hyuwah/Android-PDF-Example-App

Android PDF Example

Sandbox project on how to display PDF File (from url) and share pdf file with Android Sharesheet

Method 1 (PdfViewPager)

This library will auto download remote pdf, and display on custom viewpager

Library Used

I'm using PdfViewPager by voghDev

Code Walkthrough

Setup Library

Add implementation 'es.voghdev.pdfviewpager:library:1.1.0' on app/build.gradle

Add permission needed by the library

<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />

Setup View

If pdf source is from url, we need to use RemotePDFViewPager and we're gonna need to add it to our layout programmatically

In this example we use LinearLayout as the container

 <LinearLayout
        android:id="@+id/linear_layout_pdf"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="vertical"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintBottom_toTopOf="@id/bottom_bar"/>

Setup Code

On activity (or fragment), we need 4 main component

1. A valid PDF url
2. A PDFPagerAdapter
3. A RemotePDFViewPager
4. The listener for RemotePDFViewPager's DownloadFile

// MainActivity.kt that implement DownloadFile.Listener

private var url = "https://www.btpn.com/pdf/investor/annual-report/in/btpnar2017_ind_r.pdf"
private var adapter : PDFPagerAdapter? = null
private lateinit var remotePDFViewPager: RemotePDFViewPager

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

    remotePDFViewPager = RemotePDFViewPager(this, url, this) // <- This will start the download
}

override fun onDestroy() {
    super.onDestroy()
    adapter?.close() // Don't forget to cleanup the adapter
}

override fun onSuccess(url: String?, destinationPath: String?) {
    adapter = PDFPAgerAdapter(this, FileUtil.extractFileNameFromURL(url)) // Setup adapter with the file
    remotePDFViewPager.adapter = adapter // Attach adapter to remote pdf viewpager

    // Add it to the container
    linear_layout_pdf.removeAllViews()
    linear_layou_pdf.addView(
        remotePDFViewPager,
        LinearLayout.LayoutParams.MATCH_PARENT,
        LinearLayout.LayoutParams.MATCH_PARENT
    )
}

override fun onFailure(e: Exception?) {
    // Handle pdf download failure
}

override fun onProgressUpdate(progress: Int, total: Int) {
    // Update pdf download progress
}

Sharing PDF

To be able to share pdf (or file), we need to use / setup FileProvider on the app

Create provider_paths.xml on res/xml

<!-- Provider Path (provider_paths.xml) --> 
<?xml version="1.0" encoding="utf-8"?>
<paths xmlns:android="http://schemas.android.com/apk/res/android">
    <external-path
        name="external-files"
        path="."/>
        <!-- Need to add line below, because lib downloads the pdf into cache -->
    <cache-path
        name="cache-files"
        path="."/>
</paths>

Add provider tag on AndroidManifest

<!-- AndroidManifest.xml -->
<manifest>
    <application>

        ...

        <provider
            android:name="androidx.core.content.FileProvider"
            android:authorities="${applicationId}.provider"
            android:exported="false"
            android:grantUriPermissions="true">
            <meta-data
                android:name="android.support.FILE_PROVIDER_PATHS"
                android:resource="@xml/provider_paths"/>
        </provider>

        ...

    </application>
</manifest>

And here's the code to share the file using Android Sharesheet. By default, the PdfViewPager library downloads the file into app's cache directory.

val file = File(cacheDir, FileUtil.extractFileNameFromURL(url))
if (file.exists()) {
    // Generate file Uri
    val fileUri = FileProvider.getUriForFile(
            this,
            this.applicationContext.packageName + ".provider",
            file
    )
    // Create Share Intent with the file uri
    val shareIntent = Intent().apply {
        action = Intent.ACTION_SEND
        putExtra(Intent.EXTRA_STREAM, fileUri)
        type = "application/pdf"
        addFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION)
    }
    startActivity(Intent.createChooser(shareIntent, "Kirim PDF ke..."))
}

Preview

Method 2 (PdfView)

This library doesn't handle downloading remote pdf, it only shows pdf file We have to implement our own file download logic

Library Used

I'm using PdfView-android by Dmitry-Borodin

Code Walkthrough

TODO