fix: prevent crash when clicking null images in gallery (#110)

- Add validation in GalleryActivity.open() to check for null/invalid images before opening gallery
- Add null safety checks in GalleryAdapter to handle null image objects
- Add null checks in getCurrentImage() and menu actions to prevent NPE
- Add ProGuard rules to keep ImagesInfo classes from being obfuscated
- Show "图片不存在" toast when attempting to open gallery with invalid images

This fixes the crash that occurred only in release builds when clicking
on images in reply lists that had null or invalid image data.

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-authored-by: Claude <noreply@anthropic.com>

Author: graycreate

app/proguard-rules.pro

@@ -202,6 +202,10 @@
 
 # Keep data models used for JSON parsing (Gson/Fruit)
 -keep class me.ghui.v2er.network.bean.** { *; }
+# Keep ImagesInfo and related classes for Fruit HTML parsing
+-keep class me.ghui.v2er.module.imgviewer.ImagesInfo { *; }
+-keep class me.ghui.v2er.module.imgviewer.ImagesInfo$* { *; }
+-keep class me.ghui.v2er.module.imgviewer.ImagesInfo$*$* { *; }
 
 # Keep classes with native methods
 -keepclasseswithmembernames class * {

app/src/main/java/me/ghui/v2er/module/gallery/GalleryActivity.java

@@ -48,6 +48,26 @@ public class GalleryActivity extends BaseActivity implements SwipeToDismissTouch
     private ImagesInfo mData;
 
     public static void open(ImagesInfo imgsData, Context context) {
+        // Validate images data before opening gallery
+        if (imgsData == null || imgsData.getImages() == null || imgsData.getImages().isEmpty()) {
+            Voast.show("图片不存在");
+            return;
+        }
+
+        // Check if at least one valid image exists
+        boolean hasValidImage = false;
+        for (ImagesInfo.Images.Image img : imgsData.getImages()) {
+            if (img != null && img.getUrl() != null) {
+                hasValidImage = true;
+                break;
+            }
+        }
+
+        if (!hasValidImage) {
+            Voast.show("图片不存在");
+            return;
+        }
+
         Navigator.from(context)
                 .putExtra(EXTRA_IMG_DATA, imgsData)
                 .to(GalleryActivity.class)
@@ -134,12 +154,22 @@ public void onPageScrollStateChanged(int state) {
 
     private String getCurrentImage() {
         int index = mViewPager.getCurrentItem();
+        if (mData == null || mData.getImages() == null ||
+            index < 0 || index >= mData.getImages().size() ||
+            mData.getImages().get(index) == null) {
+            return null;
+        }
         return mData.getImages().get(index).getUrl();
     }
 
     private void saveImage() {
+        String currentImage = getCurrentImage();
+        if (currentImage == null) {
+            Voast.show("图片不存在");
+            return;
+        }
         // Already have permission, do the thing
-        glideRequest(getCurrentImage()).into(new SimpleTarget<File>() {
+        glideRequest(currentImage).into(new SimpleTarget<File>() {
             @Override
             public void onResourceReady(File file, Transition<? super File> transition) {
                 if (!FileUtils.isExternalStorageWritable()) {
@@ -148,7 +178,7 @@ public void onResourceReady(File file, Transition<? super File> transition) {
                 }
                 Observable.just(file)
                         .compose(RxUtils.io_main())
-                        .map(f -> FileUtils.saveImg(f, Utils.getTypeFromImgUrl(getCurrentImage())))
+                        .map(f -> FileUtils.saveImg(f, Utils.getTypeFromImgUrl(currentImage)))
                         .subscribe(new BaseConsumer<String>() {
                             @Override
                             public void onConsume(String path) {
@@ -166,19 +196,25 @@ public void onConsume(String path) {
 
     @Override
     public boolean onMenuItemClick(MenuItem item) {
+        String currentImage = getCurrentImage();
+        if (currentImage == null) {
+            Voast.show("图片不存在");
+            return false;
+        }
+
         switch (item.getItemId()) {
             case R.id.action_open_in_browser:
-                Utils.openInBrowser(getCurrentImage(), this);
+                Utils.openInBrowser(currentImage, this);
                 break;
             case R.id.action_save:
                 //check write external permission then do save stuff
                 saveImage();
                 break;
             case R.id.action_share:
-                glideRequest(getCurrentImage()).into(new SimpleTarget<File>() {
+                glideRequest(currentImage).into(new SimpleTarget<File>() {
                     @Override
                     public void onResourceReady(File file, Transition<? super File> transition) {
-                        Utils.shareImg(file, Utils.getTypeFromImgUrl(getCurrentImage()), GalleryActivity.this);
+                        Utils.shareImg(file, Utils.getTypeFromImgUrl(currentImage), GalleryActivity.this);
                     }
                 });
                 break;

app/src/main/java/me/ghui/v2er/module/gallery/GalleryAdapter.java

@@ -49,6 +49,10 @@ public void destroyItem(ViewGroup container, int position, Object object) {
     }
 
     private ImagesInfo.Images.Image getItem(int postion) {
+        if (mImagesInfo == null || mImagesInfo.getImages() == null ||
+            postion < 0 || postion >= mImagesInfo.getImages().size()) {
+            return null;
+        }
         return mImagesInfo.getImages().get(postion);
     }
 
@@ -59,7 +63,13 @@ public Object instantiateItem(ViewGroup container, int position) {
         root.setOnImageClicked(mOnImageClickedListener);
         container.addView(root);
         // TODO: 2019/1/4 support svg
-        String url = getItem(position).getUrl();
+        ImagesInfo.Images.Image image = getItem(position);
+        if (image == null || image.getUrl() == null) {
+            // This shouldn't happen now that we validate before opening gallery
+            // But keep it as a safety net
+            return root;
+        }
+        String url = image.getUrl();
         if (!Utils.isSVG(url)) {
             GlideApp.with(mContext)
                     .load(url)