = mImagePreview;
        BitmapUtil.freeImageView(imageView);
        showCropButton = 0;
    }


    /**
     * Standard system crop intent
     * @param uri
     */

    public void photoCrop(Uri uri) {
        Intent intent = new Intent("com.android.camera.action.CROP");
        intent.setDataAndType(uri, "image/*");
        intent.putExtra("crop", "true");
        intent.addFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION);
        intent.putExtra("return-data", true);
        mActivity.startActivityForResultWithoutAnimation(intent, ACTIVITY_CROP_PICTURE);
    }

    private void showCropDialog(Uri uri) {
        new MaterialDialog.Builder(mActivity)
                .content(R.string.crop_image)
                .positiveText(R.string.dialog_ok)
                .negativeText(R.string.dialog_cancel)
                .onPositive((dialog, which) -> {
                    photoCrop(uri);
                })
                .build().show();
    }

    private void writeCropImage(Bitmap cropImage) {

        if (cropImage != null) {

            FileOutputStream out = null;
            File storageDir = mActivity.getCacheDir();

            String fileName = mTempImagePath.substring(mTempImagePath.lastIndexOf("/") + 1, mTempImagePath.lastIndexOf("."));

            if (!fileName.contains("crop")) {
                fileName += "_crop";
            }

            String outPath = storageDir.getAbsolutePath() + "/" + fileName + ".png";

            try {
                out = new FileOutputStream(outPath);
                cropImage.compress(Bitmap.CompressFormat.PNG, 90, out);
                mField.setImagePath(outPath);
                mField.setHasTemporaryMedia(true);
                mTempImagePath = outPath;
            } catch (FileNotFoundException e) {
                Timber.e(e, "Error in BasicImageFieldController.rotateAndCompress()");
            } finally {
                try {
                    if (out != null) {
                        out.close();
                    }
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
    }

    private void handleSelectImageResult(Intent data) {
        Uri selectedImage = data.getData();
        // Timber.d(selectedImage.toString());
        String[] filePathColumn = { MediaColumns.DATA };

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

        int columnIndex = cursor.getColumnIndex(filePathColumn[0]);
        String filePath = cursor.getString(columnIndex);
        cursor.close();

        mField.setImagePath(filePath);
        setPreviewImage(filePath, getMaxImageSize());
        mTempImagePath = filePath;
        showCropDialog(selectedImage);
    }

    private void handleTakePictureResult() {
        String imagePath = rotateAndCompress(mTempImagePath);
        mField.setImagePath(imagePath);
        mField.setHasTemporaryMedia(true);
        setPreviewImage(imagePath, getMaxImageSize());
        mTempImagePath = imagePath;
        File file = new File(imagePath);
        Uri uri = FileProvider.getUriForFile(mActivity, mActivity.getApplicationContext().getPackageName() + ".apkgfileprovider", file);
        showCropDialog(uri);
    }


    private void handleCropResult(Intent data) {
        Bundle bundle = data.getExtras();

        if (bundle != null) {
            Bitmap b = bundle.getParcelable("data");
            mImagePreview.setImageBitmap(b);
            writeCropImage(b);
        }
    }
}

FilePath文件

<?xml version="1.0" encoding="utf-8"?>
<paths>
    <external-cache-path path="export/" name="export-directory" />
    <cache-path path="/" name="cache-directory" />
    <external-path path="." name="photos" />
</paths>

然而适配的并不顺利，小米和华为直接闪退，网上查了下，小米和华为不支持裁剪直接返回Bitmap，想想也是哈，毕竟Binder支持1MB的大小交互，而且闪退时的Error也有出现Binder的影子。想办法解决，那没返回值，像拍照一样直接传入写入的uri让系统裁剪程序向该Uri进行写入，再进行读取岂不妙哉。

失望

我又一次失败了，TMD，咋一直报安全异常呢

Writing exception to parcel
    java.lang.SecurityException: Permission Denial: writing androidx.core.content.FileProvider uri content://com.ichi2.anki.apkgfileprovider/cache-directory/img_201904190726581247673844.jpg from pid=3207, uid=10008 requires the provider be exported, or grantUriPermission()
        at android.content.ContentProvider.enforceWritePermissionInner(ContentProvider.java:682)
        at android.content.ContentProvider$Transport.enforceWritePermission(ContentProvider.java:497)
        at android.content.ContentProvider$Transport.enforceFilePermission(ContentProvider.java:469)
        at android.content.ContentProvider$Transport.openAssetFile(ContentProvider.java:384)
        at android.content.ContentProviderNative.onTransact(ContentProviderNative.java:262)
        at android.os.Binder.execTransact(Binder.java:565)

代码我写的不错啊！有条有理，章法清晰的复制粘贴。

public class BasicImageFieldController extends FieldControllerBase implements IFieldController {

...
    @Override
    public void onActivityResult(int requestCode, int resultCode, Intent data) {
        // ignore RESULT_CANCELED but handle image select and take
        if (resultCode == Activity.RESULT_CANCELED) {
            return;
        }
        if (requestCode == ACTIVITY_SELECT_IMAGE) {
            handleSelectImageResult(data);
        } else if (requestCode == ACTIVITY_TAKE_PICTURE) {
            handleTakePictureResult();
        }else if (requestCode == ACTIVITY_CROP_PICTURE) {
            File cropFile=new File(mTempImagePath);
            Uri cropUri = FileProvider.getUriForFile(mActivity,
                    mActivity.getApplicationContext().getPackageName() + ".apkgfileprovider",
                    cropFile);
            handleCropResult(cropUri);
        }

        showCropButton++;

        if (showCropButton == 1) {
            Button cropBtn = new Button(mActivity);
            cropBtn.setText(gtxt(R.string.crop_button));
            cropBtn.setOnClickListener(v -> {
                File file = new File(mTempImagePath);
                Uri uri = FileProvider.getUriForFile(mActivity, mActivity.getApplicationContext().getPackageName() + ".apkgfileprovider", file);
                photoCrop(uri);
            });
            mLinearLayout.addView(cropBtn);
        }
    }



    public void photoCrop(Uri uri) {
        File image;
        File storageDir;
        String timeStamp = new SimpleDateFormat("yyyyMMddHHmmss", Locale.US).format(new Date());
        storageDir = mActivity.getCacheDir();
        try {
            image = File.createTempFile("img_" + timeStamp, ".jpg", storageDir);
            mTempImagePath = image.getPath();
            Uri cropUri = Uri.fromFile(image);
            mField.setImagePath(mTempImagePath);
            mField.setHasTemporaryMedia(true);

            Intent intent = new Intent("com.android.camera.action.CROP");
            if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.N) {
                //添加这一句表示对目标应用临时授权该Uri所代表的文件
                intent.setFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION | Intent.FLAG_GRANT_WRITE_URI_PERMISSION);
            }
            intent.setDataAndType(uri, "image/*");
            intent.putExtra("aspectX", 1); // 裁剪框比例
            intent.putExtra("aspectY", 1);
            intent.putExtra("outputX", 300); // 输出图片大小
            intent.putExtra("outputY", 300);
            intent.putExtra("scale", true);
            intent.putExtra("return-data", false);


            intent.putExtra(MediaStore.EXTRA_OUTPUT, cropUri);
            intent.putExtra("outputFormat", Bitmap.CompressFormat.JPEG.toString());
            intent.putExtra("noFaceDetection", true); // no face detection
            mActivity.startActivityForResultWithoutAnimation(intent, ACTIVITY_CROP_PICTURE);

        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    private void showCropDialog(Uri uri) {
        new MaterialDialog.Builder(mActivity)
                .content(R.string.crop_image)
                .positiveText(R.string.dialog_ok)
                .negativeText(R.string.dialog_cancel)
                .onPositive((dialog, which) -> {
                    photoCrop(uri);
                })
                .build().show();
    }

    private void writeCropImage(Bitmap cropImage) {

        if (cropImage != null) {

            FileOutputStream out = null;
            File storageDir = mActivity.getCacheDir();

            String fileName = mTempImagePath.substring(mTempImagePath.lastIndexOf("/") + 1, mTempImagePath.lastIndexOf("."));

            if (!fileName.contains("crop")) {
                fileName += "_crop";
            }

            String outPath = storageDir.getAbsolutePath() + "/" + fileName + ".png";

            try {
                out = new FileOutputStream(outPath);
                cropImage.compress(Bitmap.CompressFormat.PNG, 90, out);
                mField.setImagePath(outPath);
                mField.setHasTemporaryMedia(true);
                mTempImagePath = outPath;
            } catch (FileNotFoundException e) {
                Timber.e(e, "Error in BasicImageFieldController.rotateAndCompress()");
            } finally {
                try {
                    if (out != null) {
                        out.close();
                    }
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
    }

    private void handleSelectImageResult(Intent data) {
        Uri selectedImage = getImageUri(mActivity, data);
        setPreviewImage(mTempImagePath, getMaxImageSize());
        showCropDialog(selectedImage);
    }

    private void handleTakePictureResult() {
        String imagePath = rotateAndCompress(mTempImagePath);
        mField.setImagePath(imagePath);
        mField.setHasTemporaryMedia(true);
        setPreviewImage(imagePath, getMaxImageSize());
        mTempImagePath = imagePath;
        File file = new File(imagePath);
        Uri uri = FileProvider.getUriForFile(mActivity, mActivity.getApplicationContext().getPackageName() + ".apkgfileprovider", file);
        showCropDialog(uri);
    }


    private void handleCropResult(Uri uri) {
        if (uri != null) {
            Bitmap photo = null;
            try {
                photo = BitmapFactory.decodeStream(mActivity.getContentResolver().openInputStream(uri));
                //mImagePreview.setImageBitmap(photo);
                writeCropImage(photo);
                setPreviewImage(mTempImagePath, getMaxImageSize());
            } catch (FileNotFoundException e) {
                e.printStackTrace();
            }
            Timber.i("");
        }
    }

    private Uri getImageUri(Context context,Intent data){
        String imagePath = null;
        Uri uri = data.getData();
        if(Build.VERSION.SDK_INT >= 19){
            if(DocumentsContract.isDocumentUri(context,uri)){
                String docId = DocumentsContract.getDocumentId(uri);
                if("com.android.providers.media.documents".equals(uri.getAuthority())){
                    String id = docId.split(":")[1];
                    String selection = MediaStore.Images.Media._ID+"="+id;
                    imagePath = getImagePath(context,MediaStore.Images.Media.EXTERNAL_CONTENT_URI,selection);
                }else if("com.android.providers.downloads.documents".equals(uri.getAuthority())){
                    Uri contentUri = ContentUris.withAppendedId(Uri.parse("content://downloads/public_downloads"),Long.valueOf(docId));
                    imagePath = getImagePath(context,contentUri,null);
                }
            }else if("content".equalsIgnoreCase(uri.getScheme())){
                imagePath = getImagePath(context,uri,null);
            }else if("file".equalsIgnoreCase(uri.getScheme())){
                imagePath = uri.getPath();
            }
        }else{
            uri= data.getData();
            imagePath = getImagePath(context,uri,null);
        }
        File file = new File(imagePath);
        mTempImagePath = imagePath;
        mField.setImagePath(imagePath);
        mField.setHasTemporaryMedia(false);
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.N) {
            uri = FileProvider.getUriForFile(context,
                    mActivity.getApplicationContext().getPackageName() + ".apkgfileprovider",
                    file);
        } else {
            uri = Uri.fromFile(file);
        }

        return uri;
    }

    private String getImagePath(Context context,Uri uri, String selection) {
        String path = null;
        Cursor cursor = context.getContentResolver().query(uri,null,selection,null,null);
        if(cursor != null){
            if(cursor.moveToFirst()){
                path = cursor.getString(cursor.getColumnIndex(MediaStore.Images.Media.DATA));
            }
            cursor.close();
        }
        return path;
    }
}

对比了下参考代码，唯一的区别的就是我是选择当前的app的缓存目录作为输出uri，而参考代码则是选择sdcard的外存目录的指定文件夹作为目录，于是我死马当作活马医狠下心选择外存作为写入uri. 还别说，真香

扒开云雾见月明

为什么同样是将缓存目录作为写入uri,而照相机可以成功写入，而裁剪功能却不行，会报安全异常，权限非法。分析异常可以看出是FileProvider没有授权，然而哈，我已经在FilePath进行了注册，而且拍照功能是可以正常运行的。至今仍是懵逼中。为毛同样的输出Uri，拍照Intent可以写入，而Crop Intent却不行。神奇诶。而且这个并非是定制化的锅，我在官方模拟器测过同样会报这个error，由此可见是系统rom的Crop Intent处理与Take Photo Intent不同。算是一个遗留下的坑以后看系统源码来填。