Annotation handling

Apryse SDK allows you to intercept annotation events and add custom code for when they are triggered.

Android

Customize annotation handling for Xamarin.Android

This tutorial only applies to Xamarin.Android. See Xamarin.iOS equivalent here .

By default, the Tools library will respond to user actions such as a click event on a link or form widget, or a property change event on a selected annotation. It is possible to customize such behavior before it is executed within the Tools library, as well as getting notified of an action after it has happened.

Intercept annotation events

If you would like to customize the behavior executed in response to user actions prior to it being handled by the Tools library, it is possible to do so with the BasicAnnotationListener.onInterceptAnnotationHandling(Annot, Bundle, int) API. If this method returns true, then it will intercept executing the default logic.

In BasicAnnotationListener.onInterceptAnnotationHandling(Annot, Bundle, int), the second parameter, Bundle, contains the name of the action intercepted by this function, as well as some extra information. You can get the name of the intercepted action by calling bundle.getString(Tool.METHOD_FROM):

Java

public boolean onInterceptAnnotationHandling(Annot annot, Bundle extra, ToolMode toolMode) {
    if (extra != null && extra.containsKey(Tool.METHOD_FROM)) {
        String methodCalling = extra.getString(Tool.METHOD_FROM);
    }
}

Kotlin

override fun onInterceptAnnotationHandling(annot: Annot?, extra: Bundle?, toolMode: ToolMode): Boolean {
    if (extra != null && extra.containsKey(Tool.METHOD_FROM)) {
        val methodCalling = extra.getString(Tool.METHOD_FROM)
    }
}

To get extra information, first obtain the information keys by calling bundle.getStringArray(Tool.KEYS):

Java

String[] paramKeys = extra.getStringArray(Tool.KEYS)

Kotlin

val paramKeys = extra!!.getStringArray(Tool.KEYS)

Then, you can get the information values by looping on each key obtained above:

Java

public boolean onInterceptAnnotationHandling(Annot annot, Bundle extra, ToolMode toolMode) {
    if (extra != null && extra.containsKey(Tool.KEYS)) {
        String[] paramKeys = extra.getStringArray(Tool.KEYS);
        if (paramKeys != null) {
            for (String key : paramKeys) {
                // Gets the information value
                Object param = extra.get(key);
            }
        }
    }
}

Kotlin

override fun onInterceptAnnotationHandling(annot: Annot?, extra: Bundle?, toolMode: ToolMode): Boolean {
    if (extra != null && extra.containsKey(Tool.KEYS)) {
        val paramKeys = extra.getStringArray(Tool.KEYS)
        if (paramKeys != null) {
            for (key in paramKeys) {
                // Gets the information value
                val param = extra.get(key)
            }
        }
    }
}

Common use cases

Links

Java

mToolManager.setBasicAnnotationListener(new ToolManager.BasicAnnotationListener() {
    @Override
    public boolean onInterceptAnnotationHandling(Annot annot, Bundle extra, ToolMode toolMode) {
        try {
            // Intercept clicking link annotation by return true
            if (annot.getType() == Annot.e_Link) {
                Log.d("InterceptAnnot", "handling link annotation");
                return true;
            }
        } catch (PDFNetException e) {
            e.printStackTrace();
        }
        // return false so the other events can continue executing
        return false;
    }
});

Kotlin

mToolManager.setBasicAnnotationListener(object : ToolManager.BasicAnnotationListener {
    override fun onInterceptAnnotationHandling(annot: Annot?, extra: Bundle?, toolMode: ToolMode?): Boolean {
        try {
            // Intercept clicking link annotation by return true
            if (annot!!.type == Annot.e_Link) {
                Log.d("InterceptAnnot", "handling link annotation")
                return true
            }
        } catch (e: PDFNetException) {
            e.printStackTrace()
        }
        // return false so the other events can continue executing
        return false
    }
})

Form widgets

Java

mToolManager.setBasicAnnotationListener(new ToolManager.BasicAnnotationListener() {
    @Override
    public boolean onInterceptAnnotationHandling(Annot annot, Bundle extra, ToolMode toolMode) {
        try {
            // Intercept clicking widget annotation by return true
            if (annot.getType() == Annot.e_Widget) {
                Log.d("InterceptAnnot", "handling widget annotation");
                return true;
            }
        } catch (PDFNetException e) {
            e.printStackTrace();
        }
        // return false so the other events can continue executing
        return false;
    }
});

Kotlin

mToolManager.setBasicAnnotationListener(object : ToolManager.BasicAnnotationListener {
    override fun onInterceptAnnotationHandling(annot: Annot?, extra: Bundle?, toolMode: ToolMode?): Boolean {
        try {
            // Intercept clicking widget annotation by return true
            if (annot!!.type == Annot.e_Widget) {
                Log.d("InterceptAnnot", "handling widget annotation")
                return true
            }
        } catch (e: PDFNetException) {
            e.printStackTrace()
        }
        // return false so the other events can continue executing
        return false
    }
})

Full sample code

For example, the following code demonstrates several scenarios and how you can get notified before each: clicking on a radio button, changing the annotation opacity, and clicking on a link. See the comments in the code for details.

Java

mToolManager.setBasicAnnotationListener(new ToolManager.BasicAnnotationListener() {
    @Override
    public boolean onInterceptAnnotationHandling(Annot annot, Bundle extra, ToolMode toolMode) {
        /*
            For example, when a radio button is clicked, this code will print:
            calling method: handleWidget
            property: OTHER
        */
        if (extra != null && extra.containsKey(Tool.METHOD_FROM)) {
            String methodCalling = extra.getString(Tool.METHOD_FROM);
            Log.d("InterceptAnnot", "calling method " + methodCalling);
            AnnotationProperty.Property property = AnnotationProperty.getProperty(methodCalling);
            Log.d("InterceptAnnot", "property: " + property);
        }
        /*
            For example, when annotation opacity is about to be changed to 50%, this code will print:
            calling method: editOpacity
            property: OPACITY
            key: opacity
            value: 0.5
        */
        if (extra != null && extra.containsKey(Tool.KEYS)) {
            String[] paramKeys = extra.getStringArray(Tool.KEYS);
            if (paramKeys != null) {
                for (String key : paramKeys) {
                    Object param = extra.get(key);
                    Log.d("InterceptAnnot", "key: " + key);
                    Log.d("InterceptAnnot", "value: " + param.toString());
                }
            }
        }
        try {
            // Intercept radio button from clicking by return true
            if(annot.getType() == Annot.e_Widget) {
                Widget w = new Widget(annot);
                Field field = w.getField();
                if (field != null && field.isValid() && field.getType() == Field.e_radio) {
                    return true;
                }
            }
            // Intercept clicking link annotation by return true
            if (annot.getType() == Annot.e_Link) {
                Log.d("InterceptAnnot", "handling link annotation");
            }
        } catch (PDFNetException e) {
            e.printStackTrace();
        }
        // return false so the other events can continue executing
        return false;
    }
});

Kotlin

mToolManager.setBasicAnnotationListener(object : ToolManager.BasicAnnotationListener {
    override fun onInterceptAnnotationHandling(annot: Annot?, extra: Bundle?, toolMode: ToolMode?): Boolean {
        /*
      For example, when a radio button is clicked, this code will print:
      calling method: handleWidget
      property: OTHER
      */
        if (extra != null && extra.containsKey(Tool.METHOD_FROM)) {
            val methodCalling = extra.getString(Tool.METHOD_FROM)
            Log.d("InterceptAnnot", "calling method " + methodCalling)
            val property = AnnotationProperty.getProperty(methodCalling)
            Log.d("InterceptAnnot", "property: " + property)
        }
        /*
      For example, when annotation opacity is about to be changed to 50%, this code will print:
      calling method: editOpacity
      property: OPACITY
      key: opacity
      value: 0.5
      */
        if (extra != null && extra.containsKey(Tool.KEYS)) {
            val paramKeys = extra.getStringArray(Tool.KEYS)
            if (paramKeys != null) {
                for (key in paramKeys) {
                    val param = extra.get(key)
                    Log.d("InterceptAnnot", "key: " + key)
                    Log.d("InterceptAnnot", "value: " + param.toString())
                }
            }
        }
        try {
            // Intercept radio button from clicking by return true
            if (annot!!.type == Annot.e_Widget) {
                val w = Widget(annot)
                val field = w.getField()
                if (field != null && field.isValid() && field.getType() === Field.e_radio) {
                    return true
                }
            }
            // Intercept clicking link annotation by return true
            if (annot!!.type == Annot.e_Link) {
                Log.d("InterceptAnnot", "handling link annotation")
            }
        } catch (e: PDFNetException) {
            e.printStackTrace()
        }
        // return false so the other events can continue executing
        return false
    }
})

Get notified after an action

If you simply want to get notified after the action has happened, you can do so via the AnnotationModificationListener.onAnnotationsModified(Map<Annot, Integer>) API. This event callback is raised when an annotation change has occurred. For example, in order to get notified when the value of a checkbox has been changed and when annotation opacity has been changed, do the following:

Java

ToolManager.AnnotationModificationListener annotationModificationListener = new ToolManager.AnnotationModificationListener() {
    @Override
    public void onAnnotationsModified(Map<Annot, Integer> annots, Bundle extra) {
        /*
            For example, when a checkbox's value has been changed, this code will print:
            calling method: handleWidget
            property: OTHER
        */
        if (extra != null && extra.containsKey(Tool.METHOD_FROM)) {
            String methodCalling = extra.getString(Tool.METHOD_FROM);
            Log.d("AnnotationsModified", "calling method " + methodCalling);
            AnnotationProperty.Property property = AnnotationProperty.getProperty(methodCalling);
            Log.d("AnnotationsModified", "property: " + property);
        }
        /*
            For example, when annotation opacity is changed to 50%, this code will print:
            calling method: editOpacity
            property: OPACITY
            key: opacity
            value: 0.5
        */
        if (extra != null && extra.containsKey(Tool.KEYS)) {
            String[] paramKeys = extra.getStringArray(Tool.KEYS);
            if (paramKeys != null) {
                for (String key : paramKeys) {
                    Object param = extra.get(key);
                    Log.d("AnnotationsModified", "key: " + key);
                    Log.d("AnnotationsModified", "value: " + param.toString());
                }
            }
        }
    }
};
mToolManager.addAnnotationModificationListener(annotationModificationListener);

Kotlin

val annotationModificationListener: ToolManager.AnnotationModificationListener = object : ToolManager.AnnotationModificationListener {
  override fun onAnnotationsModified(annots: MutableMap<Annot, Int>?, extra: Bundle?) {
    /*
      For example, when a checkbox's value has been changed, this code will print:
      calling method: handleWidget
      property: OTHER
      */
    if (extra != null && extra.containsKey(Tool.METHOD_FROM)) {
      val methodCalling = extra.getString(Tool.METHOD_FROM)
      Log.d("AnnotationsModified", "calling method " + methodCalling)
      val property = AnnotationProperty.getProperty(methodCalling)
      Log.d("AnnotationsModified", "property: " + property)
    }
    /*
      For example, when annotation opacity is changed to 50%, this code will print:
      calling method: editOpacity
      property: OPACITY
      key: opacity
      value: 0.5
      */
    if (extra != null && extra.containsKey(Tool.KEYS)) {
      val paramKeys = extra.getStringArray(Tool.KEYS)
      if (paramKeys != null) {
        for (key in paramKeys) {
          val param = extra.get(key)
          Log.d("AnnotationsModified", "key: " + key)
          Log.d("AnnotationsModified", "value: " + param.toString())
        }
      }
    }
  }
}
mToolManager.addAnnotationModificationListener(annotationModificationListener)

mToolManager.AnnotationsModified += (sender, e) =>
{
    var extra = e.Extra;
    /*
        For example, when checkbox value has been changed, this code will print:
        calling method: handleWidget
        property: OTHER
    */
    if (extra != null && extra.ContainsKey(Tool.MethodFrom))
    {
        String methodCalling = extra.GetString(Tool.MethodFrom);
        Console.WriteLine("AnnotationsModified calling method " + methodCalling);
        var property = pdftron.PDF.Model.AnnotationProperty.GetProperty(methodCalling);
        Console.WriteLine("AnnotationsModified property: " + property);
    }

    /*
        For example, when changed annotation opacity to 50%
        calling method: editOpacity
        property: OPACITY
        key: opacity
        value: 0.5
    */
    if (extra != null && extra.ContainsKey(Tool.Keys))
    {
        String[] paramKeys = extra.GetStringArray(Tool.Keys);
        if (paramKeys != null)
        {
            foreach (String key in paramKeys)
            {
                Object param = extra.Get(key);
                Console.WriteLine("AnnotationsModified key: " + key);
                Console.WriteLine("AnnotationsModified value: " + param.ToString());
            }
        }
    }

    // Do something with the annots
    foreach (var item in e.Annots)
    {
        var nativeAnnot = item.Key;
        var annot = TypeConvertHelper.ConvAnnotToManaged(nativeAnnot);
        if (annot != null && annot.IsValid())
        {
            Annot.Type type = annot.GetType();
            Console.WriteLine("AnnotationsModified: type: " + type);
        }
    }
};

We are always interested in expanding the customization options through APIs, and will be adding more options in the future. If you would like to suggest changes, please don't hesitate to get in touch.

iOS

Customize annotation handling for Xamarin.iOS

This tutorial only applies to Xamarin.iOS. See Xamarin.Android equivalent here .

Annotation and PDF interaction is implemented within the open-source Tools.framework. This includes annotation creation & selection, text selection, form filling and link following.

The behavior is implemented via a collection of "Tools": classes that derive from the abstract base class PTTool and that are coordinated by a PTToolManager. The PTToolManager provides the ability to customize tool behavior, and enable/disable the ability for users to create or edit annotations (both in general and on an annotation type by annotation type basis).

Create and edit annotations

To disable (or re-enable) the ability to create or edit annotations, options can be altered as shown below. When disabled, the relevant annotation tool is removed from the annotation toolbar, and from the UIMenuController.

// disables all text annotation types (highlights, underlines, etc.)
ToolManager.HighlightAnnotationOptions.CanCreate = false;
ToolManager.HighlightAnnotationOptions.CanEdit = false;
ToolManager.UnderlineAnnotationOptions.CanCreate = false;
ToolManager.UnderlineAnnotationOptions.CanEdit = false;
ToolManager.StrikeOutAnnotationOptions.CanCreate = false;
ToolManager.StrikeOutAnnotationOptions.CanEdit = false;
ToolManager.SquigglyAnnotationOptions.CanCreate = false;
ToolManager.SquigglyAnnotationOptions.CanEdit = false;

Annotation interaction and UIMenuController

Further control over annotation interaction behaviour via the PTToolManagerDelegate protocol.

There are several methods that allow you to be notified of, and if desired modify or prevent, default behavior from occurring. For all methods, if false is returned, then the default behavior will not occur.

1. PTToolManager.ShouldSelectAnnotationThis method is called just before an annotation is selected. The annotation object itself is available for the decision making process, and for further action if needed.
2. PTToolManager.ShouldShowMenuThis method is called just before the selection popup menu is shown. The UIMenuController object is passed so that menu items can be added or removed as required.
3. PTToolManager.ShouldHandleLinkAnnotationThis method is called just before a link is followed. The link is provided so that alternate action can be taken if required.
4. PTToolManager.ShouldSwitchToToolThis method is called just before a tool is activated. The tool is available for the decision making process.

Example

The sample code uses ShouldShowMenu to restrict use of the UIMenuController to copying and defining text found in the PDF. This is done by stopping the UIMenuController from popping up in any case other than selecting text, and by removing options to highlight/underline etc. from the selected text UIMenuController popup.

mToolManager.ShouldShowMenu = (sender, menuController, annotation, pageNumber) =>
{
    // remove all items except signature and free text
    if (mToolManager.Tool is pdftron.PDF.Tools.PanTool)
    {
        menuController.MenuItems = removeQuickMenuItem(menuController.MenuItems);
    }
    return true;
};

UIMenuItem[] removeQuickMenuItem(UIMenuItem[] items) {
    var itemsArray = new List<UIMenuItem>(items);
    var itemsToRemove = new List<String> {
        "Note",
        "Ink",
        "Arrow",
        "Line",
        "Rectangle",
        "Ellipse"
    };

    for (int i = 0; i < items.Length; i++) {
        var itemStr = PDFViewCtrlToolsUtil.ToolsBundle.GetLocalizedString(items[i].Title, null);
        if (itemsToRemove.Contains(itemStr)) {
            itemsArray.Remove(items[i]);
        }
    }
    return itemsArray.ToArray();
}

Default Menu Options	Customized Menu Options

Override classes

Tools.framework frequently creates new instances of objects defined within the framework (e.g. a new instance of PTAnnotEditTool is created when a user taps on an annotation). In order to customize certain aspects of the default behavior, it is required to create and use a subclass of the built-in tool. To enable this without requiring source code modification, Tools.framework includes a system to "inject" an externally defined subclass that will be used by the Tools.framework during its normal operation. This is done via the PTOverrides class as follows:

// EGAnnotEditTool is an externally defined class that derives from PTAnnotEditTool
var cls = new Class(typeof(PTAnnotEditTool));
var own = new Class(typeof(EGAnnotEditTool));
PTOverrides.OverrideClass(cls, own);

Note that in order to be compatible with the external override system, the base class must conform to the PTOverridable protocol.

Customize by modifying the source code

Because Tools.framework is open source, any and all changes are possible by editing the source code directly. The project is found in /Lib/Tools/src.

If you customize the tools source code, you will likely want to use a universal framework (one that contains architectures for both simulators and devices), which is not done automatically by Xcode. The Tools project includes a custom script step that automatically creates a universal framework, located in a folder next to the default build location, with the name {Debug,Release}-universal.

(Building a universal framework also be done manually by first building for device, then simulator, and using the terminal command xcrun -sdk iphoneos lipo -create to merge the binaries (Tools.framework/Tools) into a universal binary.)

Then create the Xamarin binding as described here: Create Tools package from PDFViewCtrlTools Objective-C source code .