NeelPowerPdfViewerLib

This is a Kotlin library for downloading and displaying PDFs in a WebView

This is just a simple pdf library you can directly display the pdf or downlad and then display a pdf

pdf size should be within 50mb

For the large pdf you can compress the pdf and show it or your pdf can be in the range between 40-50mb

Application size will be increase with 3-4 mb

step by step guide to add the library

Step 1: Add it in your settings.gradle.kts at the end of repositories:

dependencyResolutionManagement {
	repositoriesMode.set(RepositoriesMode.FAIL_ON_PROJECT_REPOS)
	repositories {
		mavenCentral()
		maven { url = uri("https://jitpack.io") }
	}
}

if you use gradle then Add it in your root settings.gradle at the end of repositories:

dependencyResolutionManagement {
	repositoriesMode.set(RepositoriesMode.FAIL_ON_PROJECT_REPOS)
	repositories {
		mavenCentral()
		maven { url 'https://jitpack.io' }
	}
}

Step 2: Add the dependency

dependencies {
        implementation("com.github.sandip4337:NeelPowerPdfViewerLib:v1.0.9")
}

Step 3: Add this in your application class

 override fun onCreate() {
     ....
     // Schedule periodic file cleanup
     FileCleanupWorker.scheduleFileDeletion(this)
     ....
}

If you want access the pdf file as file

PowerPdfLibChecker.getFilesDirPathAsFile(context, pdf.pdfName, pdf.pdfId)

If you want access the pdf file as string

PowerPdfLibChecker.getFilesDirPathAsString(context, pdf.pdfName, pdf.pdfId)

If you want to delete the file

PowerPdfLibChecker.deletePdfFile(context, pdf.pdfName, pdf.pdfId)

If you want the file is exists or not

PowerPdfLibChecker.checkPdfExits(context, pdf.pdfName, pdf.pdfId)

How to use : only open the pdf

 class MainActivity : AppCompatActivity() {

    private lateinit var pdfButton: Button

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

        pdfButton = findViewById(R.id.openPdfButton)

        pdfButton.setOnClickListener {
            val pdfUrl = "https://www.w3.org/WAI/ER/tests/xhtml/testfiles/resources/pdf/dummy.pdf"
            val pdfName = "dummy"
     
     	    // Pass the context, pdfurl, pdfname, pdfid, pdf_base_url should be must
            PdfViewerActivity.openPdfViewer(this, pdfUrl, pdfName, "123", https://www.w3.org/)
        }
    }
}

How to use : download the pdf

1: Initialize WorkManager for PDF Download

Use WorkManager to enqueue the PDF download task.

val workRequest = OneTimeWorkRequestBuilder<PdfDownloadWorker>()
    .setInputData(
        workDataOf(
            "PDF_URL" to "https://example.com/sample.pdf",
            "PDF_NAME" to "SamplePDF",
            "PDF_ID" to "1234"
     	    "BASE_URL" to "https://example.com/"
        )
    )
    .build()

WorkManager.getInstance(context).enqueue(workRequest)

2: Observe Download Progress

Monitor progress using WorkManager's getWorkInfoByIdLiveData():

WorkManager.getInstance(context)
    .getWorkInfoByIdLiveData(workRequest.id)
    .observe(this) { workInfo ->
        if (workInfo != null) {
            val progress = workInfo.progress.getInt("PROGRESS", 0)
            Log.d("DownloadProgress", "Progress: $progress%")

            if (workInfo.state == WorkInfo.State.SUCCEEDED) {
                val htmlFilePath = workInfo.outputData.getString("HTML_FILE_PATH")
                Log.d("DownloadComplete", "HTML File Path: $htmlFilePath")
            }
        }
    }

3: Load HTML in WebView

Once the HTML file is ready, display it in a WebView:

PdfViewerActivity.openPdfViewer(context, pdfUrl, pdfName, pdfId)

🔥 Features

1. PDF Download & Processing

   The PdfDownloader class is responsible for:

   ✅ Downloading PDFs using Retrofit with efficient background execution via Coroutines.

   ✅ Displaying real-time download progress through a callback function.

   ✅ Checking for existing processed files before re-downloading to improve efficiency.

   ✅ Encoding the downloaded PDF to Base64 to enable embedding in an HTML file.

   ✅ Generating an HTML file that loads the Base64-encoded PDF using JavaScript-based rendering.

   ✅ Automatic cleanup – Once processed, the original PDF and temporary files are deleted.

2. PDF Viewing in WebView

   The PdfViewerActivity ensures a seamless user experience by:

   ✅ Loading the HTML file into a WebView to display the PDF.

   ✅ Ensuring safe file access with restricted external visibility.

   ✅ Providing smooth navigation and error handling within the WebView.

   ✅ Showing a progress dialog while the file is being downloaded and processed.

   ✅ Allowing users to open the viewer with a single function call.

Why is This Implementation Beneficial?

🚀 Fast & Efficient – Uses Coroutines for background tasks, reducing UI thread workload.

🔄 Offline Access – Once processed, PDFs can be viewed anytime without re-downloading.

🔐 Secure – Prevents unauthorized access by restricting file permissions.

📜 Lightweight Alternative to PDF Viewers – No need for third-party PDF libraries.

📡 Handles Large PDFs Effectively – Base64 conversion prevents memory overflow.

📊 Download Progress Updates – Users can track file download progress.

Here is the video of NeelPowerPdfLibrary : only open the pdf

Power_Pdf_Library.mp4

Here is the repository of a project with the impementation of the library

Repo Link -> https://github.com/sandip4337/TestPDFLibrary

Here is the video of NeelPowerPdfLibrary : download the pdf and open the pdf

Here the pdfs are same because same link with different pdf name , I am saving my pdf to fileDir with different pdf name and id - it is only for demo

pdf_download_and_open_with_new_ui.mp4

📝 License

This library is licensed under the MIT License.