Integrate Android PDF Library using Flutter

This guide will help you integrate a free trial of the PDFTron SDK into your Android applications using Flutter. Your free trial includes unlimited trial usage and support from solution engineers.

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Prerequisites

• PDFTron SDK >= 6.9.0
• Flutter >= 1.0.0

Integrate

For simplicity the following guide is based on a boilerplate flutter app of flutter create myapp with git diff syntax for adding and removing lines from the boilerplate app.

1. First follow the Flutter get started guides to install, set up an editor, and create a Flutter Project. The rest of this guide assumes your project is created by running flutter create myapp.

2. Add the following dependency to your Flutter project in myapp/pubspec.yaml:

   dependencies:
      flutter:
        sdk: flutter
   +  pdftron_flutter:
   +   git:
   +	  url: git://github.com/PDFTron/pdftron-flutter.git

3. Now add the following items in your myapp/android/app/build.gradle file:

   android {
   -   compileSdkVersion 27
   +   compileSdkVersion 30
   
       lintOptions {
           disable 'InvalidPackage'
       }
   
       defaultConfig {
           applicationId "com.example.myapp"
   -       minSdkVersion 16
   +       minSdkVersion 21
   -       targetSdkVersion 27
   +       targetSdkVersion 30
   +       multiDexEnabled true
   +       manifestPlaceholders = [pdftronLicenseKey:PDFTRON_LICENSE_KEY]
           versionCode flutterVersionCode.toInteger()
           versionName flutterVersionName
           testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
       }
   	...
   }

4. In your myapp/android/app/src/main/AndroidManifest.xml file, add the following lines to the <application> tag:

   <!-- Enable usesCleartextTraffic in application attributes if you are 
   working with HTTP files. If you are only working with HTTPS files, this is not required.-->
   <application
   	android:name="io.flutter.app.FlutterApplication"
   	android:label="myapp"
   	android:icon="@mipmap/ic_launcher"
   +	android:largeHeap="true"
   +	android:usesCleartextTraffic="true">

   Additionally, add the required permissions for your app in the <manifest> tag:

   <uses-permission android:name="android.permission.INTERNET" />
     <!-- Required to read and write documents from device storage -->
   +   <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
     <!-- Required if you want to record audio annotations -->
   +   <uses-permission android:name="android.permission.RECORD_AUDIO" />

5. Add your PDFTron license key to the myapp/android/gradle.properties file.

   PDFTRON_LICENSE_KEY=INSERT_COMMERCIAL_LICENSE_KEY_HERE_AFTER_PURCHASE

   Key can be left empty for a trial

6. If you are using the DocumentView widget, change the parent class of your MainActivity file (either Kotlin or Java) to FlutterFragmentActivity.

   import androidx.annotation.NonNull
   	import io.flutter.embedding.android.FlutterFragmentActivity
   	import io.flutter.embedding.engine.FlutterEngine
   	import io.flutter.plugins.GeneratedPluginRegistrant
   
   	class MainActivity : FlutterFragmentActivity() {
   		override fun configureFlutterEngine(@NonNull flutterEngine: FlutterEngine) {
   			GeneratedPluginRegistrant.registerWith(flutterEngine);
   		}
   	}

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