在MLKit快速入门上尝试“文字转语音”

Question

我正在尝试在Android上的此入门标签检测MLKit上进行文本语音转换，但是在连接标签上的tts时遇到问题。我认为我的方法无效。该计划是“标签图形”将创建一个来自ImageLabelingProcessor的文本，但是我在将“标签图形”连接到我的“主活动”时遇到问题。任何帮助将非常感谢。

标签活动

    class LabelActivity : AppCompatActivity(), OnRequestPermissionsResultCallback,
        CompoundButton.OnCheckedChangeListener, TextToSpeech.OnInitListener  {

    private var cameraSource: CameraSource? = null
    private var selectedModel = IMAGE_LABEL_DETECTION
    var labelGraph = LabelGraphic(null, null)

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_live_preview)


        labelGraph.tts = TextToSpeech(this, this)

        if (firePreview == null) {
            Log.d(TAG, "Preview is null")
        }

        if (fireFaceOverlay == null) {
            Log.d(TAG, "graphicOverlay is null")
        }

        if (allPermissionsGranted()) {
            createCameraSource(selectedModel)
        } else {
            getRuntimePermissions()
        }
    }

    private val requiredPermissions: Array<String?>
        get() {
            return try {
                val info = this.packageManager
                        .getPackageInfo(this.packageName, PackageManager.GET_PERMISSIONS)
                val ps = info.requestedPermissions
                if (ps != null && ps.isNotEmpty()) {
                    ps
                } else {
                    arrayOfNulls(0)
                }
            } catch (e: Exception) {
                arrayOfNulls(0)
            }
        }

    override fun onInit(status: Int) {

        if (status == TextToSpeech.SUCCESS) {
            // set US English as language for tts
            val result = labelGraph.tts!!.setLanguage(Locale.US)

            if (result == TextToSpeech.LANG_MISSING_DATA || result == TextToSpeech.LANG_NOT_SUPPORTED) {
                Log.e("TTS","The Language specified is not supported!")
            }

        } else {
            Log.e("TTS", "Initilization Failed!")
        }

    }

    override fun onCheckedChanged(buttonView: CompoundButton, isChecked: Boolean) {
        Log.d(TAG, "Set facing")

        cameraSource?.let {
            if (isChecked) {
                it.setFacing(CameraSource.CAMERA_FACING_FRONT)
            } else {
                it.setFacing(CameraSource.CAMERA_FACING_BACK)
            }
        }
        firePreview?.stop()
        startCameraSource()
    }

    private fun createCameraSource(model: String) {
        // If there's no existing cameraSource, create one.
        if (cameraSource == null) {
            cameraSource = CameraSource(this, fireFaceOverlay)
        }
        try {
            Log.i(TAG, "Using Image Label Detector Processor")
            cameraSource?.setMachineLearningFrameProcessor(ImageLabelingProcessor())
        } catch (e: FirebaseMLException) {
            Log.e(TAG, "can not create camera source: $model")
        }
    }

    /**
     * Starts or restarts the camera source, if it exists. If the camera source doesn't exist yet
     * (e.g., because onResume was called before the camera source was created), this will be called
     * again when the camera source is created.
     */
    private fun startCameraSource() {
        cameraSource?.let {
            try {
                if (firePreview == null) {
                    Log.d(TAG, "resume: Preview is null")
                }
                if (fireFaceOverlay == null) {
                    Log.d(TAG, "resume: graphOverlay is null")
                }
                firePreview?.start(cameraSource, fireFaceOverlay)
            } catch (e: IOException) {
                Log.e(TAG, "Unable to start camera source.", e)
                cameraSource?.release()
                cameraSource = null
            }
        }
    }

    public override fun onResume() {
        super.onResume()
        Log.d(TAG, "onResume")
        startCameraSource()
    }

    /** Stops the camera.  */
    override fun onPause() {
        super.onPause()
        firePreview?.stop()
    }

    public override fun onDestroy() {
        super.onDestroy()
        cameraSource?.release()

        // Shutdown TTS
        if (labelGraph.tts != null) {
            labelGraph.tts!!.stop()
            labelGraph.tts!!.shutdown()
        }

    }

    private fun allPermissionsGranted(): Boolean {
        for (permission in requiredPermissions) {
            if (!isPermissionGranted(this, permission!!)) {
                return false
            }
        }
        return true
    }

    private fun getRuntimePermissions() {
        val allNeededPermissions = arrayListOf<String>()
        for (permission in requiredPermissions) {
            if (!isPermissionGranted(this, permission!!)) {
                allNeededPermissions.add(permission)
            }
        }

        if (!allNeededPermissions.isEmpty()) {
            ActivityCompat.requestPermissions(
                    this, allNeededPermissions.toTypedArray(), PERMISSION_REQUESTS)
        }
    }

    override fun onRequestPermissionsResult(
        requestCode: Int,
        permissions: Array<String>,
        grantResults: IntArray
    ) {
        Log.i(TAG, "Permission granted!")
        if (allPermissionsGranted()) {
            createCameraSource(selectedModel)
        }
        super.onRequestPermissionsResult(requestCode, permissions, grantResults)
    }

    companion object {
        private const val IMAGE_LABEL_DETECTION = "Label Detection"
        private const val TAG = "LabelActivity"
        private const val PERMISSION_REQUESTS = 1

        private fun isPermissionGranted(context: Context, permission: String): Boolean {
            if (ContextCompat.checkSelfPermission(context, permission) == PackageManager.PERMISSION_GRANTED) {
                Log.i(TAG, "Permission granted: $permission")
                return true
            }
            Log.i(TAG, "Permission NOT granted: $permission")
            return false
        }
    }
}

标签图形

class LabelGraphic(
        private val overlay: GraphicOverlay?,
        private val labels: List<FirebaseVisionImageLabel>?
) : GraphicOverlay.Graphic(overlay) {

    var tts: TextToSpeech? = null

    private val textPaint = Paint().apply {
        color = Color.WHITE
        textSize = 60.0f
    }

    @Synchronized
    override fun draw(canvas: Canvas) {
        val x = overlay!!.width / 4.0f
        var y = overlay.height / 2.0f

        if (labels != null) {
            for (label in labels) {
                canvas.drawText(label.text, x, y, textPaint)
                y -= 62.0f
            }
        }
        val firstLabel = labels!!.first().text
        Log.d("LABEL GRAPHIC", firstLabel)
        tts!!.speak(firstLabel, TextToSpeech.QUEUE_FLUSH, null,"")
    }
}

现在，当我尝试运行此命令时，它会说LabelGraphic上的tts为空。