This document outlines the steps necessary to use the MuPDF Android Library in various ways.

First, we show you how to embed MuPDF in your app. Then, we explain how to customize the viewer if you need to change how it looks or behaves. Finally, we tell you where to go if you need to do work on the library itself.

Embedding the viewer in your app provides an activity that you can start to view PDF documents from within your app. This should be enough for most use cases.

## Acquire a valid license

Before using MuPDF, please make sure that you have a valid license to do so. There are two available licenses; make sure you pick the one whose terms you can comply with.

### Open Source license

If your software is open source, you may use MuPDF under the terms of the GNU Affero General Public License.

This means that all of the source code for your complete app must be released under a compatible open source license!

It also means that you may not use any proprietary closed source libraries or components in your app. This includes (but is not limited to) Google Play Services, Google Mobile Services, AdMob by Google, Crashlytics, Answers, etc.

Just because a library ships with Android or is made by Google does not make it AGPL compatible!

If you cannot or do not want to comply with these restrictions, you must acquire a commercial license instead.

### Commercial license

If your software is not open source, Artifex Software can sell you a license to use MuPDF in closed source software. Go and fill out the product inquiry form for commercial licensing terms and pricing.

## Add the MuPDF Library to your project

The MuPDF library uses the Gradle build system. In order to include MuPDF in your app, you also need to use Gradle. The Eclipse and Ant build systems are not supported.

The MuPDF library needs Android version 4.1 or newer. Make sure that the minSdkVersion in your app's build.gradle is at least 16.

    android {
    	defaultConfig {
    		minSdkVersion 16
    		...
    	}
    	...
    }

The MuPDF library can be retrieved as a pre-built artifact from our Maven repository. Add the maven repository to your project. In your project's top build.gradle, add the bolded line to to the repositories section:

    allprojects {
    	repositories {
    		jcenter()
    		maven { url 'http://maven.ghostscript.com' }
    		...
    	}
    }

Then add the MuPDF viewer library to your app's dependencies. In your app's build.gradle, add the bolded line to the dependencies section:

    dependencies {
    	api 'com.artifex.mupdf:viewer:1.15.+'
    	...
    }

## Invoke the document viewer activity

Once this has been done, you have access to the MuPDF viewer activity. You can now open a document viewing activity by launching an intent, passing the URI of the document you wish to view.

    import com.artifex.mupdf.viewer.DocumentActivity;

    public void startMuPDFActivity(Uri documentUri) {
    	Intent intent = new Intent(this, DocumentActivity.class);
    	intent.setAction(Intent.ACTION_VIEW);
    	intent.setData(documentUri);
    	startActivity(intent);
    }

The activity supports viewing both file and content scheme URIs.

For example, to open the PDF file in ~/Download/example.pdf:

    public void startMuPDFActivityWithExampleFile() {
    	File dir = Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_DOWNLOADS);
    	File file = new File(dir, "example.pdf");
    	Uri uri = Uri.fromFile(file);
    	startMuPDFActivity(uri);
    }

## How to customize the viewer

If you've already tried embedding the viewer in your app, but are unhappy with some aspect of the look or behavior and want to modify it in some way, this document should point you in the right direction.

### Decide which viewer to base your customizations on

In order to customize the viewer UI, you will need to modify the existing android viewer activity. There are two separate code bases you can start with:

mupdf-android-viewer:
  The main viewer app. This code is difficult to work with, but has the most features and pre-renders neighboring pages into a page cache for faster page turning performance.
mupdf-android-viewer-mini:
  This is a minimalist viewer which has fewer features but is designed to be easy to understand and modify. It does not (currently) have high-resolution zooming, and it does not use the swipe gesture to flip pages (it requires the user to tap on the side of the screen to flip pages).

If all you want to do is brand the UI with your own colors and icons, you are welcome to use whichever code base you prefer. However, if you want to do extensive modifications, we suggest you base your code on the mini viewer.

### Check out the chosen project

When you have decided which project to base your modifications on, you should check out the corresponding git repository:

    $ git clone git://git.ghostscript.com/mupdf-android-viewer.git
    $ git clone git://git.ghostscript.com/mupdf-android-viewer-mini.git

Inside the checked out project you will find two modules: app and lib. The app module is a file chooser activity that lets the user open files from the external storage. The lib module is the viewer activity, which provides the "com.artifex.mupdf:viewer" package that you're already using.

The lib module is the one you want; ignore everything else in this project.

### Copy the viewer library module into your project

Copy the 'lib' directory to your project, renaming it to something appropriate. The following instructions assume you called the directory 'mupdf-lib'. Don't forget to include the module in the settings.gradle file:

    include ':app'
    include ':mupdf-lib'
    ...

You'll also want to change your app's dependencies to now depend on your local copy rather than the official mupdf viewer package. In your app build.gradle:

    dependencies {
    	api 'com.artifex.mupdf:viewer:1.15.+'
    	api project(':mupdf-lib')
    	...
    }

The lib module depends on the JNI library "com.artifex.mupdf:fitz", so do not remove the maven repository from your top build.gradle.

### Edit the viewer activity

If all has gone well, you can now build your project with the local viewer library, and access the mupdf viewer activity just as you used to.

You're now free to customize the resources in mupdf-lib/src/main/res and behavior in mupdf-lib/src/main/java as you desire.

## Working on the MuPDF Library

If you want to work on the library itself, rather than just use it, you will need to check out the following git repositories.

mupdf.git
  This repository contains the low-level "fitz" C library and the JNI bindings.
mupdf-android-fitz.git
  This repository contains an Android project to build the C library and JNI bindings. It uses mupdf.git as a git submodule.
mupdf-android-viewer.git
  This repository contains the Android viewer library and app. It uses mupdf-android-fitz.git as either a Maven artifact or git submodule.
mupdf-android-viewer-mini.git
  This repository contains the minimalist Android viewer library and app. It uses mupdf-android-fitz.git as either a Maven artifact or git submodule.
mupdf-android-viewer-old.git
  This repository contains the old Android viewer. It has its own JNI bindings and uses mupdf.git as a submodule directly. It is only listed here for history.

Since these repositories are set up as git submodules, if you're a Git expert, you can clone one of the viewer repositories recursively and get all of them at once. However, working with git submodules can be fraught with danger, so it may be easier to check them out individually.

If you only want to work with one of the viewer repositories, you can use the Maven artifact for the JNI bindings library and not worry about the mupdf.git and mupdf-android-fitz.git repositories.

Good luck!