Android 开发问题：MlKitException: An internal error occurred during initialization.

public static void recognizeChineseTextInk(Ink ink, OcrCallback ocrCallback) {

    // 指定语言的识别模型
    DigitalInkRecognitionModelIdentifier modelIdentifier;
    try {
        modelIdentifier = DigitalInkRecognitionModelIdentifier.fromLanguageTag("zh-Hani-CN");
    } catch (MlKitException e) {
        ocrCallback.onError(e);
        return;
    }

    if (modelIdentifier == null) {
        ocrCallback.onError(new Exception("no model was found"));
        return;
    }

    DigitalInkRecognitionModel model = DigitalInkRecognitionModel.builder(modelIdentifier).build();

    // 获取 DigitalInkRecognizer 的实例
    DigitalInkRecognizer recognizer = DigitalInkRecognition.getClient(
            DigitalInkRecognizerOptions.builder(model).build()
    );

    // 处理 Ink 对象
    recognizer.recognize(ink)
            .addOnSuccessListener(recognitionResult -> {
                if (ocrCallback != null)
                    ocrCallback.onSuccess(recognitionResult.getCandidates().get(0).getText());
            })
            .addOnFailureListener(e -> {
                if (ocrCallback != null) ocrCallback.onError(e);
            });
}

• 在 Android 开发中，调用上述 ML Kit 数字墨水识别代码，出现如下错误信息

  com.google.mlkit.common.MlKitException: An internal error occurred during initialization.

  解读

  初始化过程中发生内部错误

问题原因

• 通常情况下是模型未下载，识别前需确保模型文件已成功下载，未下载模型会导致初始化失败

处理策略

• 检查模型状态，如果没有下载，则下载模型，然后在调用识别

public static void getModel(String languageTag, OcrGetModelCallback ocrGetModelCallback) {

    // 指定语言的识别模型
    DigitalInkRecognitionModelIdentifier modelIdentifier;
    try {
        modelIdentifier = DigitalInkRecognitionModelIdentifier.fromLanguageTag(languageTag);
    } catch (MlKitException e) {
        ocrGetModelCallback.onError(e);
        return;
    }

    if (modelIdentifier == null) {
        ocrGetModelCallback.onError(new Exception("no model was found"));
        return;
    }

    DigitalInkRecognitionModel model = DigitalInkRecognitionModel.builder(modelIdentifier).build();

    RemoteModelManager remoteModelManager = RemoteModelManager.getInstance();

    // 检查模型是否已下载
    remoteModelManager.isModelDownloaded(model)
            .addOnSuccessListener(aBoolean -> {
                Log.i(TAG, "modelDownloaded: " + aBoolean);
                if (aBoolean) {
                    if (ocrGetModelCallback != null) ocrGetModelCallback.onSuccess(model);
                } else {

                    // 下载模型
                    remoteModelManager.download(model, new DownloadConditions.Builder().build())
                            .addOnSuccessListener(aVoid -> {
                                Log.i(TAG, "model downloaded");
                                if (ocrGetModelCallback != null)
                                    ocrGetModelCallback.onSuccess(model);
                            })
                            .addOnFailureListener(e -> {
                                if (ocrGetModelCallback != null) ocrGetModelCallback.onError(e);
                            });
                }
            })
            .addOnFailureListener(e -> {
                if (ocrGetModelCallback != null) ocrGetModelCallback.onError(e);
            });
}

public static void recognizeChineseTextInk(Ink ink, OcrCallback ocrCallback) {

    getModel("zh-Hani-CN", new OcrGetModelCallback() {
        @Override
        public void onSuccess(DigitalInkRecognitionModel model) {

            // 获取 TextRecognizer 实例
            DigitalInkRecognizer recognizer = DigitalInkRecognition.getClient(
                    DigitalInkRecognizerOptions.builder(model).build()
            );

            // 处理 Ink 对象
            recognizer.recognize(ink)
                    .addOnSuccessListener(recognitionResult -> {
                        if (ocrCallback != null)
                            ocrCallback.onSuccess(recognitionResult.getCandidates().get(0).getText());
                    })
                    .addOnFailureListener(e -> {
                        if (ocrCallback != null) ocrCallback.onError(e);
                    });
        }

        @Override
        public void onError(Exception e) {
            if (ocrCallback != null) ocrCallback.onError(e);
        }
    });
}