احصل على وتبديل ترجمات WebVTT في ExoPlayer

fun getVttSubtitles(): List<String> {
        val tracks = mutableListOf<String>()
        //  MappedTrackInfo
        defaultTrackSelector.currentMappedTrackInfo?.let { mappedTrackInfo ->
            val renderCount = mappedTrackInfo.rendererCount
            for (renderIndex in 0 until renderCount) {
                //    renderer'    TEXT
                val renderType = mappedTrackInfo.getRendererType(renderIndex)
                if (renderType == C.TRACK_TYPE_TEXT) {
                    val trackGroupArray = mappedTrackInfo.getTrackGroups(renderIndex)
                    //    
                    for (trackGroupArrayIndex in 0 until trackGroupArray.length) {
                        val trackGroup = trackGroupArray[trackGroupArrayIndex]
                        for (trackGroupIndex in 0 until trackGroup.length) {
                            //       TEXT_VTT
                            val format = trackGroup.getFormat(trackGroupIndex)
                            if (format.sampleMimeType == MimeTypes.TEXT_VTT) {
                                tracks += format.language.orEmpty()
                            }
                        }
                    }
                }
            }
        }

        return tracks
    }

fun getSelectedVttSubtitles(): List<String> {
        val selectedLangs = mutableListOf<String>()
        val currentTrackSelections = exoPlayer.currentTrackSelections
        for (selectionIndex in 0 until currentTrackSelections.length) {
            val trackSelection = currentTrackSelections[selectionIndex]
            if (trackSelection != null) {
                //     
                val length = trackSelection.length()
                for (trackIndex in 0 until length) {
                    //      
                    val format = trackSelection.getFormat(trackIndex)
                    if (format.sampleMimeType == MimeTypes.TEXT_VTT) {
                        selectedLangs += format.language.orEmpty()
                    }
                }
            }
        }

        return selectedLangs
    }

fun selectTrackByIsoCodeAndType(langCode: String) {
        defaultTrackSelector.currentMappedTrackInfo?.let { mappedTrackInfo ->
            //         
            val renderCount = mappedTrackInfo.rendererCount
            for (renderIndex in 0 until renderCount) {
                //    renderer'    TEXT
                val renderType = mappedTrackInfo.getRendererType(renderIndex)
                if (renderType == C.TRACK_TYPE_TEXT) {
                    val trackGroupArray = mappedTrackInfo.getTrackGroups(renderIndex)
                    //    
                    for (trackGroupArrayIndex in 0 until trackGroupArray.length) {
                        val trackGroup = trackGroupArray[trackGroupArrayIndex]
                        for (trackGroupIndex in 0 until trackGroup.length) {
                            val format = trackGroup.getFormat(trackGroupIndex)
                            //       
                            if (format.sampleMimeType == MimeTypes.TEXT_VTT
                                && format.language == langCode
                            ) {
                                //    
                                val currentParams = defaultTrackSelector.buildUponParameters()
                                //   ( )
                                //  
                                currentParams.clearSelectionOverride(
                                    renderIndex, trackGroupArray
                                )

                                // ,    
                                //       

                                //       
                                val override = DefaultTrackSelector.SelectionOverride(
                                    trackGroupArrayIndex, trackGroupIndex
                                )

                                //     
                                currentParams.setSelectionOverride(
                                    renderIndex,
                                    trackGroupArray,
                                    override
                                )

                                //     
                                defaultTrackSelector.setParameters(currentParams)

                                return
                            }
                        }
                    }
                }
            }
        }
    }

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