From 422c014ee74277e45a502468e031c150a52d09fb Mon Sep 17 00:00:00 2001
From: Ahmer Afzal <ahmerafzal@yahoo.com>
Date: Mon, 14 Feb 2022 15:51:31 +0500
Subject: [PATCH] Fix a potential NPE Crash due to Mismatched Thread Lifecycle

Fix a potential NPE due to out of sync render thread management [Pull Request](https://github.com/barteksc/AndroidPdfViewer/pull/824)
Update the sample app configuration so that it can compile [Pull Request](https://github.com/mhiew/AndroidPdfViewer/pull/2)
---
 PdfViewer/src/main/java/com/ahmer/pdfviewer/PDFView.kt | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/PdfViewer/src/main/java/com/ahmer/pdfviewer/PDFView.kt b/PdfViewer/src/main/java/com/ahmer/pdfviewer/PDFView.kt
index 06467b0..33a034d 100644
--- a/PdfViewer/src/main/java/com/ahmer/pdfviewer/PDFView.kt
+++ b/PdfViewer/src/main/java/com/ahmer/pdfviewer/PDFView.kt
@@ -519,6 +519,7 @@ class PDFView(context: Context?, set: AttributeSet?) : RelativeLayout(context, s
     fun loadComplete(pdfFile: PdfFile) {
         mState = State.LOADED
         this.pdfFile = pdfFile
+        if (mRenderingHandlerThread == null) return
         if (mRenderingHandlerThread?.isAlive != true) mRenderingHandlerThread?.start()
         renderingHandler = mRenderingHandlerThread?.looper?.let {
             RenderingHandler(it, this)
@@ -973,6 +974,11 @@ class PDFView(context: Context?, set: AttributeSet?) : RelativeLayout(context, s
         mAnimationManager?.computeFling()
     }
 
+    override fun onAttachedToWindow() {
+        super.onAttachedToWindow()
+        if (mRenderingHandlerThread == null) mRenderingHandlerThread = HandlerThread("PDF renderer")
+    }
+
     override fun onDetachedFromWindow() {
         recycle()
         if (mRenderingHandlerThread != null) {
@@ -1325,7 +1331,6 @@ class PDFView(context: Context?, set: AttributeSet?) : RelativeLayout(context, s
     }
 
     private fun initPDFView() {
-        mRenderingHandlerThread = HandlerThread("PDF renderer")
         if (isInEditMode) return
         mPdfiumCore = PdfiumCore(context)
         cacheManager = CacheManager()