How to open pdf file in the app using Flutter - flutter

Question

I am using flutter_pdfview which is version ^1.0.0+10 to open a PDF file in flutter apps. When my app is in debug mode, there is no error. After I build the app the PDF file cannot open in apps. My app will crash and close suddenly. I have open the permission in AndroidManifest.xml:
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
How can solve this error?

Answer 1

First you need to create a proguard-rules.pro file at /android/app/ inside there write like this:
#Flutter Wrapper
-keep class com.shockwave.**
Then at /android/app/build.gradle add this:
buildTypes {
release {
signingConfig signingConfigs.release
**minifyEnabled true
useProguard true
proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'**
}
}

Answer 2

I have this problem only on android but when the app is on production. To fix this I add the permission handler plugin and change the path. Also and very important was add the extension ".pdf" to file after download but before read.
final filename = url.substring(url.lastIndexOf("/") + 1);
var request = await HttpClient().getUrl(Uri.parse(url));
var response = await request.close();
var bytes = await consolidateHttpClientResponseBytes(response);
String dir = (await getExternalStorageDirectory()).path;
File file = new File('$dir/$filename.pdf');
await file.writeAsBytes(bytes);
pathPDF = file.path;
return file;

Answer 3

If you are running debug on an emulator and then release on a real device, this might be your problem:
PdfViewPage(path: '/storage/emulated/0/Download/$pdfName')));
Even if it isn't causing the crash it is a bad idea to hardcode download path like you've done. Different devices can have downloads in different locations. You can use downloads_path_provider to find where downloads is located.
Also, beside declaring the permissions needed in the Manifest you should also ask user for permission and handle the situation if the user doesn't give permission. For that task I suggest using permission_handler.