Effortlessly customize text selection in Android

The TextSelectionManager interface contains OnTextSelectionModeChangeListener and OnTextSelectionChangeListener, which can be used to listen for text selection changes. The default PdfActivity implementation will display a contextual toolbar — namely TextSelectionToolbar — when the text is long-pressed and the text selection mode starts. The toolbar provides seven actions for selected text: copy, highlight, redact, speak, search, share, and create a link.

Registering custom listeners

You can create custom listeners for TextSelectionManager to handle changes in text selection and text selection mode (entering and exiting):

class MyActivity : PdfActivity(), TextSelectionManager.OnTextSelectionChangeListener, TextSelectionManager.OnTextSelectionModeChangeListener {


  const val TAG = "MyActivity.TextSelection"


  override fun onCreate(savedInstanceState: Bundle?) {
    PdfFragment.addOnTextSelectionModeChangeListener(this)
    PdfFragment.addOnTextSelectionChangeListener(this)
  }


  override fun onDestroy(savedInstanceState: Bundle?) {
    PdfFragment.removeOnTextSelectionModeChangeListener(this)
    PdfFragment.removeOnTextSelectionChangeListener(this)
  }


  override fun onEnterTextSelectionMode(controller: TextSelectionController) {
    Log.i(TAG, "Text selection mode has started.")
  }


  override fun onExitTextSelectionMode(controller: TextSelectionController) {
    Log.i(TAG, "Text selection mode has ended.")
  }


  override fun onTextSelectionChange(newTextSelection: TextSelection?, currentTextSelection: TextSelection?): Boolean {
    if (newTextSelection != null) {
      Log.i(TAG, "Selected text was: ${newTextSelection.text}")
    } else {
      Log.i(TAG, "Text selection is cleared.")
    }
    // Return `false` to prevent changes to the current selection state, if needed.
    return true
  }
}

By implementing these listeners, you can add custom reactions to text selection events.

This setup doesn’t override the default behavior — it only adds additional listeners. If you need to completely change the behavior (e.g. replacing the toolbar with a custom user interface), use PdfFragment in a custom activity and bind it to the TextSelectionController.

Customizing text selection actions

The text selection toolbar can also be customized. This toolbar is only visible when the standard Android-style text selection popup menu is disabled. To disable the text selection popup and enable the text selection toolbar, set the textSelectionPopupToolbarEnabled property to false in the PdfConfiguration:

val configuration = PdfConfiguration.Builder().textSelectionPopupToolbarEnabled(false).build()

The default text selection actions can be modified using toolbar.setMenuItems(...). To access the TextSelectionToolbar, register the OnContextualToolbarLifecycleListener and configure the actions inside its #onPrepareContextualToolbar method:

class MyActivity : PdfActivity(), ToolbarCoordinatorLayout.OnContextualToolbarLifecycleListener {


    private lateinit var customTextSelectionAction: ContextualToolbarMenuItem


    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)


        // Register the activity as a callback for contextual toolbar changes.
        // It will be called once the `TextSelectionToolbar` is going to be presented.
        setOnContextualToolbarLifecycleListener(this)


        // Create a custom menu item that will be shown inside the text selection toolbar.
        customTextSelectionAction = ContextualToolbarMenuItem.create(
            this,
            R.id.custom_text_action,
            AppCompatDrawableManager.get().getDrawable(this, R.drawable.ic_my_action),
            "Custom text action",
            Color.WHITE,
            Color.RED,
            false)
    }


    override fun onPrepareContextualToolbar(toolbar: ContextualToolbar) {
        // Add the custom action once the selection toolbar is being prepared.
        // At this point, you could also remove undesired actions from the toolbar.
        if (toolbar is TextSelectionToolbar) {
            val menuItems = toolbar.getMenuItems()
            if (!menuItems.contains(customTextSelectionAction)) {
                menuItems.add(customTextSelectionAction)
                toolbar.setMenuItems(menuItems)
            }
        }
    }


    override fun onDisplayContextualToolbar(toolbar: ContextualToolbar) {
        // Register a click listener to handle taps on the custom text selection action.
        toolbar.setOnMenuItemClickListener { toolbar, menuItem ->
            var handled = false


            if (menuItem.id == R.id.custom_text_action) {
                handled = true
                Toast.makeText(this@MyActivity, "Text selection action triggered!", Toast.LENGTH_SHORT)
                    .show()
            }


            handled
        }
    }


    override fun onRemoveContextualToolbar(toolbar: ContextualToolbar) {
        toolbar.setOnMenuItemClickListener(null)
    }
}

Selecting text programmatically

You can select text programmatically by calling PdfFragment#enterTextSelectionMode and providing the text range to be selected. You can retrieve the text of the current page by calling PdfDocument#getPageText.

For example, select the first occurrence of a random string on the page:

// Search for the position of text that should be selected.
val textToSelect = "text to select"
val textIndexOnPage = document.getPageText(pageIndex).indexOf(textToSelect)
if (textIndexOnPage >= 0) {
    // Select the text.
    fragment.enterTextSelectionMode(pageIndex, Range(textIndexOnPage, textToSelect.length))
}