allow printing PDFs if we know the path

app/src/main/kotlin/com/simplemobiletools/filemanager/pro/activities/PDFViewerActivity.kt

@@ -1,13 +1,23 @@
 package com.simplemobiletools.filemanager.pro.activities
 
+import android.content.Context
 import android.os.Bundle
+import android.print.PrintAttributes
+import android.print.PrintManager
+import android.view.Menu
+import android.view.MenuItem
 import com.simplemobiletools.commons.extensions.checkAppSideloading
+import com.simplemobiletools.commons.extensions.getFilenameFromPath
 import com.simplemobiletools.commons.extensions.getFilenameFromUri
 import com.simplemobiletools.commons.extensions.getProperBackgroundColor
+import com.simplemobiletools.commons.helpers.REAL_FILE_PATH
 import com.simplemobiletools.filemanager.pro.R
+import com.simplemobiletools.filemanager.pro.helpers.PdfDocumentAdapter
 import kotlinx.android.synthetic.main.activity_pdf_viewer.*
 
 class PDFViewerActivity : SimpleActivity() {
+    var realFilePath = ""
+
     override fun onCreate(savedInstanceState: Bundle?) {
         super.onCreate(savedInstanceState)
         setContentView(R.layout.activity_pdf_viewer)
@@ -16,9 +26,31 @@ class PDFViewerActivity : SimpleActivity() {
             return
         }
 
+        if (intent.extras?.containsKey(REAL_FILE_PATH) == true) {
+            realFilePath = intent.extras?.get(REAL_FILE_PATH)?.toString() ?: ""
+        }
+
         checkIntent()
     }
 
+    override fun onCreateOptionsMenu(menu: Menu): Boolean {
+        menuInflater.inflate(R.menu.menu_pdf_viewer, menu)
+        menu.apply {
+            findItem(R.id.menu_print).isVisible = realFilePath.isNotEmpty()
+        }
+
+        updateMenuItemColors(menu)
+        return true
+    }
+
+    override fun onOptionsItemSelected(item: MenuItem): Boolean {
+        when (item.itemId) {
+            R.id.menu_print -> printText()
+            else -> return super.onOptionsItemSelected(item)
+        }
+        return true
+    }
+
     private fun checkIntent() {
         val uri = intent.data
         if (uri == null) {
@@ -36,4 +68,12 @@ class PDFViewerActivity : SimpleActivity() {
             .spacing(15)
             .load()
     }
+
+    private fun printText() {
+        val adapter = PdfDocumentAdapter(this, realFilePath)
+
+        (getSystemService(Context.PRINT_SERVICE) as? PrintManager)?.apply {
+            print(realFilePath.getFilenameFromPath(), adapter, PrintAttributes.Builder().build())
+        }
+    }
 }

app/src/main/kotlin/com/simplemobiletools/filemanager/pro/helpers/PdfDocumentAdapter.kt

@@ -0,0 +1,63 @@
+package com.simplemobiletools.filemanager.pro.helpers
+
+import android.content.Context
+import android.os.Bundle
+import android.os.CancellationSignal
+import android.os.ParcelFileDescriptor
+import android.print.PageRange
+import android.print.PrintAttributes
+import android.print.PrintDocumentAdapter
+import android.print.PrintDocumentInfo
+import com.simplemobiletools.commons.extensions.getFilenameFromPath
+import java.io.*
+
+// taken from https://github.com/HarshitaBambure/AndroidPDFPrint/blob/master/app/src/main/java/com/example/androidpdfprint/PdfDocumentAdapter.java
+class PdfDocumentAdapter(var context: Context, var path: String) : PrintDocumentAdapter() {
+    override fun onLayout(
+        oldAttributes: PrintAttributes,
+        printAttributes: PrintAttributes,
+        cancellationSignal: CancellationSignal,
+        layoutResultCallback: LayoutResultCallback,
+        extras: Bundle
+    ) {
+        if (cancellationSignal.isCanceled) layoutResultCallback.onLayoutCancelled() else {
+            val builder = PrintDocumentInfo.Builder(path.getFilenameFromPath())
+            builder.setContentType(PrintDocumentInfo.CONTENT_TYPE_DOCUMENT)
+                .setPageCount(PrintDocumentInfo.PAGE_COUNT_UNKNOWN)
+                .build()
+            layoutResultCallback.onLayoutFinished(builder.build(), printAttributes != printAttributes)
+        }
+    }
+
+    override fun onWrite(
+        pages: Array<PageRange>,
+        parcelFileDescriptor: ParcelFileDescriptor,
+        cancellationSignal: CancellationSignal,
+        writeResultCallback: WriteResultCallback
+    ) {
+        var inputStream: InputStream? = null
+        var outputStream: OutputStream? = null
+        try {
+            val file = File(path)
+            inputStream = FileInputStream(file)
+            outputStream = FileOutputStream(parcelFileDescriptor.fileDescriptor)
+            val buff = ByteArray(16384)
+            var size: Int
+            while (inputStream.read(buff).also { size = it } >= 0 && !cancellationSignal.isCanceled) {
+                outputStream.write(buff, 0, size)
+            }
+
+            if (cancellationSignal.isCanceled) writeResultCallback.onWriteCancelled() else {
+                writeResultCallback.onWriteFinished(arrayOf(PageRange.ALL_PAGES))
+            }
+        } catch (e: Exception) {
+            writeResultCallback.onWriteFailed(e.message)
+        } finally {
+            try {
+                inputStream!!.close()
+                outputStream!!.close()
+            } catch (ex: IOException) {
+            }
+        }
+    }
+}

app/src/main/res/menu/menu_pdf_viewer.xml

@@ -0,0 +1,11 @@
+<?xml version="1.0" encoding="utf-8"?>
+<menu xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:app="http://schemas.android.com/apk/res-auto"
+    xmlns:tools="http://schemas.android.com/tools"
+    tools:ignore="AppCompatResource">
+    <item
+        android:id="@+id/menu_print"
+        android:showAsAction="never"
+        android:title="@string/print"
+        app:showAsAction="never" />
+</menu>