Introduction

ComPDFKit PDF SDK for Android is developed and maintained by ComPDF, enabling developers to quickly and seamlessly integrate advanced PDF functionalities—such as viewing, editing, annotating, and signing—into any Android application. The ComPDFKit Android PDF Library provides an easy-to-use Java API that allows direct access to a wide range of PDF features without the need for complex configurations. By registering for a free ComPDF API account, developers can process up to 1,000 PDF files monthly. More Information can be found at: https://www.compdf.com/guides/pdf-sdk/android/overview

Table of Content

• Related
• Requirements
• How to Make an Android PDF Viewer in Java
• Supports
• License

Related

• ComPDFKit PDF SDK for Android Documentation Guide
• ComPDFKit PDF Library for iOS
• How to Build an Android PDF Viewer or Editor in Java
• Code Samples for Android
• ComPDF API Reference

Requirements

ComPDFKit Android PDF SDK supports Android devices running API level 19 or newer and targets the latest stable Android 4.4 or later. In addition, it requires applications to be built with Java 8 language features enabled.

• Android Studio 3.2 or newer (support AndroidX).
• Project specifications.
  • A minSdkVersion of 19 or higher.
  • A compileSdkVersion of 30 or higher.
  • A targetSdkVersion of 34 or higher.
  • Android ABI(s): x86, x86_64, armeabi-v7a, arm64-v8a.

How to Make an Android PDF Viewer in Java

This section will help you quickly get started with ComPDFKit PDF SDK to make an Android app in Java with step-by-step instructions. Through the following steps, you will get a simple application that can display the contents of a specified PDF file.

Video Guide:Build an Android PDF Editor in Java

Create a New Project

1. Use Android Studio to create a Phone & Tablet project. Here we create a No Activity project.

Installation

Integrate With Gradle

1. Open the settings.gradle file located in your project's root directory and add the mavenCentral repository:

dependencyResolutionManagement {
    repositoriesMode.set(RepositoriesMode.FAIL_ON_PROJECT_REPOS)
    repositories {
        google()
+       mavenCentral()
    }
}

2. Open the build.gradle file in the application module directory:

Edit it and add the complete ComPDFKit SDK dependency:

dependencies {
  implementation 'com.compdf:compdfkit:2.4.0'
  implementation 'com.compdf:compdfkit-ui:2.4.0'
}

3. Apply for read and write permissions in AndroidManifest.xml:

<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>
<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE"/>

Note: On your apps that target Android 6.0 or higher, make sure to check for and request read and write permissions to external storage at runtime.

4. If you use an online license, please add network access permissions in AndroidManifest.xml:

<uses-permission android:name="android.permission.INTERNET"/>

Integrate Manually

1. Copy "ComPDFKit.aar" and "ComPDFKit-UI.aar" to the "libs" directory of the app.

2. Add the following code into the app dictionary's "build.gradle" file:

...
dependencies {
    /*ComPDFKit SDK*/
    implementation(fileTree('libs'))
    ...
}
...

3. Add ComPDFKit PDF SDK for Android as a dependency to the project. Inside the app dictionary's "build.gradle", add "ComPDFKit.aar", "ComPDFKit-UI.aar", and the related support libraries to the dependencies. For simplicity, update the dependencies as follows:

dependencies {
    ...
    //glide
    implementation 'com.github.bumptech.glide:glide:4.12.0'
    annotationProcessor 'com.github.bumptech.glide:compiler:4.12.0'

    implementation 'androidx.documentfile:documentfile:1.0.1'
}

4. Apply for read and write permissions in AndroidManifest.xml:

<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>
<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE"/>

Note: On your apps that target Android 6.0 or higher, make sure to check for and request read and write permissions to external storage at runtime.

5. If you use an online license, please add network access permissions in AndroidManifest.xml:

<uses-permission android:name="android.permission.INTERNET"/>

Apply the License Key

Add this license in the AndroidManifest.xml of the main module. In version 1.13.0, we introduced a brand-new online authentication license scheme for ComPDFKit SDK. By default, the SDK performs online authentication. If you are using a version prior to 1.13.0, please refer to the following example to configure the SDK for offline authentication mode:

• Online license

<!-- Each ComPDFKit license is bound to a specific applicationId -->
<!-- For example: com.compdfkit.pdfviewer -->
<meta-data
    android:name="compdfkit_key_online"
    android:value="Your ComPDFKit Key" />

You can also initialize ComPDFKit SDK in code using:

CPDFSdk.init(context, "your compdfkit license", false);

• Offline license

<!-- Each ComPDFKit license is bound to a specific applicationId -->
<!-- For example: com.compdfkit.pdfviewer -->
<meta-data
    android:name="compdfkit_key"
    android:value="Your ComPDFKit Key" />

You can also initialize ComPDFKit SDK in code using:

CPDFSdk.init(context, "your compdfkit license");

Add Proguard Rules

In the proguard-rules.pro file, please add the obfuscation configuration information for compdfkit as follows:

-keep class com.compdfkit.ui.** {*;}
-keep class com.compdfkit.core.** {*;}

Display a PDF Document

1. Copy a PDF document into the assets directory of your Android project. For example, import the file "Quick Start Guide.pdf" to the path src/main/assets.

2. Create a new Empty Activity under your package, and set the activity name to MainActivity.

Android Studio will automatically generate a source file called "MainActivity.java" and a layout file called "activity_main.xml".

The source file:

The layout file:

3. Create a CPDFReaderView in your "activity_main.xml" to display the contents of the PDF document:

<!-- Your activity_main.xml file -->

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">

    <!-- Create a CPDFReaderView -->
    <com.compdfkit.ui.reader.CPDFReaderView
        android:id="@+id/readerview"
        android:layout_width="match_parent"
        android:layout_height="match_parent" />

</androidx.constraintlayout.widget.ConstraintLayout>

Get the CPDFReaderView from the layout or create a CPDFReaderView directly in the code in the corresponding MainActivity.java file:

// Your MainActivity.java file

package com.compdfkit.pdfviewer;

import androidx.appcompat.app.AppCompatActivity;

import android.os.Bundle;
import com.compdfkit.ui.reader.CPDFReaderView;

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        // Get CPDFReaderView from xml.
        CPDFReaderView readerView = findViewById(R.id.readerview);
        // Code to create CPDFReaderView.
        // CPDFDocument readerView = new CPDFReaderView(content);
    }
}

4. Open the document. This is a time-consuming process, so it needs to be executed in a sub-thread. After the document is opened successfully, the UI that renders the PDF is initiated:

// Your MainActivity.java file

... //imports

public class MainActivity extends AppCompatActivity {

    // Copy the PDF file from the assets folder to the cache folder.
    private void copyPdfFromAssetsToCache(String fileName) {
        try {
            InputStream inputStream = getAssets().open(fileName);
            File outputFile = new File(getCacheDir(), fileName);
            FileOutputStream outputStream = new FileOutputStream(outputFile);

            byte[] buffer = new byte[1024];
            int bytesRead;
            while ((bytesRead = inputStream.read(buffer)) != -1) {
                outputStream.write(buffer, 0, bytesRead);
            }

            inputStream.close();
            outputStream.flush();
            outputStream.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
    
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        CPDFReaderView readerView = findViewById(R.id.readerview);
        // Code to create CPDFReaderView.
        // CPDFDocument readerView = new CPDFReaderView(content);

        //Create a document object.
        CPDFDocument document = new CPDFDocument(this);
        

        new Thread(() -> {
            String fileName = "Quick Start Guide.pdf";
            copyPdfFromAssetsToCache(fileName);

            File file = new File(getCacheDir(), fileName);
            String filePath = file.getAbsolutePath();

            //Open document.
            CPDFDocument.PDFDocumentError error = document.open(filePath);
            if (error == CPDFDocument.PDFDocumentError.PDFDocumentErrorPassword) {
                //The document is encrypted and requires a password to open.
                error = document.open(filePath, "password");
            }

            if (error == CPDFDocument.PDFDocumentError.PDFDocumentErrorSuccess) {
                //The document is opened successfully and data can be parsed and manipulated.
            } else {
                //The PDF file failed to open. You can refer to the API file for specific error
            }
        }).start();
    }
}

5. Set the basic properties of CPDFReaderView :

// Your MainActivity.java file

... // imports

public class MainActivity extends AppCompatActivity {
    // Create a handler to run the code on the main thread.
    private Handler mainThreadHandler = new Handler(Looper.getMainLooper());
...
    if (error == CPDFDocument.PDFDocumentError.PDFDocumentErrorSuccess) {
        // The document is opened successfully and data can be parsed and manipulated.
        mainThreadHandler.post(() -> {
            // Set the document content for UI.
            readerView.setPDFDocument(document);
        });
    } else {
        // The PDF file failed to open. You can refer to the API file for specific error
    }
...
}

6. Your code may resemble the following at this stage:

// Your MainActivity.java file

... // imports

public class MainActivity extends AppCompatActivity {
    // Create a handler to run the code on the main thread.
    private Handler mainThreadHandler = new Handler(Looper.getMainLooper());
    // Copy the PDF file from the assets folder to the cache folder.
    private void copyPdfFromAssetsToCache(String fileName) {
        try {
            InputStream inputStream = getAssets().open(fileName);
            File outputFile = new File(getCacheDir(), fileName);
            FileOutputStream outputStream = new FileOutputStream(outputFile);

            byte[] buffer = new byte[1024];
            int bytesRead;
            while ((bytesRead = inputStream.read(buffer)) != -1) {
                outputStream.write(buffer, 0, bytesRead);
            }

            inputStream.close();
            outputStream.flush();
            outputStream.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        CPDFReaderView readerView = findViewById(R.id.readerview);

        //Create a document object.
        CPDFDocument document = new CPDFDocument(this);

        new Thread(() -> {
            String fileName = "Quick Start Guide.pdf";
            copyPdfFromAssetsToCache(fileName);

            File file = new File(getCacheDir(), fileName);
            String filePath = file.getAbsolutePath();

            //Open document.
            CPDFDocument.PDFDocumentError error = document.open(filePath);
            if (error == CPDFDocument.PDFDocumentError.PDFDocumentErrorPassword) {
                //The document is encrypted and requires a password to open.
                error = document.open(filePath, "password");
            }

            if (error == CPDFDocument.PDFDocumentError.PDFDocumentErrorSuccess) {
                //The document is opened successfully and data can be parsed and manipulated.
                mainThreadHandler.post(() -> {
                    //Set the document to the reader view.
                    readerView.setPDFDocument(document);
                });
            } else {
                //The PDF file failed to open. You can refer to the API file for specific error
            }
        }).start();
    }
}

<!-- Your activity_main.xml file -->
<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">

    <com.compdfkit.ui.reader.CPDFReaderView
        android:id="@+id/readerview"
        android:layout_width="match_parent"
        android:layout_height="match_parent" />

</androidx.constraintlayout.widget.ConstraintLayout>

7. Run the application.

Now, with the help of ComPDFKit, you can get a simple application to display a PDF file.

Support

ComPDF offers professional technical support and 5*24 responsive service.

• For detailed information, please visit our Guides page.

• Stay updated with the latest improvements through our Changelog.

• For technical assistance, please reach out to our Technical Support.

• To get more details and an accurate quote, please contact our Sales Team or Send an Email to us.

License

ComPDF offers developers a 30-day free trial license for free testing your Android projects. Additionally, you'll have access to a fully-featured product with no limitations on file or user count.