update doc

README.md

@@ -13,13 +13,10 @@
 
 ## Install
 ### Android
-Install from the Google Play Store or download the *.apk from [releases].
-
-Android provides drag-and-drop files as content URIs, which cannot be renamed, so we need to convert them to absolute paths.
 
-Drag-and-dropped files from the [AOSP Files app](https://www.androidpolice.com/2017/03/22/android-o-feature-spotlight-downloads-app-now-files-new-features/) and [Files by Google](https://play.google.com/store/apps/details?id=com.google.android.apps.nbu.files) are not allowed to get an absolute path, so drag-and-drop from them is not supported.
+<a href="https://play.google.com/store/apps/details?id=net.sunjiao.renamer"><img alt="Get it on Google Play" src="https://play.google.com/intl/en_us/badges/images/generic/en-play-badge.png" height=60px /></a>
 
-Drag-and-drop works fine with Solid Explorer and OnePlus File Explorer.
+Install from the Google Play Store or download the *.apk from [releases].
 
 ### Linux
 Download the *.AppImage or *.tar.gz from [releases].
@@ -39,6 +36,18 @@ Download the *.dmg from [releases].
 ### iOS
 Download the *.ipa from [releases] and install it using AltStore or other tools.
 
+## Known issues or possible shortages 
+
+### Android
+
+Android provides drag-and-drop files as content URIs, which cannot be renamed, so we need to convert them to absolute paths.
+
+Drag-and-dropped files from the [AOSP Files app](https://www.androidpolice.com/2017/03/22/android-o-feature-spotlight-downloads-app-now-files-new-features/) and [Files by Google](https://play.google.com/store/apps/details?id=com.google.android.apps.nbu.files) are not allowed to get an absolute path, so drag-and-drop from them is not supported.
+
+Drag-and-drop works fine with Solid Explorer and OnePlus File Explorer.
+
+### iOS and macOS
+
 In fact, I have no Apple development experience at all, and I don’t even know the Swift language. The iOS and macOS native code were completed with the following links as references: [Writing custom platform-specific code](https://docs.flutter.dev/platform-integration/platform-channels?tab=type-mappings-swift-tab#type-mappings-swift-tab), [Providing access to directories](https://developer.apple.com/documentation/uikit/view_controllers/providing_access_to_directories), [juanmartin/renamerApp-ios](https://github.com/juanmartin/renamerApp-ios). Therefore, if there are any errors in the Swift code, please feel free to point them out by opening an issue or a pull request. I'll be very grateful to you.
 
 ## todo: