Overlay PDFs to find differences in Xamarin.Android

You can visually compare pages. This resolution independent comparison allows you to quickly spot differences between pages.

There are two main ways to integrate the out-of-box UI components in your application:

1. Standalone activity
2. Comparison options dialog

The DiffActivity is a standalone component that handles from picking two files to generating the comparison result.

1. Define the activity

<activity
    android:name="com.pdftron.pdf.controls.DiffActivity"
    android:configChanges="keyboardHidden|orientation|screenSize|screenLayout|smallestScreenSize"
    android:theme="@style/PDFTronAppTheme"
    android:windowSoftInputMode="adjustPan" />

2. Show the activity

DiffActivity.Open(this);

If you have your own viewer already and only want to show the comparison options in your application, the DiffOptionsDialogFragment can be used.

public void Show(Context context, FragmentManager fragmentManager, List<Android.Net.Uri> files)
{
    var fragment = pdftron.PDF.Dialog.Diffing.DiffOptionsDialogFragment.NewInstance(
        files[0], files[1]
    );
    fragment.SetStyle((int)DialogFragmentStyle.Normal, Resource.Style.PDFTronAppTheme);
    fragment.DiffOptionsConfirmed += (sender, e) =>
    {
        CompareFiles(context, files, e.Color1, e.Color2, e.BlendMode);
    };
    fragment.Show(fragmentManager, "diff_options_dialog");
}

where compareFile is:

private void CompareFiles(Context context, List<Android.Net.Uri> files, int color1, int color2, int blendMode)
{
    Android.Net.Uri uri = pdftron.PDF.Dialog.Diffing.DiffUtils.CompareFilesImpl(context, files, color1, color2, blendMode);
    // do something with the output
}