AndroidX本机相机

Question

我是android开发者的初学者，我试着使用CameraX。是否可以打开本机相机并拍照，而不是用预览和自定义按钮创建一个页面来拍照？我读过多篇文章/教程，但找不到解决方案。

谢谢你帮我

Answer 1

使用示例这里，经过一些调整-我可以在没有任何预览的情况下拍摄一张照片。

首先，我们使用ImageCapture用例启动相机：

private fun startCamera() {
    val cameraProviderFuture = ProcessCameraProvider.getInstance(this)

    cameraProviderFuture.addListener({
        // Used to bind the lifecycle of cameras to the lifecycle owner
        val cameraProvider: ProcessCameraProvider = cameraProviderFuture.get()

        imageCapture = ImageCapture.Builder()
            .build()
        // Select back camera as a default
        val cameraSelector = CameraSelector.DEFAULT_BACK_CAMERA
        try {
            // Unbind use cases before rebinding
            cameraProvider.unbindAll()

            // Bind use cases to camera
            cameraProvider.bindToLifecycle(
                this, cameraSelector, imageCapture)
        } catch(exc: Exception) {
            Log.e("Error", "Use case binding failed", exc)
        }

    }, ContextCompat.getMainExecutor(this))
}

然后，我们可以通过调用takePhoto方法来拍照：

private fun takePhoto() {
    // Get a stable reference of the modifiable image capture use case
    val imageCapture = imageCapture ?: return

    // Create time stamped name and MediaStore entry.
    val contentValues = ContentValues().apply {
        put(MediaStore.MediaColumns.DISPLAY_NAME, "sample_image")
        put(MediaStore.MediaColumns.MIME_TYPE, "image/jpeg")
        if(Build.VERSION.SDK_INT > Build.VERSION_CODES.P) {
            put(MediaStore.Images.Media.RELATIVE_PATH, "Pictures/CameraX-Image")
        }
    }

    // Create output options object which contains file + metadata
    val outputOptions = ImageCapture.OutputFileOptions
        .Builder(contentResolver,
            MediaStore.Images.Media.EXTERNAL_CONTENT_URI,
            contentValues)
        .build()

    // Set up image capture listener, which is triggered after photo has
    // been taken
    imageCapture.takePicture(
        outputOptions,
        ContextCompat.getMainExecutor(this),
        object : ImageCapture.OnImageSavedCallback {
            override fun onError(exc: ImageCaptureException) {
                Log.e("Error", "Photo capture failed: ${exc.message}", exc)
            }

            override fun
                    onImageSaved(output: ImageCapture.OutputFileResults){
                val msg = "Photo capture succeeded: ${output.savedUri}"
                Toast.makeText(baseContext, msg, Toast.LENGTH_SHORT).show()
                Log.d("Success", msg)
            }
        }
    )
}

我已经把一个工作项目上传到Github