fix: crash with zero page count while loading failed

Author: GitHubZJY

pdfview/src/main/java/com/zjy/pdfview/PdfView.java

@@ -1,5 +1,10 @@
 package com.zjy.pdfview;
 
+import static android.view.ViewGroup.LayoutParams.MATCH_PARENT;
+import static android.view.ViewGroup.LayoutParams.WRAP_CONTENT;
+import static com.zjy.pdfview.constants.Constants.DOWNLOAD_ACTION;
+import static com.zjy.pdfview.download.DownloadService.DOWNLOAD_URL_KEY;
+
 import android.content.Context;
 import android.content.Intent;
 import android.content.IntentFilter;
@@ -12,15 +17,12 @@
 import android.text.TextUtils;
 import android.util.AttributeSet;
 import android.view.LayoutInflater;
-import android.view.View;
 import android.view.ViewGroup;
 import android.widget.FrameLayout;
 
 import androidx.annotation.NonNull;
 import androidx.annotation.Nullable;
 import androidx.annotation.RequiresApi;
-import androidx.constraintlayout.widget.ConstraintLayout;
-import androidx.constraintlayout.widget.ConstraintSet;
 import androidx.recyclerview.widget.RecyclerView;
 
 import com.zjy.pdfview.adapter.PdfPageAdapter;
@@ -41,11 +43,6 @@
 import java.util.ArrayList;
 import java.util.List;
 
-import static android.view.ViewGroup.LayoutParams.MATCH_PARENT;
-import static android.view.ViewGroup.LayoutParams.WRAP_CONTENT;
-import static com.zjy.pdfview.constants.Constants.DOWNLOAD_ACTION;
-import static com.zjy.pdfview.download.DownloadService.DOWNLOAD_URL_KEY;
-
 /**
  * Date: 2021/1/27
  * Author: Yang
@@ -144,12 +141,9 @@ public void onPageSelected(int position, boolean isBottom) {
         });
         contentRv.setLayoutManager(pageLayoutManager);
 
-        loadingLayout.setLoadLayoutListener(new PdfLoadingLayout.LoadLayoutListener() {
-            @Override
-            public void clickRetry() {
-                if (!TextUtils.isEmpty(pdfUrl)) {
-                    loadPdf(pdfUrl);
-                }
+        loadingLayout.setLoadLayoutListener(() -> {
+            if (!TextUtils.isEmpty(pdfUrl)) {
+                loadPdf(pdfUrl);
             }
         });
 
@@ -159,19 +153,17 @@ public void clickRetry() {
 
         getOperateView().addOperateListener(this);
 
-        scrollSlider.setScrollSlideListener(new ScrollSlider.ScrollSlideListener() {
-            @Override
-            public boolean scrolling(int scrollY) {
-                int pageItemHeight = contentRv.getHeight() / pageCount;
-                int scrollIndex = (int) scrollY / pageItemHeight;
-                if(scrollIndex >= 0 && scrollIndex < pageLayoutManager.getItemCount()) {
-                    scrollSlider.setTranslationY(scrollY - scrollY % pageItemHeight);
-                    currentIndex = scrollIndex;
-                    pageLayoutManager.scrollToPosition(currentIndex);
-                    getOperateView().setPageIndexText(generatePageIndexText());
-                }
-                return true;
+        scrollSlider.setScrollSlideListener(scrollY -> {
+            if (pageCount == 0) return true;
+            int pageItemHeight = contentRv.getHeight() / pageCount;
+            int scrollIndex = scrollY / pageItemHeight;
+            if(scrollIndex >= 0 && scrollIndex < pageLayoutManager.getItemCount()) {
+                scrollSlider.setTranslationY(scrollY - scrollY % pageItemHeight);
+                currentIndex = scrollIndex;
+                pageLayoutManager.scrollToPosition(currentIndex);
+                getOperateView().setPageIndexText(generatePageIndexText());
             }
+            return true;
         });
     }
 
@@ -342,6 +334,8 @@ protected Boolean doInBackground(Void... voids) {
         @Override
         protected void onPostExecute(Boolean result) {
             super.onPostExecute(result);
+            scrollSlider.setVisibility(pageCount == 0 ? GONE : VISIBLE);
+
             if (result) {
                 getOperateView().setPageIndexText(generatePageIndexText());
                 pageAdapter.notifyDataSetChanged();

pdfview/src/main/java/com/zjy/pdfview/adapter/PdfPageAdapter.java

@@ -26,8 +26,8 @@
 @RequiresApi(api = Build.VERSION_CODES.LOLLIPOP)
 public class PdfPageAdapter extends RecyclerView.Adapter<PdfPageAdapter.ViewHolder> {
 
-    private Context context;
-    private List<Bitmap> pageList;
+    final private Context context;
+    final private List<Bitmap> pageList;
 
     public PdfPageAdapter(Context context, List<Bitmap> pageList) {
         this.context = context;

pdfview/src/main/java/com/zjy/pdfview/utils/FileUtils.java

@@ -18,16 +18,19 @@ public static File writeAssetsToFile(Context context, String assetPath) throws I
         String fileName = assetPath.substring(assetPath.lastIndexOf("/") + 1);
         File resultFile = checkCacheSize(context, assetPath);
         if (!resultFile.exists()) {
-            resultFile.createNewFile();
+            boolean createResult = resultFile.createNewFile();
+            if (!createResult) {
+                return null;
+            }
         }
         InputStream is = context.getAssets().open(fileName);
         FileOutputStream fos = null;
         try {
             byte[] data = new byte[2048];
-            int nbread = 0;
+            int readBuffer;
             fos = new FileOutputStream(resultFile);
-            while ((nbread = is.read(data)) > -1) {
-                fos.write(data, 0, nbread);
+            while ((readBuffer = is.read(data)) > -1) {
+                fos.write(data, 0, readBuffer);
             }
         } catch (Exception ex) {
             PdfLog.logError("Exception: " + ex);
@@ -75,8 +78,7 @@ private static File checkCacheSize(Context context, String url) {
         }
         File[] cacheList = folder.listFiles();
         if (cacheList != null && cacheList.length >= 10) {
-            for (int i = 0; i < cacheList.length; i++) {
-                File childFile = cacheList[i];
+            for (File childFile : cacheList) {
                 childFile.delete();
             }
         }