How to Build Your Very Own Android Mobile PDF Scanning Tool

Mobile scanning directly to PDF can revolutionize your document workflows. Equipped with features like automatic page detection, built-in flash for better lighting, precise color management, and camera settings tailored for creating professional-grade PDFs, you can achieve remarkable results with just a few taps on your smartphone, thanks to cutting-edge technology.

The following guide outlines how you can harness the power of Foxit’s Android PDF SDK to swiftly develop an app with robust scanning capabilities. Whether you’re capturing multiple photos or selecting images from your gallery, generating a PDF is as simple as a single click. This project empowers you to seamlessly integrate scanning into your existing workflows, making it a valuable addition to your mobile application.

You have the freedom to incorporate your own business or application branding effortlessly, without the need to toggle elements or redesign the user interface. It provides a blank PDF viewer with a dedicated mobile scanning button, serving as a foundation for building your unique app.

System Requirements

Android devices’ requirements:

• Android 4.4 (API 19) or higher

• 32/64-bit ARM (armeabi-v7a/arm64-v8a) or 32/64-bit Intel x86 CPU

  
  

• Android Studio 3.2 or newer (supports AndroidX)
  The runtime environment for our demos:
  • Android Studio 3.2
  • JDK 1.8
  • Gradle Version 4.6
  • Gradle Build Tool 3.2
  Note: Starting with version 8.2, Foxit PDF SDK for Android will only support AndroidX, and no longer service the Android support library.

Development Configuration

Start up Android Studio and open the androidrdk/samples/viewer_ctrl_demo project.

Add the scanning dependency library in the gradle file (view_ctrl_demo/app/build.gradle) as below:

implementation(name:'FoxitPDFScan-UI', ext:'aar') 
implementation(name:'FoxitMobileScanningRDK', ext:'aar') 
implementation 'com.nostra13.universalimageloader:universal-image-loader:1.9.5' 

Define permission settings

Before calling the Scan function, you need to obtain storage permission and permission to take pictures. If the permission to use the camera and photo album is not obtained before calling the Scan function, the app will not run correctly. Follow the steps below to set permissions.

Add permission-related declarations in the AndroidManifest file using the code below:

<manifest xmlns:android="http://schemas.android.com/apk/res/android"> 

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

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

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

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

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

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

Then add the following permission request code in MainActivity.java:

if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.KITKAT) { 

    int permission = ContextCompat.checkSelfPermission(this.getApplicationContext(), Manifest.permission.WRITE_EXTERNAL_STORAGE); 

    if (permission != PackageManager.PERMISSION_GRANTED) { 

        ActivityCompat.requestPermissions(this, PERMISSIONS_STORAGE, REQUEST_EXTERNAL_STORAGE);      

@Override 

public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) { 

    super.onRequestPermissionsResult(requestCode, permissions, grantResults); 

    if (requestCode == REQUEST_EXTERNAL_STORAGE) { 

        if (grantResults[0] == PackageManager.PERMISSION_GRANTED) { 

         //Application permission is successful 

        } else { 

            UIToast.getInstance(getApplicationContext()).show(getString(R.string.fx_permission_denied)); 

            finish(); 

        } 

    } 

Now, let’s add the code related to the Scan function:

Add a button to the UI to call the Scan function.

First, write some code to add the camera button icon. You’ll define the layout, positioning and image resource for the button. This code is added to the onCreate method of the MainActivity file to make sure that the button is displayed as soon as the project loads. Make sure to add this after:

protected void onCreate(Bundle savedInstanceState) { 

   (...) 

// Make sure to add this block of code after all the already existing          // view_ctrl_demo onCreate code is loaded 

    mRootView=uiExtensionsManager.getContentView(); 

    RelativeLayout.LayoutParams layoutParams = new RelativeLayout.LayoutParams(RelativeLayout.LayoutParams.WRAP_CONTENT, RelativeLayout.LayoutParams.WRAP_CONTENT); 

    mIvScan = new ImageView(this); 

    mIvScan.setImageResource(R.drawable.fx_floatbutton_scan); 

    layoutParams.bottomMargin = 80; 

    layoutParams.rightMargin = 50; 

    layoutParams.addRule(RelativeLayout.ALIGN_PARENT_BOTTOM); 

    layoutParams.addRule(RelativeLayout.ALIGN_PARENT_RIGHT); 

    mIvScan.setLayoutParams(layoutParams); 

    mRootView.addView(mIvScan); 

    setContentView(mRootView); 

    initScan(); 

} 

Now, let’s set the foundation for the app’s scanning feature. The last line of code in the onCreate method above is a call to initScan(), which is the method we’ll use to initialize the relevant classes for the project.

The code below shows how you will instantiate an object from Foxit’s main PDF Scan class (PDFScanManager), then use that class to initialize the scanner and the compression features. The final method displays the scan functionality once you click the camera button.

  PDFScanManager pdfScanManager = PDFScanManager.instance() 

if (!PDFScanManager.isInitializeScanner()) { 

    long framework1 = 0; 

    long framework2 = 0; 

    PDFScanManager.initializeScanner(App.inst().getAppActivity().getApplication(), framework1, framework2); 

} 

if (!PDFScanManager.isInitializeCompression()) { 

    long compression1 = 0; 

    long compression2 = 0; 

    PDFScanManager.initializeCompression(App.inst().getAppActivity().getApplication(), compression1, compression2); 

} 

if (PDFScanManager.isInitializeScanner() && PDFScanManager.isInitializeCompression()) { 

    //Loaded Successfully 

        pdfScanManager.showUI(activity.this); 

}

The initialization code is then added to the initScan method as follows. This method will also be added to the MainActivity class and called as soon as the project loads. This ensures your project will have all the scanning libraries and functionality available.

The following imports and variables are necessary for the project:

import com.foxit.pdfscan.PDFScanManager; 

  

private ImageView mIvScan; 

 private ViewGroup mRootView; 

  

private  void  initScan(){ 

        final PDFScanManager pdfScanManager = PDFScanManager.instance(); 

        mIvScan.setOnClickListener(new View.OnClickListener() { 

            @Override 

            public void onClick(View v) { 

                if (!PDFScanManager.isInitializeScanner()) { 

                    long framework1 = 0; 

                    long framework2 = 0; 

                    PDFScanManager.initializeScanner(getApplication(), framework1, framework2); 

                } 

                if (!PDFScanManager.isInitializeCompression()) { 

                    long compression1 = 0; 

                    long compression2 = 0; 

                    PDFScanManager.initializeCompression(getApplication(), compression1, compression2); 

                } 

                if (PDFScanManager.isInitializeScanner() && PDFScanManager.isInitializeCompression()) { 

  

                    pdfScanManager.showUI((Activity) mContext); 

  

                } else { 

                    UIToast.getInstance(getApplicationContext()) 

                            .show(AppResource.getString(getApplicationContext(), R.string.rv_invalid_license)); 

                } 

            } 

        }); 

    }

Now that we have initialized the library and the foundation has been set, we will write two basic callback interfaces that will be used to save the document after it’s scanned: the first, ScanPDFDoneCallBack, which is entirely custom, and the second is IPDFScanManagerListener, which is available out-of-the-box in the SDK. See both below:

public interface ScanPDFDoneCallBack { 

  

    /** Success, and no error occurs */ 

    int e_ErrSuccess = 0; 

    /** Failed, any unknown error occurs. */ 

    int e_ErrUnknown = 1; 

  

    /** 

     * After saving PDF successfully, return to the saving path 

     * 

     * @param errorCode if the scanned file is successfully saved as a pdf document, the errorCode is {@link #e_ErrSuccess}, otherwise is {@link #e_ErrUnknown} 

     * @param savePath the document file path. 

     */ 

    void doneCallBack(int errorCode, String savePath); 

} 

public interface IPDFScanManagerListener { 

    /** 

     * Success, and no error occurs 

     */ 

    int e_ErrSuccess = 0; 

    /** 

     * Failed, any unknown error occurs. 

     */ 

    int e_ErrUnknown = 1; 

  

    /** 

     * Called when if the scanned file is successfully saved as a pdf document. 

     * 

     * @param errorCode if the scanned file is successfully saved as a pdf document, the errorCode is {@link #e_ErrSuccess}, otherwise is {@link #e_ErrUnknown} 

     * @param path      the document file path. 

     */ 

    void onDocumentAdded(int errorCode, String path); 

}

The difference between the two interfaces is if the monitoring of ScanPDFDoneCallBack is set, when you click the ‘Done’ button in the lower right corner of the figure below, it will directly save the document to the default path and exit the scanning interface, and return to the default save path through the parameter savePath.

If ScanPDFDoneCallBack is not set, when you click the ‘Done’ button in the lower right corner of the figure below, an interface for selecting the save directory will pop up. The user selects the specified directory, and the document will be saved in the directory selected by the user.

https://developers.foxit.com/dk_utwp/2021/10/android-mobile-scanning-tool-pdf-sdk-app.mp4

Now, you must implement the interfaces by adding them to MainActivity.java.

pdfScanManager.setDoneCallBack(new ScanPDFDoneCallBack() { 

    @Override 

    public void doneCallBack(int errorCode, final String savePath) { 

        if (errorCode == e_ErrSuccess) { 

             //The document was saved successfully 

        } 

    } 

}); 

  

PDFScanManager.registerManagerListener(new IPDFScanManagerListener() { 

    @Override 

    public void onDocumentAdded(int errorCode, String path) { 

        if (errorCode == e_ErrSuccess) { 

             //The document was saved successfully 

        } 

  

    } 

});

If you want to implement further interfaces of the pdfscan class, please refer to the API Reference documents in foxitpdfsdk_8_1_android/docs.

Done! The scan functionality has been successfully added to your application. Run the app, click the Scan button you’ve created previously and start your scanning experience.

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