Firebase MLKit文本识别错误

我正在尝试使用Firebase MLKit OCR我的图像，但它失败并返回错误

文本检测失败并显示错误：无法运行文本检测器，因为self为零。

/// Detects texts on the specified image and draws a frame for them. func detectTexts() { let image = #imageLiteral(resourceName: "testocr") // Create a text detector. let textDetector = vision.textDetector() // Check console for errors. // Initialize a VisionImage with a UIImage. let visionImage = VisionImage(image: image) textDetector.detect(in: visionImage) { (features, error) in guard error == nil, let features = features, !features.isEmpty else { let errorString = error?.localizedDescription ?? "No results returned." print("Text detection failed with error: \(errorString)") return } // Recognized and extracted text print("Detected text has: \(features.count) blocks") let resultText = features.map { feature in return "Text: \(feature.text)" }.joined(separator: "\n") print(resultText) } } 

Answer 1

看起来您需要对textDetector保持强引用，否则在调用完成块之前检测器会被释放。

稍微改变你的代码：

 var textDetector: VisionTextDetector? // NEW /// Detects texts on the specified image and draws a frame for them. func detectTexts() { // ... truncated ... textDetector = vision.textDetector() // NEW let visionImage = VisionImage(image: image) textDetector?.detect(in: visionImage) { (features, error) in // NEW // Callback implementation } } 

您也可以打开它以确保它在分配后不是零：

 guard let textDetector = textDetector else { print("Error: textDetector is nil.") return } 

我希望有所帮助！